Having problems with compressor surge

[CyFi6]

I have been having problems with compressor surge from the first time i fired up this new engine. I did a 7mge to 7mgte swap, so i have nothing to compare to.
I will start with a list of mods..
7mgte
stock turbo elbow- 3"dp
Gutted CAT, 2.5" catback
Probe pistons/Cometic HG to keep stock compression
Apexi air filter kit
SpeedSource turbo outlet harpipe
Factory intercooler/piping (besides speedsource pipe)
Stock bypass valve
Stock, 7PSI boost measured at the manifold

At the beginning i had a pretty severe compressor suge. A quick check of the stock bypass valve showed the diaphragm was leaking, so it was replaced with a used, working valve. The surge decreased significantly, but under boos and full snap closing of the throttle, surge was there.

Tested the BPV-
No vac- Cant blow through either side
Vac applied- Can blow through

Tried another known good BPV, same surge, and same test results.

Checked vac line, good vac. Temp replaced the stock line with a large single line directly to the manifold, little to no improvement.

Question is, where can i go from here? I know i could go the Bosche route, but i dont see why the stock should not work with stock boost. If i boost, then let the throttle down to about 1/8 open, i can hear the BPV bypassing air, and no surge, but even if i hardly boost, if i let off the throttle 100% fast, it surges every time. Please help me figure this out, and save my turbo!

BTW, looked for how to test a BPV and only came up with this. Seems stock BPV relies entirely on Vac to open, as at idle and low load, the valve can remain open with no ill effects.
http://www.supramania.com/forums/sh...ork-(and-why-they-sometimes-don-t)&highlight=

 

[Zumtizzle]

hmmm.

test the new working one?

Could it be too long of a vaccume line as well?

 

[TurboStreetCar]

Could it be too long of a vaccume line as well?

Could cause a delay in opening witch would make the problem worse.

Get an after market one, the stock ones small.

 

[Reiketsukan]

The Bosche BOV is good to replace a busted stock one because it's cheaper, but I didn't like it too much.
I have one I'd sell you for shipping, but it probably won't be too long before you want a solid aftermarket one.
Another thing to keep in mind is that the Bosche bov kinda 'hoots' when it blows off and sometimes sustains the 'hoot' at lower RPMs at a certain throttle position.
It made my girlfriend giggle every time she heard it. She still makes the noise when she rides in my Supra even though I have an SSQV now lol.

I'd save up a bit and nab a good used aftermarket BOV here in the classifieds.

 

[CyFi6]

That would be cool if you would give me that bosche one. Maybe i can figure out a way to quiet it down, but im not too concerned with that right now as i really just need a way to prevent my surger problems. Only issue i have with aftermarket is finding a recirculation type that is affordable, then i have to get an aftermarket pipe for it to flange to. I dont really want it to be loud, and i want it recirc'd

 

[Reiketsukan]

I know the HKS SSQV can be re-circ'd, but I don't know what others can aside from the Bosch. I ran the Bosch recirc'd and heard the 'hoot' louder than when it actually opened.
PM me an address and I'll see what shipping would be if you're serious. I'll send you all the rubber hoses and clamps that were used to make it work too, so it'll be pretty easy.
Remember, these aren't new pieces, but they worked fine when I took them off shortly after getting the car. Now I've got to go hunt them down lol.

 

[aljordan]

One way to eliminate the hooting of the Bosch valve is to reverse it.

I never liked the Bosch valve and actually went back to the working stock valve about a dozen years ago.

 

[Reiketsukan]

That would have been nice to know... Does it adversely effect the way it works?

 

[3p141592654]

Bosch makes a number of similar looking BOVs. This has been discussed elsewhere many times. You want a 110 or 114.

Bosch 110 and 114:
Audi 06A145710N
Bosch 0280142110
Bosch 0280142114
Porsche PP993.110.337.50

 

[SupraDupra500]

One way to eliminate the hooting of the Bosch valve is to reverse it.

I never liked the Bosch valve and actually went back to the working stock valve about a dozen years ago.

Hey stranger!

I went through two or three stock valves a few years back, thay always broke and were stuck open. I went with a 1st gen DSM valve then when I upgraded turbos I went with an HKS Race type II. Best valve I've EVER had hands down. Expensive piece but well worth it.

 

[GrimJack]

Remember that 'stock boost' doesn't apply as soon as you start upgrading stuff... your hardpipes will increase flow significantly. Boost pressure isn't a good yardstick in this case, you are more concerned with the amount of air flowing through the system.

Sounds to me like you are already at the point where the stock valve just can't flow enough, and this is causing surge.

The Bosch unit will help, and may put you back over the top, but realistically, you are better off just putting in a valve that can flow LOTS more. The HKS system is a good start...

 

[Reiketsukan]

The Bosch unit will help, and may put you back over the top, but realistically, you are better off just putting in a valve that can flow LOTS more. The HKS system is a good start...

This man speaks the truth! I'm going to give him my old Bosch bov just so he can get around, but you really should try your best to get a good used one off of here.
I got a lightly used, latest-style HKS SSQV for $160 shipped and it works fantastic. I'll do my best to ship that Bosch tomorrow and I'll let you know how much it cost!

EDIT: Found it! Got it all boxed up! Shipping tomorrow!

 

[CyFi6]

Thanks for the advice, and i will upgrade in the future, i just figured i wasnt flowing enough yet to max out the stock valve. I will see how the Bosch one does and go from there. It kills me to hear my fresh turbo screaming for mercy!

 

[Reiketsukan]

Should be there Monday! Let us know if it fixes your problem!