How important are drag race shock absorbers, at least on a slower, footbrake car?

My goal is to narrow the spread of my 60' times, which on a bad day can vary perhaps .04 second or so. And I want to shorten my vehicle reaction time.

Bucky recommended on another thread to video tape my launches, which may in fact answer my own question. I'll need to work on that.

This YouTube video well demonstrates the value of video taping one's car.
https://www.youtube.com/watch?v=sjZDXBXRC9Q

I'd never heard of 'tire crush' before. I have a still photo of my truck at launch, showing the slicks all wadded up, but I thought at the time it was due to running 13 PSI tire pressure.

My S-10 has stock springs and what appears to be OEM-type shock absorbers, front and rear, non-adjustable. It does have a pair of Cal-Tracs, set up with the bottom hole.

The truck weighs about 3,100# with driver. This weekend at the track I'll weigh it for front-to-rear bias.

The slicks are Hoosier 28 x 10s.
Gears in the Ford 9" rear are 4.11. The transmission is a TH350 and the converter I believe to be a Street Fighter unit with a fairly modest stall speed.
I launch at 2400 RPM. Personal best ET was 11.67.

Remarks? Thanks!

You need the front end to work in order to get the back end working better. Your Caltracs need lots of front end travel, I believe they want 5-7" of lift in the front end.

Good front drag shocks (I prefer and recommend double adjustable) will allow you to tailor how quickly it rises and the compression. You could get away with a good 90/10, an "R" series shock would be betterso you can play around with the extension to see what the truck likes. I would also recommend a pair of Santuff front springs for your truck. They should be able to tell you the proper spring rate once you weigh the truck this weekend.

Stock control arm bushings are designed to bind up the front end and limit body roll for street driving. Back before I had my tubular control arms, I loosened all the lower control arm bolts and double nutted them. I also installed longer bolts that bottomed out in the uppers to free up the front end. It made a huge difference on my Nova. Depending on how far you want to go with it, get a set of rod end mounted control arms and zero friction ball joints from Autofab Race Cars. Light weight and no bind thru the range of travel.

One more thing, tire pressure is going to depend on the wheel tire combo. You say 28x10 tire but what is the wheel? An 8" wheel/10" tire will need different air pressure than a 10"tire/10" wheel combo. With my old 8"/10" combo, I ran 11-12 lbs. Pictures show the tire wadding up like you mentioned above. With the same tire and 10" rim, I run them at 15-16 psi now.

Just my .02

Thanks, Tom; your $02 is quite worth the price of admission.

I am running my 10" slicks on 10" rims; I like to use the widest wheel that the tire manufacturer suggests, believing I can get the most even tire patch. I'll use my 8" rims with 9" slicks though.

Many things I'd never heard of; thanks again.

I'd thought about getting softer but taller springs for the front end, but I'm not sure how much time and money to invest in this truck. I can tap my Roth IRA in a few months and want a different combo, like a third-gen Camaro maybe.

Mike -- lol

I run Koni SPA1 struts on the front of my car. Adjustment is very minor. I can control them from being very soft where I can grab the fender and bounce the car up and down to adjusting them to be very stiff and I can't move the car around at all.

If set on super soft, the front end rises far too quickly so I have them set on stiff and use travel limiters to help keep the front end down.

Rear shocks are a little different. I use 12 way double adjustable shocks. A lot of it will depend on how your suspension is set up. You want the tire to plant hard to the pavement. This means the back of the car rises and the shocks extend. You want that movement to be quick but want them to slowly compress back as you start picking up speed.

Last pass I did at a track, I didn't have my front end limiters adjusted and the front shocks were set to full soft. I got all 4 tires off the ground in a sky high wheelie. Never needed wheelie bars before but have them now.

You have two different threads here about getting your race car to hook up good. But you do not have any idea why it is not hooking up so we are all just throwing ideas out there which may be completely wrong direction you need to go.

Getting a car to hook up good is a balancing act to get all the weight on rear tires at the hit with out pulling front end straight up. On lower powered cars you need really loose front ends with lots of travel to help transfer the weight to rear and hook up back tires. On higher powered cars need less up front.
The rear tires need to have enough air to support whole car when front tires are in the air. Rear shocks need to be able to keep shocks from topping out (Unloading rear tires)and control the rear end. Ladder bar, four links, caltracks etc all react different and with a four link is critical on how it is set up on how it reacts.

Then you have the weight of the car as another variable and we are all assuming the tires are good and sidewalls not gone.


You have already kind of answered your own question, you need to video it in slow motion where you can see the tires and what they are doing. Then we can give you an intelligent direction to go. With out a good video we are throwing dart in the dark.

Curly1 and Alky: Thank you much for the thoughtful, detailed and courteous remarks here.

I've been exploring possible reasons why my 60' times vary by .03 or .04; inconsistent traction I thought to be one possibility.

I'll try to shoot some video this weekend. I appreciate the fact that it's hard for you all to tell what my truck is doing without video. I see now the value of slow-motion video, like in that YouTube Mopar video link I posted.

Every remark that you and other racers have made here has been valuable and has really made me think of things. I've learned a lot the past few days about the mechanics of race suspensions.

Today I'm skipping eliminations and just turning in a test-&-tune-only card. For now I'll weigh my truck front and rear, and dabble some with tire pressures, ballast and Cal-Trac settings. And talk to this one very successful driver at the track who freely gives information.

Thanks again to all who are helping me here and have a successful & safe race weekend if you're going out.
Cheers!
Troy

quote:

Originally posted by Bad Nusz:
Curly1 and Alky: Thank you much for the thoughtful, detailed and courteous remarks here.

I've been exploring possible reasons why my 60' times vary by .03 or .04; inconsistent traction I thought to be one possibility.

I'll try to shoot some video this weekend. I appreciate the fact that it's hard for you all to tell what my truck is doing without video. I see now the value of slow-motion video, like in that YouTube Mopar video link I posted.

Every remark that you and other racers have made here has been valuable and has really made me think of things. I've learned a lot the past few days about the mechanics of race suspensions.

Today I'm skipping eliminations and just turning in a test-&-tune-only card. For now I'll weigh my truck front and rear, and dabble some with tire pressures, ballast and Cal-Trac settings. And talk to this one very successful driver at the track who freely gives information.

Thanks again to all who are helping me here and have a successful & safe race weekend if you're going out.
Cheers!
Troy

As you build your operation over time you'll not only learn but acquire better products into your racing effort. I used to run 375 pounds of lead on a bar tying the two bars that come through the speaker tray into the trunk. I had the weight as high as I could get it over the back tires and still be able to close the trunk. You have the perfect deal to throw bags of concrete mix in the back of the bed of your truck. It don't matter how fast or slow you go bracket racing. I'd throw ten fifty pd bags of concrete mix in the back, it'll hook!

We do want to help you that is what this forum is all about. I agree the rear tires probably need more air but I do not think that is the only problem.

Bags of concrete in bed of truck is considered loose ballast and any track who saw that would say no way.

quote:

Originally posted by Bad Nusz:
Thanks, Tom; your $02 is quite worth the price of admission.

I am running my 10" slicks on 10" rims; I like to use the widest wheel that the tire manufacturer suggests, believing I can get the most even tire patch. I'll use my 8" rims with 9" slicks though.

Many things I'd never heard of; thanks again.

I'd thought about getting softer but taller springs for the front end, but I'm not sure how much time and money to invest in this truck. I can tap my Roth IRA in a few months and want a different combo, like a third-gen Camaro maybe.

Mike -- lol

Put 18psi in your rear tires and forget about the 3rd Gen! Your truck is WAY more easier to work on and buy stuff for. I have two 3rd Gens, take it from me!

Mike and Curly1, I'm grateful; you guys are the best! I still wish I'd started racing about 20 years sooner! I'd know much more by now! I'd have spent my money on race cars, rather than women! ;^)
But it may take as much as 375# of ballast? Whew.
I get the joke about the loose bags of concrete, heheh.
As it is I'm using 10# barbell plates, as I describe in the 'ballast' thread. I've put 50 lbs. of ballast to good use so far and plan to add maybe 20 more.

Mike Beck, thx too. I've tried 17 PSI with some success; I'll probably boost that to 18.

Can you tell me what it is about the 3rd Gen F-bodies that you hate the most? I know I'm concerned with that '3-link', torque-arm suspension. If I'm not mistaken, it attaches to the transmission output housing? Seems like a dumb idea.