Knock after BPV intall

[zaka]

Hi!!

I installed used SU Turbosmart bpv today and after couple WOT I get some 4-5 KR with same boost as stock bpv.

Ltft doesn't change, do you think there's some leak or problem with bpv.
I've checked everything and it seems ok.

Thanks

 

[Darth Vader]

Is KR at WOT or other conditions? Too much BPV spring pressure could cause knock at non-WOT conditions....

 

[zaka]

Is KR at WOT or other conditions? Too much BPV spring pressure could cause knock at non-WOT conditions....

Only at WOT in 4-5 gears

 

[MSMS3]

Just to confirm it is the BPV adjustment and not something else, consider putting the stock BPV back on and check KR again. You might have something else going on that just happened to coincide with your BPV change out.

 

[zaka]

I forgot to tell that I've got the "hard" spring in. The guy didn't send to softer spring so I couldn't test it.
Do you think harder spring could cause Knock at WOT?

I've already put back stock bpv and I'll see tomorrow if it's ok or not

 

[darkthunder]

I have also been experiencing KR. I see very little when at WOT, 1.8 is usually the max i see, and thats with heatsoak. But after i installed the ssqv v3(recir) i see up to 5.9 right as i let off the throttle. Any ideas?

I know it steps down boost slower than other bovs which is why i got it. Boost after shifting is immediate. Which is great and all, but that much knock is concerning.

 

[MSMS3]

Hope not to be jacking the thread, just thinking about the HKS. I address the same issue and keep the stock BPV by flat shifting when it really matters. lol. Really easy to stay up on boost that way if trying to haul ass at WOT at the track or merging on a highway ramp or passing quickly, etc. Nice valve though, the HKS. No knock/detonation issues with the stock BPV.

 

[darkthunder]

I actually have an AP and have launch control and flat foot shifting as well, i like the hks for daily shifting. I figure ill just do all the little things i can to make the car better before i go big turbo and forged. Eventually that is.

 

[zaka]

I put back stock bpv and No knock.

So it was because of the bpv

 

[CorkSport]

Hi!!

I installed used SU Turbosmart bpv today and after couple WOT I get some 4-5 KR with same boost as stock bpv.

Ltft doesn't change, do you think there's some leak or problem with bpv.
I've checked everything and it seems ok.

Thanks

A leak should give you too much fuel not a lean condition. With a stiffer spring I could see this happening if the stock valve was leaking.

You have a Piasani tune correct? If the tune was setup to compensate for the stock valve and it is not leaking now you could be hitting a spot where the tune is causing the lean condition.

-Derrick

 

[zaka]

Thanks Derrick

I'm waiting for the softer spring, and remap if it doesn't work.

I had Piasini tune before but now we've done a custom tune with EcuEdit on my car and works great

 

[Darth Vader]

The advantage of an aftermarket BPV is simply adjustability. You can tune the BPV to give yourself the throttle response and blowoff reaction you desire. The stock valve is fine for the stock turbo, as long as you're happy with what Mazda engineers set it at, keeping in mind they always play it a bit safe. My car was doggy with an intake only using the stocker and changing it out for a firmly sprung Forge cleared that up. The factory valve never leaked under load or showed any other problems just, doggy throttle response.

 

[darkthunder]

The advantage of an aftermarket BPV is simply adjustability. You can tune the BPV to give yourself the throttle response and blowoff reaction you desire. The stock valve is fine for the stock turbo, as long as you're happy with what Mazda engineers set it at, keeping in mind they always play it a bit safe. My car was doggy with an intake only using the stocker and changing it out for a firmly sprung Forge cleared that up. The factory valve never leaked under load or showed any other problems just, doggy throttle response.

I do agree, however with the Hks you cant adjust it. To put it simply, it works great from low to high boost. Throttle is more than greatly improved and it is actually closed at idle. The only problem i have is the KR, due to the fact that I do need a custom tune. Im gonna go back to the stocker soon, but the high where i live today was 18. A little too cold for me.

All Bpv's and Bov's will work as long as they are tuned right. Where i live there are so many ricers, they all think that back spool (compressor surge) is "cool!" I hear it all the time and it makes me CRINGE!! Turbo destroyers! There's a blue srt 4 that runs a 19 psi spring, and only runs 14-15 pounds of boost. He has surge every time and claims its his bov. Too bad bov's don't let off pressure for 4-5 seconds and you cant hear a bov in your exhaust.