civic turbo question

[dsm king]

so my buddy just got this turbo gsr swapped ek. when your driving and build up boost then let off the gas you can clearly hear the bov. but when your stopped with the motor revving and let off you cant hear it. is this normal? cuz all my turbo cars you can rev the motor and let off while your not moving and hear tho bov. does any of this make sense or did i lose all you?

[mx-6er]

Yeah it's normal, mine wont either Ryan. Mine probably wont see any revs at all for a while.

[M@]

What kind of BOV?

[bd_240]

you dont really build much boost unless your under load, the only exception would be 2 step.

[integra_drk]

god your so smart brian. what size is the turbo? there might not be enough exhaust gas in neutral to spool that jenkins

[dsm king]

its a greddy type s, turbo is, im guessing, a 60trim.

[M@]

Well, apparently the Type S has a standard or a stiff spring. There's a chance he might have the stiff spring in it. Just a possibility.. who knows.

[HONDA GHANDI]

Its not building any boost during a load free rev.

[hrcDSM719]

Agreed with Ghandi and anyone else whos stated that its not making enough boost to actuate the BOV. If it bugs him, or you, you can adjust it, just be careful you dont adjust it too loose to where it wont hold boost. Not having it blow off without load isnt a big deal, so long as it works under full boost and prevents compressor surge, its doing its job...

[bigturbo]

A lot of cars cant build boost stopped but there are some that can. The turbocharger size and engine dispacement are the largest factors(aside from a 2 step BOV). My 20v jetta with a slightly larger would blow off all day at idle and I was using a HKS supeer sequential.

[hrcDSM719]

Your lil ko4 will do that, just as a 14b or t25 will. But, I doubt he's running a lil turbo like that. A 60trim will make boost without load, but only with the aid of a 2step....which will then let the BOV vent...

[john]

The BOV is there to release pressure from the system when the throttle plate closes. It is opened via vacuum and releases pressure to protect the compressor.

There's probably no boost without load (ie, revving in neutral), so there's no pressure to release when it opens (without load).

[hrcDSM719]

exactly

[HONDA GHANDI]

My HKS doesnt prevent surge on the Hellement. But it only surges when Im at WOT climbing a hill at 5-6k rpm. :yikes:

Damn turbo is too small.

[floored4door]

I still have a tad of surge on my set up. Is this pretty bad for the turbo. It got better once i trimed the spring a tad. BOV is a TIAL.

[M@]

It's not good for it, that's for sure. It's the pressure in your system left over after having the throttle open exiting out through the first open source it can get to, which is back out the compressor wheel/inlet. So, figure your turbo is spinning in one direction at about 50-100k RPM, then suddenly stops and spins in the opposite direction. It's bad on pretty much every part of your turbocharger. Usually a vacuum leak causes this from what I've found, and causes the BOV not to open properly to let the pressure escape.

[floored4door]

It's not good for it, that's for sure. It's the pressure in your system left over after having the throttle open exiting out through the first open source it can get to, which is back out the compressor wheel/inlet. So, figure your turbo is spinning in one direction at about 50-100k RPM, then suddenly stops and spins in the opposite direction. It's bad on pretty much every part of your turbocharger. Usually a vacuum leak causes this from what I've found, and causes the BOV not to open properly to let the pressure escape.

Could this also be caused from not enough boost or too strong of a spring? Im not sure what PSI spring i have where can i get smaller psi springs?

[M@]

I would say too strong of a spring is a definite possibility, especially in the Tial BOV's since they have specific springs for certain app's depending on what vacuum their engine produces.

Engine Vacuum Reading Range ----------- Spring to Use

-22 through -23 ------------------------ -12 PSI

-18 through -21 ------------------------ -11 PSI

-14 through -17 ------------------------ -9 PSI

-10 through -13 ------------------------ -7 PSI

If your BOV can't open properly, it's going to exit through your compressor wheel and create comp. surge.