took the car to the track on sat, troubles

Phast SVX · #1 07-31-2006, 11:29 AM

Well i went to the track on saturday, with bad results. I couldnt get a complete run in as teh car was choking out.The car was dropping out and going to vacuum on high rpms, seemingly dieing. Either the new filter i installed doesnt flow enough(it was super hot, so the turbo has to work much harder to make the same amount of boost) or the turbo itself has an issue. Either way a very dissapointing day at teh track. Car ran ok on the highway,boosted it a few times but nothing like full throttle and revs from a standstill, so im guessing the filter was the culprit. Too badi couldnt trouble shoot it at teh track, was 95 degrees and my buddies b20 turbo hatch broke into the 11's on only 7lbs of boost

so my car was not the focus of the attention.
phil

cdigerlando · #2 07-31-2006, 02:33 PM

Your problem sounds a bit familiar (me). Do you think the detonation sensor were pulling timing? What parameters are you able to monitor? I have always felt that this issue was due to either lack of fuel and/or detonation sensors. Have you ever run a wideband on your car and done some pulls?

cdigerlando · #3 07-31-2006, 02:49 PM

I know that we are going to hear some long detailed explaination from someone regarding exhaust pipe lenth and issues of that nature. The backpressure on the exhaust manifold should not have been excessive in my case, since my wastegate is wide open at 5-7 psi boost.

SVXRide · #4 07-31-2006, 03:11 PM

Phil,
What "filter" are you talking about? I thought you had the set up pretty much dialed in, fabrication-wise, with just "fine-tuning" left.
-Bill

cdigerlando · #5 07-31-2006, 03:51 PM

Quote:

Originally Posted by Phast SVX

Well i went to the track on saturday, with bad results. I couldnt get a complete run in as teh car was choking out.The car was dropping out and going to vacuum on high rpms, seemingly dieing. Either the new filter i installed doesnt flow enough(it was super hot, so the turbo has to work much harder to make the same amount of boost) or the turbo itself has an issue. Either way a very dissapointing day at teh track. Car ran ok on the highway,boosted it a few times but nothing like full throttle and revs from a standstill, so im guessing the filter was the culprit. Too badi couldnt trouble shoot it at teh track, was 95 degrees and my buddies b20 turbo hatch broke into the 11's on only 7lbs of boost

so my car was not the focus of the attention.
phil

After reading a little closer

Vacuum? That is wierd. Your setup looks excellent. Do you think you may have some leaks? Bad BOV?

Phast SVX · #6 07-31-2006, 10:06 PM

Quote:

Originally Posted by SVXRide

Phil,
What "filter" are you talking about? I thought you had the set up pretty much dialed in, fabrication-wise, with just "fine-tuning" left.
-Bill

Bill
in a burst of idiocy, i changed out my conical air filter for a cheap ebay filter(that was new) in thoughts of having it be cleaner. Turns out it chokes out my car! it literally was a blockage to the intake, since the turbo has to work much harder to make the same pressure ratio with the hot (140 degree track temps) ambiant temps it didnt show up on the highway, i hadnt been takign pulls from a stand still and after the car had been sitting. Ill choke up for a nice filter, but take the filter off and test it out tomorrow just to be sure, the turbo may be going bad as well but that will become more pronounced without the filter on the car. Either way i will know the problem and it is easily fixed.

Chuck,
I have a wideband in the car, i have the AEM UEGO/Guage, and AFRs were where they need to be. I dont believe detonation to be teh issue as i tried a pass with the car on 7 degrees less base timing, a huge pull and had the same results. Did not occur to me what the problem was, and talked to michael and he agrees that its the filter or the turbo. it has to be some kind of intake blockage due to the fact that it goes to vacuum, with the throttle open i would still have pressure even if detonation or rich condition occured.
phil

Phast SVX · #7 07-31-2006, 10:09 PM

Quote:

Originally Posted by cdigerlando

Your problem sounds a bit familiar (me). Do you think the detonation sensor were pulling timing? What parameters are you able to monitor? I have always felt that this issue was due to either lack of fuel and/or detonation sensors. Have you ever run a wideband on your car and done some pulls?

Can you take a nice pic of your exhuast collector for me? I have a theory, if you send me your collector i can greatly fix your issue. i believe. I have to take my header off soon to change the wastegate spring.
phil

Phast SVX · #8 08-02-2006, 07:37 AM

I am on vacation for a week up at my girlfriends cabin, ill check for back in when i get back

phil

mikecg · #9 08-02-2006, 09:20 AM

I'm suspecting knock, due to temps. Intercooler may not be cooling enough.

cdigerlando · #10 08-02-2006, 12:33 PM

Quote:

Originally Posted by mikecg

I'm suspecting knock, due to temps. Intercooler may not be cooling enough.

If he is running 8psi or below, I doubt it is knock due to temps. I do agree that it is probably knock though. Probably due to a combination of timing and AFR, although according to LAN timing should not be an issue. So maybe AFR. We need more data! I wish I had more too.

longassname · #11 08-03-2006, 08:26 PM

he goes to vacuum while the throttle is wide open. That means there is an intake restriction.........

cdigerlando · #12 08-04-2006, 01:58 PM

Maybe you have a hamster nest in your intake pipe.

cdigerlando · #13 08-04-2006, 02:01 PM

Are you sure you go to vacuum, or is it your foot reacting to a change in condition of the motor. I agree with you LAN that an intake restriction would cause vacuum, but it would have to be a pretty sudden closure to go from boost to vacuum that fast. Almost like something is slamming shut all of a sudden.

SVXRide · #14 08-05-2006, 02:13 PM

Quote:

Originally Posted by cdigerlando

Are you sure you go to vacuum, or is it your foot reacting to a change in condition of the motor. I agree with you LAN that an intake restriction would cause vacuum, but it would have to be a pretty sudden closure to go from boost to vacuum that fast. Almost like something is slamming shut all of a sudden.

Chuck,
Couldn't the "cheap" intake filter Phil used just have collapsed under the boost load, then "sprung" back once the boost dropped off?
-Bill

cdigerlando · #15 08-06-2006, 01:40 PM

Quote:

Originally Posted by SVXRide

Chuck,
Couldn't the "cheap" intake filter Phil used just have collapsed under the boost load, then "sprung" back once the boost dropped off?
-Bill

That is possible. I didn't know the filter he used was cheap.