[Jacobs__Garage]

Recently got a drag pack, I have noticed my launch control isn't properly working. Car has an Lt4 blower, is an A8 with trans and ecu tune. Have tried different things but the launch control still isn't working properly.

With launch control engaged, the rear tires immediately begin spinning for about half a second and the car lurches forward a few inches, stops spinning, starts spinning again, stops, and so on. Once I let off the brakes, the car seems to properly launch.

I am wondering if anyone might know what is causing this to happen. Could this be a tune issue? Torque Converter?

[6spdhyperblue]

To get the car to launch harder with a tune, typically you’ll have to give up launch control

[cjperformance]

Did you change either the front or rear dia diameter compared to stock? If all you changed between working/not-working was tires, I suspect tire dia may be a factor.

Sounds weird, but tire dia change can play all sorts of hell on ABS and TC.

[JSH]

Originally Posted by Jacobs__Garage

Recently got a drag pack, I have noticed my launch control isn't properly working. Car has an Lt4 blower, is an A8 with trans and ecu tune. Have tried different things but the launch control still isn't working properly.

With launch control engaged, the rear tires immediately begin spinning for about half a second and the car lurches forward a few inches, stops spinning, starts spinning again, stops, and so on. Once I let off the brakes, the car seems to properly launch.

I am wondering if anyone might know what is causing this to happen. Could this be a tune issue? Torque Converter?

I've been a member here for three years, and the consensus is that launch control isn't worth wasting time on. It has too many issues.

[Jacobs__Garage]

Originally Posted by JSH

I've been a member here for three years, and the consensus is that launch control isn't worth wasting time on. It has too many issues.

I would probably agree and just won't bother with it anymore. I just need to lower my psi when doing digs on unprepped surfaces. Have had trouble hooking through first and second on the ET Street Rs which is why I thought launch control might be a better option.

[joekd]

A decent driver and do the job better then the OEM launch control

I had my car at a drag day, was a lot of card breaking down so I was just doing hot lap runs. Would do one with LC, comp mode, let car shift (a*), next with same but without LC, then do same in sport mode, etc

By about run #4 or 5 I was getting better times then LC could do

[laynlo15]

Originally Posted by Jacobs__Garage

I would probably agree and just won't bother with it anymore. I just need to lower my psi when doing digs on unprepped surfaces. Have had trouble hooking through first and second on the ET Street Rs which is why I thought launch control might be a better option.

If your trying to use that at the track it just won't launch as fast as just flat footing it. I've tried everything between 3 cars and you'll always run slower. I tried launch control on the street and wasn't impressed with either of the cars.

[lt4camaro]

Its been known and proven over and over, a super good driver will always do better 0-60 or 1/4 mile passes with the nannies off.

[BigDawgMuscleX]

Originally Posted by Jacobs__Garage

Recently got a drag pack, I have noticed my launch control isn't properly working. Car has an Lt4 blower, is an A8 with trans and ecu tune. Have tried different things but the launch control still isn't working properly.

With launch control engaged, the rear tires immediately begin spinning for about half a second and the car lurches forward a few inches, stops spinning, starts spinning again, stops, and so on. Once I let off the brakes, the car seems to properly launch.

I am wondering if anyone might know what is causing this to happen. Could this be a tune issue? Torque Converter?

Despite what the data has shown for LC vs idle launches, my car has consistently ran respectable times in the 1/4 with a 1.5x 60ft on the street with just a puddle burnout or two and using launch control. The trick for me is I've always used sport mode/competitive mode. It doesn't give you the LC settings like track mode but has never bogged the car or messed it up like track mode has.

Now.. been going through revision tunes on the same set of mods but have also added the front skinnies 28x6 tire.. and doing my first test passes with it it's now doing the same exact thing you've mentioned.. sits for a split second with the rpms and just jerks forward and tries to reset but keeps jerking and isn't working. Someone mentioned the ABS could be getting out of whack readings or whatever for the increased tire height.. I believe stock is 26.8" and the skinnies are 28".. rears have always been 28" (325/50-15) but all of a sudden its doing that jerking..

The reason I've used launch control is because in that sport mode setting it has hooked the car with ease and does NOT feel like it's pulling any power. Tour mode and all nannies off CANNOT hook the car up. I obviously want to run my fastest times but with all the testing I've done, the launch control has been the safe bet for me.

Best thing for me and you to do is probably put the stock fronts back on and test it again OR of course learn to launch it off idle.

[lt4camaro]

Originally Posted by BigDawgMuscleX

Despite what the data has shown for LC vs idle launches, my car has consistently ran 9s in the 1/4 with a 1.5x 60ft on the street with just a puddle burnout or two and using launch control. The trick for me is I've always used sport mode/competitive mode. It doesn't give you the LC settings like track mode but has never bogged the car or messed it up like track mode has.

Now.. been going through revision tunes on the same set of mods but have also added the front skinnies 28x6 tire.. and doing my first test passes with it it's now doing the same exact thing you've mentioned.. sits for a split second with the rpms and just jerks forward and tries to reset but keeps jerking and isn't working. Someone mentioned the ABS could be getting out of whack readings or whatever for the increased tire height.. I believe stock is 26.8" and the skinnies are 28".. rears have always been 28" (325/50-15) but all of a sudden its doing that jerking..

The reason I've used launch control is because in that sport mode setting it has hooked the car with ease and does NOT feel like it's pulling any power. Tour mode and all nannies off CANNOT hook the car up. I obviously want to run my fastest times but with all the testing I've done, the launch control has been the safe bet for me.

Best thing for me and you to do is probably put the stock fronts back on and test it again OR of course learn to launch it off idle.

Stock should be 27.7

[6spdhyperblue]

ZL1 is 26.8 for the front and 27.2 in the rear

[lt4camaro]

Originally Posted by 6spdhyperblue

ZL1 is 26.8 for the front and 27.2 in the rear

Didnt know that, most configurations are 27.7 front and rear.