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-   -   Drag race setup? (https://67-72chevytrucks.com/vboard/showthread.php?t=400001)

Terry'sToy 04-29-2010 01:45 PM

Drag race setup?
 
I've done some racing in my 01 TA and now I want to drag the truck more seriously. The car dead hooks and I'd like the truck to do this as well.

After tons of reading from all the knowledgable guys on here, I think I have a plan, but would like everyones input.

The truck is a 69 lwb fleetside, LS1 4l60E with a yank 3500 stall, 3.73's.
Front end weight is 2320 lbs, rear 1595 lbs with me in it (170lbs).

So far from the advice and calculations here, I was thinking of running a 47140 moroso and shimming to get 9" installed height along with a 1574 QA1 drag shock (I've run QA1's on the TA and really like them)

Now for the rear I need more help. Going to reposition shocks and had planned on a 1661 QA1 in the stock repositioned location. Not sure on the rear coil though. I want the truck to have the lowered stance still. It sits about 3/5 right now.

Whats everyone think?

Terry'sToy 04-30-2010 02:33 AM

Re: Drag race setup?
 
maybe a cheaper or better set-up

should I do a rear coilover?

any advice is good.

Super73 04-30-2010 03:26 AM

Re: Drag race setup?
 
Your truck sounds almost dead on to what mine was when I started..

If memory serves me, it weighed 2260 on the nose with those springs and is sat at about 9-9.25" compressed. I would put the springs in and see where you are at height wise before shimming them. Put them in, get a few miles on it and let them settle in first. (My old ones are for sale BTW).

Qa1's are nice, but pricey compared to the Rancho 9000's. I'm running them in the front and rear and they work great.

If I were you, I'd take a measurement for both locations from eyelet to eyelet compressed then jack the front/rear till the tires are off the ground and take that measurement (back you might have to put it on jack stands to let the rear fall down some). This will give you your installed height as well as your max height needed. Then you know more or less what you need as far as overall length both compressed and uncompressed.

I read somewhere on here that someone was using rear Jeep springs for the rear (not sure if they were Wrangler or Cherokee), but they said it lowered it like 4".. If they are like the Grand Cherokee ones I run in fornt, they are a little longer/softer and will store more energy (yes stored energy is good in the rear too, if there is antisquat set up in it, it will hit the tires even harder).

I did a little fabing on my rear control arms and run a Hal 14-130 spring on my rear set up. I'd prefer a 14-110, but I'm not going to re-buy them right now.

Terry'sToy 04-30-2010 04:08 AM

Re: Drag race setup?
 
this is great, thanks
Are your springs un-cut?

I'll check into the Rancho's tomorrow.

So I need to get the front and rear springs in ( gonna try the jeep springs in the rear). Just read that today. might get a set for dirt cheap. Then I will re-measure everything again.
I never thought of the stored energy in the rear. Makes sense as it helps drive the diff into the ground.

So you are running 14" coil overs on the rear behind the diff now?

Keep the info coming. Tks

Super73 04-30-2010 04:19 AM

Re: Drag race setup?
 
I don't believe in cutting springs meant for drag racing, so yes, they are factory length.

I run a coil over spring but in the factory location. I took a piece of 3" exhaust tube and cut four 2.5" pieces. Welded one to the bottom of the frame and one to the top of the control arm on both sides. Spring can not come out with weight on it.

Terry'sToy 04-30-2010 11:22 PM

Re: Drag race setup?
 
how much would you like for your springs?

I like your rear spring idea. How much lower does the truck sit compared to stock with those? Or maybe I should ask what is the compressed height of that spring? And why the need for the 110 versus the 130's? Did you lighten the rear?

For the rear shocks, how much travel am I going to need? I can measure compressed, but how much seperation am I going to need so that I don't top out the shock? With stock 1/2ton springs the measurement will be different than with the jeep springs, because the lighter wire will let it hang farther down.

Tks again.

Nick's81 05-01-2010 01:15 AM

Re: Drag race setup?
 
ok i'm watching this 1 my 64 best 60 ft was 2.1 just can't get it to hook have to pedal off the light

Terry'sToy 05-01-2010 03:49 AM

Re: Drag race setup?
 
Nick's81 are you running slicks?

Nick's81 05-01-2010 11:52 AM

Re: Drag race setup?
 
no slicks no locker just stock 393 open with old hard 26in hoissers will be changing tires soon

Nick's81 05-01-2010 12:24 PM

Re: Drag race setup?
 
Tread jack for a minute Super73 searced can't find and pics of you'r springs front or rear and anti roll bar HELP us out please thanks nick

Ont67shortbox 05-01-2010 03:48 PM

Re: Drag race setup?
 
Super 73 do you have the part number of the rear Ranchos and the extended length? Thanks Brian

Super73 05-02-2010 10:42 PM

Re: Drag race setup?
 
Quote:

Originally Posted by Terry'sToy (Post 3950990)
how much would you like for your springs?

I like your rear spring idea. How much lower does the truck sit compared to stock with those? Or maybe I should ask what is the compressed height of that spring? And why the need for the 110 versus the 130's? Did you lighten the rear?

My rear weighs in at 1,760lbs. The batterey is in the rear as well as about 100lbs added to a spare tailgate. The top part of the wheel opening in the rear is at 24".. The top of the frame in front of the rear cross member comes in at 21 1/2".. That should help tell you where my rear is sitting.

If I went with a 110lb spring I might be able to remove the 2" lower blocks.. Heck for that matter a 90lb might have been great because it would sit lower with out the block?? Plus I bet if I adjusted to some antisquat, it'd really hit those tires.

Quote:

Originally Posted by Terry'sToy (Post 3950990)
For the rear shocks, how much travel am I going to need? I can measure compressed, but how much seperation am I going to need so that I don't top out the shock? With stock 1/2ton springs the measurement will be different than with the jeep springs, because the lighter wire will let it hang farther down.

Tks again.

I think if you had 6" of total travel, you'd probably be ok. Try to get the shocks in the middle so there is 3" of up and down travel. If you can get 8" awesome, too much never hurt.

Yes, the rear will squat further with the lighter spring, but, you should be able to adjust the rate in which it squats with the rear shock. If your bottoming out, tighten it up. If your having a hard time hooking then loosen it up, I doubt you'll run in to it bottoming out if it ain hooking :) Keep in mind the suspension should be as tight as possible as long as it works. Loosen it up to the point it works and not anymore than that. The looser it is the slower reaction time the vehicle has (longer it takes to move forward when hitting the go fast pedal).

As track conditions start getting worse, loosen it up a bit.

Super73 05-02-2010 10:44 PM

Re: Drag race setup?
 
Brian, my Rancho's are well in to my bed. They are far from the factory upper mounting location. If you still want the number, I can look at them... Just not sure you want them like I have them mounted.

Ont67shortbox 05-04-2010 04:12 AM

Re: Drag race setup?
 
Thanks Super, I measured and checked and I think the RS999113 should work.it is 20 inches extended and 13.125 compressed.I will double check my measurements again now that the rear is in place.Thanks for all your help.

fiddy9apache 05-04-2010 12:00 PM

Re: Drag race setup?
 
its wrangler springs that will lower the rear.

Super73 05-04-2010 12:21 PM

Re: Drag race setup?
 
Quote:

Originally Posted by fiddy9apache (Post 3957002)
its wrangler springs that will lower the rear.


Right on. Is this what you are running?

If so

Any idea on:
Free height?
Compressed height in your truck at ride height?
What the rear of your truck weighs?

fiddy9apache 05-04-2010 12:27 PM

Re: Drag race setup?
 
i know there a softer spring and seemed like it transfered better. it was a long bed truck so it was a little heavier in the rear. thats all i remember, hope that helps

Ont67shortbox 05-04-2010 05:09 PM

Re: Drag race setup?
 
Once I tack the trailing arm brackets to the housing I will take everything apart and give you the spring heights,for the Wrangler springs.Although I have a shortbox the ride height should be close.

Terry'sToy 05-05-2010 12:09 AM

Re: Drag race setup?
 
Thanks again for the help.

Super73, with the other vehicles I've raced, when set up properly, the rear didn't squat, it separated. Do these trucks tend to squat? My understanding was that squat was the rear end moving up into the chassis and therefore not aiding in traction.

thanks everyone else as well.

Super73 05-05-2010 01:37 AM

Re: Drag race setup?
 
Terry,

You are correct.. On a properly set up suspension, it should have antisquat built in to it to seperate the rear suspension and force the rear tires in to the ground. This is why having a very soft spring in the rear is a wise idea (again storing energy). But, You will never get these trucks to have antisquat if you do not do something about the LCA mounting location. You need to raise the front eyelt on the LCA. If you do a little digging, you'll find a post I put up about adjustabe LCA brackets that I fabed out of some square tube.

Things to consider though, if youe weight bias is way off, it's going to be even harder to get the front to raise if your putting antisquat in the rear. At that point your now pushing back down on the front as the rear seperates.

For a vehicle that isn't hooking, setting the rear up to squat is going to make it easier to hook. It's absorbing some of the energy so to speak.

Dialing in suspension takes time and understanding what the track is doing as well as what each suspension adjustment does.. One never finishes learning :)

Terry'sToy 05-22-2010 12:12 AM

Re: Drag race setup?
 
As usual work has been keeping me too busy.

tiny update,
got some wrangler springs (TJ's in Canada) for the rear. Wife made me order 47140's for the front (sorry super 73), and some QA1 RC1574P drag shocks for the front. Still have to relocate the rear shock mounts and install springs before measuring for rear shocks. A friend has some rally's for the rear, so I can mount my slicks.
Need a real driveshaft still.
Getting closer.

Terry'sToy 06-03-2010 10:22 PM

Re: Drag race setup?
 
The stuff finally showed up. Putting it together tomorrow.


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