Advice about wheelie bars.

[v8 jago]

As my jeep is only short i cannot use nitrous of the line without my jeep going vertical in a split second, So i got some wheelie bars and had them so my jeep would lift about 2 foot high before the bars touched the floor, But when i used gas of the line my jeep seems to twist and take a sharp turn to the left. On watching the video of the run i noticed that the left rear wheel was nearly leaving the floor as well which would make me think it was loosing traction and causing me to go left. My question is : If i put the wheelie bars so they were just about touching the floor would this enable me to use gas of the line and stopping it going up on the rear wheels and pushing hard on the wheelie bars causing me to break tracking. I know there is some serious drag racers out there who will have knollage and experience with wheelie bars, so any advice would be greatfull. Thanks,

[anonymous-user]

v8 jago said:

As my jeep is only short i cannot use nitrous of the line without my jeep going vertical in a split second, So i got some wheelie bars and had them so my jeep would lift about 2 foot high before the bars touched the floor, But when i used gas of the line my jeep seems to twist and take a sharp turn to the left. On watching the video of the run i noticed that the left rear wheel was nearly leaving the floor as well which would make me think it was loosing traction and causing me to go left. My question is : If i put the wheelie bars so they were just about touching the floor would this enable me to use gas of the line and stopping it going up on the rear wheels and pushing hard on the wheelie bars causing me to break tracking. I know there is some serious drag racers out there who will have knollage and experience with wheelie bars, so any advice would be greatfull. Thanks,

The wheelie bar will serve two purposes, as you mentioned.

1) it'll stop the car's front end rising too high at the hit, and will help consistency in launches (it's in a fixed position and will more often than not, react in the same way each time).

2) It's a traction limiting device, in so much as too low a setting wont help push kinetic energy backwards into the tyres. It needs some force applied in order to work effectively. This will be based on the centre of gravity both vertically and horizontally. There's a sweet spot in any given chassis where the power can be applied and put down most effectively. This is easier on slicks, as the window to work with on treads is about that of a shoebox.

Having seen the Jago leave the line at Shakey last year (oh my word....), I'd say a wheelie bar would be beneficial. You'll still get the wheels up, but possibly in a safer and more predictable way. It may not work straight away, and will need some tweaks, but one of the chassis builders can point you in the right direction as to baseline settings.

Hope that's of some help

[v8 jago]

Ill have a play about with them to see if i can get them so when i plant the throttle it allows the rear suspension to sit enough without the bars touching the floor to early. If you go onto, You tube and type in either jago jeep as the video or meathumper you should get the video up of the run. Its only 4 seconds long of where i nearly wipe the lights out at york, But it will give you a good idea of what i mean.

[leecb05]

i think you might find that the rear wheel is lifting due to the fact you have a very short and proberbly very rigid chassie.
therfore when you leave the line under load the torque is going through the chassie and bringing the wheel up.
i used to have a similar problem in a car with a short rigid chassie a while back and i limited it by putting a harder and slightly shortet shock on the side that didnt lift and the wheel that lifted i used a longer shock with a bit more travel on it. its not the ideal fix but it helped a bit. if your rear axle is located by a 4 link try adjusting the one side to compensate

[Bigmouse]

I'm sure Jon Webster could advise the right course of action but if you're from 'oop north' then Sleathy ought to be able to sort you out with suspension settings.

[Cliffv8]

did you ever see this pic I toke of you the last time you had a wheelie bars on
(click for full size)

Edited by Cliffv8 on Thursday 9th August 17:41

[GreenV8S]

Is it a live axle?

[v8 jago]

I got the axel done of sleathy, Its a 9" axel with a detroit locker with 4 link, And spax adjustable shocks.

[v8 jago]

Ah ! Cliff i hadnt seen the picture but i think you must of been stood with dave when he took the vid.

[Nitrohaulic]

I'm thinking this is a perfect candidate for an anti-roll bar at the rear? More than obvious that you're unloading the left rear. As already mentioned, a shock with a stiffer rebound/seperation on the front left. I've seen many cars with a travel limiter (often consisting of a length of chain) at the front left, allowing the right front spring more travel to help bring the car up more evenly.

I'm sure some version of this is available over there. One side of your body/rear axle won't be able to move toward or away from each other without the other side. Should prevent your body from rolling to one side, creating the momentum that's unloading your left tire.

http://chassisengineering.com/shop.asp?catid=10&am...

"Designed to help control a car that turns out of the gate rather than leaving straignt. Our SPORTSMAN anti roll bar helps equalize traction by keeping the car level from side to side improving 60 ft. times. Perfect for faster bracket cars where body roll can be a problem."

If you do it and it works, someone's gotta post a pic of the same Jeep leaving straight!

Edited by Nitrohaulic on Friday 10th August 05:16

[v8 jago]

When i first got it done it used to wheelie and leave the line perfectly straight. The only thing that has been altered is when the diff wore out in 500 miles i took it out and had to take the bar that goes diagnal from back left to front right on the 4 link. As it was tight to put back on i had to slacken it off and then tighten it up to where it was. Ive asked a few people if this would affect it and they said no it wouldnt. Do you think this might be why ??
If you look on my profile then you will see the photo of how it used to leave the line. It doesnt always leave the line like that, mainly when i have wheelie bars on but sometimes its the same when i have not got the wheelie bars on.

[Bigmouse]

v8 jago said:

i took it out and had to take the bar that goes diagnal from back left to front right on the 4 link. As it was tight to put back on i had to slacken it off and then tighten it up to where it was. Ive asked a few people if this would affect it and they said no it wouldnt. Do you think this might be why ??

The locator bar (the diagonal bar) locates the axle in the centre of the chassis; if you move it then it alters the geometry. Moving the axle to one side of the car by even a few mill will upset the balance of the car and probably the preload as well. It needs to be replaced, measured and preferably while the car is on the scales to check the pre load at the same time.

I would suggest getting the car baselined again.

And pull some of the power out of it on the startline