| Setting up MN12 suspension for drag racing |
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All of us had traction problems in a big way with your cars, but here are the things we suggest you have it done to get your 60 foot times (directly related to traction) into reasonable territory.
- First off, the front sway bar. You want weight to transfer rearward as quickly as possible, and the sway bar is not very hard to disconnect at the track, just remove the links attaching it to the suspension, and make up some hangers to hold it up and out of the way of everything solidly. The car will go straight fine, but you will want to be slowed down before turning onto the return road, as the car will handle similar to an aircraft carrier around turns.
- Now, also thinking wieght transfer, get the battery out from under the hood. The 65-650(or 65-850, Like I have)is not a lightwieght battery, weieghing in at nearly 60lbs. And it is in the absolute worst place it can possibly be, up all the way in the front left of the car. Mount it in the trunk, behind the right rear tire, and put it into a sealed battery box (Summit makes a really nice one). Just get one of those sidepost adapters (the things that screw into a GM style battery to use in a top post car), make up rubber bushings (to isolate it from the chassis), and mount it, ungrounded, where the battery is under the hood is right now.
Then attach the stock positive cable to it, this gives you a convenient jumpstart location. Then run a 0 Guage cable under the car to the starter, and a ground strap from the battery to any ground available in the trunk, and another strap from the chassis to the engine. NHRA also requires a cutoff switch in the + line, I don;t have one in my car, but have yet to be called on it at the track, most tracks won't get into that until you hit 11's. If they do, Moroso makes a "remote" switch, I plan to just drill a samll hole thru the bottom black poart of my tailite to pass the handle thru...
- Back to the suspension. Unfortunately, there are no 90-10, 60/40 or other biased drag shocks or struts available for these cars, however, if this is not a daily driver, there is an old as hell trick you can use. Find the most worn out front struts you can, they will be rea;lly loose, and while not as effective as 90/10sm they will allow the front end to raise up really fast...unfortunately, they will also come back down just as fast....but they will get you out of the hole in a hurry...and hopefully by the time the nose drops back down, you are at halftrack and don't need the off the line traction you had.
- Replace the rear bushings with either solid or (if you can find them) urethane bushings. This will reduce suspension deflection.
Also, I have found that the stock ride hight works well, but SLIGHTLY lowered works even better. I mean slight...as in an inch or so up front. Go as stiff as you can find for the fronts, this stores more engergy in the springs, and when unloaded as the car launches, they tend to raise the front end more, transferring more weight rearward. With airbags in the rear springs, try to inflate the right rear a bit more than the left for better traction(think about torque and you can see why).
- You want to leave the rear sway bar intact. The "perfect" launch is when the car RAISES, not squats in the rear. Think about laws of motion...for every action, and opposite and equal reaction...as the rear bumper and frame go down on the suspension, compressing the springs, the tires move UP, away from the track, breaking loose.
- If there was a way to, I would try and maching offset rear bushings, or reset the rear suspension mounts to create a NEGETIVE caster out back..so as the tires move forward on the suspension on launch, in therory they should also be moving
down, getting planted.
- Also, experiment with tire pressures. The fronts you will want to keep high at the track (typically run 45PSI with street radials). Out back, despite rumors that radials don't work well at low pressures, depending on the track conditions, temperatures, ect....You can get btter launches at as low as 15PSI in street radials. Drop the pressures a half lb at a time until your 60 ft times are the best they can be. On the slicks I used to have, I was running 8Psi at times.
- Just remeber, these are trick for the track, and the car will handle spooky on the streets with things like worn shocks, no sway bar(these cars are heavy...and will roll alot without the front bar...and the front tires overinflated to 45 PSI, if you hit a pothole, can very easily blow out, and rears running under 20 on the streets will overheat and you may find yourself doing an imitation of a Ford Exploder SUV after more than a 5 mile drive at 60+MPH. Also, trust me, solid rear bushings are noisy...they squeak and rattle quite a bit....not to mention that they will transmit every little vibration thru to your butt in the seat...
V8 Thunder
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