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Discussion Starter · #1 ·
I have a 70 Duster with a mild 440, 727 w/4200 stall converter and transbrake, Dana 60 w/4.10 gears, 10.5x29" MT slicks, Comp Eng. adjustable drag shocks set at 50/50, no pinnion snubber (currently) and a set of the 002/003 super stock springs.

When I launch with the transbrake, I get some wheel hop, with or without the pinnion snubber. When I foot brake launch, I get no wheel hop, pull the front wheels a few inches off the ground, and have about the same 60' times. I've asked around a bit, and get quite a few reasons for this. Use of/lack of or improperly set pinnion snubber, shocks to short, played springs, etc. I've tried with the snubber, without the snubber, set the snubber to touching the body, 1/2" and 1" clearence. The shocks are definately long enough with 4" of excess travel with the springs full extended. The springs are installed properly and only have about 15 passes on them.

I haven't tried the aluminium busings in the front or putting extra straps on the front section of the springs yet. Would either of those help or are the SS springs just not a good choice when using a transbrake? Would I be better off going with the Caltrac setup?. The car sees some street time, but I'm more interested in launches at the track.
 
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Have you tried front spring clamps yet ? Cal-tracs sound like a great way to go beyond trying clamping the front spring segments. Two per side will be all you need. This is an old school Direct Connection fix which worked for me .

   Chryco  ;)

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Discussion Starter · #4 ·
Thanks for the tips guys. I was hoping there were a few more things I could try before scrapping the springs and going to the Caltrac setup...since I'd want to get the whole setup with the mono leafs and 9-way Ranchero shocks and the racing budget is low this year. :'(

As for the clamps, what is the proper placement on the front section? I don't have my Mopar chassis book handy.

Thanks again.

BTW - nice pic Chryco :)
 

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Go to my site an you can see where I clamp my springs. From my experince the harder you try an leave with ss springs the softer the car will leave. Thats why it works better footbraken.

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I have fought wheel hop before and in my opinion the angle that the leaf sping in is installed is the most important factor. The front spring eye should be lower than the axle. The angle of the spring from the side of the car should angel downwards from back to front. I used five clamps on the front segment, I also used an upper link when I went to a trans brake and worked amazingly well. Not a leaf link but close.... If your front spring eye is higher than your axle you will always be prone to wheel hop in some conditions in my opinion.
 

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Discussion Starter · #7 ·
I did move the springs inboard using the Mopar relocation kit a long time ago. The front eye is definately lower than the axle. The angle does look like you described. Originally, I had the spring mounted in the top hole in the hangar and then moved it to the lower one with no difference in the launch.

5 clamps?! That seems like a lot. I've seen 1 or 2 on the front, but not that many. Did you have to keep adding them until the hop went away?
 

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I have super stocks with a trans brake in my duster. I ran into the problem with mine. I clamped the rear of the springs at every segment, poly bushings. I left the stock clamps on the springs. I 60 foot at 1.45 and run [email protected] 130mph. with out wheel hop. Hope this helps..
 

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Discussion Starter · #9 ·
One more question...should I be running with or without a pinion snubber with my setup? I can't seen to get a definative answer on that.
 

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How much pinion angle are you running? I've never experienced it but, I have heard that an insufficient amount of nose down pinion angle will result in a wheel hop like symptom. You might try a longer rear shackle. If your car launches violently and extends the springs to the extent that the shackle runs out of travel abruptly I could see that unloading the tires also. The longer shackle will raise the car up in the rear and affect pinion angle though.
 

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Discussion Starter · #12 ·
I'm running with 6 degrees nose down on the pinion angle. I also have longer aftermarket rear shackles.

I'm going to try the spring clamps and setting the shocks to a higher extension setting. Not sure when I'll have a chance to get to the track for a test run though.
 

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I am having the same troubles as your Duster. I just made some clamps for the springs to try this weekend. I seem to launch and not get the weight transfer, but a lot of body rise. My shackles angle correctly, at a 45 degree angle, we just put a relocation kit in it over the winter and a dana 60, figuring the weight might help, but i still spin. The 2 other cars we run do not have the problem, their 60' times are very consistent, in any heat at all mine fall off. I have super stock springs, and comp. engineering 3 way drag shocks in the back. I was leaving at 3000 rpm this last weekend. My 60' times last weekend were a 1.49, 1.50, 1.49, but when the track warmed up in eliminations they fell to a 1.52 first round, and a 1.56 second round, and you can't win with those. I am going to try the clamps, one thing I noticed after I put those on is that when you push down on the rear bumper the car is a lot stiffer than my dads cuda. I am going to up my launch rpm to 3500, where it used to be anyway. But if the clamps don't seem to help Saturday, I will switch to the junk old shocks, and take the clamps off and make it loose for Sunday...we'll see what happens or what works best. The next step is either ballast, or caltracs...Unless anyone else has something thats working?

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I think slick treatment would be unnesessary...and a pain the butt. A launch like this is few and far between and as soon as the front wheels come up it normally feels like it unloads the suspension. I can't exactly explain it, but it is doing it because the 60ft times are all over on this car and there dead on with the others and it's the same suspension...we'll see what the clamps do.

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After clamping my springs I was a little leary of letting go of the button the first pass, I copied the way it was on the '64 from carpetperfect.com. I launched the car at 3500 rpm, and I have never had the car leave that straight, it pulled both front wheels and I had 3 different comments on how well it left. My 60' time actually slowed down a little with the clamps on. I went from 1.49-1.50 60' times to 1.52-1.54, they are more consistant, however the car still spins when the sun is out. I am not sure if it was poor track preperation, but during first round my 60' time fell to a 1.57, it was plenty hot, and I figured it would go 1.54 so with my 10.91 dial...I ran a 10.96...Not too impressive, treeing the guy still lost by .0025. My point is, the car leaves amazingly straight, and with good track conditions it helped the launch, but the 60' times were slower. Did anyone else have the same results with this?
 
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SuperStock - get someone to videotape your car from the side and rear, focusing on the rear suspension, leaving the line and really analyze it in slo motion. Your car might need more tire. It's really working well when you can lift the wheels like that. I'd also try the car at a different track and see if the track itself is to blame for the slow 60 ft times.
The clamps on the front half of the spring really help when you have a bit of horsepower. Think of the front half of the spring lke a ladder bar - and the thru bolt on the front half as the point where all the car's energy is applied to drive the car forward. The stiffer the front half of the spring is the more of that energy is transferred into the car, instead of it bending the spring. Also, the higher the front spring eye is the harder the hit on the tire, just like moving a ladder bar up one hole in the front makes the car hit the tire harder.
 
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