Snook

iTrader: (12)

Are there some turbos that just get it no matter what?

I had a post about using the stock bovs with a t66 turbo where I was raped by the forum members about a week ago...so if you arent interested in this and really dont know what you are saying or dont have any experience please dont post. If you dont know for sure but are really trying to help then thats different Id love to hear what you have to say. Just no ******** is what im going for

Ive done some further testing since then. I want to understand what the problem is. Its not that I want to be cheap or do it the wrong way trust me I love my car I just want to understand what the problem is.

I tried using a surpra stock bov and that worked MUCH better but I still get the surge. This is what gets me...I took off the bov totally which created a huge boost leak...I then reved the engine from the throttle cable and still heard TONS of the surge going back to the turbo. This leads me to believe that the hole on the corner of the stock elbow just isnt big enough to let all of the air out that it needs to OR that my turbo is going to do this no matter what bov I get...what do you guys think? Will a hks ss bov or a tial with a big flange fix this problem or what?

ive tried the stock bovs in different locations, 2 at the same time, different vacuum sources, no bov and now a supra bov and still it makes the surging noise when I snap the throttle shut. If I close it slowly I heard the bov releasing but when I do it fast I hear the bov and lots of surge at the same time.

So what can we conclude?

Thanks everyone for contributing

Snook

iTrader: (12)

right on no replies yet!!

RotorJoe

Sorry I am not sure I can help, but maybe you can help me?

What does compressor surge sound like and how do you know if you have the correct size BOV?

Thanks

$150FC

I will not be an ******* (because i'll admit i was cutting it kind of close on that last thread but there were others doing better jobs than I).

Have you tried using a large aftermarket BOV, as we suggested? You are still only using stock ones (although now you've graduated to Supra valves )

I am simply wondering if you have tried one. A T66 will flow a lot of air and I am thinking that any stock BOV is just simply not going to flow well enough.

I can't remember from the previous thread- you've tried it on the GReddy elbow, and where else?

Also, what size intercooler piping are you using? A larger BOV with a bigger flange (as you suggested) welded to IC piping isn't always the prettiest but it may work better than using the smallish hole on the GReddy elbow with stock BOVs (or none at all).

it does surprise me that you still got compressor surge with the big boost leak, though. Leads me to believe that the holes are not big enough, so regardless of the BOV you use in that location, it would not work.

Are you sure you are hearing surge and not just hearing boost fly out the hole, though?

edit: i see you are still using the stock elbow, is that correct? that may be affecting lots of variables since I'm pretty sure the pipe itself is smaller than the GReddy elbow.

-victor

Snook

iTrader: (12)

150 MUCH better bro thanks

now you see im not just playing around

im possitive that it is surge because I hear it from the turbo and the filter infront of the turbo shakes when I rev the engine!! even with that huge boost leak it still did it. So all we can conclude is that the hole there is too small...I didnt try to get a big flange and an aftermarket bov yet because its going to cost me about 250 total for welding and the bov but it looks like Ill have to do that. Im just going to be upset if I get it and it still does it, ill feel like an idiot. The greddy elbow is only better because it is metal. It doesnt have that hole where the AWS used to be where i am running the bov now. I also have the air temp sensor and water/alcohol injection tapped into the stock elbow so getting a greddy elbow which is shorter would be a pita I just dont need it. The thing that still gets me about the surge is that it will do it at 1psi if I let off quick, it does it revving at idle where I cant even get into boost, and it does it with a huge boost leak and no bov!!! I think the 2 stock bovs are working just as good as any aftermarket unit will and the surge is just going to happen


x605p747R1: ill get a sound clip for everyone. Any aftermarket bov should be fine especially on the stock twins. I suiggest hks, greddy, or tial only though

Crusader_9x

get a turbo xs bov there big and cheap. also make abigger hole and put it there.
https://www.rx7club.com/showthread.p...hreadid=249576
look at my bov in that thread. if u can do something similar then almost no welding required and it flows alot of air. i got a t04r, 3" pipes, 15 lbs of boost and it works fine for me.

Snook

iTrader: (12)

no turbo xs for me i want hks or tial

thanks for the pics though that helped a lot

IGY

Compressor surge on a free rev is not going to cause any problems for your turbo. Now surge after full boost will cause problems. I have a 67-1 with a Greddy type R blow off. I get a little surge at any boost under .5. Full boost I get none. It is a combination of pressure in the pipe and vaccuum in the manifold that opens a blowoff. If there isn't enough pressure in the pipe but there is vaccuum in the manifold the blowoff will open slow and not all the way causing compressor surge(that cool chattering noise, for the ricers).

Snook

iTrader: (12)

ok so what am i doing wrong to get the surge? it haens at any boost level if i sna the throttle shut. if i let off slowly its fine i just hear the bov

SPOautos

where is your bov's vac line tied in at? What nipple?

Also, just to rule out that its not a problem with the turbo itself why not just pull the IC pipe off it, free rev the engine, then let off and see if you still get some wierd noises from your turbo.

STEPHEN

Snook

iTrader: (12)

ive tried it at both the front of the uim and just where the uim meets the lim with the same luck. I think my turbo just makes that noise....I was going to try taking off one of the intercooler pipes to test that out thanks...

i believe the turbo will still make that noise...what if it does? does that mean its damaged?

Snook

iTrader: (12)

well I think this is good news. I took off the IC pipe after the intercooler and free reved the engine and no noise at all after I quickly let off of the throttle...I guess this means the noise is surge and that the AWS hole on the stock elbow simply isn't big enough where the stock bovs are. I couldnt believe how much air was coming out of the intercooler pipe while I reved the engine and my car doesnt even get into boost without load!!

Im having a hks ss bov welded to the intercooler pipe after the intercooler very soon. I can't wait to see it work and ill also have a plus of a cool sounding bov. Altough im not sure anything will sound cooler than the surge!