Flatirons Tuning Project Car

Part 7: Proceed With Caution

Have you ever had that feeling that you were forgetting something? That thought at the edge of your mind that you just can’t seem to bring into focus?

Well, I had two realizations recently.

First, Sema is right around the corner.

Second, that means that I am really behind on updating the progress of our Project Car.

Up to this point, what we have done is basically make the most of what Subaru gave us to begin with. Subaru does lots of research and testing before releasing their cars for us to buy. What we have done is to tweak the car a little here and there to realize overall better performance. We have definitely improved things a lot, however, if we want to go further, that means that we are going to have to cast away many of the key stock components and replace them with something else.

So since we are going to be making some big changes, we need to make sure that we do our homework so that we can actually improve upon what Subaru gave us, rather than make things worse. Basically, we need to proceed with caution.

So before we move forward, we need to look at what we have done, and decide how best to further improve upon that foundation. This might sound easy, but it can be deceiving. Basically what we need to do here is to decide what we want our car to do, and then decide what kinds of compromises we are willing to make to get it there.

In other words, it is great to set your car up for a specific purpose, like road racing for instance. But then driving your car to work every day may end up being a lot less fun. Not to mention you might end up burning through a set of tires every couple thousand miles, which would not be much fun. Or maybe it would. We will have to make that choice.

To begin with, we’ll take a broad look at some of the things that we might want to change, and then we’ll come back in further chapters and go in depth in regards to the choices that we made and why.

First, we need more power!

Thankfully we picked a turbo-charged car to begin with, so all we have to do here is turn up the boost. More boost means more power, right?

Nope.

Well, sort of, but it isn’t that simple.

One of the most important things to understand about a turbocharger is that it has a pressure/RPM range where they produce the most pressure, while adding the least heat. This is what a compressor map shows if you are able to find one for your turbo. In other words, if you were to graph a turbo’s efficiency, it would not be a straight line, it would actually look something like a bell curve.

The idea here is that there is a point where a turbo can make more pressure, but it does so less efficiently (so it is heating up the air more), so there is less power potential, and if you ask the turbo to make even more pressure, the power potential goes down even more. It is possible, for instance, that your car will make the same amount of power at 18 psi. as it does at 15 psi. because they are both in roughly the same location, but on opposite sides of the ideal pressure for the turbo.

This can be a hard idea to grasp, so let’s simplify things. If you have two containers pressurized to 10 psi., but one is at 70* F, and the other is at 140* F, the air in the cooler container will be more dense (and have more oxygen) than the container at 140* F.

If you are thinking this sounds a lot like how a hot air balloon works, you are on the right track.

The other very important thing to understand is that when Subaru picked the Turbocharger, Intercooler, and Fueling system for this car, they knew all this, and made sure that they could all work together. The TD04 turbo was picked because it matches the flow rate of the 2.0 liter engine with the boost that they specified, and they picked an intercooler that would be able to cool down the intake charge sufficiently, and they picked a fuel system that is capable of delivering enough fuel for the air that is being sent to the engine.

Something interesting to note is that in 2006, when Subaru went to the 2.5 liter motor for the WRX, they kept the same turbo. Because that motor had a higher flow, the turbo was pushed out of its efficiency range sooner, so it ran less boost from the factory, but still made roughly the same power. The big difference comes when you start to turn up the boost. Where there is a reasonable amount of room to increase boost pressure and still make power with the 2.0 liter WRX, the 2.5 liter WRX is all ready pretty close to the limit of what the TD04 can do. This is one of the reasons for the difference in power increase between the two cars if you were to look at the Cobb Stage 1 and Stage 2 maps.

So what does all of this mean? Well, if we want to make a lot more power, and who doesn’t, we need a turbo that can make the same, or more boost pressure more efficiently. In other words, we need a bigger turbo. We also need to pick our intercooler and fuel system so that they can support the amount of air that we will be sending to the engine. We could pick one single area to improve, but if we do, more than likely the gains that we could make would be limited by the other two, so we need to take a balanced approach here.

One other thing that I will mention has to do with the fuel pump. What ever injectors we decide to go with, it is a good idea to switch out the factory part with a high-flow aftermarket alternative. This will ensure that we have an adequate amount of fuel going to our larger injectors. You probably don’t absolutely have to do this, but fuel pumps are cheap insurance. Something else I will mention is that just installing a fuel pump by itself will not increase the amount of fuel that is getting into the cylinder because there is a fuel pressure regulator that makes sure that the fuel pressure heading to the injectors is consistent, so you have to replace both.

Stopping is important too.

I said before that the one thing that was borderline inadequate on the stock WRX was the brakes. We have turned up the wick a little, and have up-graded our pads, but if we are going to take things even further, more than likely we’ll have to do something more drastic with the brakes.

This is actually really important because no matter where you are driving, street or track, if your brakes fail, bad things almost always happen.

Fortunately there are a lot of options out there, and they don’t necessarily require a high dollar big brake kit. Believe it or not, in some cases a big brake kit can actually increase your stopping distance. This is because if you dramatically improve the stopping ability of your front wheels, and don’t do anything for your rear wheels, your brake bias can be shifted so far to the front that the front wheels will be doing all the work, and the rear’s will just be along for the ride, so you aren’t able to make full use of the car’s traction to haul everything to a stop.

That being said, what a big brake kit does offer is a much better ability to dissipate heat. So even though your stopping distance may be a little longer, it will be consistent time and time again, where as a stock brake system would succumb to heat and fail much sooner, dramatically increasing stopping distance.

If we weren’t going to go with a big brake kit though, we can still dramatically improve the car’s stopping ability by using a more aggressive brake pad. This is an option that is often overlooked, and there are now a wide range of pads available that have a higher operating temperature with a more aggressive friction compound. You can actually get close to the same performance with a upgraded pad to what you could get with a big brake kit (you still have to keep bias in mind and look at both front and rear), but there are two things to consider.

First is that many more aggressive pads have a higher minimum operating temperature, so you actually have to heat them up a bit before they work. This means that they are really something you should only use at the track. The other thing is that they are able to generate a dramatic improvement in stopping because they have a much more aggressive friction compound. Think of this as a rougher gauge of sand paper compared to the less aggressive pad. This means that they will wear out your rotors a lot faster the more aggressive of a compound you pick. Using Cryo-Treated rotors will help minimize this, however when used sparingly, this is a very good alternative to a big brake kit.

What about tires?

I probably should have mentioned tires earlier. In an All Wheel Drive car, you usually have plenty of traction for acceleration, but good tires are essential when it comes to braking and cornering speed. Your tires are the only four points where your car is actually in contact with the road, but it is amazing how easy it is to forget them.

I am currently of the opinion that a good summer tire is best if you really want a good performing tire. The problem with all seasons is that they are designed for all conditions, so the tread design is usually a little too knobby, and the compound leaves too much on the table in terms of summer performance to try to get good traction in the cold and snow.

We might as well mention wheels here as well. A slightly larger wheel that will allow you to run a wider tire can also be a big help. You just have to make sure that you get a wheel that will work properly with your car. For instance, a 7.5" wheel is about as wide as you can go on a WRX wagon, where as you can fit an 8" wide wheel on a sedan because they have fender flares. Also, don’t get too greedy when it comes to tire width. Sure, wider is better, bit if you are rubbing, it can be a real headache.

Oh, and when it comes to wheels, don’t forget to think about weight. A bigger wheel typically weighs more than a smaller one. But if you don’t check the weight of a wheel before you buy it, you could be in for an unpleasant surprise. You definitely want the lightest wheel in the size that you want because it will help to reduce un-sprung weight, and you will have less rotational inertia to overcome to get the wheel to accelerate, or decelerate. So a light wheel can have a positive affect on all aspects of your cars performance. Just make sure that the lightweight wheel you pick hasn’t sacrificed strength to shed the weight.

So what’s left and/or right?

This brings us to suspension. Well, up to this point, all we have talked about is sway-bars. And I haven’t really discussed those yet. This stuff gets pretty complicated, but I think that I am just about ready to really get into some of this. But not right now…

What I will tell you is that I am just about happy with what we have done to the car, and it took a couple of trips to the track to play with some things to get everything dialed in.

For now, I’ll just touch on some of the things to consider. I still feel that sway-bars are a perfect place to start. I still have the Whiteline 22mm bars on front and rear. I have just moved the rear up to the medium setting. Then there are springs or coilovers, upgrading bushings, and maybe a little chassis bracing. Okay, a lot of chassis bracing. Oh, and alignment.

I have to confess that I have become a corner junky. If you think about it, if you have your car set up so that you can carry a lot of speed into, and through, a turn, all of a sudden braking and acceleration become less important. All you need brakes for is to slow the car down to your corner entry speed, and then once you come out of the corner, accelerate down the straight, and repeat. Simple really.

Versatility is the key here. Having the ability to change settings so you can get the car dialed in, versus being stuck with some of the factory settings, makes a huge difference. Having a knowledgeable person to point you in the right direction doesn’t hurt either. This is why I am now a big fan of coilover suspension over springs, you just have to make sure that you pick a well designed set, and get the set up correctly.

Well, that is the direction that we are heading. Rest assured that we haven’t stopped working on the car. Actually, we are just getting started, and now things are getting interesting. And with any luck, the next entry won’t take me nearly as long to write.

Words by Jon Cooley, Pic by Jenny Orin

Track Day

Click HERE for Pictures!

Part 6: Some not so Basic… Basic Maintenance

It is easy to think that maintenance and performance don’t really have much in common, but in reality, you can’t have one without the other.  A car can not perform at its peak unless it is properly maintained.

The thing is, once you see what can be accomplished by adding this and tweaking that, well, pretty soon, you have a long list of things that you want to do to your car.  It can become an obsession, really.  What you have to watch out for is getting tunnel vision.  Focusing on what you can put on or modify next to get that extra little bit of performance, and loosing sight of doing the little things necessary to keep your car happy can have some pretty nasty consequences.

How do I know all this you might ask?  Well, as you may have guessed from my previous installments, I definitely have a tendency to get obsessed.  I am usually pretty good at keeping things in perspective; however, you also may have noticed that we are at something of a crossroads with the car.  All the simple things have been done, and from here on out it gets a little more complicated, and I have been busy trying to decide what to focus on next.

But rest assured that some big changes are on the way.  Actually, a lot of them are sitting right here, waiting to go on.

What am I waiting for?  Funny you should ask.  You see, I got a wake up call a few weeks ago when I pulled into work.  It was a cool morning like most this time of the year, but when I pulled into the parking lot at work, and turned the car off, I noticed something funny.  My radiator fans had been running.

This caught my attention because I don’t have a long drive into work, less than 5 miles actually, and it is winter here in Colorado, and so most mornings when I am making the drive in, the outside temperatures are below freezing.  Yet in my 15 minute drive in, my car has warmed up to the point that the fans have cycled on.  The real clincher was that I have a Koyo Aluminum Radiator that should give me an even better cooling capacity.  Add that to the equation, and it was pretty clear that I had problem.

Now in reality, is this a serious issue?  Well, no.  Not yet any way.  You have to be really mindful of cooling issues on Subaru’s though because if you overheat even once, there is a chance that you will warp your heads, blow a head-gasket, and maybe even score your cylinder walls.  What is a little deceptive about the factory temp gauge is that once it reaches its “normal” level, it will stay there through about a 30 degree temperature range.  So if it starts to go up, it needs to be addressed immediately.  But I wasn’t there yet, and as long as I get taken care of, no harm done.  More than likely, it was a sticking thermostat which is both cheap and easy to replace.

So what does this have to do with maintenance?  Well, while I have been figuring out what I was going to put on the car next, and amassing parts, I had totally forgot about keeping the car in top running condition.  And what further complicates matters is that I bought the car used.  I got the car with 64,000 miles on the clock.  Did it have the 60,000 maintenance done?  Yes.  Well I think it did.  But did they take care of everything that needed attention, or did they just do the minimal service?  I have no idea.  Not only that, but what about my timing belt?  Subaru recommends replacing it every 62,000 miles, but they should be good to 100,000.  So do I have the original, or a new one?

Now, if I was simply using this car for commuting, I could certainly wait a while.  The thing is that I really want to start improving the power, handling, and brakes on the car with the full intention of taking it to the tack as much as I can this summer.  The last thing I want is to be worried that my timing belt is going to skip if I push too hard, or about the car overheating, or anything else for that matter.

My point is that if you are going to improve your car’s performance above and beyond the way it came from the factory, then you need to not only keep up with scheduled maintenance, but go above and beyond there as well.  This means staying up on all fluid changes, and using top quality fluids, and maybe replacing parts that might wear out before they get the chance to ensure that your car will perform at its best.  This is essential, even if it means you have to wait a little longer to get your car to go, stop and turn the way that you want it to.

It was with this realization that I decided to leave the parts where they sat, and make sure that my car was in top mechanical shape before I started throwing parts at it.

All right, we all ready know that the car needs a thermostat, and togo one further, I decided to replace the water pump as well.  Since the timing belt has to be removed to get at the water pump, I decided I might as well put on a new belt and tensioner as well.  Fortunately, once we got everything apart, I was relieved to find that everything looked to be in good shape.

When we started to put things back together, I was just going to use a factory timing belt, but after doing a little research, I decided to go with the STI Timing Belt instead.  There are two reasons.  First, the STI timing belt uses Kevlar fibers for reinforcement rather than Cotton fibers like to OEM belt.  I was told that makes it 2 – 3 times stronger than the OEM belt.  Second, it turns out that there may be some other improvements made to the STI Timing Belt, but because it is very similar the timing belt used on the Subaru WRC car, so they couldn’t tell me. I decided that if it was good enough for the World Rally, it would be more than good enough for me.

But I didn’t stop there.  I decided to do a little more preventative maintenance.  First off, since we were here, I decided to re-seal my oil pump.  This isn’t too hard since we are here all ready, but if it should start to leak, then we would have to do all this over again.  Also, since you use Fuji-bond to re-seal the pump, it is something that you should only have to do once.

Lastly, there is a small idler pulley for the timing belt that has a tendency to fail more than the rest.  I decided to replace that as well.  If you look at the picture, you can see that the original has a single bearing in the middle, making it a bit unstable, where as the up-dated part has two bearings, one at the top and one on the bottom to make it a lot more stable.

Once all that was done and we were putting everything back together, I decided to put on a Cobb Lightened Crank Pulley.  I must admit that I have been a little skeptical of the improvements this could give, but I have been pleasantly surprised.  I wouldn’t say that I feel that the car is making any more power, but the engine rev’s and accelerates a lot more smoothly.

Finally, I decided to throw in a new set of NGK spark plugs.  I actually stuck with the stock heat range.  Spark plug heat ranges are a little counter intuitive.  When you put in a “colder” plug, that means that the plug is better at transferring heat out of the combustion chamber.  This is important if you are generating a lot more heat because you are making a lot more power.  What you have to consider is how often are you getting to that point?  The potential down side to a colder plug is that if you don’t get the plug hot enough, it can develop deposits and foul quickly.  Since I drive around town for the most part, I am just going to play it safe and stick with the stock heat range.

Now did I go a little overboard with all these parts?  Maybe.  But considering what I am trying to accomplish with the car, I really just did some basic maintenance.  I have no doubt that my car should be trouble free for thousands of miles and a few track days to boot As long as I don’t create a problem with all these parts that I am throwing on…  But that will be for the next installment. 

Words and Pics by Jon Cooley

SEMA 2006

If you have been following the progress of our project car, chances are that you have been looking for some new part to raise the performance of your car to a new level. 

Hopefully we have done a good job so far giving you some ideas as to what is out there.  But even we need some inspiration sometimes.  Fortunately, every year, right around this time in fact, there is a convention where all the car people go for that exact reason, and it doesn’t hurt that it’s in Las Vegas.

Yep, it is time for SEMA!!

We can only imagine what we will find, and rather than just telling you about it, we decided that it would be a lot more interesting to show you, and even let the manufacturers tell you themselves! 

So we are going to take a lot of pictures, and put some podcasts together too. We will be publishing them every couple of hours to our SEMA 2006 Blog. 

Check it out, and start checking back on November 1st for an insider’s look at SEMA.

Part 5: INTAKES DON’T WORK! Or do they???

Whether you just bought your Subaru, or you have had a WRX since they first came to our shores, chances are that you have run into this issue.  It is easily one of the most discussed issues out there as far as performance, and just about everyone will tell you that they know the real deal when it comes to intakes and Subaru’s

Well, I have no idea.  Or, at least had no idea.

There are basically two theories out there.  The first is that the best intake that you can get for the WRX happens to be the one that comes with the car.  This is nice because everyone all ready has it.  Of course, you can add a high-flow filter to help it flow a little better, but otherwise, just leave it alone.

The second is that an intake of some kind, ideally a cold air intake, will free up a lot of Horse Power, make your turbo spool up sooner, give you improved throttle response…  Heck, maybe even better gas mileage.  These range in price widely, and there are few different types to choose from, and it seems like for every story about one of these delivering great results, there is a story about one that didn’t work at all… 

Now, as you have noticed from all the previous installments of this Blog, I have subscribe to the Stock Air Box theory.  In fact, this is my second WRX, and on both cars, I put in a high-flow filter, and never though another thing about it.  But there have been a few new intakes that have come out recently that have made me ask a fateful question…

Is there horse power out there that I am missing out on?

Well, I have had my suspicions for a while, but they were just that.  Suspicions.  There have been a couple intakes that have come out lately, namely one made by Subaru Performance Tuning (SPT) that made me wonder if I was still holding fast to a concept that has gone the way of OBDI.  Then there is the fact that for virtually every other tuner car out there, an intake is the first power mod that people do, and with good results.  Clearly it was time to do some experimentation.

I mentioned my idea to Kris at Logic Imports, and it turns out he was as curious as I was.  With a dyno secured, all that was left to do was to pick an intake, and set up a testing criterion. 

  As far as what filters to use, well, the baseline was clearly going to be the stock air intake system, with a Subaru filter.  Next, I have been running a Perrin Foam Panel filter for the last couple thousand miles, so that was a natural second filter.  The Foam filter is at least as free flowing as a cotton gauze filter, if not even better, so it should give a reasonable result for a panel filter. 

Then came the hard choice.  What kind of intake to test…

If you decide to put an intake on your car, the most important piece of information that you need to know is if it is designed to work with the stock Mass Air-Flow Sensor (or MAF).  If there is something that separates Subaru’s from other cars when it comes to intakes it is the fact that their MAF sensors are much more sensitive.  If an intake isn’t designed to work with the stock MAF, it can create turbulence that cause the MAF to read out of range.  This will throw a Check Engine Light (CEL), and it means that there is air getting past the MAF that isn’t being metered, causing you to run lean.  This is a real problem.  In my opinion, if you have an intake that is throwing a CEL, it needs to come off immediately, or get your car tuned to re-calibrate the MAF signal.  Those stories about an intake blowing up the engine if your Brother’s Cousin’s former room-mate’s WRX could very well be true.  I have seen it happen a couple of times, and I just don’t think it is worth the risk.

So first we need an intake.  There are a few out there to choose from, and we decided to go with the SPT intake for two reasons.  First, it bolts on easily, and it almost looks like a factory part, which isn’t surprising as Subaru made it.  Second, this is the intake that got me curious.  It was a pretty widely held belief that the stock intake was best, so for Subaru to come out with one…  I also have to confess that I had the opportunity to talk to one of the people that helped develop this intake at Subaru, and he assured me that they had spent a lot of time developing this intake to work properly, and to make power.  But I had to see the numbers for myself.

Now on to the testing.  What we decided to do was to take out as many variables as we could so that we knew that any gains that we saw on the dyno would be clearly attributed to the changes we made, and nothing else. We wanted to perform the testing in a short amount of time so the atmospheric conditions would be the same for all the tests.  We also decided that we would re-set the ECU with the Access Port after installing each filter so that they would all be starting from the same learning point.  We would then do between 7 and 10 pulls to allow the ECU to adapt to the new system.  Then we let the car cool off for 20 minutes, after which, we let the car come back up to normal operating temperature, and did a few more pulls to make sure that we were getting consistent numbers, and that would be our result.  One more key testing point was that we performed all the tests with the hood closed to try to better simulate actual driving conditions.

 

So here is what we found.  On this graph, run number 46 is the car with a brand new Subaru filter,  49 is the car with the Perrin filter, and run 58 is the SPT intake.  All of there are of course on our Project Car, with the Cobb Stage 2 Protune that you can read about in our previous installment.  I will tell you what run number 68 was in a moment.

From looking at this graph, you can see that we gained about 4 ft/lbs of torque over the stock filter with the Perrin between 3,500 rpm to 5,500 rpm, and gained about the same over the Perrin with the SPT over the stock range.  All in all, the panel filter is definitely a great modification for the cost, but the SPT definitely out performs it.  Now, we did measure the intake temperature for all the tests, and it was pretty consistent at 90 deg. Fahrenheit no matter what system we were using, so I believe that the heat shield on the SPT intake definitely does its job.  We did get a temperature spike once with the SPT intake, but we let the car idle for a minute with the fan still on, and the intake temperature immediately dropped.

Now, what was really interesting was what the Ignition Advance Multiplier did.  First, the Subaru ECU is dynamic.  It is always looking at the information it gets from its sensors and trying to make more power.  This is what people often refer to as “learning”.  One way to gauge how well this is going is with the Ignition Advance Multiplier, or IAM.  This is a measure of how much more timing the ECU feels it can run with out putting the engine in jeopardy.  The higher this number, the more power you are getting just by your ECU being a little more aggressive. 

When we re-set the ECU before each test, the IAM goes back to its starting point of 12.  With each of the panel filters the IAM would stay up for a run or two, and then go to zero, and once it did, we couldn’t get it to come back.  (One possible explanation for this is that the car was tuned with this set up, and was pushed pretty much to the max, so there wasn’t much room if any for the ECU to change anything).  However, with the SPT intake, the IAM would stay at 12 no matter if we heat soaked the intercooler, or engine by doing successive pulls.  Basically, the engine was telling us that it was happier with this intake than with either of the panel filters.

This leads me to run number 68.  Kris had the feeling that with the SPT intake there was some more room for tuning, so he spent literally 10 minutes, and tinkered with a couple load sites and the result is that run.  This is easily the best result, and notice that we never drop below 200 whp after about 5,000 rpm.  He definitely felt that there was more power potential there, but it was too late to really explore that.

I have now been driving around with the car for a little over a week, and I can say that it does feel like there is a little more power, but more than that, it seems like the turbo is a lot quicker to spool between shifts.  I also think that it feels like the car is pulling harder in the higher rpm range than before, as the dyno chart shows.  Over all, I am very happy with the results, and am now sorry that it took me a few years to warm up to the idea of an intake on my WRX.

I have to say that these are by no means the ultimate power numbers that these intake systems will produce.  It is entirely likely that if the car had more time to learn between testing that it may have been able to deliver higher results for each intake.  The problem there is that the more time goes by between each test, especially if we are talking days or weeks, there is a greater chance of outside conditions skewing the results.  Also, what we were looking at here was the merits of each system, given as close to identical conditions as possible.  By keeping the tests close together, and not letting the ECU learn too much, what we are looking at is a more accurate assessment of the individual merits of each system.

I bet at this point you are wondering why we didn’t test a whole bunch of other intakes at the same time to see which one was the absolute best.  First, time was something of an issue.  The longest brake between testing was when we had to install the SPT intake, and if we were installing a few cold air intakes, that would have made the testing take a lot longer.  Also, that wasn’t what we were trying to find out; we wanted to know first if there was a gain to be had by going with an aftermarket intake.  Now that we know that there is, we will more than likely do another test between a few different styles of intakes to see if there is a difference there, and what the best design is.  In other words, this is just the first installment of this test… 

I have to thank Kris and Mike at Logic Imports for all their help with this test.  I would have been doing a lot of driving around in the middle of the night on deserted roads risking life and limb if it hadn’t been for them.  I thank you for reading this and apologize for the delay getting this out.  Hopefully I will finally be able to get that Sway-Bar installment done before winter hits..  I make no promises though…

Words and Pics by Jon Cooley 

Part 4: On the Dyno

Sooner or later, generally the night after you make your first “power” mod, you will begin to be haunted by a question…

“How much power does my car make?”

Pretty soon, this question will consume you, and you will find yourself thinking about how to increase your engine’s output every waking moment.  Sometimes, even in your dreams. 

Okay, maybe that’s just me.  But if you really want to know, or if you want to do any tuning, or have your car tuned, you will need to seek out a Dyno.  Fortunately for us, Logic Imports, the Cobb Protuner for Colorado is just a stones throw down the street from us, so once the time came to find out just how much, or how little power the Project Car was putting down, we didn’t have far to go.

First a word about Dyno’s.  There are a lot of different Dynamometers out there, and many of them use slightly different means to calculate Horse Power and Torque.  They are all going to be similar, but keep in mind there a lot of factors to change your final numbers.  For instance, the Dyno has to be calibrated to read accurately, but over time, they can fall out of spec.  Weather conditions, such as temperature, humidity, and altitude can also play a huge roll in your car’s power out put, which brings up the dreaded “correction factor”.

The Society of Automotive Engineers has come up with a way to calculate what power your car would make on a Dyno at sea level under ideal conditions using information such as temperature, humidity, and altitude.

My point in telling you this is to say that all Dyno’s will read differently.  If you took your same car, on the same day to two identical Dyno’s across town, you will most likely get different numbers, even though you haven’t changed a thing on your car.  And as far as correction factors are concerned, ideally this would give us a standardized Horse Power number that we could compare with other cars.  However, sometimes the correction factor is exaggerated to show a higher number, so you have to take them with a grain of salt.

So what does all this mean? 

Well, first, don’t get obsessed with big numbers.  This is going to be hard.  Really hard.  What you should really focus on from a tuning stand point is not what your peak horse power is, but how much it has changed after you got tuned, or put an exhaust on, etc…  Of course, to do this, you will need to start with a baseline Dyno pull,  and then go back to that same Dyno each time you want to have your car Dyno’d or tuned so that you have consistent numbers to compare.   For this reason, it is a good idea to build a relationship with the person that is doing your tuning, etc.

For our Project Car, we started out with a baseline dyno run, which you can see here.

This is pretty typical for a stock 2.0 Liter WRX, which is pretty good concidering that we now have 66,000 miles on the clock.  Notice that the Torque (the solid blue line) peaks at about 4,000 rpm, then falls down, and is mostly gone by 6300 rpm.  Also notice how our peak horse power doesn’t come on till about 5400 rpm, and also falls off completely by about  6300 rpm.

Then we loaded up the Cobb Stage 1 map with our Access Port.

We got a 19 horse power increase, which is great, but notice how much smoother the torque curve is.  We have more torque throughout the rpm range, and because of that we are making a lot more horsepower in the higher rpm’s where the stock tune was falling off.

Then Kris put together a Protune, and we ended up with this.

He was able to get another 10 ft/lbs. of torque, and 10 horse power, and still maintained a very flat torque curve so power delivery was very smooth.  Remember this is a totally stock car, with no exhaust mods at all, and we have increased its output by nearly 30 horse power.

Then we put on our Prodrive Flex Up-Pipe, and my MRT Exhaust, and re-flashed the car to a Cobb Stage 2.

We are only getting 8 more horse power more than the stage 1 Protune, but 18 more than the Cobb stage 1 tune.  But notice how much sooner we are able to make our peak torque.  We make 210 ft/lbs. of torque almost 500 rpm’s sooner than with the stock exhaust, and because we have less restriction, the top end horse power is better too.

Kris then made a stage 2 Protune.

He was only able to get another 4 Hp, but got another 20 ft/lb of torque.  Notice how much earlier the Hp comes on too compared to the base stage 2.  Even though we weren’t able to make lots more power, I am very happy with the tune.  The power comes on much sooner, and compared to stock  (the light blue line at the bottom), this is virtually a whole new car.

The car is so different from what it was, it's almost hard to compare, but what I will say is that acceleration is much smoother, and almost explosive compared to what it was before.  The car was fun before, but now it is hard not to have a silly grin every time I step on the throttle.  Not to mention the exhaust note is much improved too.  It is pretty clear though too that the turbo is running out of air over about 6000 rpm’s, but that will be for another installment.

Also, of course we did all this to get the car ready for Cobb’s track day.  People have asked how a tune will affect your mileage.  Well I averaged just over highway speeds out and back with the air conditioner on, and still got just over 29 mpg.  Now, at the track, I only got 16 mpg, but that was pretty much full throttle all the time I was out there.  So just because the car makes substantially more power, it doesn’t necessarily need more gas.  But of course, mileage in any turbocharged car is mostly dependant on driving, so I will keep track and see what it is after a few more tanks.

Well, I am very happy with the power that the car is making, and since the next step will involve upgrading the turbo, intercooler, and injectors, I think we will go back to tweaking the suspension for the moment.  Stay tuned because I am finally going to write that Sway-Bar article that I have been promising.

Once again, I have to thank Kris from Logic Imports for all his help tuning the car, and putting on the Up-Pipe and Exhaust.It made for a late night, but the results speak for themselves.

Words and Pics by Jon Cooley

Part 3: 2006 Cobb Track Day

There are three things that you must have when you start working on a Project Car: A goal, and a plan to achieve that goal, and patience.

Our goal was simple, to achieve the maximum overall performance while keeping the car streetable.

Our plan was to start by tweaking the brakes and suspension, then to move on to the engine, and go back to the suspension and brakes as we made the car faster.

Patience is of course the most important thing.  Most likely, you won’t be able to do everything over night, so you have to be willing to take your time, and we weren’t in any hurry, so that wasn’t a problem.

Then we got invited to participate in the 2006 Cobb Track Day at Miller Motorsports Park. We needed to get the car prepped for the track so we could at least be safe and have fun, so needless to say, our timeline got moved up.

All right, let me bring you up to speed.  At this point, the only parts that we had put on the car other than what you can read about in the previous installments are 22mm Whiteline Sway-Bars on the front and rear, with Endlinks to match.  This gave us a dramatic improvement in handling, but we decided to go with some Whiteline Rear Camber Bolts to get some more negative camber and a Whiteline rear strut tower brace to increase chassis stiffness.  This makes a big difference on the Wagon’s especially.

If you read part 1, you know that WRX radiators have a tendency to fail.  Well, in the process of going over the car, we noticed that ours was leaking coolant from the top tank, and we had green crud everywhere.  We opted to replace it with a Koyo aluminum racing radiator which bolted right in, and actually gives us an increased cooling capacity, which would most likely come in handy while turning hot laps in the summer heat.  And since we were there all ready, we put in some Samco Silicone Radiator hoses too.

Then there are brakes.  If you have an otherwise stock car, you can still head out to the track and have a great time, but the one weak link that must be addressed is your brakes.  With repeated hard use, you put a substantial amount of heat into your brake system which can cause it to begin to fail.  This is referred to as “brake fade”.  At worst what this means is that you will mash the brake pedal to the floor, your car won’t slow down, and you head off track into the weeds.

There are two main causes for this, first is that you heat up your brake pads beyond the range that they were designed to operate, and the second is that you put enough heat into your fluid that it boils.  Boiling your fluid means that there are bubbles of gas trapped in your lines, which are easily compressed.  This is generally the more common failure, but both areas need to be addressed.

For our car, we went with Goodridge Stainless Steel Lines to improve pedal feel (and let us detect fade sooner), with ATE Super Blue Brake Fluid.  The Super Blue is a DOT 4 brake fluid, which has a higher boiling point than the stock DOT 3 Fluid.  For pads, we went with the Hawk HPS pads on all corners which give us a higher operating temp, and much better initial bite.  Lastly, we put Powerslot Cryo-treated rotors on the front.  The slots in the rotors scrape the pads to reduce the chance of glazing, and also reduce the chance of hot gasses building up a cushion between the pad and the rotor, which can also reduce the brake’s effectiveness.

Well, as you may have guessed, after putting all this energy in improving our brakes and suspension, we couldn’t bear to leave our engine in stock trim.  I am actually going to write another entry dedicated to dynoing the car and the results that we had.  I will tell you that we put on a Go Fast Bits WRX Hybrid By-Pass valve, Prodrive Flex Up-Pipe, and the MRT 3” exhaust from my old WRX.  For engine management, we went with the Cobb Access Port of course, and got a custom Pro-Tune from Kris Graham at logic Imports.  All this gave us 210 whp, which was quite a jump up from the stock 169 whp that the car put down before we started messing around.

Overall, we were very happy with this set up.  The car had plenty of power, and was very neutral in the corners.  We did go with a slightly more aggressive alignment with a some toe-out up front, and none in the rear, and -1 degree fo camber up front and -.7 degrees in the rear.  The brakes were definitely up to the task of stopping the car at the track.  There was only minor fade towards the end of the 20 minute sessions that we were running.  And on the street, this set up inspires a great deal more confidence than the stock pads, etc…  If I had the chance to change anything, I probably would have went up to the medium setting on the rear Sway-Bar to give the car a little more turn in, but even at the soft setting it would only under-steer badly if I went into a corner a little too hot.  On the street however, the car feels just about perfect, and is dialed in just right for high speed sweepers.

Next time, we will go in depth into putting the car at the dyno, with lots of charts to show the increase in Horse Power and Torque at each stage of tune.

Lastly I just have to thank Jamie Miller and Kris Graham because they both were a huge help with getting the car ready for its day at the track.

Words and Pics by Jon Cooley

Part 2: The Basics

All right, so you have your WRX, and are ready to start unleashing the full potential of the car. So what is the first thing to do? Exhaust? Re-flash? A Bigger Turbo?

Nope, change the oil.

We made sure that all the fundamental systems of our car were in good working order before we bought it, so now we are about to start modifying it. But getting more power out of our car means putting more stress and strain on our engine and drivetrain than they are used to seeing. The first and best thing we can do to help them hold up the demands that we are going to be putting on them is to make sure that we are using the best possible fluids.

 

It is pretty well agreed upon that synthetic oil is better able to keep your engine and transmission lubricated, especially under hard driving conditions. This is because Synthetic's maintain their viscosity better than conventional oil under higher temperatures and pressures. Sure, synthetic oil changes cost a little more, but the benefits in the long term are well worth the added expense, especially in a turbocharged engine.

 

We decided to go with Redline motor and gear oil. What makes Redline really neat is polyol ester. If you haven’t heard of polyol ester, don’t feel bad, I hadn’t either. But here is why it is really cool. Redline uses polyol ester as their base for their synthetic oils because it is the only lubricant able to withstand extremely high temperatures in modern jet engines. So they will be right at home in our turbocharged engine. It also has natural multi-grade properties, which means that they don’t need to add any potentially unstable thickeners to their oil.

 

What this means is that the viscosity of Redline oil is substantially more consistent regardless of extreme temperature, hot or cold. So you are going to get the lubrication you need whether the oil is going through a scorching hot turbo, or sitting in your oil pan when it is well below zero. Redline gear oils give your transmission the same level of protection, and they have formulated a wide variety of oils specifically for transmissions and limited-slip differentials.

 

Beyond all that, this is the oil that we have been using in the Flatirons Rally Car for its entire life, and its engine and transmission are still running strong in spite of the brutal conditions we have subjected it to.

For our car, we are using Redline 5W30 for the engine, Redline 75W90 NS for the transmission because it is specifically formulated to work with synchros, and Redline Lightweight Shockproof for the rear differential.

 

It is a little early to see if the engine oil is making much difference, but what I can tell you is that for the first day or two after putting the 75W90 NS in, the shifter just kept getting smoother. Yep, even reverse seems to be easier to get into. If the other oils are working as well in the engine and differentials, we can be sure that they are getting the protection they need.

 

Samco Intercooler Hoses.

 

Sure they look great on your engine, but they do serve a purpose. First, notice how much smoother the silicone hose is than the stock one. This will make it easier for the intake charge to get into your intercooler, and silicone is much better able to withstand high temperatures and pressures than the stock plastic, so it should last for years. Second, I am sure you will agree that it is a heck of a lot easier to get the silicone hose on and off than the plastic one.

 

A quick note for installation… I do recommend using a little silicone spray, or some kind of lubricant on the hose and the mounting surface to allow it to slide into proper position with ease. It takes a lot less effort to allow the hose to slid into place than it does to force it, and as the intercooler is over most of the hose, it is difficult to get leverage on the hose. Also, make sure your hose clamps are snug, but not overly tight. If you tighten them down too much, they will just tear your nice new hose.

 

 

Well, we will really start feeding our need for speed in the next installment, but again, maybe not in the way you expect. Next timer, we will give you the dirt on Sway-Bars, and why there are possibly the best handling improvement you can make to get rid of under-steer…

Words and pictures by Jon Cooley

Part 1: Getting a WRX

The most important thing necessary to begin modifying a Subaru WRX is the car itself.

The first model year for the WRX was 2002, and now that they have been out for a few years, it isn’t that difficult to find a clean car for under $15,000. So this first installment of our project car will be all about what to look for in a used WRX.

The first thing to do is to figure out how much you want to spend, and see what cars are available in your price range. Then go and look at a couple of cars, and see what you think. Sometimes it is worth spending a little more money to know that you are getting a car that was well taken care of.

When you are looking at a WRX, there are a few things to look for.

First, look at the top of the radiator, and see if there is any green powdery residue. If there is, this is a sign that the radiator is leaking where the aluminum clamps the plastic top to the radiator, and it will most likely need to be replaced.

Also, the doors and fenders are made of aluminum and light gauge steel to reduce weight, but that also means that it is really easy to get dents. Look at the doors, and particularly the front fenders above the wheel to see if there are any dents. If you can find a car with few or no dents, it is a good sign that it was well taken care of.

Now, if you are planning on modifying the car, there is a saying… “The cheapest way to build a project car is to buy someone else’s”. If you find a car that has been modified all ready, you can almost always get the car for much less than what it would cost you to buy a stock car, and modify it yourself, but you have to be careful that you don’t buy someone else’s problems. If you decide to go this rout, it would be a very good idea to take the car to a dealership, or shop that specialized in modifying Subaru’s, and have then give it a once over before considering buying the car. You will want to make sure that the mechanic performs a leak-down test to make sure that the engine is still in good shape, and not the victim of bad tuning. You will also want to have the transmission checked to make sure that it is still in good shape too. These are the two key areas to consider when looking at a used WRX.

For our purposes, we want to start from scratch, and build the car on our own. Another thing that you have to be aware of when buying a used sports car, such as the WRX is that some people will “De-Tune” the car before selling it. This means that you could end up with a car that has been modified, and driven within an inch of its life, then parted out and returned to stock so you don’t even get the advantage of the car coming with an assortment of aftermarket parts.

There are a couple of things to look for in the engine bay that can give you an idea as to whether the WRX that you are looking at has been modified.

First, look at the heat shield that covers part of the turbo. It is down and to the left of the intercooler. If it has been cut at all, or if there are only a couple of bolts left holding it on, there is a good chance that the car has at least had an aftermarket exhaust on it. The stock heat shield is too small to fit over any aftermarket down pipe, so it is usually cut, or left off all together. There are also a lot of tiny bolts that hold it in place to keep it from rattling, which are hard to put back on, so they are often left off when putting the car back together.

Next is the intercooler hose. Look just below the intercooler, and you should see a black plastic hose connected to the turbo. This plastic hose is very difficult to put back on the turbo once removed, and is basically a one time use piece. The intercooler must be removed for many basic modifications, so the first thing people will often do is to replace this plastic hose with one made of silicone. If you see a silicone hose, perhaps with Perrin, or Samco on it, again, there is a good chance that the car has been tinkered with.

The last thing to look for is something that isn’t easy to see. If you look under the crank-case on the passenger side, you can catch a glimpse of the up-pipe. This is not a very easy part to install, and it is really no fun to try to put the stock up-pipe back in after you put an aftermarket up-pipe in, so the stock part is rarely put back on the car. If you don’t see any heat shielding on the up-pipe at all (it looks just like a plain piece of pipe), or If there is an exposed flex joint, the car that you are looking at has an aftermarket up-pipe.

Once you have found a car that passes all these criteria, it is time to take it for a spin. See how the car feels. If the car comes with an OEM boost gauge, you should be hitting about .8 bar of boost. Also, pay attention to how the transmission feels. You should have no trouble shifting up the gears, and no trouble shifting down, except into first. I have only seen one WRX transmission that liked downshifting into first, even if you match rpm’s. You are looking to make sure that the syncros are still doing their job, which is a good measure of the condition of the transmission. I should also mention that it is normal to have some difficulty shifting into reverse. It is a straight cut gear, so sometimes it is a little difficult to get it to engage. If you are having trouble, put the shifter in first, let the clutch out a little, then push the clutch back to the floor and try reverse again. This will usually work.

Another thing to pay attention to on your test-drive is the clutch. There is a reasonable amount of slip in these cars, but if it doesn’t feel like the clutch is fully engaged until the very end of the pedal travel, it could indicate that the clutch is wearing out. Also, if you take the car out on the highway, look for slippage in fifth gear when going up hill.

Once you have found a car that is in good shape, and drives well, see if the owner has service records. A car with all the scheduled service done in a timely manor is ideal, and you will usually have to pay a little more for it, but it is worth every penny.

Lastly, it is still a good idea to take the car to a mechanic and have them give it a once over. A trained Subaru mechanic may see something you didn’t, and it is no fun to buy a car, only to find out that it needs major work. If it passes this test, there is nothing left to do but buy it.

We went looking, and were able to find a 2003 Yellow WRX wagon that was in very good shape, with no previous signs of tuning. A leak down test told us that the engine was still in very good shape, even though it has more than 60,000 miles on the clock, but the clutch felt a little soft. It may be on its way out, but since we will most likely be replacing it soon, that isn’t really an issue for us.

Good luck in your search for a WRX, and don’t be afraid to keep looking until you find a car that is just what you are looking for. If you all ready have a WRX, and are looking for tips on getting the most performance our of your car, stay tuned. We will start the quest for more power, better brakes, and a balanced suspension in Part 2.

 

Words and Pics by Jon Cooley

Welcome!

Welcome to the
Flatirons Tuning Project Car Blog.
We will be posting, step-by-step, the process of completley overhauling a Subaru WRX.
Stay tuned for pictures, advice, and much more!