Sierra Sierra EVO 8 – 1:44.2 and Dropping

Last week I went testing with the Sierra Sierra team to test out a bunch of new stuff on the EVO 8 at Buttonwillor Raceway. Some of these new modifications include revised front suspension geometry, stiffer spring combo, larger Garrett T04 turbo, Full-Race twin scroll exhaust manifold, larger exhaust, and a pair of larger custom Cosworth cams. Did it all work? So far so good. I think we are definitely making progress. On Hankook C91 DOT tires and the middle boost level, Dave Empringham piloted the car to a 1:44.2 on Buttonwillow's configuration 13 clockwise. Good enough to smoke the Tomei/Cusco STi's, but not quite HKS' 1:43.523 yet.

LIsten carefully at what Dave says at the end of the clip.

We were only really had less than 3 hours of actual track time and this included making setup changes. If we would have spent the entire day on the track, who knows how fast the car could have gone? Emp was still getting used to the car after a weekend at Daytona driving a Mustang (imagine the difference).


Q: Do you think there's a faster time in the car?
A: Yes. We were only testing and setting up the suspension during this test. Dave was still going faster during setup changes. After the 1:44.2 lap, the ring gear in the rear end decided to strip its teeth.

Q: Why did the rear end blow up?
A: Actually the ring gear stripped all of its teeth. It was only designed to have to handle 150hp on street tires. We are asking for it to handle a whole lot more on much stickier tires. There are three sections on the track where the car gets wheel spin and that doesn't help either. You can't really hear it through the tiny mic on video system, but you can hear it loud and clear from the hot pits. I have some tricks up my sleeve to combat that with the Pectel SQ6 ECU and Center Diff Controller.

Q: How much boost was the engine running?
A: I'm not sure why people always ask this question, but I know somebody will ask. Since I'm not discussing turbo size it really is kind of irrelevant, but FYI that pass was at 26psig. Turbo sizing is subject to change anyhow. And yes, it is a genuine Garrett T04 and not a GT. I have set an unofficial limit of 32psig though.

Q: How fast will the SSE EVO 8 go with Emp at the wheel?
A: Nobody knows the answer to that, but it is a personal wish of mine's that it will go 1:40.xx or faster. What a lot of people forget is that the SSE EVO 8 is the newest unlimited class car and has only had 7 months of development. It's first event was at Willow Springs in May of 2009 where it took 1st in class and 2nd overall.

Q: What's next for the car?
A: The usual: more development and testing. The suspension still needs some more setup changes and I need to fine tune the diff and boost. It never ends until we have the fastest time attack car on the planet! Perhaps we will have a chance to fight for the title in Australia.

Here's a pic of the new turbo setup when it was on the dyno at Sierra Sierra. The rubber hoses have since been replaced with Teflon hoses and AN fittings. The Full Race exhaust manifold is a work of art. Geoff and the guys over there really make beautiful parts that truly work. The combination of the new Garrett T04, Full Race exhaust manifold, new exhaust and Cosworth custom cams made peak boost 200rpm earlier and extended the powerband another 400rpm when compared to the GT35R and previous components. Mike at Sierra also fabricated a whole new larger exhaust to accomodate the increase in power. The exhaust note now sounds more pissed off than ever.

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