Engine/Transmission (1998.5 - 2002) Drive Pressure / Boost for Twins

[Dave Ratcliffe]

I've just put a set of twins on. Its a 35/40 hybrid with a 14cm housing over an S400. It has an external 38mm tial wastegate. I'm going to put studs in soon but my head is o-ringed.



Anyone have an idea of what a safe boost level would be until I get studs? I'm guessing 40 lbs to be safe, but please tell me if I'm wrong. I ran a single 62/14 up to 45 lbs all the time with no problems but I know this is a totally different situation.



How about drive pressure with this setup? I'm sure its higher than 1:1. Thanks in advance.



Dave

 

[AFarmer]

Ran that same identical setup personally and loved it but didn't produce the power level I was really after. Your drive pressure will probably be just fine considering it has an external wastegate - that helps greatly. If you don't have studs then I'd keep the boost down but studs are probably going to be a must really soon if you're looking at twins.

 

[J.Keith]

Just put a drive pressure gauge on it.



You should be ok though. I run a super 40/14 internal wastegated over a BHT3B/26. With some minor adjustments to the wastegate I never exceed 1 to 1 on drive pressure. Max boost I see out of it is 57 to 59 psi.