Need tips to improve sixty foot on a sec gen Camaro

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Z28SBC427
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Need tips to improve sixty foot on a sec gen Camaro

#1 Post by Z28SBC427 » Thu Nov 24, 2016 4:33 pm

Hello all,

This is my first post here and I'm glad I found all these great advise you guys give here. :thumb:

I own a '73 Z28 street strip deal, 427" SBC with 656 N/A HP, turbo 350 trans with ATI 8" converter, 488 gears and a posi.
Car race weight is 3240lbs, 54-46% F-R weight distribution. Have a ten point roll cage, welded subframe conectors,moroso front springs and single adjustable QA1 shocks up front (set at full loose) and DA QA1s at the rear (set at four clicks rebound and six clicks compression) , have home made Caltracs on the bottom hole ,have installed Poli bushings everywhere and I have upgraded now to Calvert split mono leafs with alloy bushings (car had the stock five leafs "clamped" springs before.Front suspension have 5.4" inches total travel.

With the old leaf springs and 28x10" Hoosiers slicks at 13 psi, best 1/8 ET was 1.44/4.11/6.42 @ 109mph.

I haven't raced the car with the new split monos yet, and I'll also upgrade to 29x10.5W stiff sidewalls hoosiers soon, so I d like to hear advises on what might be a good start on front and rear shock settings and tire pressure for these new suspension setup to hopefully lower ET?

Thanks in advance for responses

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John_Heard
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Re: Need tips to improve sixty foot on a sec gen Camaro

#2 Post by John_Heard » Thu Nov 24, 2016 10:46 pm

Welcome to the site...

I'd probably start around 12psi on those tires. As far as shock settings, probably best to start where you left off and see if the car wants anything different. I can't recall how many clicks those shocks have, are you saying your 4 clicks from full tight rear extension? If so, that sound like it's pretty tight. If that's the case and it's hooking good fine, but if not might want to loosen that extension up a bit.

Get someone to video the launch if you can, maybe with one of those iPhone's that can do slo-motion, it'll help a lot with figuring out your shock settings.

Z28SBC427
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Re: Need tips to improve sixty foot on a sec gen Camaro

#3 Post by Z28SBC427 » Fri Nov 25, 2016 2:33 pm

John_Heard wrote:Welcome to the site...

I'd probably start around 12psi on those tires. As far as shock settings, probably best to start where you left off and see if the car wants anything different. I can't recall how many clicks those shocks have, are you saying your 4 clicks from full tight rear extension? If so, that sound like it's pretty tight. If that's the case and it's hooking good fine, but if not might want to loosen that extension up a bit.

Get someone to video the launch if you can, maybe with one of those iPhone's that can do slo-motion, it'll help a lot with figuring out your shock settings.
Thank you.

Sorry, I forgot to say the front and rear shocks have 18 clicks at all. Front are at zero (full loose) and rears are set four clicks from full loose on extension and six clicks from full loose on compression.

Once I tryed to stiff the rears to 8E-12C clicks to hopefully lessen rear separation, which was severe with the stock leafs BTW, but the car spun the slicks off the line with the stiff settings.

Yes, slo-motion video is a nice idea, I'll try to do that next time on the strip.

What suspension behavior at launch should I be setting for to best ET I mean, less front end lift ? less rear separation?

Thank you very much for the tips Jonh, very helpfull :thumb:

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Re: Need tips to improve sixty foot on a sec gen Camaro

#4 Post by John_Heard » Fri Nov 25, 2016 2:48 pm

I would venture a guess it doesn't want or really need the front shocks to be full loose. How much tighter is something that will have to be experimented with. Overall you want the car as tight as you can get it but both dead hook AND not get upset down track on a bump. Wheelies are great for pictures, but that's about it.

4 clicks from full loose on extension sounds pretty loose, you run the risk of topping out the shock when they are overally loose, again tighter is faster if it will take it and still hookup. 2" of extension or maybe a bit more is quite normal on a leaf car, if you're stretching it out like 4" of travel in the rear I think that's a bit too much.

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Re: Need tips to improve sixty foot on a sec gen Camaro

#5 Post by Z28SBC427 » Fri Nov 25, 2016 3:25 pm

John_Heard wrote:I would venture a guess it doesn't want or really need the front shocks to be full loose. How much tighter is something that will have to be experimented with. Overall you want the car as tight as you can get it but both dead hook AND not get upset down track on a bump. Wheelies are great for pictures, but that's about it.

4 clicks from full loose on extension sounds pretty loose, you run the risk of topping out the shock when they are overally loose, again tighter is faster if it will take it and still hookup. 2" of extension or maybe a bit more is quite normal on a leaf car, if you're stretching it out like 4" of travel in the rear I think that's a bit too much.
Got it!

Yes car was stretching the leafs about 4-5" off the line. Was scary to watch. I checked and the rear shocks have plenty of extension stroke to not top them out.

I got the Calvert split monos to hopefully decrease this streching and also for safety.

In your experience, what sixty foot would be achievable with a setup like mine? I ask because I feel she could do better than 1.44 but :?:

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Re: Need tips to improve sixty foot on a sec gen Camaro

#6 Post by John_Heard » Fri Nov 25, 2016 5:21 pm

I'm not used to a combo like yours to guess at what kinda of ET it can possibly get, maybe one of the other guys will put their 2 cents in.

There's always more in them with work it seems, just getting the launch smoothed out might have a noticeable difference.

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Bruce69Camaro
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Re: Need tips to improve sixty foot on a sec gen Camaro

#7 Post by Bruce69Camaro » Tue Nov 29, 2016 6:16 am

Welcome to the site....

Are you using a transbrake or are you foot braking the car?

I'm probably the last person to give you expert advise, but I can tell you what I tried on my car.
Those who think they know it all have no way of finding out they don't......... :scratch:

Z28SBC427
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Re: Need tips to improve sixty foot on a sec gen Camaro

#8 Post by Z28SBC427 » Tue Nov 29, 2016 2:50 pm

Bruce69Camaro wrote:Welcome to the site....

Are you using a transbrake or are you foot braking the car?

I'm probably the last person to give you expert advise, but I can tell you what I tried on my car.
Hi Bruce, thanks for the welcome!

Its a Foot Brake Car. Starting line rpm at 1800 converter flashs at 5300 off the gate.

Any real life advise is welcome! :thumb:

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Re: Need tips to improve sixty foot on a sec gen Camaro

#9 Post by Bruce69Camaro » Wed Nov 30, 2016 5:27 am

I can tell you, I tried to footbrake my car and I ended up switching to a transbrake.
I was advised that I need to get the RPM's up higher because I was running a short stroked motor and a brake would definitely help.
It was dead coming off the line, so I added the brake and the car came out a lot better.
We tried a few different RPM settings and 5200 gave us the best results.
We also found out that the front end was coming up against the bumps, so I removed them and added adjustable stops.
That seemed to help too.
But for me, I thinking my biggest help was how I did my burnouts. Even though my buddy Ray, helped me in the burnout box, I just didn't get them down right until, unfortunately, my last two runs. I paid more attention to shifting and watched my tach better.
My 60's were terrible at 1.6 and on that day, my best was 10.43 @ 125, with a 1.515 60, but the motor broke, so we don't know if we could have done better, but still we did something right for it to act this way.
Those who think they know it all have no way of finding out they don't......... :scratch:

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