Author Topic: Rear weight percentage on short wheelbase  (Read 7274 times)

Offline Nitro hillbilly

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Rear weight percentage on short wheelbase
« on: March 30, 2015, 06:26:50 PM »
Roo, what kind of weight percentage should be on rear wheels on 115" wheelbase dragster? I have weight scales available. Under 300hp stick shift.

Offline rooman

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Re: Rear weight percentage on short wheelbase
« Reply #1 on: April 01, 2015, 04:28:15 AM »
Unless you are willing to move the motor or add ballast what you have is what you get. Does it wheelstand and if so how badly? Does it go straight if and when it is carrying the front end? If it is rotating violently at the hit it may need some ballast or a different launch technique but there is no hard and fast rule as to the ideal weight distribution as combinations vary so much.

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Offline Nitro hillbilly

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Re: Rear weight percentage on short wheelbase
« Reply #2 on: April 01, 2015, 07:16:50 PM »
I'm in the building process. So I can move the motor were it needs to be in moderation. Thought there might be a rule of thumb. I figured you might have had to rework a car or two.  Looking for wisdom.

Offline rooman

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Re: Rear weight percentage on short wheelbase
« Reply #3 on: April 02, 2015, 04:51:27 AM »
Usually I put the motor 42"-45" out in a 200" plus car but have also built them at 36". Once again it is all dependent on your overall package. If you run a hard compound 8" tire it is more likely to leave with the front end on the ground than if you have a sticky 14" wide deal.  Under 300hp and 115" is a small part of the equation as there are a lot more variables that will have an effect.

Roo
Yeah, I am from the south--any further south and I would have been a bloody penguin.

Offline PSweeney

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Re: Rear weight percentage on short wheelbase
« Reply #4 on: April 03, 2015, 01:54:15 PM »
I ran a 115in wb slingshot with 280bhp and 4sp.  With the manual box, the car will wheelstand no problem, so if this is your thing, have a robust front end end that wont bend on landing.  IF you want to stop it wheelstanding get as much weight forward as you can, battery, fuel, weightbars, filled tube axle.  If you run a wheelie bar it needs to be long and flexible or sprung so that its progressive in its action.  A fixed bar on a manual car will unload the tryes as you hit the bar hard on the launch.  If you don't want it to wheelstand at all run a tall gear.

Offline wideopen231

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Re: Rear weight percentage on short wheelbase
« Reply #5 on: April 14, 2015, 05:31:57 AM »
Air for show and on ground for dough. With FED's being know for wheels up which leads  to most of the misconception that they are ill hndling,I would set motor out aways as Roo man said.Then his knowledge of these cars is  10,00o x's mine and at 2 cent my opion is probably over priced. I spent quite a few hours working to get my engine out to 50" because some guy named Parks suggested 52" and 50 was as close as I could get with work that had been done at time.
Relecting obama is like shooting right foot because it did not hurt enough when you shot left foot

Offline PSweeney

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Re: Rear weight percentage on short wheelbase
« Reply #6 on: April 15, 2015, 06:46:57 AM »
my motors about as close as you can get it with a powerglide, shorty trans, have to engage coupler with the engine hoisted and then slide the whole assembly home.  A full length glide in a car under 140in looks odd in my opinion.  Altered or Funny car it's no big deal.

Offline janjon

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Re: Rear weight percentage on short wheelbase
« Reply #7 on: April 15, 2015, 08:19:27 PM »
Yeah, well the rear in an altered or funny is about as far behind YOUR behind as it is in front of it in a FED.
Just keep the same amount of stuff on the right
as there is on the left. Seeing straight ahead is highly overrated....