Wheelspin knock

[turboaddict2]

Everytime when I get on it the car just screams like a raped ape and I see the lights on the knock gauge go up to yellow then stop. I even got 16.6* on the scanmaster! S@#t, can wheelspin knock be eliminated or its just normal that the car knocks when the tires spin.

 

[Turbojorge]

You prolly have your downpipe or something else hitting somewhere. Do you have new motor mounts? Do you have a tie down strap?

The same thing happens in my car even with everything that I listed. The main reason why my burnouts at the track are so crappy is because I start seeing 24.6, 29.8, 32.6* of knock on the SM and I just take a sh!t and lift. I KNOW it's false KR, but it still scares me a bit.

I can't figure it out either.

 

[87SFI]

I get the same thing and my downpipe does not even come close to hitting. I think it's from the vibration from the wheels spinning. it's false knock.

 

[stickybones]

I get it too. 20 or 30 degrees of retard with tire spin and I don't believe anything under the hood is hitting.

 

[NASSTY]

Are you guys getting any wheelhop while you're spinning.Wheel hop can cause false knock.With stock trailing arms that are 16 yrs old wheel hop can be a problem.

 

[OKTurbo]

I used to get bad wheelspin knock too....

Translator Plus / 3.5" LS1 MAF / Extender chip

No more knock....Lovin' it.

I can't point to what fixed it. Whether it's the new MAF or the awesome Extender chip. I almost think the old stock MAF sensor couldn't keep up with the air flow when the wheels started spinning.

John

 

[Vader 87]

its probably real knock.....your motor is over revving. I used to have the same problem and posted about it 3 times.....my problem was solved now that i have a new tranny that shifts likes its supposed to at 5300 rpm. Previous stock tranny delayed causing over revved motor.....now i can boil the tires and the scanmaster shows 0.0, JMO!

 

[turboaddict2]

I think my dp is touching the frame. I do have a tie down strap but still need to replace those motor mounts with Poly mounts.

 

[Turbojorge]

You should be able to feel if it's wheel hop. The best thing to do (or what I did) is just have one person standing on each side looking to see if your getting wheel hop while the tires are spinning.

 

[Vader 87]

Originally posted by turboaddict2
I think my dp is touching the frame. I do have a tie down strap but still need to replace those motor mounts with Poly mounts.

My downpipe used to sit touching right on my frame when i first installed it and would bounce and bang around during normal driving and it was very loud....i ran it about 5 times at WOT and didnt get any knock from it.

 

[turboaddict2]

I can feel the 3" dual exhausts bang around when I do normal driving. Probably hitting the underside parts of the car. And it probably hits the rear axle too. Really annoying as well Anyone else who has 3" duals have this problem?

 

[Turbojorge]

I have 2 1/2 ATR duals and I have that problem.

 

[GN HEAD]

I have the wheelspin knock too, finally ran at the track with slicks, just to see what would happen........guess what.....no knock. The same day, with the street tires, exact same settings and the sensor went crazy with knock. I would like to know what is going on....I have the boxed lower control arms and plan to do the poly bushings on the control arms this spring, nothing is rubing on the exhaust and I have a tie down and one new motor mount....any other ideas??

 

[Vader 87]

Originally posted by GN HEAD
I have the wheelspin knock too, finally ran at the track with slicks, just to see what would happen........guess what.....no knock. The same day, with the street tires, exact same settings and the sensor went crazy with knock. I would like to know what is going on....I have the boxed lower control arms and plan to do the poly bushings on the control arms this spring, nothing is rubing on the exhaust and I have a tie down and one new motor mount....any other ideas??

As stated earlier....

its probably real knock.....your motor is over revving. I used to have the same problem and posted about it 3 times.....my problem was solved now that i have a new tranny that shifts likes its supposed to at 5300 rpm. Previous stock tranny delayed causing over revved motor.....now i can boil the tires and the scanmaster shows 0.0, JMO!

 

[87GN&98VET]

I've got the same problem. It's not due to overrevving the transmission though because a) rev limiter, and b) it is instant as soon as I jump on it, not at redline rpm.

Sean

 

[GN HEAD]

Vader 87..... My motor is not over-reving my tranny has been built PMAC about 3k miles ago, it shifts quick and crisp, as it should, my knock shows up when the tires break loose, around 2500 rpm, not at the top end of a gear and the slicks solving the problem leads me to believe that it IS false knock from possible wheel hop/worn bushings in the control arms.
87GN&98VET.....exactly.......... Have you replaced your control arm bushings for the rear end, or do you have the stock ones too. I am going to try poly ones this spring, hopefully.

 

[BEATAV8]

I have this problem too. False knock when the radials spin on the street, no false knock with the slicks at the track. It still shows up even when the tires spin without wheel hop usually 6-10 degrees, although it much more severe when the wheels do hop, up to 20 or 25. Poly DS motor mount did not help, exhaust does not hit anywhere, and it only happens when I hear 'em screamin' for mercy, hop or no hop.

Only good thing about it is it sorta acts like traction control. Several times when I eased into it in second gear I've noticed it pull enough timing out such that the tires will clear up, then the timing attack comes back in and she'll start to haze the tires some more. I may have some DS files showing it happening.

Does anybody think it may have something to do with the trans mount?

 

[Vader 87]

Originally posted by 87GN&98VET
I've got the same problem. It's not due to overrevving the transmission though because a) rev limiter, and b) it is instant as soon as I jump on it, not at redline rpm.

Sean

LOL, rev limiter...yeah right Most chips raise the rev limiter to rpms that are way too high for our motors.

Anyways, i used to have the same problem and now its fixed...the only other solution ive heard is a maf translator.
I talked to Red Armstrong about the problem one day and he believes its not false knock. It only happens when the rpms rise very quickly like when you spin and not when you have on slicks since rpms are rising slower due to traction....give him a call, he can explain better.

 

[XLR8]

I think what vader 87 is saying - and correct me if I'm wrong - is that when your tires spin, your engine revs faster than the MAF tells the car to add fuel. You may actually be getting real knock caused by a momentary lean condition.

 

[Vader 87]

Originally posted by XLR8
I think what vader 87 is saying - and correct me if I'm wrong - is that when your tires spin, your engine revs faster than the MAF tells the car to add fuel. You may actually be getting real knock caused by a momentary lean condition.

Thats a possible cause also, in my case however, my tranny would not shift quick enough and the car would stay in first gear way to long.