Different length chassis questions

dylancc23 · 5/20/21, 11:23 PM

Hi, I have a few questions on chassis length's. Every car I've owned have all been 87/40's raised rail. Over the off season I purchased a used J&J from a guy and its a 88/41 raised rail. I know he raced mostly winged 410 shows with it and I mostly race winged 358 shows on 3/8-1/2 mile tracks. My questions are, what's the advantage/disadvantage of having a longer car.? Where is the extra inch located on the front and back of the chassis.? What radius rod lengths should I be using.? And should I been adjusting from my base setup with a longer car? if so, how? Just looking for some tips. I know everyone will have they're own opinion on the setup but just looking for a little guidance.

Thanks to everyone in advance!

Rhody · 5/21/21, 5:10 AM

I raced a an 88/40 on dry slick quarter miles with a 360 and it worked well. The 88/41 is going to be harder to get weight transfer to the rear wheels. If you are running high speed tracks with a wing it should work OK, but you are going to start out with more static weight on the front end. As far as radius rod lengths, the distance from the torsion bars to the axles should not change, so I would put the axles in the car, square them, set the front caster and level the birdcages and then measure the distance between the pickups. A bunch of websites have directions for setting the axle locations properly in the car. (I think DMI and speedmart have them on their websites) you can probably find a good video on YouTube also

Hustlin-Hoosier · 5/21/21, 6:03 AM

you might try contacting J&J Chassis , I'm sure that they have the Radius Rod lengths that you need and probably set up info available

dylancc23 · 5/21/21, 10:07 AM

Quote:

Originally Posted by Rhody

I raced a an 88/40 on dry slick quarter miles with a 360 and it worked well. The 88/41 is going to be harder to get weight transfer to the rear wheels. If you are running high speed tracks with a wing it should work OK, but you are going to start out with more static weight on the front end. As far as radius rod lengths, the distance from the torsion bars to the axles should not change, so I would put the axles in the car, square them, set the front caster and level the birdcages and then measure the distance between the pickups. A bunch of websites have directions for setting the axle locations properly in the car. (I think DMI and speedmart have them on their websites) you can probably find a good video on YouTube also

So maybe lower my base set up in the rear on the blocks?

Rhody · 5/21/21, 10:35 PM

With the 88 wheelbase I actually blocked the whole car a little bit higher, but I only ever ran that car on really dry slick tracks. Using the higher mounting holes for the radius rods in back might be better. Blocking lower will change the angle of those bars and the the torque tube. Raising the front a bit may be what it wants. You will have more front axle weight, so it will probably want to turn in pretty good. I would start with a standard setup and see what the car does.

5/21/21, 10:35 PM	#5
Rhody Member Race Count This Year: 9 Join Date: Mar 2011 Posts: 196	With the 88 wheelbase I actually blocked the whole car a little bit higher, but I only ever ran that car on really dry slick tracks. Using the higher mounting holes for the radius rods in back might be better. Blocking lower will change the angle of those bars and the the torque tube. Raising the front a bit may be what it wants. You will have more front axle weight, so it will probably want to turn in pretty good. I would start with a standard setup and see what the car does.