The two biggest things I can recommend are wide, sticky (H-rated or better), low-profile tires (50 series or lower) on wide rims, and lighten up the truck as much as possible. You might de arch the rear leafs too.

Lou

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Home of Slant6-powered fun machines since 1988

Justin-

On the wide tires....295/50/R15's fit on the rear of mine with the suspension bottomed out--no rubbing (On an 8.5" wide rim with -1" offset)

Those same tires will rub on the front if suspension is bottomed out. The 245/60/R15's i have on the front now do not rub (bottomed out, same rims as the rear)

Where did you find the slotted rotors for the front, and have you found a source for a rear disc conversion on the 80's trucks?

-Aaron

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The "Silver Bullet"
87 Ram D150

There's enough out there about suspension tuning to fill several books. I would suggest reading one of them to get a good understanding of what the effects of various changes will be, and how you can test the handling and see how it is improving. The best introductory handling book out there is probably Fred Puhn's <i>How to Make Your Car Handle</i>.

For important mods, I would definitely agree with Lou's suggestion of stickier tires. My Dart rolls along on Z-rated Yokohama AVS Intermediates, which make a huge difference. If you are going to autocross it, I would suggest something even more aggressive, like a set of Kuhmo Victoracer V700's (note: you may want to keep these on a spare set of wheels and save them for racing). I would also add a rear sway bar and a stiffer front one at the same time. Adding just a rear sway bar may make for too much oversteer.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

Wow i havent been around for awhile

Ok i already have the tires, they are a pair of Cobra GT's and are 295/50/R15 (were HARD to get) and i have the fronts 255/55/R15

I'll get the name of the company with the slotted front rotors (and they AINT cheap!) and the rear disc conversion is from http://www.tsmmfg.com/ (thanks Lou) As for lightening the truck i have been looking into a set of Fiberglass front fenders (the truck is 3400lbs with out me in it and a full tank of gas) but i want to lighten the front end a bit. I have also found a company (via my moparman) that makes lowering kits for these trucks.

Matt, thanks for the name of the book, i'm going to look for it tommorow, As for the front sway bar, i dont have a clue who makes one, the rear isnt too stiff b/c i have never had a problem with the rear end in my truck, its always been the front that wants to take a dive around the corners (the 3/4tonn springs helped lots for this)

Thanks again and keep the suggestions comming

Justin

Justin,

If the ends of the truck are actually rolling independantly of each other in corners, you've got some pretty serious chassis flex problems. What is more likely is that the axis the truck rolls about is tilted, so rolling will make the front end dive and the back end come up a bit. Stiffening it at either end would reduce the front end diving, so the ballance of stiffness front to rear is not to reduce the amount by which one end rolls compared to the other. It is to produce a ballance between oversteer and understeer. The book I mentioned does a great job of explaining how this works.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

Hey,

The chassis isnt flexing that much at all i dont think, what it is from my veiw is the truck is a shortbox (very light rear) and a very heavy front end (the rear sits about 3" higher than the front) and the front dives in the corners because of this and i really need to lighten and stiffen the front end up, The truck is great even though the front end is so soft (its a pretty soft ride but since the spring change its gotten sooo much better) I can take offramps at 75MPH plus tires have great grip, the only thing is i need to know how i can stiffin up the front.

I have all new MOOG front end parts on it (complete rebuild) and brakes exceptionally well (hehe i know that one for sure ) so the only things i can think of is a bigger sway bar (got no clue who would make one ) and PST bushings. Possibly new shocks.

As for the rear, it handles exceptionally well and i'm surprised that it doesnt want to pass me. It has only happend one time (with my father driving we hit black ice at 60MPH and almost rolled) but it sticks exceptionally well

Cheers
Justin

Those Cooper Cobra's were hard to find justin? Those are the same tires i have and the tire shop even had them in stock up here... They are excellent "grippy" tires. They whine a lot on corners taken at twice the "suggested" speed but never let go (you think YOU have body roll issues ) What i find amazing is that these tires are also pretty darn good on ice (not SNOW now...ice)

Good luck. Id like the name and some contact info for that lowering company too if it isnt too much trouble

-Aaron

I can understand why you're thinking that way, Justin. The front of the truck is diving when you corner, so it seems reasonable to assume that more stiffness at the front would make for less dive. However, this is not the whole story. A lack of rear roll stiffness could cause this, too. This seems counter-intuitive, but here is an explanation of what's going on.

First, let me state that this applies to steady state corners - things like very long cloverleaf onramps. If you are accelerating or braking through the corner, there are other forces you will have to consider that would make the front end dive. Now, consider the forces acting on your truck as it makes a left turn. The momentum of your truck will try to carry the truck to the right, giving you the feeling of "centrifugal force" that physics types will always remind you is not a "real" force. Well, it's close enough to a real force that we can treat it as a real one for purposes of analyzing your truck in a corner. The cornering will create a force that pushes your truck to the right. This is the only force due to the cornering - all other forces will be no different from what the truck experiences in a straight line at the same speed.

So, you've got a force pushing the truck to the right in this case. You do not have any forces from the cornering that are pushing the truck backwards or forwards. The only effect this force can have is to move weight from the left side of the truck to the right side. It <i>cannot</i> move the weight from front to back, or vice versa.

Next, we have to consider how your suspension will react to this weight transfer. On many vehicles with an independant front suspension and a solid rear axle, the car will rotate about an imaginary line that is higher at the back than at the front. This line is likely to run from a point close to the center of the rear axle to a point directly between the front wheels and an inch or so off the ground - although this point may be on or even below the ground. The result is that the truck will lean in such a way that the right front fender comes down steeply, the left front fender comes up slightly, the right rear come down slightly, and the left rear comes up steeply.

It would not truly be diving in this case, as it would if you hit the brakes hard. The truck is instead pivoting about its roll axis. It is important to understand the difference. Diving can be reduced by stiffer front springs or by changes to the front suspension geometry, and will not be affected by anti-roll bars or any changes to the rear suspension. The pivoting effect, on the other hand, is the only effect pure cornering can cause, and the way to reduce this is to reduce body roll (OK, bringing up the front roll center or dropping the rear roll center will do this too, but that is not something I want to get into here!). Body roll can be reduced by stiffer springs or anti-roll bars, and this stiffness can be added at either end with the same result as far as body roll is concerned. Most of the time, if you have this problem and stiffened the front suspension, you could reduce the stiffness at the rear suspension to the point where the front end drop due to pivoting would be every bit as severe.

I know this is a bit hard to follow. The book I suggested may make this easier to understand.

On the other hand, your comment that you are surprised that the rear doesn't want to pass you suggests that adding more stiffness to the rear suspension would make for downright scary handling if you do not also stiffen the front suspension. This is because additional rear stiffness will often create oversteer, and too much of that could easily make a pickup try to swap ends.

By the way, Addco sells stiffer sway bars for your truck. Most of their kits are designed so that both the front and rear bar should be installed together for best results.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

Hey,

Wow thats alot to take on at once

But i understand and know where your comming from now, Thanks for reccomending that book to me, i picked it up and its got alot of great info and can explain things very well!

Justin