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Author Topic:   rear percentage
bbracer17
Member
posted May 28, 2000 09:30 PM
I had to add 100 lbs of ballast to the rear of my car just to get 56% rear. I would like to try 57 or more. My question is that I can move my motor back 1 inch to get the 72 inches from the rear end center line to the trans bell housing flange that IMCA allows, will this make much of a difference on the rear percentage or is it alot of work for little results? Also I can use a 2 inch shorter fan spacer and move the radiator back 2 inches, what do you guys think? I'm just trying to avoid adding anymore ballast, the car weighs 2550 with 22 gallons of fuel and me.


jammin
Administrator
posted May 28, 2000 10:32 PM
The easiest way to do this is go to a 32 gallon fuel cell, which is legal also. This will give you appox 70 lbs of weight to put where you want it(almost 3 percent). I think this would be the best move.


awkwardjeff
Member
posted May 29, 2000 11:10 AM
hey, ive got a idea.....instead of adding wieght to the rear of the car why not lighten up the front??????????how big is you rad. maybe you could go to a smaller one. How about taking some wieght off the frame??
shorter front bumper,maybe???? lighter spindels and rotors, hollow bolts in the front of the car???????? there are all kinds of ways to change percentages around.....where is you battery?????remember the farther you move something the more effect it has.........meaning if your battery is above the rear end move it to just infront of the rear bumper.......maybe a combination of these things can work for you......... I JUST THOUGHT I WOULD give you some other ways of doing the job......jammers is the easy way but you did say you didn't want to make the car any heavier.........balance is more important than total wieght though.........JEFF


bbracer17
Member
posted May 29, 2000 11:27 AM
Thanks for replying. I'm using a 24 inch wide radiator but I'm running gas so I don't want to go any smaller. Also hollow bolts anywhere on the car are not legal nor is lightening the front rotors, that is if I'm reading IMCA rules correctly. I did machine the rotors as thin as I'm willing to go. I have already found some lightening that I can do around the front bumper area, I'm just waiting till I need to build a new one which will probably be soon enough. I have the motor out right now so I guess I'll go ahead and move the engine back and see how much change it makes. Thanks again for answering, I have a better car this year because of this forum.


jammin
Administrator
posted May 29, 2000 04:42 PM
IMCA is pretty stiff on the front end stuff too. It is hard. If you move the mounts an inch farther back, it will help a little, but if you use the tank as a ballast itself, you can control your weight as you burnoff fuel, which has always helped me. Any time you take weight off the front it does got to the rear, as Jeff says, but getting the weight where you need it is another thing. Hope this helps.


awkwardjeff
Member
posted May 29, 2000 05:42 PM
okay, moving the motor is what you are going to do.......... PLEASE....make sure you get the drive shaft the right length......also, what year stock front clip do you have??????
sure your rules a restricked, but the pinto spindles help with bump steer and wieght....
also if using a metric front clip you can use lower a frames off a 70-72 nova this will widen the front but also move the front wheels forward....changing the wheel base this would help with rear percent too.....although this needs some thought because of upper a frame mounts, bump steer and a host of other things that happen when you move the front wheels forward......just a rambling thought you already choose your route to get your rear percent........good luck.........JEFF......ALSO: HI TO YOU JAMMIN


bbracer17
Member
posted June 02, 2000 10:30 PM
I was planning on letting you know how much difference moving the motor back 1 inch made but the new motor I installed appears to be about 25 lbs heavier. It has a steel crank and its an older block but I sure didn't think it would way that much more. I guess I'll just add the lead for now.


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