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April 24, 2009

EVO, EVO, STi: Part 3 Subie Pipes & Coils

The third installment of our Japanese make-over mini series stars a 2008 STi. All new coils for the struts, sway bars front and rear, complete new exhaust including down pipe, and new trans and engine mounts.


We first disconnected the sways and started on the coils for the struts. The customer decided to save some money and just swap out the stock springs with some slightly lower and stiffer aftermarket versions from Cobb instead of going the full coil-over route. The result is improved center of gravity (lower) and sportier cornering (stiffer). The overall visual effect is awesome, just enough lowering to improve the overall stance of the car without that ricer slammed looked. Aiding in the improved handling are much stiffer sway bars, also from Cobb. The rear ones, shown below, are a trick three piece set-up similar to what is used on race cars.

Here's a shot of the rear sway bar (note end link) and new coil installed on rear strut:


Next we moved to the engine and transmission mounts. The customer went with stiffer JDM mounts. The stiffer mounts transmit a bit more noise, vibration and harshness but the theory goes that less flex in the drivetrain makes for more precise shifting and better power delivery. The trans mount was no problem but the engine mounts required more effort. Since they reside between the engine and sub-frame, the engine mounts are tough to get to. Our solution was to hold up the engine with a standing jack, disconnect and carefully lower the sub-frame or axle carrier until the mounts were accessible.

Finally we tackled the exhaust. We had to remove the intercooler to replace the "dog bone" (engine torque limiting mount).


While the intercooler was out, we had better access to the downpipe. Despite only about 1000 miles on the car, the nuts that attach the downpipe to the turbo bolts were very hard to break loose. The Cobb pipe did fit perfectly, as did the new heat shield.

From the top:


From the bottom:


We installed a Perrin exhaust system from the downpipe back. All components fit with only a minimal amount of tweaking. And the resulting sound is great!

Starting at the front:


Ending out back:


While we aligned the STi we took the time to do a quick weigh in-- so we could compare it to the EVO X we had in the shop earlier. Here are the results:


3400 lbs with a full tank of gas (about 3340 with a half tank) is not terrible, and about 100 lbs lighter than the EVO X.

We have to admit that when the latest evolution of the STi came out we were not excited. Our first impression was that Subaru went soft on us, from the frumpy hatchback to the heavier chassis and slower handling. But after spending a week with this one, we're won over. The upgrades we did really transformed the car into something we can get excited about again. And the visual tweaks the customer already made like the red tail lamp lenses and black mesh grill really help the looks.


EVO, EVO, STi: Part 2 EVO X Sway Bar

Part 1 of EVO, EVO, STi went through a brake rebuild on an EVO 8. In this installment we go over a sway bar installation on an all new EVO X.


The customer already installed new springs and rear sway bar, leaving "just" the front sway bar for us. The front sway bar is a bit of a trick, and installation is not recomended for the shade tree home mechanic. Just check out our last EVO sway bar installation here.

The installation of this bar was not quite as bad since there is more space between the firewall and engine. Nonetheless, it required disconnecting the front sub frame and slowly lowering the engine to make room.


Here you can see the OEM bar, disconnected and ready to be wrangled out:


A comparison of the OEM bar (black one) and the one from Cobb. (Note the Cobb bar is hollow.)


While not too terribly complicated, the job does take the better part of a day with the proper equipment. Without a lift it's pretty near impossible.

While we had the EVO X at the shop, we did a quick weight check and here are the results:


3541 lbs with a half tank of gas, not exactly lightweight. But the cross car balance is very good at 49.4%.

EVO, EVO, STi: Part 1 brake rebuild

Spring is in the air and the sun is rising on our Japanese performance car customers. The last few weeks we've had a rally of AWD sports sedans come through the shop: a couple of EVOs and a new STi. In part one we describe rebuilding brakes on an EVO 8. Part two goes through a sway bar install on a new EVO X. And part three follows a complete suspension and exhaust upgrade on a new 08 Subaru STi.


A common problem with the red Brembo calipers in Mitsubishi EVOs (and other cars) is that they don't stay red for very long-- especially if they see some hard track use. The heat generated during hard braking at the track quickly turns the bright red into a brownish red and the "brembo" logo yellows.


The only fix is to repaint or powder coat the calipers another, less sensitive color. In this case, the customer wanted to go with a simple black repaint (powder coating, while more durable, is much more expensive and potentially damaging to the caliper if you split the calipers). At the same time, we decided to replace all the dust boots and seals which were also damaged and worn out.

Here you can see the dust boots and seals extracted from the caliper. To get the pistons to come out of their cylinders, we force air through line holes. This should be done carefully as to avoid damaging the pistons should they "pop" out too quickly.


Here's a closer look at a heat damaged dust boot which has dried out and the piston from which it came:


A closer look at the piston, note the grit and particles in the fluid and the marks on the piston:


We polished the piston and replaced the dust boot and inner seal (each piston has a dust boot which can be seen on the assembled caliper, and is designed to keep grit from migrating into the cylinder, and an o-ring style piston ring or seal which is located in a groove in the cylinder and "seals" the piston to the cylinder).

Here's our brake rebuild assembly line, note the cleanliness of the work area. You must keep all brake parts as clean as possible before reassembly!


A picture of a disassembled front caliper before paint:


We did not paint the calipers ourselves; instead we sent them off to the experts. Autometric, a local auto body shop painted the caliper for us, and they really did a nice job.





Since Brembo sold the rights to the caliper parts to Mitsubishi, they do not sell specific rebuild kits. Here is what we used:

Front Calipers
Large piston Small piston
Dust boot Brembo p/n: 20 4872 51 Dust boot Brembo p/n: 20 4872 46
Seal: 46mm ID, 51mm OD, 3mm thick Seal: 40mm ID, 45mm OD, 3mm thick

Rear Calipers
Dust boot Brembo p/m: 20 4872 46
Seal: 40mm ID, 45mm OD, 3mm thick

These p/n and sizes worked for this EVO 8, double check your own calipers.