≡ Building a 2.2l Race Motor for the Evo IX
⊆ February 15th, 2009 by evolved |I know this blog has been quiet for a while (and more posts on my stupid little tweaks to the X5 don’t count), but after the debacle of having a mechanical failure at Targa for the second time in as many years, I wasn’t really feeling the love for the Evo.
In fact, my car came back from Targa in the back of Bill Arnold’s rig by late September and sat in the trailer for a good month before I even went to look at it. The disdain I was feeling towards the car (and myself for not prepping the motor better before Targa) is pretty clear when you realize that Bill’s trailer is stored about 50 yards from the WORKS headquarters and race shop at Infineon Raceway. With the year rolling by, and with the prospect of having a dead car sitting in storage with no real future ahead of it (an unfortunate trend among my friends), I finally got off my butt and decided to do something with my Evo IX.
Deciding What to Do With My Evo IX…
After 2 bad years and way too much money spent in Canada, I’ve decided to not return to Targa Newfoundland with the Evo. Maybe I’ll go back if/when I have the funding to bring a support crew and proper spares, but for now I think I’ll go back to running a full season of events locally where I can get more seat time for my money. But which series?
I really, really, really want to go run Rally America, but I calculated the cost to build and maintain the Evo across a full season of rallying and the expenditure is just insane relative to road racing. I’ll stick to the occasional rental ride and eventually buy a cheap FWD rally car that I can ball up and not be sad about.
So road racing it is. But with who?
After reading the rule books, seeing who runs with what clubs, and thinking about conversion effort on my car, I’ve decided to split my time between a few different series in 2009 to help decide which group I’ll concentrate on for a full season in 2010. My plan is to start converting the car for road racing and to make it legal for both our local SCCA region’s ITE class — a “run what ya brung” catch all for monster race cars including a supercharged S2000, various Vettes, Vipers and Porsches, and whatever else won’t fit elsewhere — and NASA ST2 power-to-weight equalized national class. Those events will be rounded out by select time trial events. Having to be competitive in any of these classes, I’ll need to replace the failed motor in the Evo with something capable of BIG power to run with the ITE cars (the current champion S2K makes 400whp @ ~2400lbs), but also being able to be choked down to ~350whp at my current 3100lbs to be legal for ST2.
Building a Proper Race Motor
Pete Kang at WORKS and I planned out a build for my Evo IX RS that would take everything they’ve learned in their time attack cars. We would increase displacement on the stock block to a mild 2.2l (10% increase in size), which would allow us to make more power across the rev range while still allowing for high-revs. You can go bigger (2.3l or 2.4l are common), but the piston speeds start to get out of control with such a long stroke. This would be fine for a street car, but we wanted something with a wide, usable power range and enough revs to not have to row through the gears constantly.
The final build sheet that WORKS developed includes WORKS/CP custom 86mm pistons, Eagle H-beam rods, WORKS 94mm crank, custom treated race bearings, and ARP hardware. These parts would compliment the existing WORKS valvetrain parts and Cosworth cams already installed in the car. The engine is being torn down and rebuilt by the crew at WORKS.
One of the most important things to address is the root cause of the rod bearing failure that took us out of Targa. Our current hypothesis on the failure is a combination of intermittant oil starvation, combined with a dilution of the oil by unburned fuel from the misfire. The Accusump we installed last year was insufficient to keep the engine oiled (although it still works well for pre-oiling, so we’ll put a fresh unit in the car).
Limiting oil starvation under hard cornering can only mean keeping the oil in the pan near the pump. The stock pan design allows engine oil to slosh away from the oil pump pick-up under hard cornering, and (other than going to a high $$$ dry sump set up) we would need to add baffles to the pan to limit the oil from sloshing.
The timing of the motor build coincided with the launch of a new AMS performance oil pan. AMS’s pan design (co-developed with Moroso) incorporates a custom oil pickup, an extra trap and flaps to keep oil near the pump, is constructed of aluminum to save weight, and holds an additional 1.5 quarts of fluid which helps cut oil temps. The pan also comes with a crank oil scraper as an added benefit. As soon as the pan was announced I placed an order, and was lucky to be one of the first on the list.
Rounding out the changes are an AMS upgraded oil cooler. The stock cooler is really only sufficient for street and occassional track use, but excessive oil temps are the norm under race conditions. AMS offers an upgraded cooler that fits into the stock location and bolts up to the factory fittings. With 25 rows (compared to the stock cooler at 11) and 30% greater surface area, the AMS cooler should drop engine oil and water temps dramatically.
While You’re In There…
Any racer will tell you that the 4 most expensive words in racing are “while you’re in there…”, and I’m not immune. Being that the entire front end of the car would be apart, and with my credit card already on fire in the hands of the guys at AMS, I decided to have WORKS install a couple more race parts to try to cut some more weight out of my too-heavy Evo IX.
The AMS Lightweight front cross member saves a whopping 7 pounds out of the nose of the car while retaining the stiffness of the factory design. That doesn’t sound like a lot of weight, but every little bit helps when it comes to cutting weight from the front of the nose-heavy Evo.
The AMS Moustache Bar Eliminator shaves another 13 pounds from the rear of the Evo. It comes with solid-mount bushings for the differential, although we’ll be retaining Energy Suspension bushings to limit the possibility of the mounts cracking or tearing due to the increased stress of solid mounting.
The Final Element - Upgrading the Turbo
Completing the rebuild, we decided it was time to upgrade the turbo. Being a road racer, having a quick spool up and a broad power band is paramount. The big, peaky numbers of some of the aftermarket turbo set-ups won’t work. With that, I turned to the rebuild services from Forced Performance.
The new FP Red turbo for the Evo IX uses the stock Evo IX compressor and bearing housing, while upgrading the compressor and turbine wheel for increased flow. Independent dyno results for the turbo show a stock-like powerband with a close to 100hp jump in peak power! You can either purchase a new turbo from Forced Performance, or do what I did and send your turbo to the company in Texas for a rebuild to FP Red specs.
We’ve optimized the air flow into and out of the engine by extrude honing the stock intake manifold, upgrading to the WORKS Aperture II throttle body, extrude honing the exhaust manifold and the WORKS Exhale 02 Housing, and replacing the Tanabe downpipe with a thermal coated WORKS Exhale 76mm downpipe. The target horsepower with improved engine breathing, increased displacement, and the new turbo is ~450 to the wheels on full race gas. I’m cautiously optimistic that we’ll beat that number.
The motor should be done this week. I plan to do a gentle break-in (for longevity) before putting the car back on the dyno for the race tune. I’ll post the dyno charts as soon as we’re done!
≡ Recent Entries
- It’s Alive (Almost)!
- Motor FAIL… Again.
- One More Chance…
- WORKS=FAIL, or Why I Am Parting Out My Evo…
- C-West and Rexspeed Goodies
- The Good News and the Bad News… and More Bad News
- Building a 2.2l Race Motor for the Evo IX
- Installing Invision DVD Headrests on the X5
- In-Car Video - Leg 2
- In-Car Video - Prologue
