Drag Setup

[FL Stinger]

Ok, guys. I need some advice on an issue I'm having at the drag strip. I am trying to achieve a decent pass with this car on street radials, however, the setup seems to be all off. Have a look at my signature for current wheel/tire and suspension setup. I am running ALL Megan Racing control arms in the rear. I recently had the car aligned at a reputable shop (alignment specialist only). The car drives straight as an arrow on the street and corners impressively. All four tires are making solid contact with the ground.

Here's where the issue begins. I made several passes over the weekend at the strip and I am unable to run the car at full power. I had to turn off the methanol, try map 2, and map 1 as well. I have tried lining up in the groove, out of the groove, and adjusting pressures for testing purposes to see what works. The car gets VERY squirrely about 1/3 way down the strip. So bad in fact, that I have to completely get off the throttle and regain control of the car before flooring the throttle again. I had a buddy stand behind the car and watch the launch. From his perspective, he said the rear tires are toeing out noticeably on the launch which could equate to the vehicle acting the way it is once it gets up to a certain speed.

I can cut 0.18 and lower reaction times with this vehicle using launch control. When I track the car it is also with zero rear seats, bench, and gutted trunk (for weight reduction purposes). I am open to any suggestions you guys have.

 

[MerlintheMad]

Put everything back in, and put the mother-in-law in the back, or even the hatch if you can manage. Your lightened Stinger is trying to take off to Hawaii.

 

[cncBilly]

Put everything back in, and put the mother-in-law in the back, or even the hatch if you can manage. Your lightened Stinger is trying to take off to Hawaii.

I have to say Merlin that is one stupid assed reply. A real head shaker. But hey 1 in 16+,000 is not bad.

 

[GT Elite]

Ok, guys. I need some advice on an issue I'm having at the drag strip. I am trying to achieve a decent pass with this car on street radials, however, the setup seems to be all off. Have a look at my signature for current wheel/tire and suspension setup. I am running ALL Megan Racing control arms in the rear. I recently had the car aligned at a reputable shop (alignment specialist only). The car drives straight as an arrow on the street and corners impressively. All four tires are making solid contact with the ground.

Here's where the issue begins. I made several passes over the weekend at the strip and I am unable to run the car at full power. I had to turn off the methanol, try map 2, and map 1 as well. I have tried lining up in the groove, out of the groove, and adjusting pressures for testing purposes to see what works. The car gets VERY squirrely about 1/3 way down the strip. So bad in fact, that I have to completely get off the throttle and regain control of the car before flooring the throttle again. I had a buddy stand behind the car and watch the launch. From his perspective, he said the rear tires are toeing out noticeably on the launch which could equate to the vehicle acting the way it is once it gets up to a certain speed.

I can cut 0.18 and lower reaction times with this vehicle using launch control. When I track the car it is also with zero rear seats, bench, and gutted trunk (for weight reduction purposes). I am open to any suggestions you guys have.

What kind of bushing do the suspension arms have? If they are rubber they may be squishing under load allowing the suspension to deflect resulting in toe out. It may be time for poly bushings!

 

[FL Stinger]

What kind of bushing do the suspension arms have? If they are rubber they may be squishing under load allowing the suspension to deflect resulting in toe out. It may be time for poly bushings!

Thanks for the laugh, Merlin. As for the control arms, they are already poly bushings.

 

[NS_Stinger]

What do you mean by squirrely? Like traction loss?

 

[FL Stinger]

What do you mean by squirrely? Like traction loss?

The car starts swaying from side to side and gets worse as the speed of the car increases. I fight the steering wheel to keep the car going as straight as possible down the track until it gets so bad that I have to let off the throttle. The car starts heading for the wall or crossing the center line heading for the other lane. It’s almost as if it’s losing traction, but it launches ridiculously hard from the start without so much as a chirp from the tires. This set of tires is practically brand new too.

 

[oddball]

You'll need to talk to the few guys that do serious drag runs, but my guess is that tire on a 20" rim is not helping at all.
How close is the rolling diameter of those tires? I'm curious if the AWD system starts getting confused mid-track.
I do notice on mine that the front end can lift at higher speeds - not just at launch. But mine is RWD. A splitter might help?

 

[BadTrainDriver]

The car starts swaying from side to side and gets worse as the speed of the car increases. I fight the steering wheel to keep the car going as straight as possible down the track until it gets so bad that I have to let off the throttle. The car starts heading for the wall or crossing the center line heading for the other lane. It’s almost as if it’s losing traction, but it launches ridiculously hard from the start without so much as a chirp from the tires. This set of tires is practically brand new too.

Let's keep this simple and stick to facts:

There are 10 second Kia Stingers and low 11 second Genesis G70's that don't have this issue. Nor, at least to the knowledge provided by them, do they have the suspension "upgrades" you have. You've not stated what you're running in the 1/8 or 1/4 mile, but unless you're 1000+HP and TQ running 8 seconds or less 1/4 mile, your suspension is not "toeing out" mid track...you simply don't have the power to cause that issue.

Now, what you do most likely have is a bad aftermarket part causing higher speed stability issues. Can you post a picture of your alignment? Are you sure all installed parts are tight(no movement at all under load)? Start with everything you've replaced, because that(somewhere) is what's causing your problem.

 

[Ozstung]

Squirrely was a common description mentioned early on in the Stingers incarnation. Eibach sways helped that backend twitch under accelleration including going in a straightline.

 

[FL Stinger]

I was able to tear into the car the last few days and found the issue. A connection with the methanol had come loose and was spraying inside the engine bay just enough to find its way on the track and make contact with the rear passenger tire. This caused a loss of traction and the swaying I was experiencing. The methanol was traced from the passenger side of the engine bay, under the car, back directly in line with the rear tire. I have made sure that won't happen again. I noticed the track personnel was wiping something up after one of my runs and didn't think anything of it. Now I know. Thank you for all the suggestions here. @oddball the car already has a front splitter

 

[BadTrainDriver]

Boom! I called it!