Bov Causing Spiking?

[RBwhatever]

Hey guys, I got a mate with an S15.

His mods are --> Pod, Cat Back, Boosted to 10psi by replacing one of the factory hoses (was like that when he bought it), Boost gauge plumbed in before the plenum.

Anyway, he reckons that it seems to be spiking 3-4psi on gear changes, and thinks his stock BOV is causing it, and thinks he might need a new one.

Is that possible? or impossible?

It doesn't sound quite right to me.

Thanks...

[Adriano]

The boost gauge is simply plumbed into the wrong spot, it should be in the plenum

[RBwhatever]

I agree.

Thanks mate

[ansch]

It is caused by the free boost upgrade he's done. ie. removed the restrictor in one of the factory hoses. It seems normal to me. When I did the same thing to my s15, on the dyno it showed a peak boost spike of 12psi. It should be safe but he can run it on a dyno to check a/f just in case.

[mad082]

where you have the gauge hooked up from won't cause the spiking. the best place to have it running from is actually the wastegate hose. that way you actually see what boost the turbo is running, not just what is going into the motor. things like the intercooler add restriction, so the plenum may see 10psi, but the turbo may be boosting up to 12psi.