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911st 911st is offline
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Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
+1 on the effect of cams, ports -- pre boost onset.

A larger intercooler can add to this some as it can slow down the intake velocity quickly. This adds a bit of additional restriction and creates more area that has to be pressurized.

Compression and ideal AFR & ignition help most here.

A a light FW dose let it spin up a little faster from idle to clutch engagement. This is when the motor is only making maybe 5-25hp so less mass to spin up before the clutch is dropped will make for some improvement.

I think I had a cup flywheel on my 91 turbo but not sure. Added a 3.6T sport clutch later.

My biggest improvement to off idle was getting the AFR's to near 13/1 (ignition was not adjustable) and aggressive manipulation that lowered control pressure quickly at first to get the metering plate out of the way. I think this might be doable with a D-WUR.

I believe is what effects the area off idle to the first hint of boost (boost onset).

Twin plugging +3%
SC cams -2%
C2 cams -4%
3400cc +3%
3500cc +6%
ideal timing and AFR 0-10%
.5 increase in CR +2%
1 point more CR +4%
Pressure sensing EFI conversion (no restrictive metering system) 10%+.
Ports, do not know.
Muffler to lower back pressure, yes.

These are just approximation and gut feel. However, SC cams lower effective compression about .5 and C2's about 1 point. Going from 7/1 a full point of compression it good for about 4-5% in power.


The biggest reasion for a dual mass flywheel on a G50/C2 turbo is to quiet the transmission. Thus some additional chatter might be noticed with a light weight.

Last edited by 911st; 02-13-2010 at 09:59 AM..
Old 02-13-2010, 09:53 AM
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