Wheel Spin Knock..again

If you're using a LS1/LT1 MAF do you get wheel spin knock?


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KEVINS

Post count: 24,375
Joined
May 24, 2001
I want to do a poll which is why I started a new thread on this old topic.
Like a lot of people I get wheel spin knock. I usually start at 55mph in second gear then either mash the throttle or roll into it but either way this sets the tires ablaze. If I mash the throttle fast and set the tires ablaze I get wheel spin knock but if I roll into it slower to get the tires spinning I don’t get any. This happens at any speed while in 2nd gear so the common factor is how quickly I mash the throttle.
A common thought is that the ECM can’t keep up but could it be the MAF? My MAF goes to 255, but can wheel spin knock be caused by the MAF not being able to keep up?
Anyone with an LS1/LT1 MAF and translator get wheel spin knock?

ks
 
Knock is based on the frequency the knock sensor sees. MAF has nothing to do with it. Mashing the throttle vs. rolling into it is probably changing the loading on drivetrain changing the frequency transmitted to the sensor.
 
Knock is based on the frequency the knock sensor sees. MAF has nothing to do with it. Mashing the throttle vs. rolling into it is probably changing the loading on drivetrain changing the frequency transmitted to the sensor.

I think the thought that it is false knock is still anyones guess since soooo many people have tried a lot of ideas trying to resolve the issue, ie motor mounts, trans mounts, suspension bushings, etc and still not able to cure it. I'm not convinced that it's somehow not real knock. I always figured it was false knock but what if it truly is real knock caused by something else? I know real knock from detonation has a steady rise on my Direct Scan but this should look different if I get knock as the car starts to lean out and never recovers due to lack of fueling. With WS knock there is enough fuel available so the reading may look different as it's trying to recover. When I hear the knock detector going off I will stay into it for about 2 seconds HOPING that the knock detector stops but it never does so I let up in case it is/becomes real knock.

I still run stock MAF that still goes to 255 and the stock ECM..

So my question still stands: If you have an LS1/LT1 MAF do you still get WS kock?

I tend to lean towards the ECM not being able to keep up, not that there is a frequency in the driveline that's causing it or that the readings from the MAF to the ECM to the TPS to the injectors to the ?? isn't responding quick enough..

ks
 
I wouldn't think it's the computer that can't keep up but the way the chip is written. In the program there are attack rates and recovery rates programmed into it for knock. If the attack rates are too slow or recovery too fast it could cause an issue. If you mean the "chip program" as the "computer" then you may be correct in your thinking.
 
I run an LS1 MAF and a translator I had the exact same problem and chased it for a while it drove me freaking nuts.....I was convinced it was false but still I hated to see kr on the scan master not to mention it pulled timing and decreased power which sucked!

My fix was very simple......bigger better tires! I switched to a 275/50/15 drag radial....I just changed to a 275/60/15 because I like the look of a taller tire and more meat! The tires do still spin if I go from a dig with zero stall but since the tires are a much better compound it is more of a controlled spin if that makes sense.....they are spinning but the car is really moving well instead of spinning wildly and causing the problem.
 
I run an LS1 MAF and a translator I had the exact same problem and chased it for a while it drove me freaking nuts.....

Well, that sucks.. I guess I won't plan on buying an LS1 MAF, then.. I was hoping that this may help it..

ks
 
guys please dont mind my ignorance but is wheel spin knock common? and from what i am understanding the knock sensor is picking up a vibration or sound the tires make while spinning/bouncing on the street and sending a false signal to the sensor?

im totally new to this so im trying to learn, i did see in back searches how downpipes hitting the inner fender can make fake knocks sending the knock sensor off.. just wondering if someone can explain, or if im correct, thanks
 
Do you have anybody local you can borrow a translator and new style MAF from? I recall back when they first came out people were going nuts about the pleasant side effect of getting rid of wheelspin knock.

(much in the same way Casper's cam sensor failsafe turned into a quickstart device)
 
Wheel spin knock happens when the tires start to spin the knock sensor goes off and starts to pull timing to get rid of the knock it "hears".
There is a lot of opinions on whether this is a frequency that the sensor hears either from real detonation or driveline vibration or possibly the computer not being able to keep up with the calculations and goes into "stupid mode" or ??

Nobody has ever been able to identify what causes it but everyone can repeat it with their own cars. Mine only happens when I quickly mash the throttle. If I lay into slower then it doesn't do it.

MANY people have replaced motor mounts, tranny mounts, suspension parts, moved downpipes, etc, etc and never been able to get rid of it. For this reason I thinks it's more due to the computer/sensors not comunicating fast enough and going into "stupid mode" compared to a vibration..

ks
 
Do you have anybody local you can borrow a translator and new style MAF from? I recall back when they first came out people were going nuts about the pleasant side effect of getting rid of wheelspin knock.

(much in the same way Casper's cam sensor failsafe turned into a quickstart device)

Noone around here..
Maybe I'll dig deeper into the archives and see what was said or get ahold of Bob B. and see what his take is on it but given Amelios comment above I doubt it will fix it..

ks
 
Wheel spin knock happens when the tires start to spin the knock sensor goes off and starts to pull timing to get rid of the knock it "hears".
There is a lot of opinions on whether this is a frequency that the sensor hears either from real detonation or driveline vibration or possibly the computer not being able to keep up with the calculations and goes into "stupid mode" or ??

Nobody has ever been able to identify what causes it but everyone can repeat it with their own cars. Mine only happens when I quickly mash the throttle. If I lay into slower then it doesn't do it.

MANY people have replaced motor mounts, tranny mounts, suspension parts, moved downpipes, etc, etc and never been able to get rid of it. For this reason I thinks it's more due to the computer/sensors not comunicating fast enough and going into "stupid mode" compared to a vibration..

ks

thanks buddy, i appreciate it
 
I believe the chips programmed for the LS1 MAF by TurboBob such as the extender and extremes etc. ignore the KR when the load isn't great most likely 1st and perhaps 2nd gears.

3rd gear probably isn't included, just off the line, so I would think you would hear the detector screaming but the timing may not be pulled in a more advanced chip and MAF setup in the lower gears.

I'd check with the chip experts first as to what will happen in what gear with an LS1 setup and false/real KR.
 
Wheel spin knock happens when the tires start to spin the knock sensor goes off and starts to pull timing to get rid of the knock it "hears".
There is a lot of opinions on whether this is a frequency that the sensor hears either from real detonation or driveline vibration or possibly the computer not being able to keep up with the calculations and goes into "stupid mode" or ??

Nobody has ever been able to identify what causes it but everyone can repeat it with their own cars. Mine only happens when I quickly mash the throttle. If I lay into slower then it doesn't do it.

MANY people have replaced motor mounts, tranny mounts, suspension parts, moved downpipes, etc, etc and never been able to get rid of it. For this reason I thinks it's more due to the computer/sensors not comunicating fast enough and going into "stupid mode" compared to a vibration..

ks

Hey kevins....

I did not think I could find it either for the longest.....I try to get my tune close on the street before I go to the track and beat on the car....this is when I found traction was the answer. I remeber a few years back I made some fuel system changes to the car and was having the problem we are speaking of....this was on a Friday and I was going to the track the next day. What I ended up doing was adding fuel and it seemed to fix it on the street.

When I got to the track and got my good tires on and some heat in them the car hooked but it was a turd!

Basically what I did was add so much fuel that the car was pig rich and would not turn the tires as violent...then when I got to the track and actually hooked the car was slow due to being pig rich. I leaned it back out where it was when I was getting bad kr on the street from violent wheel spin. Since I was at the track and hooking well I surprised to see the problem still not there. So this was telling me that real hard wheel spin was the problem....maybe it is like you say the ecm gets stupid.....I just figure it can not keep up and weird sh8t I can not explain happens.

Either way I found that traction fixed the problem.....now I am not talking complete traction because my car still will not hook on the street even with 275/60/15 Mickey T dr's but it is more of a controlled tire blowing off scenario if that makes sense....o_O its kinda like spinning the tires with a good set of drag radials versus spinning in the rain with crappy hard radials.....yes they are both spinning but with good tires the load is there and the computer can do what it needs versus spinning so hard and violent it can not calculae fast enough to keep up.

I dont know if this is really what happens but it has been what I have seen with my car and it has worked that problem doe not happen anymore.

hope that helps some of you others with the same issue.
 
oh I also wanted to add I tested this theory again yesterday kinda not really with this point in mind but the same results anyway.

As I mentioned I just installed a set of 275/60/15 Mickey T drag radials I also had to roll the inner fender lip in the rear in order to let some air out of the bags so the car would squat. (Thanks to Bob a member on this board for letting me rent the tool...thanks Bob!)

Anyway after an afternoon cruise yesterday I went down my lil test road area to see how much better my new tires were:cool:In the hopes that with the 2" taller tire and stickier compound it would hook better so I stalled to 6psi and let the brake go...instantly the tires went up in smoke.....I stayed in it thinking they would recover....I kept thinking this by this point the car was skating across the road pretty bad taking up both lanes just to keep it somewhat straight by this time I was well into 3rd and close to 70mph the wife was screaming and I was laughing but also getting a bit nervous cause it was about to be in bad shape. I got it calmed down and there was smoke billowing out of the car (T-tops were off) it was pretty freaking hilarious:D

Anyway my point to this story is the car was spinning hard and all of first second and 3rd and never once did it have any kr and that is due to my theroy that yes it was spinning but the engine was under load and working so it was not a violent wheel spin like being in the rain and getting "stupid" as we say.

hope that helps
 
The stock ECM is very fast. There really isn't any situation where it can't keep up with what the engine is doing. It reads airflow every .00625 seconds, or 6.25 milliseconds. For reference, one complete engine cycle (fire all 6 cylinders) at 8000rpm takes 15 milliseconds.

From my testing, wheelspin knock is almost always false, unless it's accompanied by overboosting and the tune doesn't compensate.

Eric
 
The stock ECM is very fast. There really isn't any situation where it can't keep up with what the engine is doing. It reads airflow every .00625 seconds, or 6.25 milliseconds. For reference, one complete engine cycle (fire all 6 cylinders) at 8000rpm takes 15 milliseconds.

From my testing, wheelspin knock is almost always false, unless it's accompanied by overboosting and the tune doesn't compensate.

Eric
well there you have it fellas....its not a matter of the ECM not being able to keep up.....that leaves the tune into question and if you are sure that is dead on then it has to be harmonics from hard wheel spin.......i guess lol:confused:
 
I agree that the computer is fast enough to do the computations but I'm still leaning towards that there is a certain combination of circumstances when the accelerator is floored quickly and boost builds from zero psi to Xpsi very quick that causes the computer to go into stupid mode.

TPS + ENGINE LOAD + MAF + BOOST + ??? = Stupid Mode

Based on all the historic data in past threads noone will convince me, at this time, it's a vibration that is causing it..


The stock ECM is very fast. There really isn't any situation where it can't keep up with what the engine is doing. It reads airflow every .00625 seconds, or 6.25 milliseconds. For reference, one complete engine cycle (fire all 6 cylinders) at 8000rpm takes 15 milliseconds.

From my testing, wheelspin knock is almost always false, unless it's accompanied by overboosting and the tune doesn't compensate.

Eric

Eric,
I'm guessing that you can program my chip with some knock ignore? If so, how would this look on Direct Scan and my audiable knock detector? Would I still be able to see it on DS but the computer wouldn't do anything about it or would it just not show up on DS?

I don't like ignoring it but even cranking up the alchy doesn't get rid of it so I'm getting more comfortable with having the chip to ignore it if possible.

ks
 
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