Blow off valve, good or bad for the GN

[Gnx6]

This was a loaded question I asked many months ago when planning my next load of modifications.

I purchased an HKS SSQV blow off valve. I chose this one because it is a pull type and will not leak 1 ounce until you make it blow off by pressure differential. I tested it mounted to a pipe before installing it on the car. I put 20 Psi on the pipe and the nipple. When I dropped the pressure on the nipple the valve tripped berifly. With a kleenex on the valve I did this repeatedly cycling the pressure on the valve & pressure fitting, no leaks. In a non blow off event the kleenex stayed motionless. If there was even a small leak it would have fallen off.

I now have it on the car and it works perfectly. I was scared to try it for a while as many had told me it was a bad idea. It gets rid of the turbo Stall worble sound, I have no black smoke, no driveability problems at all. This will help your turbo live longer and HKS SSQV will work on these cars without a problem.

http://www.hksusa.com/products/more.asp?id=793

http://www.hksusa.com/images/?id=1859

 

[progress1vebmx]

Do a search, you'll find PLENTY of information.

 

[MistaScott]

You could get a remanufactured stock turbo for the price of one of those...

 

[Maltman]

Originally posted by MistaScott


You could get a remanufactured stock turbo for the price of one of those...

Seriously!!! I can't believe what there getting for those things....I toyed with the idea too, but the price always drove me away.

I've come to believe that they serve a purpose on turbo cars, just not one of the guys sold on using it for "automatic" cars anymore....or at least not until I run out of "true" performance mods that I can do....but if it works without any driveability problems, then I don't see a problem (to go against the "majority" of posts).

IMHO....there is a ton of things that one could do for the price you have to pay that would provide for larger returns.

P.S. Do you have any pics of your finished install?? I'd like to see where it is and what it looks like.

 

[MadMike]

In my dealings with blow off valves, I started with turbo cars with DSMs. To me the best bang for the buck is the first generation also known as a 1G, blow off valve. they hold about 20-22 psi in stock form and can be crushed slightly and will hold up to 30. Depending on how bad the car will have compressor surge when I let off the gas, I will probably end up putting on on my car.

 

[V6UnderPressure]

Originally posted by MistaScott


You could get a remanufactured stock turbo for the price of one of those...

Most of us arent running stock turbos anymore. The HKS SSQ is an excellent choice. I believe someone else had raving success with this one also.

Scott

 

[Gnx6]

I'm using an HKS SSQV on my GN and it is near stock trim and I don't have any troubles at all. I think the key here is to buy a good quality valve. They run about 200 bucks plus 30 for the flange. If you use a lesser quality brand then you can expect headaches. I asked someone to host the pictures online for me so I will post the pictures here shortly.

 

[Ormand]

If it will help the turbo live longer, I should go out and get one right now. My turbo has 177,000 miles on it, and I have been worrying about the expense of a new one.

 

[Gnx6]

Here are the pics of my HKS SSQV.

The third one is just my updated hose, assembly. The first ones have that awful hose clamp on it from when I was trying out the valve before I did a more permanent mounting.

 

[Blown&Injected]

beat the hell out of my stock turbo for about 220K miles untill i started to blow some oil

 

[Gnx6]

Manual trans cars (Not Buick GN's) would get much more beating on the turbo as this event occurs every time you lift'n'shift.

The more boost you run the harder it is on the turbo. Like I tell everyone, it is an ever debated subject, so do your research learn how a turbo operates, what a BOV does and make up your own mind!

 

[Lunkan]

A question for all... Why is it the uppipe hose blows off from the throttle body some times if when You drop the pedal? Has happened to me a couple of times.

 

[GNVYUS 1]

HKS SSQV is a great blow off, good buy.

To answer your initial question, its not a bad thing to add a blow off valve. The real question is it nessasary on an automatic?

I think Ormand and Blown & Injected have some pretty impressive numbers on their non blow off turbos.

Most GN turbo's die from debris than compressor surge.

On my Auto DSM, when the FMIC went on, the blow off came off.

 

[V6UnderPressure]

A simple way to look at it is this:

IF your at full throttle all the time (car only sees the track) you don't need one.

IF your on the street where you constantly have it at WOT and sometimes need to let off right away for any reason, you can definitely use one. They are more of a necessity on manuals because when you shift, you are closing the throttle when letting off the gas. Same Idea goes for when you are driving an automatic, have it floored, and some unexpected diversion or traffic comes your way, when you let off that throttle you can hear the fluttering.

My 2 cents.

Scott

 

[Ed Valvo]

If it will get rid of light throttle compressor surge, I'll put one on. I hate hitting corners, off ramps, or even accelerating on the freeway and having to either be light throttle or WOT.

 

[Gnx6]

The HKS SSQV works great, it is a dual pull type valve so they don't leak. No check engine light, no smoke, no problems. You may want to try a different insert though, they sound a bit ricey. I have also been told by others that they do not work well in high boost situations like 20 psi or so. I know most of the supra guys run 2 of them on their cars to solve this issue. I believe it is because they can not disperse the amount of airflow/pressure needed fast enough.

You will still get a very slight flutter but nothing like they are stock with the wicked wob wob wob (3 stooges) noise.

 

[turbo2nr]

I am making one out of two stock WRX units for about $30. I would save my money on the new stuff, They will hold 30psi when crushed a little. Anything is better to my ears than, BlaBlaBlaBlaBlaBla, and every passanger has to say, What the hell was that?! Do we need a tow home? I say, no thats the way Buick designed this car, to sound like curly on the three stooges. wobwobwobwobwob.

 

[ijames]

Ed, a blow off valve doesn't get rid of compressor surge (boost instability at light throttle), it gets rid of compressor slam (closing the throttle suddenly under boost makes all that compressed air go backwards through the compressor and slams it against the bearings). You are getting surge at light throttle, and need to change something in your combination. Intercooler and piping volume make a small difference but it is mostly the compressor wheel so you may need to change to a different size turbo.

 

[bruce]

Originally posted by Ormand
If it will help the turbo live longer, I should go out and get one right now. My turbo has 177,000 miles on it, and I have been worrying about the expense of a new one.

It's really not rocket science, when you on the low end of the boost scale, like which only 30 PPH injectors can support, you can get by with alot of things that aren't as critical as when you run the higher boost levels. Do some *track type* road racing, with say 28 PSI of boost and get back to the list with how many miles it lasted. Application has alot to do with when you can make universally true sweeping overgeneralizations, or not.

For an appllication where one does *alot* of high boost throttle lifts, a BOV is an excellent investment, both for the reduction in throttle lag on reaccleration, and in turbo life, IMO. Opinion here being based on having played with several turbo applications.

Other then a fly by wire triple TB set-up, IMO, the BOV are a good answer for the respooling problem.

 

[Gnx6]

One other note on this subject. Yesterday I got on it at about 40-45 mph, let off the throttle completely and got back on it, the spool up and back into boost was damn near instant. I very was pleased because as we all know typically the car will take a few seconds to get back into boost after the turbo does it wob wob wob.