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: How do you build boost in a five speed without presenting a load on the engine, (like a partial clutch engaement)? [ http://sonic-motorsport.com/racelogic/buildboost.mpg ] What happens is hard cut limiter is set at 5500rpm, when the engine "bounces" off the limiter this sets up sonic & gas pulses in the exhaust system which starts getting the turbos moving. You can hear the exhaust note harden just slightly when it builds boost. Look very closely at the mpeg above.. you'll notice that I get the revs upto 5500rpm and the engine bounces off the limiter, then I push my foot hard on the throttle, this creates enough airflow to get the turbos spinning up to speed. Heres what the 4000rpm limiter sounds like outside the car:
[ http://sonic-motorsport.com/racelogic/rear_4k_launch.mpg ] Trust me - it does build boost and my foot is hard on the clutch!!!! there is no load on the engine other than the exhaust pulses. The soft cut limiter at low revs (4000rpm) WON'T produce boost, the hard cut limiter at med revs (5500rpm) WILL produce boost. I didn't believe it at first, but when we first ran the launch control there were 4 very stunned New Zealanders looking at the boost gauge on my car. Note the hard cut limiter is interesting - the whole car shakes when the engine goes "barpbarpbarp".. just like a Rally car on the line. You can go one step further and fit a LINK Anti-Lag system and produce flames on the line, but turbo life goes downhill remarkably (Anti-Lag is designed to allow a fresh rich fuel charge come out of the exhaust ports and ignite in the exhaust manifold creating explosions which really get the turbos spinning. As used on Group A rally cars)
Rowan Hick
Sonic-Motorsport.com
Auckland, New Zealand
90 TT Manual 2 Seater Stage 3 (loves Racegas)
ICQ 6565710 
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