Front end setup (Drag Racing)

-
Mopower71

Mopower71

Speed Demon
Joined
May 31, 2004
Messages
2,183
Reaction score
39
Location
Poughkeepsie, N.Y.
What's the best way to set up the front suspension on a drag car, using the the original suspension.
I already have the 6 cyl torsion bars on the front, and the suspension has all been rebuilt. I beleive the shocks are 90/10's but I'll have to double check.
The front suspension feels stiff, when pushing it down, or pulling it up by hand.
I need recomendations on how to get it loosened up for the best front end rise.
 
Does it have ploy bushings in it ? They are tighter then rubber so switching to rubber bushings will loosen it up.
 
K. There seems to be two schools of thought here. One is to run the tired shocks and torsion bars. The other is too build the front end tight. This from Mancini's when I ordered my Cal's. There is logic in the latter. From what I understood, there's forward motion lost when the car's front raises, catches air, and whatnot. He suggested I get rid of my 90/10's and upgrade to a pair of Atco. You decide. I have.
 
lenweiler said:
K. There seems to be two schools of thought here. One is to run the tired shocks and torsion bars. The other is too build the front end tight. This from Mancini's when I ordered my Cal's. There is logic in the latter. From what I understood, there's forward motion lost when the car's front raises, catches air, and whatnot. He suggested I get rid of my 90/10's and upgrade to a pair of Atco. You decide. I have.
Click to expand...

Who did you talk to at Mancini's when they gave you that advice??
 
My opinion is..You want it lose, but not uncontrolled. A have a friend who installed roller type bearings in his Cutlass (available for GMs) so the nose would rise consistent. I would use the urethane, but make sure it's well lubed so it can rotate smoothly. Rubber stuff is much less forgiving when it comes to twisting. The urethane will not deform, and the tub dwon the center makes a good rotation center. Your shocks should be simple cheapies, or good adjustables. A cheap 90/10 is about as good as an entry level hydraulic shock IMO. I run non gas Monro-matics on mine...lol, but they are a few years old. The T bars should be small diameter, so they have to be preloaded a lot to stay at ride height. Then they will help the nose rise during acceleration. I havent had to, but I know racers that have ditched the bump stops too...so the nose can rise even more. You should be able to bounce the nose around quite a bit. It shouldnt be stiff at all. Then there's the alignment..once you ge tthe parts right, have it dialed in with as much positive caster as you can get, little of no camber with the nose up( they should use a jack to simulate this) and 0 toe again with the nose up. Aslo run high pressures in the front tires.
 
What possible benefit would having the nose raise possibly give you? Every ft-lb of torque wasted in lifting the front of the car (from the rear) is a ft-lb not being used to move the car forward. I would concentrate on traction and let the nose do what it wants. Sure it's gonna come up a little, but I wouldn't spend any money trying to see how high I could make it go. A better approach would be to move as much weight away from the front of the car as possible.
 
DERICKS said:
Who did you talk to at Mancini's when they gave you that advice??
Click to expand...

I think it was "Steve"? Been racing a long time. What he said made sense. I don't pretend to know much about suspensions. Know even less about that than picking cams..............
 
And a wise man he is, although both are actually used successfully. If your trying to make traction on a narrow/short set of tires, letting the front rise can actually make you quicker, the purpose being to get as much weight shifted to the rears as fast as possible at launch. If traction is not a question, ie say a set of 33" tall 18" wide monster meats, then staying flat to the trac will get you there sooner. It really depends on how your set-up as to which will be better.
 
C130 Chief said:
What possible benefit would having the nose raise possibly give you? Every ft-lb of torque wasted in lifting the front of the car (from the rear) is a ft-lb not being used to move the car forward. I would concentrate on traction and let the nose do what it wants. Sure it's gonna come up a little, but I wouldn't spend any money trying to see how high I could make it go. A better approach would be to move as much weight away from the front of the car as possible.
Click to expand...


There is no benefit until you have maximized your traction for a static body. But once you have maximized the bite with the instant center forward and low, you aim to raise it and move it towards the rear so more weight is felt by the rear tires. Then you maximize it again with the extra weight that is transferred to the rear tires. With a 4 link setup, you can set the instant center so the car doesnt waste power transferring weight. Which is why race suspension cars when set right move straight forward, not up and then forward. For everyone else, weight transfer is crutial. I dont want it to move much, but it should be free to move easy, and it should be easy for it to raise via thin torsion bars that are preloaded a lot.
 
lenweiler said:
I think it was "Steve"? Been racing a long time. What he said made sense. I don't pretend to know much about suspensions. Know even less about that than picking cams..............
Click to expand...
I've never talked to Steve over there so he must not work the counter and do phone sales only. Thats really the first time I heard that and it makes me curious. I've been considering some traction problems I'm having and was told to loosen up my suspension even more by a reputable engine builder/racer here in MI. Maybe I'll stop by Mancini this week since there a mile from my house and pick their brains a bit.
 
As was said earlier. When the front end of the car comes up the weight of the front end has to go some where. So where does it go? The rear end! The quicker you can transfer weight to the back of the car the better the car will hook and react. If you sit back and watch the Super Stock cars how do they leave? Front end in the air. Why? Much to your disappointment its not for the show. Its all about the weight transfer. They have the ability with four link suspension to calm down the launch but they still allow the cars to leave in the manner in which they do. But, as stated also there is a point where so much bite and transfer will also slow you down. If you are using a 4 link system you want to adjust to where you get the most consistant bite with the least amount of power loss. This will be done by adjusting the instant center and the pinion angle. Now as far as the front suspension is concerned. I have worked with many cars from cheap foot brake cars to ex-pro stockers. In a low power heavy car I would run the front end loose and I personally used the oldest oil filled shocks I could find and that worked great for us.
 
BJS racing said:
I have worked with many cars from cheap foot brake cars to ex-pro stockers. In a low power heavy car I would run the front end loose and I personally used the oldest oil filled shocks I could find and that worked great for us.
Click to expand...
If the front end is already rebuilt using rubber and not poly or rollers, how does one loosen it up.
When it warms up here, I'll pull the shock, and see exactly what I have on there. I do have a set of Summit cheap 3 way adjustables I can put on the front if the ones that are on the Demon are too stiff, which I think they are
 
The biggest thing that we did was made sure that there was nothing in the front end that would slow the travel. I.E. bent strut bars and well lubricated joints and ends. After that we used the most wore out shocks we could find. Some people say use 90/10 shocks. With those shocks there is a lot of times where the front of the car hasn't settled back down by the time you get to the finish line. Our cars aren't very arrowdynamic as it is and then you leave the front end up in the air at those speeds it hurts your et and MPH more. The motor should have enought power to keep the rear from unloading after the launch and then settle back down. This is the best way that we have found to run with a lower HP heavy car.
 
What he said...lol. The 6 cylinder bars can be helppful like I said witha lot of preload. Norm, on your car, the nose sits low to begin with. So "trick one" is to try to get it a little more level. I would use the MP drag T bars and even the ride height out so the rake is only about 1" when measured from the from of the rocker's pinch weld to ground, and rear of the pinch weld to ground. You may also find your pinion angle gets changed when you do this. So reset that if you have a snubber.
 
On my Duster I just adjusted the torsion bars with the /6 bars to bring the front end up. I was real cheap and didn't want to spend a lot of money on the fancy stuff. The car worked really well for me.
 
The nose on my Valiant was low, but the car hooked reasonably well.

I raised the front end, and now it won't hook for chit. No weight transfer anymore.

'66 Valiant, Slant 6, stock front end, worn out shocks-12:001@110.
 
Actually, you changed the "time" during the launch that the transfer happens by raising the nose. It's probably hitting the tires a bit harder (more sudden) now. Did you check and correct your pinion angle? A pinion that now points up will also change the hit on the tires making it hit harder.

Edit: You can also get a front spring hanger with extra holes to help "tune" the hit. That way you can have the nose at the right hieght, the pinion angle dead on, and the front of the springs down slightly to ease the hit on the tires.
 
[QUOTE='64 Cuda]Awsome wheelstand! Too bad he (or she) redlighted.[/QUOTE]
Yeah, Tobbe's car hooks real well and flies running on that alcohol.
 
Got a chance to get out to the Garage today. It warmed up, so I did a bit of cleaning in the garage, and pulled the front shock off the right side front.
Loosened that side right up.
The shocks it has is Koni adjustable. The type you push together then turn to change the setting. It was set in the loosest setting. but boy does it hod the front end stiff.
On old shocks, where do you drill the hole to drain the oil?
 
I wouldn't recommend drilling and draining the oil from the shocks. It's like not having any front shocks at all!

Koni SPA1 shocks on the loosest setting extend pretty easily but have a stiff compression. The cheapest front shocks I could find seem kind of even on compression and extension. Front drag shocks that Mopar use to sell are in between.

What kind of rear suspension do you have? My 2 cents - Typically, the less adjustability you have in the rear, the more seperation you need in the front to transfer the weight. (i.e.: SS springs) When you start getting into Cal-Tracks, ladder bars and 4-links, you can, and usually need to, start limiting or stiffening the front. SS cars pull good wheelstands. But how much seperation do they have in the front? The faster they are, the less they need it because the rear suspension can be made to do the work. They have wider tires too.
 
Mopower71 said:
What's the best way to set up the front suspension on a drag car, using the the original suspension.
I already have the 6 cyl torsion bars on the front, and the suspension has all been rebuilt. I beleive the shocks are 90/10's but I'll have to double check.
The front suspension feels stiff, when pushing it down, or pulling it up by hand.
I need recomendations on how to get it loosened up for the best front end rise.
Click to expand...
Hi I am new to FABO. I just started racing my 71 Demon. I had a similar problem an you. My car has 28 in tall front tires from MT. With car at ride height, the front end was dead stiff, with no reaction. After talking with Angelo Phillips, I checked my shocks (CE 90/10s) and they were bottomed out! They were too long even though were supposed to be for a body. I installed the CalTrak front shocks, are shorter by an inch. Now with frontend same ride height, it is loose, and lots of reaction.
Would never have thought to check that! Might want to check yours!
Chuck.
 
So, for a cheap weekend suspension, SS springs, 90-10 fronts, and what for rears? Just the Mopar longer shocks? Maybe a snubber?
 
Mopower71 said:
Got a chance to get out to the Garage today. It warmed up, so I did a bit of cleaning in the garage, and pulled the front shock off the right side front.
Loosened that side right up.
The shocks it has is Koni adjustable. The type you push together then turn to change the setting. It was set in the loosest setting. but boy does it hod the front end stiff.
On old shocks, where do you drill the hole to drain the oil?
Click to expand...
long time ago. 67belveredere, worn front shocks w/ 1/16" hole drilled to let the oil out. 318 stock torsion bars, went 10.40-10.60~s fror 14 yrs. only handling problem(other than traction issues) was when a driveshaft broke at 128mph, and cut a 14" slick.
 
You must log in or register to reply here.
-

Back
Top