A detailed look at the build of our 2021 Pikes Peak Race Car

As we are about to head into race week for the 2021 Pikes Peak Hill Climb, we have gotten a few questions about the build of the car, and what changes we have made for this year's race.  The first year that we ran this car was 2014 so this is now the 8th consecutive year running the car, and it has changed to a reasonable degree each of those 8 years.

But those changes have all been a part of the refinement process to help make the car faster, handle better, be more reliable, and this year, stay cool.  And each year we have been able to make improvements to those goals to the point where this year, we feel that the car is better than it has ever been, and we are really getting to a point where we feel that the car is close to our performance targets of being both fast and reliable.

As we started to think about the build of the car, Ryan from DSX Motorsports made a great observation that pretty much everything short of the cage, and maybe some of the aero parts are all available on our site.  So in going through this list, if you have a 2011+ WRX or STI, you could pretty much bolt on all of this list of parts and build yourself the same capable race car that we have developed to this point.

Just cut out any un-necessary weight and add a cage!

Let's start with the engine.

Up until 1 year ago, we were running a stock EJ255 engine, with stock D25 heads, cams, valves, etc.  With the engine failure last year, we have now moved to an STI Type RA block, but with the same stock D25 heads from the 2014 WRX.

Yes, you read that correctly, we are still running the stock Single AVCS engine.  And honestly, it has worked out very well for us.

A few years ago we landed on the Turbo Dynamics LM450 twin scroll turbo.  We ran that up until last year when we went to the Roger Clark Motorsports 4-Stage Dry Sump oil pump.  At that point, we had to convert the turbo to a standard single scroll version, but fortunately, all we had to do was to bolt on a different hot side, and we are now effectively running the Turbo Dynamics MDX555-450 turbo.  This turbo has a fantastic power band, and with the switch to E85 this year, we are now making 420 whp, and 460 ftlbs of torque.  The car pulls like crazy now, and has a lot of dig out of the corners.

Would we recommend running this amount of power on a street car?  No, definitely not.  But for our race car, the stock engine and heads have proven to be really reliable as we have moved up to this power level.  Cooling has been the root cause of all of the failures that we have had to date.

For timing, we are still running the stock cam pulleys, but we have up-graded to the HKS timing belt and Roger Clark High Grip Tensioner, and the Roger Clark 4-Stage Dry Sump Oiling system.

For the intercooler, we are running the Crawford Performance front mount intercooler, and this has been the case since the first year we ran the car.

For fueling, we now have the Cobb 1300CC injectors with a special AEM 340 fuel pump in our Fuel Cell.  We are also running the Cobb Fuel Pressure sensor to keep an eye on the fuel delivery, and a RCM Fuel Pressure Regulator.

All of this is Tuned by Harvey from The Boostcreep on a Cobb Accessport.

With cooling having always been an issue on this car, we have added a Killer-B Radiator this year, as well as AEM Water Injection sprayers for misting the radiator when needed.  So far, those have proven to be a very effective combination.

When we started running this car, we had the WRX 5-speed drivetrain for a few years, but we have since up-graded to the 2007 STI transmission and rear differential.  They are both stock for the time being, and we are using the MAP-DCCD controller to make use of the DCCD.  The addition of the front and rear torque-biasing differentials, and the function and adjustable of the DCCD with the MAP controller made a huge difference.  The car now has a lot of grip, and we have the ability to really adjust the way that the car handles and uses the power, and that has been a huge help for set-up.

In addition, when we swapped in the STI 6-speed, we installed the Driveshaft Shop Carbon Fiber Driveshaft.  This saves us a bit of weight, and more importantly rotating mass.  We really like this mod because it made the car just feel more responsive when going on or off throttle.

For a Clutch, we are using the Exedy Twin Disk Ceramic Clutch.  We picked this because it has a great pedal feel, and it has a very predictable and consistent engagement.  With a race car, you are often shifting gears a lot on track, and especially up Pikes Peak where there are 156 corners.  We wanted to make sure that the clutch was up to the task, and the fact that it saves us a little weight doesn't hurt either.

For stopping power, we have not landed on the RCM/Alcon 365mm front brake kit, and we are running the 2008 - 2017 STI Brembo calipers in the rear.  For pads, we use Ferodo 1.11 pads all around and the stopping power that the car now has is immense.   And that stopping power is also very consistent.  The large RCM/Alcon brakes up front can take a ton of abuse, and now that we have landed on this set-up, I don't think that we will need to change any time soon.

We run the Enkei RC-T5 wheels (Sometimes the RC-T4's) because they are very strong, and light weight.  They also have huge caliper clearance so we don't need to run any spacers.  We stepped up to the 18 x 9.5" RC-T5's last year to fit the bigger brakes, and that also let us run a wider tire.  Currently we are running the Hoosier 245/40-18 tires, which are actually pretty much a 275 width tire.  They give us plenty of grip, but some day, we'd love to be able to run something like a 305. 

When we went up to the 18" wheel, this also allowed us to run the Wisefab Front Knuckles, which made it easy to switch from the WRX 5x100 wheel bearings and hubs to the STI 5x114.3 bearings and hubs.  We previously were having some issues with the WRX wheel bearings, and the larger STI bearings have definitely worked better for us.  And the Wisefab knuckles have given us 50mm or roll correction, which also gives us a lot more caster up front.  This gave the car significantly more turn-in, and really changed the handling characteristics of the car.

Understeer is no longer a problem.

It is worth mentioning that we have also installed a 2015 STI Steering Rack to give us a quicker steering ratio.

We have installed the Feal 442 Suspension this year, in part to go up to a stiffer front and rear spring, and because these coilovers can be re-built, and re-configured easily to whatever we need, we now have a great platform going forward if and when we start adding a lot more detail to our aero package. 

We are also running the Voodoo Thirteen Rear Lower Control Arms and toe links in the back.  This gave us 1" more stroke in the rear as well as much better control over our rear camber and tow.

To round things out in the back, we are also running a Whiteline 22mm Rear Sway bar.

And honestly, that is pretty much it.  I have to admit, even as I was putting this list together I thought that there was a lot more to it, but this pretty much covers it.  We have made it through Tech, so we are now into race week, and with just a little luck, and if the weather holds out to give us dry conditions, we should be able to put down a good run this year!

- Jon Cooley