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Old 04-22-2004, 07:37 PM   #1
Scooby Specialist
Member#: 34672
Join Date: Mar 2003
Location: Northern VA
2003 wrx
WR Blue Pearl

Default Solution to RPM "surge" under boost?

I'll do my best to explain this:

Under heavy throttle (not necessarily WOT), it's very obvious that when I shift when still making boost, I get RPM surge.

In other words, I'm on the gas making boost, I get off the throttle to go to shift, and even though I'm off the gas, as soon as I clutch in, my RPMs will rise a few hundred or so rather than dropping immediately.

The problem doesn't exist when shifting when not making boost (or when only boosting a few psi or so), so my theory is that the factory recirculating valve just can't "blow off" the extra boost quick enough between shifts.

Its become very annoying, even more so because revs in my S2000 drop so fast between shifts that you have to shift like mad to keep up.

I certainly don't expect the WRX to respond in the same manner as the S2000, but I'm wondering if there is a solution for this "problem" of rising revs between shifts when under boost.

Has anyone noticed with a fully or semi-atmospheric BOV that this problem is alleviated? I'd be curious to find out...
Although I'm not really interested in a BOV due to the problems it causes with running rich between shifts, I'm wondering if I might learn to live with it to solve my other issue.

Looking forward to any suggestions...
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heffergm is offline   Reply With Quote