The RaceComp Engineering BRZ "Clubsport" Build

[Racecomp Engineering]

This story began in February 2012 when Subaru of America loaned us one of their pre-production BRZ's for testing and initial product development. From the time that the BRZ/FR-S was unveiled, RaceComp knew that we had to have one. Driving the test car not only reinforced that decision, but it gave us the opportunity to get a head start on doing what we do best: designing and producing suspension components for this exciting new platform.



Our first order of business was to work on our performance lowering springs, designed to be used with the stock dampers. We don't believe in guess work or designing something that's "close enough." When we develop a new part, we do our research and engineer it properly from day 1. So we began by removing the stock springs and dampers and measuring everything; stroke, bump/droop travel at stock ride height, bump stop length, spring rate, spring length, etc. Then came the important part, analyzing the dampers on a shock dyno.



We also put the car on scales to check overall curb weight, front/rear weight distribution, and cross weights.



Armed with all of this information, we had a set of prototype springs on the car in a matter of days. Our research paid off, and only minor ride height tweaks were needed before the spring specs were ready to be sent to production.

[Racecomp Engineering]

After patiently waiting, the RaceComp Engineering BRZ Limited in Satin White Pearl was delivered in May 2012. We got one of the first cars delivered in the US.



Naturally, we already had some mods lined up to go on the car as soon as it arrived. The first thing to go on were RaceComp Engineering lowering springs along with Whiteline Com-C front strut top mounts. This would be the first of many suspension setups.



We also added BBS CH-R wheels in 18x8 with 235/40/18 Michelin Pilot Supersports. One major shortcoming of the factory BRZ and FR-S is the Michelin Primacy HP tires. I don't know why they would fit such mediocre tires to a car this performance oriented but needless to say, the Supersports made a HUGE difference.

[Racecomp Engineering]

With a nice baseline established, it was time to really improve the car's suspension and see what this chassis can do. We started by adding the STi pillowball rear control arms, which replace the factory rubber bushings with sealed spherical bearings.



Whiteline was kind enough to send us a big box full of bushings. We installed the following:

-Rear upper control arm inner bushings with camber correction
-Rear crossmember insert bushings
-Rear trailing arm lower front bushings
-Positive shift kit bushing





Whiteline has just announced the release of several new bushings that we look forward to adding in the coming weeks. We also received the following bushings from AVO:

-Front lower control arm rear bushings (+0.50 caster adjustment)
-Front lower control arm front bushings

All of these suspension bushings were a vast improvement over the factory rubber bushings. Turn-in was more precise and it was much easier to feel what the car was doing mid corner. With a minimal increase in NVH, these mods are almost a no brainer for anyone looking to improve their BRZ or FR-S's handling for a reasonable cost.

[Racecomp Engineering]

With the bushings installed, it was time to put some proper dampers on the car. As with any new chassis, we will be testing as many different suspension setups as possible. We decided to start with something we have had success with on other chassis: the JRZ RS1. This is a single adjustable monotube damper with adjustable gas pressure. After this upgrade, the car exhibited the excellent chassis control we have come to expect from JRZ dampers. We were also impressed with the exceptional ride quality, especially given the relatively stiff 450 lb/in springs front and rear.





While the JRZ's really did blow us away, we knew that they wouldn't remain on the car for long. Given the success of our RaceComp Engineering Tarmac 2 coilovers for the GD, GH, and GR Impreza chassis, we decided early on that we wanted to develop a Tarmac 2 for the BRZ/FR-S. They are based on the popular KW Variant 3, with our own valving and spring rate specifications. We received our first prototype set and they went on the car the same day.



We were very satisfied with the results of this test set, but the valving isn't 100% there yet. We are continuing to work on the development of these dampers, and once we get the valving dialed in they will be sent to production. Rest assured, once we are finished with this development process, we will be testing plenty of other damper options.

Another relatively simple modification that can vastly improve a car's handling characteristics is a set of upgraded sway bars. Whiteline provided us with their 20mm front and 16mm adjustable rear bars. The install was very quick and easy and they really helped control body roll during steady state cornering.





We also wanted to pay some attention to upgrading our brakes. While the factory brakes are actually quite good with excellent pedal feel, this car will be tracked (with significant future power upgrades) so we decided to go a bit overkill in the braking department. We installed an Essex Competition front brake kit, which utilizes AP Racing 4 piston calipers and 325x32mm J-hook 2 piece rotors. While the rotors are approximately the same weight as stock, we saved around 6 lbs. per corner in caliper weight. The kit also provides much improved cooling, better pad and rotor wear, and a much more solid pedal feel. For the street, we are using Ferodo DS2500 pads front and rear. For the track, we have a set of AP Racing C300 pads.

[Racecomp Engineering]

With handling and braking pretty well covered, we wanted to add a few minor visual improvements to really set our BRZ apart from the crowd: the icing on the cake, if you will. We started off with an Alcantara wrapped steering wheel from JPM Coachworks. To say the quality of their work is exceptional would be an understatement. Not only does the wheel look amazing, but it feels great too. While a fairly subtle upgrade compared to some of the other mods we've done, it really did improve the driving experience. It just makes you feel like you're behind the wheel of something special.



For a little extra exterior flair, we added an STi front lip (known as the V-Limited on the GD Impreza). This subtle ABS plastic piece is a very tasteful yet noticeable part. It is also functional, offering a minor decrease in front lift.

[Racecomp Engineering]

At this point the car looked and handled great, but it was missing something important: POWER! We here at RaceComp Engineering aren't generally too hung up on making huge power. We're suspension people, so we go for chassis balance rather than straight line speed. But once you have a car that can truly fly around corners, it just feels downright ridiculous to only have 200hp! So we decided to start with some minor power mods.

First was a Perrin Cat Back and Front Pipe. We went with a matte black muffler for a more stealthy appearance.





We also added an AVO silicone inlet pipe and panel filter (not pictured). Finally, we had the car dyno tuned using ECUTek software. The tuning was done by Jorge Carrillo from P&L Motorsports on the Dynojet 424 chassis dyno at IAG Performance in Westminster, MD.



The final numbers were 178whp and 146wtq, which is not too shabby. Most importantly, the powerband was smoothed out and the mid rpm range dip was eliminated. Now the car pulls smoothly to redline and feels much stronger than stock. It's still not breaking any land speed records but it feels like the engine has been uncorked somewhat with minimal mods. Even so, we have a very significant power increase coming soon from AVO

[Racecomp Engineering]

So, this is how the car currently sits. Understated yet unique enough to stand out. Subdued enough for our fearless leader to drive it every day (even if he is old and crusty).





Keep your eye on this thread for updates as we continue to develop this car. We will be doing significant power upgrades, trying new suspension components, wheel and tire combos, and more!

[F1point4]

Subbed. Good work going on here.

[chutrain]

You guys are doing a great job on suspension development. Thank you for showing the process and dedication you put into all your projects.

[jduffy]

We also put the car on scales to check overall curb weight, front/rear weight distribution, and cross weights.

Can you post these measurements? Thanks.

[BoxeRZ]

Sub. Really liking this.
Any lower measurements on those original springs? Still happy with the results?

[ultra]

Thanks for compiling everything you guys have been up to in one thread.

I've based a lot of my chassis mods on your build and various advice you've given on this forum and you've never steered me wrong (no pun intended).

Appreciate your contributions and am interested to see what you guys get up to in the future.

My 'build':
http://www.crankandpiston.com/on-the...the-water-msw/

[RYU]

You guys are my hero.

How about some guidance on tire selection given your suspension components?

For example, this car will only ever see RS3s or StarSpecs, best case scenario, and mostly on street tires like Ventus V12s. I doubt i'll ever have Hoosiers or even NT-01s on this car which might make some of the suspension parts (like stiffer sways/springs) futile?

[driver01]

Originally Posted by Racecomp Engineering

While the JRZ's really did blow us away, we knew that they wouldn't remain on the car for long. Given the success of our RaceComp Engineering Tarmac 2 coilovers for the GD, GH, and GR Impreza chassis, we decided early on that we wanted to develop a Tarmac 2 for the BRZ/FR-S. They are based on the popular KW Variant 3, with our own valving and spring rate specifications. We received our first prototype set and they went on the car the same day.

I have a set of KW v3 for my FR-S. Will it be cost efficient to send these to you and make them into tarmac 2 Spec?