Launch problem

[99camaro]

Here is a you tube video of my launch problem. I am thinking I may have to big of a tire and not enough air pressure. http://www.youtube.com/watch?v=coLcj-Rvbu0

[LittleJ]

squats way to much...do you know the IC length and height?

strikes the tires so hard the wheelie bars and smacking the ground....extension setting on shocks is where?

check with the tire manufacturer if the tire matches the application.

if i spot your car at the grove sometime ill stop by.

[99camaro]

I have tried all types of IC settings. Also tried a bunch of different shock settings. Tried strapping the front end down. Nothing seems to change anything. The only thing I can think of is not enough air pressure, no wheel speed at all, and too big of a tire.

[BillyShope]

I have tried all types of IC settings.

What percent antisquat?
http://www.racetec.cc/shope

[want-a-be]

I have tried all types of IC settings. Also tried a bunch of different shock settings. Tried strapping the front end down. Nothing seems to change anything. The only thing I can think of is not enough air pressure, no wheel speed at all, and too big of a tire.

In order for us to help you out we are going to need some numbers........ You made a few changes on the ic.... what were the lengths and how high were they off the ground???? You seems to have a mile of shock/strut length on the from end, or it at least looks like it raises a mile with the wheels still on the ground. The wheelie bars seem too close to the ground. You're hitting them so hard it upset the tires and starts everything bouncing around, dribbling the tires off the line. I'm betting you have around 50" inches or less for an ic as hard as you're hitting the tires there, and it's a foot off the ground. EVERTHING on this launch is happening too fast and hard. Nothing at all about it is smooth. Slow is smooth, smooth is fast.

Here is what I would do before you god out next.

: I would map out everything on the rear suspension and start out with an ic of about 58"-60" inches. With it about 4"-6" off the ground. Have the top bar as close to the rear end as possible. Have the bottom bar as close to the same height as the bead set of the rim is off the ground.

: Loosen the compression a bit on the rear shocks. After the first run look at how things are going and with the rear end travel. If you've slowed hitting the tires down enough you might also want to loosen the extension of the shocks also. from what I'm seeing on the video the rear tires are acting like the shock due to everything being too stiff back there.

: Raise the wheelie bars another 2" inches. You're hitting them too hard.

: Stiffen the front shocks up a few clicks on the extension and limit it's extension to about 2"-3" inches from it's ride height.

From what I'm seeing there you ought to be able to tune this thing the way it is then hit the juice and tune it from there. You're asking for trouble if you juice it with the chassis like it is. imo anyways.

Don

ps...I didn't mean to come off as being rude at first. It's just that thing is way off. I'd be getting a steak dinner if I was there to help out at the track.

[John_Heard]

That "squat" is actually the tires, if you watch the relationshop between the rim and the rear qtr corner, the rim really isn't moving much at all in the wheel well. The car never gets up on the tire, it's dead hooking, bouncing ball syndrome. I'd bet more pressure would be a move in the right direction.

Either that or fire that fogger off at launch and see what it does with some power on the tire.

[race9899]

I am still going to go with not enough shock for the Gear and Hp...

It is smashing the tire down then you can see the back of the car bounce back up

How stiff do you have the rear shocks set right now?

[John_Heard]

Yup acts like a solid mounted rear end.

If you talk to Ronnie Santhuff about shock settings, he'd tell you to start off softer than you think it needs to be then go tighter if it will take it. Soft will get down the track more often than tight.

Wheelie bar needs to be move up as mentioned earlier too.

[99camaro]

That night I tried 3 different settings. First was all the way tight on the shocks, then all the way loose, then on the run in the video I set them in the middle and removed the front limiter straps.The wheelie bars are set at 7 inches. The ic ends up being about 70 inches out and 3 inches up. I have tried shorter but not longer. The car seems to react the same way on every setting. The tires are at 7 - 8 psi.

[want-a-be]

Try about 6 psi in the tires along with the other stuff I've talked about. Have you tried anyone elses air gauge to to compare it to yours?

Rear shocks in the middle again maybe.

I've seen prostock cars use less then what I'm asking you to run....but they are a different animal and can't be compaired to what you are running in the bell housing. They were winning championships at the time.

What rear spring pressure are you running?

When you put the car on jack stands....can you jack the rear end up and down through it's motion and things move freely? Look for some kind of binding. I don't recall what kind of shocks you are running. You may have already said though. QA1s maybe.... if so look at getting some better ones. I've not been around them but I've heard good things about the Santuffs. With your power shocks can tend to make or break a smooth combination.

Good luck this wek end if it doesn't rain you out and let us know what happens.

Don

[sunsation540]

: I would map out everything on the rear suspension and start out with an ic of about 58"-60" inches. With it about 4"-6" off the ground. Have the top bar as close to the rear end as possible. Have the bottom bar as close to the same height as the bead set of the rim is off the ground.

: Loosen the compression a bit on the rear shocks. After the first run look at how things are going and with the rear end travel. If you've slowed hitting the tires down enough you might also want to loosen the extension of the shocks also. from what I'm seeing on the video the rear tires are acting like the shock due to everything being too stiff back there.

yes and yes i would take the bars off ,as it only hits them when it smashes the tire and rear springs, they are another tuning tool for further down the road.. what is the weight front and rear.. the IC is to long and the front of the car is dead.. with no help from the frontend the rear is trying to lift the entire car long IC, shorten the IC so it thinks it is only lifting the rear of the car.. make the front do it's own work.that's also why it's twisting the car up.. make it carry the wheels and it will 60 faster and as you add power tune the wheele out! you are over working the shock/spring package..on the rear...again the problem is in the front of the car!!!

[supernova]

The springs might be too heavy (stiff) for your car. That might be why nothing changes when you change the setting on the shock. It does look like a solid rear end.


My 2 cents