Ladder bar Vega going hard left during wheelie

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Ladder bar Vega going hard left during wheelie

Post by VegaJohn » Tue Sep 11, 2018 1:18 pm

I’m having issues with my Vega going left during initial launch. I have been bandaiding the issue with wheelie bar stagger and wheelie bar spring preload but this weekend it got worse and I had to pedal it when it was up pretty good and I smacked both oil pans on the track. I scaled the car and this is the car with me in it.
Lf733 rf666 lr656 rr565.
Pic is car without me
Looking at the numbers it should be going right not left I would think. Is it possible I’m hitting the left tire so hard that it squishes so far that it’s diameter causes the quick left condition? I’m going to pull the ladder bars and look for bent front heims and reinstall them with zero preload and start from scratch. Best 60ft has been 1.31 car runs 6.12@111
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VegaJohn
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Re: Ladder bar Vega going hard left during wheelie

Post by VegaJohn » Tue Sep 11, 2018 1:30 pm

I also measured my slicks. Left one is bigger by 7/16” car never did this with less HP. Tire psi I was running was 8.5psi wish I would have tried 9.5-10

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Re: Ladder bar Vega going hard left during wheelie

Post by 6.50camaro » Tue Sep 11, 2018 4:45 pm

The car will drift to the side with less traction ,that tires is not pushing forward as hard. Add preload to the left side or take preload away from the right. Dan

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Re: Ladder bar Vega going hard left during wheelie

Post by SupStk » Tue Sep 11, 2018 6:36 pm

Is the dimension difference on your slicks in circumference?

There is lots of things which could be causing the issue.
First since its gotten worse and ruling out slicks that are going away and track conditions, I wonder if the frame hasn't diamonded? Before measuring for that I'd check all suspension pivot points for bent, binding parts and the rear axle is straight under the car.
Concerning preload, try using a piece of angle iron with the V pointed up on a floor jack under the middle of a front cross member. With the drivers weight in the seat, the front wheels should be close to the same distance off the floor. If it isn't close its a good place to start and you can adjust from there.
Keep us posted on your results, might be able to help you figure it out.
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Re: Ladder bar Vega going hard left during wheelie

Post by VegaJohn » Tue Sep 11, 2018 9:47 pm

The left slick circumference was 7/16 bigger than the right side. So far I found that both front ladder bar heims were quite loose. The left rear lower coil over mount is bent and Is lower than the passenger side is. Also I had my coil overs preload almost all off. I’m wondering if I was bottoming out the passenger coil over with the twist of engine torque on launch and it was driving the passenger tire down hard.

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Re: Ladder bar Vega going hard left during wheelie

Post by Monza Harry » Fri Sep 14, 2018 10:01 pm

Vega John, don't rule out anything! Check everything from the welds holding the tubes in the "Pumpkin" to the suggestions above. "You added power and now it steers" if I understand your remarks, that means something is no longer up to the task at hand and you need something more robust. I would look HARD at the chassis, something is moving/flexing that didn't before, just some of my collected/learned experience. Please share your chassis specifics, maybe some more to learn/share for us and you. Harry

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Re: Ladder bar Vega going hard left during wheelie

Post by Ladderbar » Sun Sep 16, 2018 9:09 am

did you swap the rear tires? after you check everything and if it still dose it swap the rear shocks. but make sure every thing is good first.

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Re: Ladder bar Vega going hard left during wheelie

Post by VegaJohn » Sun Sep 16, 2018 9:43 pm

Ladderbar wrote:
Sun Sep 16, 2018 9:09 am
did you swap the rear tires? after you check everything and if it still dose it swap the rear shocks. but make sure every thing is good first.
I didn’t swap the tires yet, so if adjusting everything else doesn’t fix the problem I will try that. I suppose the odd time a slick might just not hook up like it’s mate? They are 1 season old. My last pair were date coded 2004 and came with the car and still hooked up good but it was only running 6.4s then. 6.1s now.

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Re: Ladder bar Vega going hard left during wheelie

Post by af2 » Thu Sep 20, 2018 3:41 pm

7/16" is a bunch. Fix what you see is wrong. Don't preload as it will affect everything else down track. You can lift the front end while on scales and see the weight. On mine the 60" bars are 2" off the ground. When I raised them shyt hit the fan with the 2' wheelie and what happened after damn near wrecked the car using both lanes.
When buying tires they should have been measured as a pair.
Also are you running a spool? The right tire is making it go left.
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Re: Ladder bar Vega going hard left during wheelie

Post by wheelsup330 » Sat Sep 29, 2018 6:37 am

Before Changing too many things, 1st pull your shocks and pull the springs off, and then put on shcoks only and check the action of your rear axle when you jack it all the way to the stops!!
Then reinstall the springs (keeping left/right same) and try to simulate your condition on the scales. put sand bags in the seat and then jack up your front end with placement of "cribbing" if you have to - to simulate a wheelie (gravity is the same equivalent of an air gap created by a jack!) But run up the front till you see your wheelie bars touch and look at stuff. might identify a broken weld or something!! A lot of people never check their pre-load with driver weight in the seat!! both front Ladder bar pivots should be more or less floating - or else you have preload.

My Vega LOVED to wheelie out almost on the bumper past 300' on 25 YEAR OLD FIRESTONES.... that I have NEVER 'taped one time, so dont blame the tires until you've ruled out the chassis. Still ran low 9sec 1/4's with huge wheelies....

I just went thru a similar case with a new to me 4-link altered and I found that the 4-link had over a full turn of negative pre-load. Tire Taped out 1/2" the wrong way. Large Tire on the Right and Car still going Hard Right.... Turns out the guy had pulled the shocks and used a set of 4130 tube solid struts which made everything scale different. I got learnt.

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Re: Ladder bar Vega going hard left during wheelie

Post by VegaJohn » Sun Apr 14, 2019 10:47 am

This is what I have come up with and maybe you guys can chime in. When I bought the car years ago I lowered the rear coil over spring pressure. Not sure why I did it but I did. This is the 3rd and most powerful by a fair margin engine I’ve had in it. The coil overs aren’t very long and they run a thick bump stop. At ride height there is only about 1.5-2” of ride left in the shock. When my car was wheelieing really high it also due to engine torque was twisting to passenger side. I’m sure the right rear coil over was bottoming right out and loading the right slick way harder than the left. This is the only thing I can think of. I have. New longer coil overs that are single adjustable this time and better mount brackets for the bottoms off the diff. My mounts were really chicken shat and were flexing. Coupled with some double adjustable front shocks and some front travel limiters I think I can make this thing pull some monster 60fts this season.

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Re: Ladder bar Vega going hard left during wheelie

Post by John Wallace » Sun Apr 14, 2019 2:46 pm

I’m sure the right rear coil over was bottoming right out and loading the right slick way harder than the left.
If right rear is bottoming the shock/spring, the right rear tire has less traction.

I'd check 1st thing to see if rear end is perpendicular to the front to back centerline.

:?:
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Re: Ladder bar Vega going hard left during wheelie

Post by VegaJohn » Sun Apr 14, 2019 4:22 pm

John Wallace wrote:
Sun Apr 14, 2019 2:46 pm
I’m sure the right rear coil over was bottoming right out and loading the right slick way harder than the left.
If right rear is bottoming the shock/spring, the right rear tire has less traction.

I'd check 1st thing to see if rear end is perpendicular to the front to back centerline.

:?:
When I say bottoming I mean the car has pushed on it so far that there is no more travel. All the weight of my car is on the back wheels at that point and due to twist more toward the pass side. If the shock can’t compress anymore and becomes solid does that not load the tire harder than if there was give there?

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Re: Ladder bar Vega going hard left during wheelie

Post by John Wallace » Sun Apr 14, 2019 5:09 pm

No?

:?:

The shock should be TOPPING out if anything if the right rear tire is planting.
If the tire is going into the body wheel well on launch it's losing traction.

But you actually need to adjust the 4 link so it doesn't top out or bottom out.

:)

Try reading some of this:

Shope Calculators

:)
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Re: Ladder bar Vega going hard left during wheelie

Post by VegaJohn » Sun Apr 14, 2019 5:51 pm

John Wallace wrote:
Sun Apr 14, 2019 5:09 pm
No?

:?:

The shock should be TOPPING out if anything if the right rear tire is planting.
If the tire is going into the body wheel well on launch it's losing traction.

But you actually need to adjust the 4 link so it doesn't top out or bottom out.

:)

Try reading some of this:

Shope Calculators

:)
I’m not sure I follow how the spring will not be compressed when the front wheels are 2feet in the air and all the weight is on the back 2 tires?? I know due to leverage on launch the tires plant and you should get seperation but if I have my coil overs too soft can’t exactly what I have suggested be an issue? Car is ladder bar not 4 link

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