Car jerks violently after letting off gas at high boost

[GinNBoost]

Anyone else ever experienced this problem? Whenever I boost up to 18psi and let off on the throttle, my car will jerk really hard. Could this be a tranny problem? I'm starting to think it is. Any insight would be appreciated.

 

[duke52]

by jerking do you mean it decelerates sharply,... more then you would expect then operates normally? are you compleatly off the throttle or are you at partial throttle? If you are at partial throttle it could be a boost leak that cause the motor to stumble due to a rich condition,

 

[Jeff_Jeske]

Does this happen between slower shifts during a race?

Have you played with the TPS or swapped injectors?

Made ANY recent changes?

 

[GinNBoost]

Well it happens when I'm completely off the throttle. And this didn't happen when I was racing or anything. I was just messing around with my boost controller and testing things out and I suddenly noticed it. It's like a hard short jerk.

 

[PaleDSM]

Do you hear any compressor surge from the bov when this happens?

 

[polarmoment]

does it jerk like that too even if you try to roll off the throttle slowly? if so, like duke52 said, check for a boost leak.

 

[fwdturbobov1996]

ok when ur at high boost 18 psi and you let off the throttle your getting no more gas and no more air . while the turbo is still spooled ur giving it no gas or air to make any power . Could it be like detination or somethign? Just a wild guess.

 

[Thomas91169]

i too just started experiencing this problem. its happened due to the denser colder air.

i could drive fine and shift fine normally, but if i say go wot and hit full boost but still shift at 4k itll jerk when i let off the throttle, it jerks while the bov is going off. i believe that my greddy is a little too tight for the colder air now, so i will be turning it a little soft for the winter. ill check back and tell you how it goes.

 

[Mr96GSX408]

Its the bov, the bov is not responding fast enough so it jerks the car due to the pressure. Swap out the bov to a 1g one and vent it back to the intake, that should fix the problem...or adjust the aftermarket one to respond faster.

 

[MattO]

A couple of nights ago I installed a Dejon tool 3" intake and K&N filter on a SBR GT13. Prior to the install I was running an open turbo inlet (with the exception of some metal screen over the turbo intake for large debris). The car ran great. Pulled like a MF! Zero indication of compressor surge. When I went WOT and lot off the Tial BOV made a nice subtle wooosh sound. Once I installed the Dejon intake, I seem to have an issue with what I'm guessing is compressor surge. I did a 1Gina2G swap, MAFT with GM (after the turbo), DSMLink, SBR FMIC, all hard pipes, 750cc FIC, etc... With the intake pipe and filter installed, when I boost 15-18 lbs and let off, the boost gauge flutters back and fourth and the car stutters in unison with the flutter. However if I go WOT and let off the BOV now makes this screeching sound , kind of like chirping BF Goodwrenches on an old school muscle car in second gear. I'm guessing this is compressor surge but I'm not 100% certain. The car has plenty of vacuum (20-23 inches at idle).

Is the most likely compressor surge? Why would adding an intake pipe and filter to the turbo cause surge? What are my options to eliminating it?

MattO