Front End topping out or Tire Bouncing traction lost

Lady L

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Hello,
Long time lurker on this forum and was a big help during my build of this car. I was building this for about 2 years now and finally got to test at the strip. Most of the things that I have done are from the ideas I got from reading here.
Engine wise, I am already good for how it is and doesn't see myself wanting for more. Other than a driver mod and the suspension, I am already quite satisfied on the performance of this build. In the driver side, I am still working on it. But what I really need help the most is the suspension tuning. I just can't get a perfect launch. The rear tire hooks on the initial hit but then unloads and looses traction. I can make it better by lowering my launch rpm. So my question to all the experts and experienced drag racers here, is my front end topping out and yanking my rear wheel or is it my tire bouncing and loosing traction when it unloads???


Full Vehicle Weight running pump gas 93 OCT
Front Strut = Strange Single Adjustable ( Full stiff @ 10 clicks)
Rear Shocks = Vikings Crusader Double Adjustable (18C/14R)

If I posted this in the wrong section, please feel free to get it transfer. Sorry.
 

stkjock

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do you still have a front sway bar?
 

Lady L

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Loosen the front dampers 5 clicks and let some air out of the rear tires.

wouldn't it make the front rise quicker and unload the rear? The front tire separation is already maxed about the same time the rear loses traction. The front end only extends about 3" from sitting when I measured it when the car is on jack stand.

Definitely loosen the front. Post the time slip. What was your 60ft? What size rear tire?

The ET and 60ft is on the video. 10.86 @ 1.56 60ft. Tire diameter is 27" with 18psi. Increasing the psi to 19 made it worst. Traction was better when I lowered the launch rpm to 3K from 3.5K. You can see the differences at the later part of the video.

do you still have a front sway bar?

Yes, sway bar is still on. How does removing the sway bar help aside from losing some weight. I have read a lot about this sway bar removal/disconnect but can't be able to find the rationale behind it. Every thing is voodoo to me :angry1:
 
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stkjock

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if you loosen the front shocks and either remove the sway bar or disconnect the links when you go to the track, it will allow the front end to lift more, there by transferring weight rearwards and keeping it there enabling better traction.
 

Lady L

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if you loosen the front shocks and either remove the sway bar or disconnect the links when you go to the track, it will allow the front end to lift more, there by transferring weight rearwards and keeping it there enabling better traction.

"Allowing the front end to lift more" makes more sense to me now. It would not top out early due to have more extension distance. I will try disconnecting the sway bar links on my next visit to the track. I got 2 more weeks to go before the track closes for the season. Hopefully I can still be able to make it. If not, I will keep this thread open until I get the chance to test it and will report back with the results. Thanks everybody for the advise.
 

Rich Grundza

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Turn the knobs on the strange struts full counterclockwise then go two clicks clockwise
What year is your vehicle to pop the sway bar you’ll need to remove the plastic that attaches to the bumper and on the 13 and 14 the brace from k member then disconnect the upper link leave the link connected to the swaybarand unbolt from the rad support and then fold the links down to the bar it’ll come right out
I’ve done it a bunch of times
 

Lady L

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Turn the knobs on the strange struts full counterclockwise then go two clicks clockwise
What year is your vehicle to pop the sway bar you’ll need to remove the plastic that attaches to the bumper and on the 13 and 14 the brace from k member then disconnect the upper link leave the link connected to the swaybarand unbolt from the rad support and then fold the links down to the bar it’ll come right out
I’ve done it a bunch of times


2013 Boss 302. Do I need to remove the sway bar or disconnecting one of the links would be enough? Any preferred side?
 
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I am running the same shock setup, I'd agree with everyone else that your front shocks are way too tight. I've removed the front swaybar and I have the front shocks on position 2.

How old are your rear tires? I put on some fresh stiff wall slicks this year and it was night and day launching the car.
 

86GT351

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This is something that nobody here can advise you. You need to experiment. Every car is different, and every track condition can change how the car reacts.
 

Lady L

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This is something that nobody here can advise you. You need to experiment. Every car is different, and every track condition can change how the car reacts.

Most of the runs I did have videos taken. I was more on to getting to understand by looking at the video on the reason why the rear tires react that way after the initial hit. The more I understand, the better educated guess I can make.

15 psi in rear tires, 18 is too much imo.

That is part of the plan to also play with different tire pressure.
 
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86GT351

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Most of the runs I did have videos taken. I was more on to getting to understand by looking at the video on the reason why the rear tires react that way after the initial hit. The more I understand, the better educated guess I can make.
I get that. There is nobody that can tell you exactly what to do. All we can do is make suggestions based on previous experience with our own cars. every car is different. Take some of the suggestions and experiment.
 

Lady L

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I am running the same shock setup, I'd agree with everyone else that your front shocks are way too tight. I've removed the front swaybar and I have the front shocks on position 2.

How old are your rear tires? I put on some fresh stiff wall slicks this year and it was night and day launching the car.

The tires are Hoosier QTP 27" brand new. Before that was a MT ET Street Bias. The QTP seems to hook better but have a softer wall from what I experienced. It wads more than the MT's using the same launch rpm.

It was your post that I followed trying to get this dialed in. But the thread didn't have a conclusion on what you ended up setting your shocks/struts that finally got it to work.

I get that. There is nobody that can tell you exactly what to do. All we can do is make suggestions based on previous experience with our own cars. every car is different. Take some of the suggestions and experiment.

I surely will.
 
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stkjock

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I'd also suggest only making one change at a time, adjust the shocks, make a few passes, then work on the pressures, or vice/versa
 

Lady L

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I'd also suggest only making one change at a time, adjust the shocks, make a few passes, then work on the pressures, or vice/versa

I surely will do it methodically, one variable at a time. When I get this one dialed in, hopefully before the track closes for the season, I will report back whatever the result is. This way it may also help some other people like me who sought help in this forum.

You guys are all great ... Thank you very much.
 

86GT351

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I'd also suggest only making one change at a time, adjust the shocks, make a few passes, then work on the pressures, or vice/versa
Very good point. Too many things at once and you don't know if the individual changes were beneficial or ot.
 

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