kkarim

iTrader: (2)

Hey..

After tuning my car to a setup i like, with NO counts of knock (maybe the occasional 1-2), i noticed that doing a drag style pull with fast gear changes, the car starts knocking like crazy, reaching up to 10+ counts, killing my timing and my power. If i shift normally, i can kick it as much as i want from 1st to 6th, without any knock, i can do a WOT 3rd gear pull with no knock, but as soon as i shift fast (almost all gears) i start getting knock.

I did some research, found a couple of threads but no definitive solution yet...

Can anyone help me there?

This is really killing me, as i can feel the car gaining and losing power during drag type pulls...

BigBallin

iTrader: (9)

i think the losing the power is in your head, the knock during fast shifting is normal as long as it isnt like 20+ counts.

kkarim

iTrader: (2)

It's not in my head. My car has slightly more power than my friend's STi, when we drag together, i pull off until i change gears and start knocking for a few seconds. He starts catching back until the CEL (Knocklite, thanks Tephra! ) turns off, then i start pulling away again, until the next gear change. when i don't change gears very fast, the car doesn't knock, and keeps a constant pull...

EvoVIII808

iTrader: (4)

are you Venting you BOV? that could cause knock, and poor performance on your stock ecu when shifting, Which puts you in a very rich condition between shifts.
could be the cause..... just throwing that out there.

4WS Tuning

iTrader: (73)

Thats correctable, shoot me a pm and i'll give ya couple pointers.

Cheers!

RoadSpike

iTrader: (5)

I had that exact problem actually.

What I did was found out the load cells where the knock was starting to happen like 4-6k and around 80-140 load. Then what i did was simply richen up that block of area to reflect my fuel map on the higher load. This prevented a lean spot when the pressure was releasing and stopped the knock.

kkarim

iTrader: (2)

Thanks for the help. 4ws sent me a solution that i will try tomorrow.

Billy@EnglishRacing

iTrader: (18)

can be cause by the clutch or just the shift itself

sharkm87

iTrader: (29)

well whats the solution

nikkadanny

iTrader: (31)

does it bogg right after you shift?

Evo_Jay

iTrader: (17)

I had the same thing. SHift knock. It turned out to be my DP.

Also, when setting the settings for the knock light, use a short time for the light, so you can see if the knock goes away or if it sustains.

Asmodeus6

iTrader: (7)

Yeah I'd be curious to the solution... I used to have knock up top that would cause me to shift early, and sometimes carry it into the next gear. But that was solved by pulling about 3* of timing on top in the higher rpm load cells I was in. And then simply turning the boost up another lb.

Check your timing carefully. The one thing I did notice is load spikes in logs when I would switch gears quickly and slam the pedal back down.

Which equated to momentary spurts of 315-330 load.

Unrelated but possibly related, alot of the shift change knock I experienced stopped when I got the ES bushings that kept s*** from slamming around when I'd lift and stomp on it.

But my bov is vta, and currently I have no shift change knock, or carry thru knock either.

Like always, go and do some logs and it will likley shed some light on WHY its happening.

sharkm87

iTrader: (29)

my dp hits my cross member bars like a mother too.....started when i went back to a stock mani from the meagan headers......but i think they sell cross bars with a lower clearance which is what i will look into purchasing.

Colt4g63

iTrader: (8)

Shoot me a PM as well if ya could. Im having this issue and it needs to go away!

Colt4g63

iTrader: (8)

BUMP someone has to have experienced this and has a solution...