Suspension ideas...need input please

[TheBac]

I've been thinking about this for next year, and need opinions:

Instead of running Caltracs, would running adjustable solid rear bump stops (like Todd Greene's for sled pulling) and a pinion snubber help with traction? Would using those help control rear squat but still use the rearward force to plant the tires?
I'm thinking that in 4wd, we really DONT want the truck to lift in the front and shift weight dramatically to the rear, but rather have the truck launch level. Am I wrong??

Also, does the front pumpkin want to rotate under load in a clockwise rotation, similar to what the rear axle does? If so, would it be a good idea to run a strap from the crossmember down to the rear of the pumpkin to keep it from rotating?

Lastly, besides protecting the mount from breaking under load, would bolting the drivers side motor mount (using Johnboy's method) help the truck launch harder, due to the motor no longer using its energy to stretch the mount?


I'm trying to think outside the box on this one. Any comments are welcome.

 

[malibu795]

pinion snuber will work to controll axle wrap.. something i have thought about as well.

IMO anything that can be done to solidify the drivetrian will allow you to run faster. since it is spending more time moveing hte truck forward vs. flex/twisting.

one that could be done is mount a camera under the chassis pointed at said components to see what they do under a load.

the front diff will rotate the same direction as rear but pinon yoke will go in opposite directions.

also solidifying the tranny mounts as well.

brace the entire lower IFS bracketry with a couple striagh bars running rearward to the chassis

 

[TheBac]

I was hoping you'd chime in, Adam.

Just thinking of "poor man's" ideas for my run at 12.20's next year. Things that a person with reasonable fabbing skills can make/do.
Suspension has to be upgraded for the attempt, and I dont want to add a bunch of weight.

 

[J Spruill]

use a spring clamp on the front side of the rear axle.solid mounts are a good idea.you could also consider using limitng staps for up travel on the front end...

 

[SteveFord]

I thought of limiting starps on the front end before but haven't made them yet. I found one good place to mount the straps. Has anyone tried an air bag on the passenger side rear to help maybe?? I also tried looking around the engine(but not very hard)to see if I can make a heim joint brace to keep the engine from moving during a boosted launch as my friend made one for his car to keep it solid then takes it off for street use.

 

[TheBac]

use a spring clamp on the front side of the rear axle.solid mounts are a good idea.you could also consider using limitng staps for up travel on the front end...

Thanks Jess. I probably should have posted that I already use clamps on front of the springpacks. Just trying to find other ways than Caltracs to plant the rear without lifting the front.

I thought of limiting starps on the front end before but haven't made them yet. I found one good place to mount the straps. Has anyone tried an air bag on the passenger side rear to help maybe?? I also tried looking around the engine(but not very hard)to see if I can make a heim joint brace to keep the engine from moving during a boosted launch as my friend made one for his car to keep it solid then takes it off for street use.

Thats what I mean by Johnboy's motor mount mod. Run a bolt thru the mount to hold it solid for racing, but with enough give not to be a PITA onthe street.
I have to get under the truck and see where limiting straps can mount. I'd think there are a few good spots for them. IMO that would help the front end stay "down".

 

[TheBac]

What about the added option of running 1/2ton springs with airbags? Would that add anything? Maybe the airbags could be used to help preload the suspension? If this is viable, which 1500 springs fit the 2500hd CC/SB length?

 

[RPM Motorsports]

I use my pulling blocks set with about 1/2" gap without a pinion snubber. I've also got the front and rear of the leafs strapped @ the overload. no problems so far with slicks launching at 3K.

 

[TheBac]

well, a 1.64 60' time (like in your sig) would be close to what I want to do.

I found that clamping the rear of the spring pack caused nasty wheel hop with a 2100rpm launch. Thats why i took the clamps off the rear...only clamping the front stopped the wheel hop. Now have to stop the excessive wheel spin.

 

[J Spruill]

what shocks do you use?

 

[RPM Motorsports]

I dont even get a chirp out of the tires! Try dropping the PSI some more. I was running 35 front 25 rear with my stock 245's pulling 1.70 60's. Im now running 30lbs on all four with the slicks. It has never had a problem @ all with hopping.

 

[Drholliday]

I dont even get a chirp out of the tires! Try dropping the PSI some more. I was running 35 front 25 rear with my stock 245's pulling 1.70 60's. Im now running 30lbs on all four with the slicks. It has never had a problem @ all with hopping.

x2 on the tire pressure. I only clamp my springs and have the front end dropped. I run toyo proxes with 30 psi in the front and 22 in the rear. I had tried a couple different pressures but kept spinning but never had hop. When I finally ran that pressure I was launching at 2500 rpm's in the 20-25 psi boost range and it hooked hard cutting consistent 1.68 to 1.69 60 ft's all night.

 

[TheBac]

what shocks do you use?

Bilstein yellows.

I dont even get a chirp out of the tires! Try dropping the PSI some more. I was running 35 front 25 rear with my stock 245's pulling 1.70 60's. Im now running 30lbs on all four with the slicks. It has never had a problem @ all with hopping.

Well, a lot of my 60' issues are probably because of tires (or lack thereof). The Michelins are a a very hard-compound tire...which obviously brings wheelspin into play. I found that below 38F/32R my 60' got slower. Was still getting 1.76-1.78's consistantly, with a low of 1.74 while spinning them. I wish I had video of those 12.40 runs to show how much wheelspin there was.
I was hoping to have a set of Toyo's at the end of this last year, but my tire place screwed up and didnt get them in. So first thing April I should have a set of Proxes on the PY0 wheels, or may even buy Jeff's tire/rim set if they're still for sale this Jan.

I just want to make sure the suspension is setup correctly to take full advantage of the tires. I figure I may only get a limited number of shots at 12.20s with the stock engine setup before something goes wrong, and dont want to waste any time. Maybe I'm overthinking all this (I have a tendency to do that), but no-one really ever talks about suspension setup on our trucks. It is something worth exploring, if just for information.
My ultimate goal/fantasy is to catch Buck and Jess and their 12.18 ( or was it 12.14?) pass on the stock LB7 that Cole talked about.

 

[J Spruill]

i was using those back in my active dmax days,by switching to rancho 9000s i got decent improvement...

 

[TheBac]

i was using those back in my active dmax days,by switching to rancho 9000s i got decent improvement...

Tomac told me the same thing. Is there something about them that make them act like drag shocks?

 

[J Spruill]

you can adjust the stiffness of the recoil thus keeping the front end and tires on the ground to transfer power...

 

[SteveFord]

x2 on the tire pressure. I only clamp my springs and have the front end dropped. I run toyo proxes with 30 psi in the front and 22 in the rear. I had tried a couple different pressures but kept spinning but never had hop. When I finally ran that pressure I was launching at 2500 rpm's in the 20-25 psi boost range and it hooked hard cutting consistent 1.68 to 1.69 60 ft's all night.

I have yet to try a second gear launch. Thats alot of boost to leave with so obviously it works well for you. I ran Michelins also and ran as low as 28 in front and 25 in the rear and still can't leave with more than 8 psi of boost or it spun bad. Can't blame track prep as the cars there were cutting low 1.50's 60fts that night. I do know the harder my front end came up the more it spun. My stock shocks aren't working for me. I was told from behind my truck squats hard and fast then comes back up too fast almost like it bounces. This is a great thread and the input from you guys that cut great 60fts will be helpfull to anyone that reads it.

 

[IdahoRob]

The RS 9000 shocks helped me with 60' times.

I've cut 1.64's with michelen atx "e", 1.65 with proxies, and 1.69's with stockers, 1.7x's with slicks.

Tom how is the track? Have you tried another track for comparison? Do other trucks at that track cut good 60' times? I've found certain tracks do not hook no matter what you do.

My set-up is as follows. Lower tbars, clamp front of rear spring, adjust shocks to the stiffest setting, lower tire pressures. I don't have caltracs or any other bars.

I have tried many, many different setups as far as shock settings, different tire pressures, tire choices.

2nd gear launches work on a slippery track, but on a good track I can cut better 60' in 1st. Fun launching with 30#'s and 3000rpm though.

I'd think a pinion snubber may help. I've tried strapping the front(with slicks) and almost totaled the truck as it turned left towards the wall. If you block the rear, leave some travel. Biggest thing is to keep the weight forward on your drive wheels.

 

[SteveFord]

The RS 9000 shocks helped me with 60' times.

I've cut 1.64's with michelen atx "e", 1.65 with proxies, and 1.69's with stockers, 1.7x's with slicks.

Tom how is the track? Have you tried another track for comparison? Do other trucks at that track cut good 60' times? I've found certain tracks do not hook no matter what you do.

My set-up is as follows. Lower tbars, clamp front of rear spring, adjust shocks to the stiffest setting, lower tire pressures. I don't have caltracs or any other bars.

I have tried many, many different setups as far as shock settings, different tire pressures, tire choices.

2nd gear launches work on a slippery track, but on a good track I can cut better 60' in 1st. Fun launching with 30#'s and 3000rpm though.

I'd think a pinion snubber may help. I've tried strapping the front(with slicks) and almost totaled the truck as it turned left towards the wall. If you block the rear, leave some travel. Biggest thing is to keep the weight forward on your drive wheels.

My tires are Michelen X radials. Thats nice to know about strapping the front end so we should becarefull with that. So the key would be to keep front end travel at a minimum and the rear squating some with the adjustment from the shocks?

 

[Rhall]

Ive heard that about strapping the front end too, its a bad idea resulting in really bad wheel hop. Ive cut 1.68 60' times on 285 nitto terra grapplers, bars all the way down, 25lbs in the front 30 in the rear, and the rear of the leaf springs clamped, and its never hopped on me. I cut better 60's with either the rear clamped or both, but with just the front i could never get below 1.7's. I also run bilstein yellows, and havent tried the 2nd gear launch in drag racing yet.

Rob