Effects of weight removal
 

Well, the season is over and time to make some changes to the car. I run J/SA and my minimum weight is 3170 lbs, but my car weighs 3225 lbs with me in it and no ballast. The weight distribution is 57% front and 43% back, not that good but it could be worst. The good news is that I can remove 105 lbs off the car with 85 lbs coming off forward of the front spindles. The bad news is that it will cost about $1500 dollars or $15.00 dollars a pound. What I would like to know is, will you see any improvement in your sixty foot or ET by changing the weight distribution. Lets say going to 54% front and 46% rear.

Re: Effects of weight removal
 

Alan, I have played with the weight distribution deal for 3 years straight. I documented and have scale sheets on what I have done. We were able to take my car from 1.57 60' down to a best of 1.462'. All with the same trans and rear gear combo. My A1 converter did help with .03 of that. My car is 56% on the nose at 3100 lbs. Every lb moved from the front to behind the rear axle centerline, just makes it a better car. Keep in mind to play with the corner weights so the car "sees" an easier push down the track.

Good Luck!

Wade

Re: Effects of weight removal
 

What if a car weighs more on the rear? Can it ever be to much on the rear

Re: Effects of weight removal
 

Yes.
I think one thing that is forgotten, when dealing with weight and moving it around in the car, is the "Ride Height"
If you move 50 to 100 lbs off the front and to the back put the car back at the original ride height. Sometimes moving weight to the rear resets your rear suspension as well as making the rear % more. What is really helping the car be quicker or slower?? Weight bias or suspension change??? Was the car too high in the rear to begin with?

Re: Effects of weight removal
 

Suspension wise, the best thing I ever did was loose the multi-leaf rear springs (SS Mopar style, both with and without Cal-Track bars) and install Calvert rear springs. Not only did it take about 40-45 pounds off the springs, it put it in the trunk. But the real deal on that was lowering the rear of the car. John Calvert worked with rear spring segments with me until I got it where I wanted it. The car no longer danced around when I shifted it; something my friend Mark thought was me yanking the steering wheel all along. First pass was straight as an arrow with the lowered ride height. Depending on my class (E/S or D/S it was around 51.5% to 52.5% weight on the front.

I spoke to a rather hard leaving '71 Z-28 stocker owner. He claimed 46% on the front! I can see that as possible in one of those cars.

Re: Effects of weight removal
 

Jeff,
My car works like it should with 51front/49 rear weight balance. It works so well it will be upset and slow down if you put wheelie bars on it. It also responds to some side to side % with the left front corner carrying the most weight. When I change classes and add weight it usually ends up in the 47.5-52.5 area and it is just not as good on the suspension or the tires. It has too much dead hook. The tires and the little engine just don't get along well with it that way. I'm thinking about trying a longer, heavier rear spring with the weight and see if I can get the rear end to react like it does with the lite combo. That should allow me to raise the ride height on the rear a little. There is nothing like tinkering with suspension to get it to work better. The suspension is one area that will show you results real quick. Good or bad!

Re: Effects of weight removal
 

I was talking to my buddy Don Kennedy yesterday. He just returned from the 2 races in Vegas. He played with the 4-link a lot as his car is still somewhat new. His car is a GT/AA Pontiac Jelly Bean car with a SD455. His 455 makes around 650 HP while his competitors there make in the 700 HP range. He had the second fastest 60' times (1.24 @ the altitude track). He has a new engine coming that will have him in the top tier of the GT/AA field. Your right, there's a lot to be found in the back end of a race car.

I learned a few lessons on the rear of my AMX. With the multi-spring The 60' times were constantly in the 1.52-1.55 range for a long time. I thought when I built the car 1.45 would be the norm. Based on what I know now, it was in a bind; too stiff. Now I realize how I could have fixed it. But just bolting on the Calvert springs sure made it easy. And that allowed more weight in the trunk.
60' times dropped to the 1.47-1.48 range and after learning more about clutches & more power from the engine I had it down to 1.40-1.42.
I believe 1.38's are not unconceivable but I then placed the car in SS/H. Automatic cars tend to have even quicker 60's.
Also, I constantly scaled the car when making changes. Scales are under used & are a great tool.

Also, not enough racers look at 330' times. I think that is more telling than anything else. There may be a 1-2 shift before the 60' clocks that can skew the data.

Re: Effects of weight removal
 

Adger, you are right. In my case, I have 2 extra sets of rear coils to adjust ride height for a particular class/weight. It doesnt seem to mind exactly where it sits though. The 60's seem to stay close.....

Wade

Re: Effects of weight removal
 

Jeff,
I think one of the reasons my car doesn't like the wheelie bars is the extra 15 lbs of unsprung weight they hang out on the rearend. That has to cause unwanted issues with shock and spring control. I proved my point by raising the bars and not even letting them touch the ground.I can see your improvement with the less spring weight.
Wade,
Good idea about extra springs.

Re: Effects of weight removal
 

My comment doesn't relate to weight removal so much,since stockers have a minimum,establishing an absolute that always prevails, but when I built my first '68 Chevelle several years ago,I used 70 Monte Carlo 454 rear springs right out of the Moog catalog, used the lightest Moroso front springs i could and the loosest shocks I had, and the car used to hook pretty well, but it had a rotational effect upon initial launch. The car would leave,squat on the right rear,twist,and yank the left front tire pretty high.It always went straight, it was only a 327/250 horse, but there was a lot more going on than there needed to be.A rule change mandated that a 5 point roll bar be installed about a year later. That seemed to take some of the body roll out after I replaced the rear springs, then some Koni shocks and new front springs took most of the rest out. On an A body,I came to the conclusion that the right rear spring is as critical as the left front. Photos of the car leaving at Pomona seemed to reflect the fact that the body roll is nearly eliminated.It's easier to drive, as well. Larry Petersen's '71 B/SA car works about perfectly.