Time to Work on Suspension

[Ne-max]

Finally got around to doing some work on it this week. Put stock length shackles back on. Removed 2 of the leaf springs(Overload was already out) and then installed caltracs. Took off my regular traction bars. Still need to relocate the shocks but that will have to wait. Grabs so much better now. Hoping I can make it to the track tomorrow if the rain misses us.

 

[COMP461]

first fix the pinion angle problem to stop the drive shaft problem. I like cal tracs , you need to soften the rear springs so that they just hold the truck up .
I changed the rear end in Project X to a 9 inch and lost 400 lbs of un-sprung weight . I went with a 395 45 17 M&H drag radial. and 4.56 gears . I used a GearVendor and that helped a lot. I was heading to a 4.88 with nitrous and in a fuel only race like the super stock I would use a 5.13 or 5.33.

with the 4.56 and 29 tall tire and only having 3600 rpms then it still ran 129 mph

go with as long a front springs as possible that will still hold the truck up and use a adjustable shock setting the extension dead soft, and the compression a little off of dead hard .

the idea of this is to let the truck transfer weight and keep the front up. the cal trac will set the tire off the hit. some times to soft a hit will spin more if the tire in not sit.


I has 1.60's 60 foot at will

 

[Ne-max]

Thank you for the info.

I picked up a pinion angle gauge tonight and will check them tomorrow. I am down to 2 springs and that's it. Seems to be perfect. I can push down on the ass end with my body weight. Before it would not move. When I relocate the front shock mount to rear I am going to go with some adjustable shocks. Right now I am running the M&H 31.5x12 slicks with a factory 3.73 posi. I gave the caltracs 1/2 a turn of preload and it seemed to make it worse. Would spin tires at 55mph. Gave another 1/2 and it made a huge difference. I figure after I make sure my pinion angle is correct I can make small adjustments at the track. Once I can get my 60ft in check I will have to look into gearing like you said. I am new to this drag racing. Its a lot harder then it looks to go fast

 

[COMP461]

gearing is the secret to this , most diesel guys are trying to lug the motor , it takes gear to move the mass.

even if it hits the rev limiter on the big end , who cares , there is zero et to be gained in the last 100 ft , unless you can double your hp

which CalTracs do you have . I had some where the front was spread apart a lot more then the originals .

that tire sounds really good , I like a biased slick , in that you can spin it and it will come under the truck.

the problem you are having with spinning is the 3.73. drop a 4.56 in it and it will stop that .

PM me if you need help.

 

[gmduramax]

I completely disagree. He needs 3.42's.
No way should be be crossing the traps in 6th gear.

 

[Ne-max]

I completely disagree. He needs 3.42's.
No way should be be crossing the traps in 6th gear.

You are correct cause I have a 5 speed.

 

[Ne-max]

gearing is the secret to this , most diesel guys are trying to lug the motor , it takes gear to move the mass.

even if it hits the rev limiter on the big end , who cares , there is zero et to be gained in the last 100 ft , unless you can double your hp

which CalTracs do you have . I had some where the front was spread apart a lot more then the originals .

that tire sounds really good , I like a biased slick , in that you can spin it and it will come under the truck.

the problem you are having with spinning is the 3.73. drop a 4.56 in it and it will stop that .

PM me if you need help.

I have the 3410s.

 

[COMP461]

with a heave truck you can not get enough gear. let it go on the rev limiter , it will still get there quicker. but with a 6 speed and 31 tall times what will it trap at say 4000 rpms

 

[gmduramax]

My six speed at 3700 RPM is 149mph with 32 inch tall tires.
I'd agree to go through the traps at 4000+rpm in 4th gear 1:1 ratio, if possible.

 

[Noreaster]

if you look on CompD there is a good post by Dockboy on setting up caltracs, something about caltracs setup recommendations are for transbrake cars not footbrakes
the rear shocks calvert sells are just painted rancho 9000s

 

[COMP461]

my experience with CalTracs is foot braking diesel trucks . Calvert made his fame with foot brakes cars in Stock eliminator where you can't run a trans brake.


here is one of the most famous pictures of a diesel truck in the mainstream media. this was with the 395 45 17's

that guy swapped rides with use for the next 20 miles during Drag Week, David Kennedy of diesel power took turns driving the GT , it had 57 miles on it

here is the 9 inch ford I put under it .

 

[Ne-max]

Well. I made major progress. 7.78 with a 1.76 60ft. Track was crap. Cant wait to get back up to our 1/4 mile strip. I could not believe how much it helped launching at almost 2000 instead of 1600 rpms. Now I need to figure out how much preload I should have. I had almost 2 turns last night and it seemed like it helped a lot more then 1 turn.