Greddy type s BOV not holding past 20psi or so

[Toni]

So during the dyno session on Saturday we were having problems with the bov fluttering while trying to lay down 3rd gear pulls above 20-22psi. Tightened the spring all the way and even tried to connect the lower nipple to the turbo intake tube to hopefully get some vacuum to help pull it closed from the other side. Opened up the bov today and the diaphragm looked good and the springs were not broken.

Seems odd because the springs just have to hold any pressure differential between the manifold post throttle and intake pre throttle. Any thoughts/ideas as to what's going on here?

[mb3000]

Maybe this can help:

Stealth 316 - Anatomy of the GReddy Type-S BOV (http://www.stealth316.com/2-greddy-bov-anatomy.htm)

[Jimvr4]

Toni I pressure tested mine a while back and it didn't hold much past low 20s. Might need to upgrade

[Toni]

Interesting. That seems to conflict with the 25-30 I have seen on the webs. I'll have to test mine as well, maybe the oring on mine is damaged and I didn't notice when I inspected.

[NOMIEZVR4]

C'mon man...you know you want to upgrade your BOV...its one of the most exciting mods anyone can do! :D

[Toni]

Haha yea, love spending money on top of money :)

[Chris@Rvengeperformance]

metal evo bov is cheap or if you want something more bulletproof the tial qr will fit in the stock location

[Toni]

I am blow through. Looks like there are some greddy adapters out there for HKS and TIAL so I wouldn't have to get a flange welded on if I move to another.

[NOMIEZVR4]

Hey I've got a metal evo BOV if you're interested FYI..

[mb3000]

I prefer the HKS SSQV myself, the Evo guys don't like their factory BOV's for high boost, which is why there are always used ones available.

I think Dave was going to do a back to back dyno to see, not sure if he ever had time to do it.

[Toni]

So now I am confused. My BOV will hold 25psi no problem. I even tried hooking up a mittyvac to the BOV while pressure testing it to see what differential would need to occur in order for it to open. 5psi it would start to crack open. The screw isn't even cranked in all the way.

:confused:

[mb3000]

Weird. Maybe the CFM and pressure is what's doing it?

[AdamVR4]

I think mine started leaking in the mid 20's which is why I bought the type-R ~10 years ago... that big ugly bitch still works well.

[Toni]

Weird. Maybe the CFM and pressure is what's doing it?

Not sure. I would think that the flow of air in the IC pipe would even help the situation as it may create a slight pressure drop in the short tube coming out for the bov. Isn't that how it works? Fast moving air creating a lower pressure area past a hole? I'm not fluid dynamics engineer lol.


I think mine started leaking in the mid 20's which is why I bought the type-R ~10 years ago... that big ugly bitch still works well.

Hmm, well mid 20s I can see and surely others have reported the same. Maybe I should just get another BOV and stop wasting my time with it.

[Toni]

Could someone tell me why a greddy style BOV wouldn't hold boost? It seems if the diaphragm has a matching pressure source as the IC pipe, it should never leak unless the differential from the IC pipe to the manifold overcame the intake manifold pressure. Does it have something to do with the design of the valve orings sealing properly?

[green-lantern]

TIAL

that is all

[Toni]

Looking into going with a tial as well. Luckily there are adapter flanges to a greddy so it would be an easy swap. Same with the SSQV but I am worried about the valve area. Seems like the Tial would let me move forward with something larger.

[green-lantern]

Looking into going with a tial as well. Luckily there are adapter flanges to a greddy so it would be an easy swap.

If the size of the old flange is smaller you might want to just get the new one welded in.



Same with the SSQV but I am worried about the valve area. Seems like the Tial would let me move forward with something larger.

Not sure what you mean by this

BTW are you sure that the greddy doesn't have some kind of vac leak in the hose or something?

[CoopKill]

Are you recirc? I had to replace the recirc adapter due to it leaking like a bitch. Unsure if that means beans, but something to look at if applies.

[mb3000]

I've always used the SSQV with success.

[Toni]

So Hans mentioned that I may be building boost fast enough for the manifold pressure to not catch up with the IC pipe so it will blow off.



If the size of the old flange is smaller you might want to just get the new one welded in.




Not sure what you mean by this

BTW are you sure that the greddy doesn't have some kind of vac leak in the hose or something?

The Tial is large which means it can dump a lot more air faster to prevent surge issues. I'm worried that the SSQV is too small if I want to run race gas and 25+.



Are you recirc? I had to replace the recirc adapter due to it leaking like a bitch. Unsure if that means beans, but something to look at if applies.

Nope, atmos


I've always used the SSQV with success.

To what boost levels? I can't seem to get definitive answers on what it can really handle. Seems that this design would work better with faster spooling turbos.

[green-lantern]

So Hans mentioned that I may be building boost fast enough for the manifold pressure to not catch up with the IC pipe so it will blow off.

Have you checked the hose for pin holes or leaks around the nippes? From what I understand using a small hose is bad also.



The Tial is large which means it can dump a lot more air faster to prevent surge issues. I'm worried that the SSQV is too small if I want to run race gas and 25+.



Gotcha, the TIAL has been great for me. I'm using a recycle type now. (QR I think)

[Toni]

Have you checked the hose for pin holes or leaks around the nippes? From what I understand using a small hose is bad also.




Gotcha, the TIAL has been great for me. I'm using a recycle type now. (QR I think)


I don't have any leaks and the hose is sized appropriately.

[Toni]

Twss.

[green-lantern]

I don't have any leaks and the hose is sized appropriately.


Twss.

That's just a nice way to say it's small :D

[Toni]

Eff it. SSQV on order.

[mb3000]

:bigthumb:

[CoopKill]

Damnit! I will be running into this soon, and was hoping for another answer... :p

[CoopKill]

So Hans mentioned that I may be building boost fast enough for the manifold pressure to not catch up with the IC pipe so it will blow off.



So if this is the case then a larger TB/Mani-Tank should/would help?

[Toni]

Who knows if it's really the problem? Kinda speculation at this point.

[green-lantern]

Eff it. SSQV on order.

Booo I hope you have the same problem :p jk

though not only is TIAL the most bullet prof BOV but it's a sexy bitch.


http://www.built4g63.com/images/D/tialQbovred-01.jpg

[Toni]

I was certainly checking it out but if I may end up having the same problems due to it's similar design as the greddy. I want to make this a one stop swap and not keep throwing parts at the prob.

[Chris@Rvengeperformance]

I'm running the tial qr with the 3.5 and DR750s. it doesn't leak.

It is a little slow compared to the ssqv. If I let off slightly and then immediately get back on sometimes it doesn't blow off and the car will surge a little. It may need a softer spring for my application.

[Toni]

I would probably guess that the DR750s flow quite a bit more compared to the DR650s so you certainly want something that can handle the air. Chances are I won't be maxing out an SSQV.

[Chris@Rvengeperformance]

the supra guys end up running 2 SSQVs to keep up and I don't mean guys making 1000 wheel either...

[Toni]

At what kind of airflow are they needing two?

[mb3000]

HellBringer is running mid 10's with one (1).

[Chris@Rvengeperformance]

At what kind of airflow are they needing two?

I don't know for sure, seems like with fairly mid range setups (500-600 wheel) the SSQVs have fallen out of favor. I'm sure the SSQV will work okay for you, it just seems like in my opinion for the same money you can get a tial, so I don't know why you wouldn't.

I'm sure at really low boost part throttle type of stuff the ssqv is more driveable. It is pretty widely believed that the greddy type s doesn't work well getting in to the 20s boost wise though, so I am sure you will have better results with the HKS than you have now.

[Jimvr4]

It is pretty widely believed that the greddy type s doesn't work well getting in to the 20s boost wise though

Good to know. I may have to upgrade as well. Is the Tial recirc or atm?

[Chris@Rvengeperformance]

they make both styles. tial q is non recirc, tial qr recircs

[Jimvr4]

Which way is recommended? I've always heard recirc is best so you don't lose metered air.

[Chris@Rvengeperformance]

Recirc if you are draw through.

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[GTOJOE]

Which way is recommended? I've always heard recirc is best so you don't lose metered air.

This matters if you are running a draw through MAF. If running no MAF (ie MAP) then it doesn't matter. As per Forest Gump's post, it implies "Blow through" also does not matter.

When I switched from my Blitz system which was running a vent to atmo plus using the stock rec adapter and stock ecu the car ran fine. The stock BOV/rec adapter started the old hooting owl trick so I simply removed it and went pure vent to atmo and the car would stumble after it "blew off". I switched to a TurboXS Racing Bypass Valve [setup like the stock system] and the problem went away. I have since gone standalone ECU and MAP so it no longer matters.

[Toni]

Got a log of it on the street. Apparently happening at about 19psi as well. Showed up as single psi blip and I could hear the bov flutter. It was worse with more boost. BOV came in but the adapter won't be in until Friday.

https://dl.dropboxusercontent.com/u/29716828/carstuff/logs/bovleak01.png