Help! Greddy Type-S BOV in stock location problem

[Pepperoni]

I've tried searching for days (not only here but on other forums as well) along with trying out different things. I have the turbo (t25) set at 9psi.

Basically, I have a greddy type s blow off valve with an RX7 flange/pipe. I decided to mount it in the stock location seeing that i had extra hoses and such. I also wanted to keep the stock look (california). Heres a pic of what it looks like



first off, i kept getting compressor surge no matter how i adjusted the bov. I read that people take out the bigger spring of the two springs inside, so i did. After i did this, I eventually got to the point of no more compressor surge after the adjusting screw is in about half way.

SO heres my problem:If i boost UP to 3000RPM and let off the throttle, i get no compressor surge. But anything over 3000RPM, i get surge. Either situation im at full (9psi) boost.

Adjusting the bov screw barely does anything apparently; i even took out the screw entirely and it did nothing (engine idle-wise). I thought it was supposed to leak without the screw.

I have the upper (bigger of the two) nipple connected to the corresponding nipple on the throttle body. I also tried connecting the lower nipple to the wastegate, reason being that i read this would help get rid of the compressor surge; i still got compressor surge with or without connecting the lower nipple.

Should i cough up the money and just get a flange/pipe for the hotpipe and plug up the SMIC, or is there something i can do about this? Im out of ideas. Thanks guys.

[Silvia007]

The lower smaller nipple connects to the hotpipe, not the wastegate. Where did you hook up the top nipple to? If it's the intake manifold, check your vacuum, if it's around -18 to -19, it should open when you let off the gas.

I would probably run to a muffler shop and find some 2 inch mandrel bend piping and weld up your own hot pipe. Works great and relocate the BOV to the hotpipe.

[RMiller]

I don't think the lower nipple is meant to be attached to anything. I have a Type S as well. Make sure you connect the vacuum line behind the throttle body, otherwise you won't get any vacuum and your bov won't open.

[Luke]

Before, most people told me that you do not need to hookup the smaller lower nipple on the type s BOV. I found that the BOV releases much better and bobs/chatters a lot less. It also changed the sound to much higher pitched chirp. I just fed a boost/vacuum signal from the hotpipe to there.

[BaliLover]

I'm also running the type-s with only the upper nipple connected and I have no problems.

Have you tried running the BOV atmosperically instead of recirculated? its possible that the noise you are hearing isn't compresser surge but rather just how a recirculated BOV sounds. I would run it atmospherically and see how it reacts before saying the BOV is hooked up wrong or non-functional.

[Luke]

Well let me rephrase my statement from earlier. When I didn't have the lower nipple hooked up, i noticed at lower boost and when only lifting the throttle partially it would give compressor surge a lot. When I hooked the other vacuum line up, it no longer has the compressor surge sound and blows off equal to if it was a full throttle release at full boost.

I noticed the spring has to be tightened down a lot more doing this.POINT: The lower nipple is there for a reason and the Type S performs much better with it hooked up.

[RMiller]

Pepperoni's problem doesn't make sense to me. Ok, at 3000 and 9psi, no surge, but over 3000 at 9psi (so more air is flowing) he gets surge. It sounds like the bov can't flow enough air. Check for a kink in the return tubing, or the tubing to the bov for that matter. Is there anything else you changed (Pepperoni), or did you only change the bov? Did it work better with the stock bov?

I get compressor surge if I give enough throttle to get about 4 psi, then let off. I don't get surge any other time. This is not harmful to the turbo.

[Silvia007]

Well let me rephrase my statement from earlier. When I didn't have the lower nipple hooked up, i noticed at lower boost and when only lifting the throttle partially it would give compressor surge a lot. When I hooked the other vacuum line up, it no longer has the compressor surge sound and blows off equal to if it was a full throttle release at full boost.

I noticed the spring has to be tightened down a lot more doing this.POINT: The lower nipple is there for a reason and the Type S performs much better with it hooked up.

Yep, I hooked up my Type-S the exact same way. Works great. A lot of DSM guys hook it up the same way also.

[Pepperoni]

Thanks guys for the replies. I fixed the problem! All the stores were closed on thanksgiving day, so I ended up cutting the RX7 flange, to get rid of the bottleneck design

For those that don't know, it looks like this

and after i cut the little end, it's now like this

Turns out that the RX7 pipe was just way too small and couldn't flow enough air.

I also ended up rerouting everything to the engine bay; now the BOV is by the air filter. So now the hose from the BOV to the Intake is only about 3" and now the BOV is much louder than before, when the hose used to be a good 10" length at least.

I have the lower nipple free but i heard it should have be hooked up to a boost source. Right now everything is working perfectly; thanks guys.

[RMiller]

Luke and Silvia007--

Are you hooking the lower nipple to a boost or vacuum source? Won't get much vacuum before the throttle body. Do you know what causes the bov to act differently when you hook that nipple up to something?

Pepperoni--

Glad you got the problem resolved.

[IanS]

The lower nipple is supposed to help with response, think about it, upper nipple has vacume, vacume = pull, lower nipple has boost, boost = push. The vacume pulls the diaphram open when the throttle body closes, and allows blow off, the lower nipple pushes the diaphram open when the throttle body closes when boost begins to spike. The push alone isnt usualy enough to make the bov open unless your running a lot of boost, thats what type RS and R are for, but at lower psi It makes the bov much more responsive.

[Luke]

The lower nipple is supposed to help with response, think about it, upper nipple has vacume, vacume = pull, lower nipple has boost, boost = push. The vacume pulls the diaphram open when the throttle body closes, and allows blow off, the lower nipple pushes the diaphram open when the throttle body closes when boost begins to spike. The push alone isnt usualy enough to make the bov open unless your running a lot of boost, thats what type RS and R are for, but at lower psi It makes the bov much more responsive.

He said it all, it helps with lower boost response. I tried removing the smaller 2nd spring out, and could NOT get it to stop leaking at idle. The article I read was for an Evo so maybe it's different.

[nonvtecaccord]

I have the greddy vspec fmic and it has the stock bov nipple thing and I was wondering how to hook up my Bov to that nipple, should I try it like the first picture only facing straight up with a hose to the intake? would that work good.