Wierd Problem

[Kevin Turch]

I have a strange one here, last night i was putting my cold air kit on my car, for the 2nd time. First time my Filter fell off, but thats another story . I also changed to a thrasher 93 chip for kicks. So I set fp to 45 and took it out for a drive, i noticed it ran real crappy at about 7-10 lbs of boost the car bucked like crazy, the boost was all over the place as i couldent hold it steady. If i go to full boost it was fine. So I take the thrasher out and put my regular chip in, And take it out again. This time it seemed a little better but it still bucks quite a bit. I didnt have TL hooked up so im not sure of any readings, but it was definatly the first time ive had this problem, one thing i did notice when under the hood, was my EGR hose had broken through, connecting to the EGR. So I took it off and put a screw in there for the time being, not sure if that was causing my problems anyway. I also just got a ls1 maf and translator, which I sure hope isnt the problem

Any help woul be great, as im at a loss.

TIA

Kevin

 

[twin 93 svt]

Try swapping back to origional maf, Although new , you may have a faulty unit. good luck,

 

[Kevin Turch]

t

 

[Kevin Turch]

Anything else i can try?
Thanks

 

[UNGN]

What's your max boost set at? If it's 18 psi and you are trying to hold 7-10 psi with your right foot, you are experiencing compressor surge.

The LT1 sensor and other improvements have increased your cars breathing capability and made it more suseptable to compressor surge.

Before the changes, you needed to give it more right foot to achieve the 7-10 psi of boost. More right foot means the throttle blade was open further, so the chance of compressor surge was less. The turbo is spooling against a partially closed throttle and bucking and unsteady boost is the result.

To solve this problem, lower the set boost and give it more throttle, or buy a bigger turbo

 

[Kevin Turch]

My Max boost is at 23 lbs.
Should i lower it to 18 or so?

Also i dont know if i mentioned it but this is really bad bucking, the car jerks pretty good. Is that normal for compressor surge?
and If so it really sucks!!!!


Thanks
Kevin

 

[UNGN]

Originally posted by Kevin Turch
My Max boost is at 23 lbs.
Should i lower it to 18 or so?

Also i dont know if i mentioned it but this is really bad bucking, the car jerks pretty good. Is that normal for compressor surge?
and If so it really sucks!!!!


Thanks
Kevin

If I drive home from the track with my boost set at 23 psi and a Honda pulls up to "race", I have to let him go.

If I try to part throttle "pace" him (he's not worth the gas for any more than this) the surge will shake me out of car.

 

[Kevin Turch]

heh, well ill lower my boost and report back, thanks for the help!!

Kevin

 

[Kevin Turch]

Well i lowered the boost to 20psi, and its still doing it. Im wondering if i should go even lower?

Kevin

 

[donZ]

do you have the maf, facing the right way?

 

[Kevin Turch]

heh, i better

yes its facing correctly, flow arrow towards turbo

 

[donZ]

i just put one on my car, the arrow goes to the air cleaner side.
it should say, right on it.
sorry, i just looked, arrow goes to turbo

 

[UNGN]

Originally posted by Kevin Turch
Well i lowered the boost to 20psi, and its still doing it. Im wondering if i should go even lower?

Kevin

Oh, it 's always going to compressor surge at part throttle from this point forward. The idea of lowering the boost is that you go to full throttle at lower boost.

You could look into a blow off valve. A properly set up blow off valve should reduce if not eliminate surging, in theory.

In cockpit adjustable boost controller will allow boost changes on the fly.

If your turbo doesn't have one, a PTE housing may slow the spool down enough to reduce surging.

 

[Kevin Turch]

I have a prec. .63 housing on my car now, i think ill live with it till i get a bigger turbo next year

Thanks for all the help

Kevin