Launching Problems--HELP

[MMAX]

I need some advice on keeping my front end down when I launch. Seems like kinda a "nice" problem to have but I can't leave off my trans-brake without standing on the back bumper. First off.....
1968 Camaro, back halved, 3200lbs
582 BBC 800hp/736ft/lbs, TH400 with B&M brake, Ford 9" 4.57:1 gears
Peak hp @ 6200rpm, Peak tq @ 4500rpm
31 X 13 X 15 M/T slicks
Stock front suspension, Comp Eng drag shocks set at 70/30
Mono leafs, ladder bars and factory 50/50 shocks in rear

This is a very simple set up but it works--almost too good.
The question is do I need wheelie bars or is there another solution to my problem? If I can launch off my T-brake @ 4500rpm the car will go high 9s @ 140mph, right now all I can do is leave off idle and the car bogs big time. I've heard that maybe a powerglide would work because it limits your power off the line. Any help would be appreciated.

[Craig W.]

Better front shocks and travel limiters should let you tune it for a manageable launch. Never liked those CE shocks. Not enough adjustment.

[John_Heard]

X2 what Craig said - or turn the power up, sounds like you're dead hooking it.

[MMAX]

X2 what Craig said - or turn the power up, sounds like you're dead hooking it.

Never heard of this term, can you go into some detail?

[sc racing]

X2 what Craig said - or turn the power up, sounds like you're dead hooking it.

Never heard of this term, can you go into some detail?

Let it spin a little, you wont stand it up on the bumper.

[CDR Performance]

Getting the tire too slip "some" not too much would help. This is what wheelie bar do on a big tire car.
But just adding bar will not help you could hi the wheelie bars too hard. You need to work on tuning the front.
Travel limiters would be the first thing, better shocks, and see what it does from there.

[MMAX]

X2 what Craig said - or turn the power up, sounds like you're dead hooking it.

Never heard of this term, can you go into some detail?

Let it spin a little, you wont stand it up on the bumper.

When you say "turn the power up" you mean launch at a higher RPM? I try to launch close to 4500 to be right at the peak torque range. I know I'll have to play with it a bit but should I try 5000RPM next?

[supernova]

Man I wished I had his problem!

[John_Heard]

You probably would if you had 13" wide 31" tall slicks...

MMAX dead hooking means your tire isn't slipping at all. You're right at the transitional stage where things get to be interesting to work with in regards to HP vs Tire vs Weight vs suspension setup.

If this car isn't likely to add power, other wise you're not going to be running some power adder and it's going to continue to run about where it's at, probably the best thing to do is get better front shocks that will let you control the extension rate better. Double adjustables would be nice if you have the budget. Also some limiters might be useful. When you restrict how fast of a rate the front end comes up, you'll calm down the wheelie.

Scratch that - no matter what you do with the car except for slowing it down, you want better shocks.

Here's the deal though, at some point if you keep adding more power, the car is going to keep standing up even if you get the front end tied down and not moving much. That's the point you're either going to need bars, or you're going to have to learn how to introduce a little bit of wheel speed - slip at launch. It can be tricky finding just the right amount of power to get the car "up on the tire" which means some slippage where the tire is still round and still hooking vs a dead hook which is no slippage and extreme distortion.

What are you doing with the car? TNT, Brackets? Shootout racing?

[MMAX]

Is this what you mean by limiters? I've been told these bolts are what they are but I don't know exactly how to adjust them.





Some brackets, mostly heads up shootouts 1/4 and 1/8 mile.

[John_Heard]

Yes, those are travel limiters.

You can screw them down to reduce the travel the front end has, but those things can be temperamental. If the shocks are loose and it hits those limiters too soon, it can break the tires loose from the shock of running out of travel at the wrong time.

Typically it's better to work with the shock extension settings and slowing the rate the front end goes up vs limiting the travel w/loose shocks. If you screw those suckers down to where it's only got like an inch of travel, with your current loose shocks, it'll probably blow the tires off. Might not too.. Hard to say, each car is different, but they will knock the wheelie out of it. Trick is finding the exact combo your car wants.

In general when a car is getting up to high in the front, you tighten the front shock extension and/or take some travel out of it. If it's spinning you'll loosen up the front end and give it more travel. How much of each is something you have to experiment with.

[MMAX]

Thanks for all your help. What do you suggest for shocks? Koni SPA-1? Just bought the CE shocks last year so maybe I'll set them at the lowest setting for now and play with the limiters.

[John_Heard]

What kind of budget do you have for shocks?

I'd recommend something that is double adjustable if you can afford it. That means you can adjust the bump and rebound (compression and extension) separately with the shock in still in the car. The SPA-1's have to be removed from the car to make an adjustment and you can't adjust just the bump or rebound individually.

Ideally instead of buying shocks multiple times and having to spend more as you make your car faster (assuming that's the intent) you'll save money in the long run by investing in a good set the first time around.

Since you're dealing with stock a-arms, getting a Double Adjustable shock in there might be an issue. Not sure who has what off the top of my head that works really well and will fit what you're working with. Sometime down the road you're probably going to put tubular a-arms on it, ideally you would buy something that later you can change over to a heim joint top and bottom, but would fit the stockers for now.

Maybe one of the other guys will chime in with some suggestions that work good with stock a-arms.

[Craig W.]

I think you'd like the QA1-R shocks. The R version is rebound adjustable without removing the shock from the car and the compression is fix at a stiff valving. I've been using these shocks for a number of years with good results. There are probably better shocks out there, but for $140 they are a good balance of performance and budget.

Work with those travel limiters and see what they'll do for you. I usually adjust in 1/4" increments. Find out what thread they have and you can count the turns to know how much adjustment you've made. I'd run them down until it effects the hook and then fine tune from there.

[505r10]

I need some advice on keeping my front end down when I launch. Seems like kinda a "nice" problem to have but I can't leave off my trans-brake without standing on the back bumper. First off.....
1968 Camaro, back halved, 3200lbs
582 BBC 800hp/736ft/lbs, TH400 with B&M brake, Ford 9" 4.57:1 gears
Peak hp @ 6200rpm, Peak tq @ 4500rpm
31 X 13 X 15 M/T slicks
Stock front suspension, Comp Eng drag shocks set at 70/30
Mono leafs, ladder bars and factory 50/50 shocks in rear

This is a very simple set up but it works--almost too good.
The question is do I need wheelie bars or is there another solution to my problem? If I can launch off my T-brake @ 4500rpm the car will go high 9s @ 140mph, right now all I can do is leave off idle and the car bogs big time. I've heard that maybe a powerglide would work because it limits your power off the line. Any help would be appreciated.

A glide should calm it down on the launch and may even pick up the et a little bit. The glide's gonna take less power to run and dropping from a 2.48 low gear to a 1.80 or so low gear should make a big difference. Dead hooking's not a bad thing if it's actually doing it which I doubt if it is with the kind of power your making plus the total overall gear ratio.

Roger
gotta 582 too