Frame questions

[bruno]

This is the mock up my frame for my 35 dodge. I am going to have Cornfield Customs build it. The front suspension has a 4" dropped axel, a 2" dearched Posies spring, Total Performance bat wings, and the bottom of the spring perch will be even with the top of the cross tube and will have 28" tires. The rear suspension is a Total Performance pro street 30" Eibach leaf spring set up and will have 30" tires.
I want to have 5" of ground clearance. I figure the front spring will drop 2 to 2 1/2" but i have no idea about the rear springs. The front will have a 2" Z ( do you think i should have more or less Z or will 2" be ok ?). I plan on having a 3/16 u shaped radiator cradle and a cross member under the front of the oil pan by the motor mounts. The straight 8, adapter plates and transmission weigh about 1000lbs. With Cornfields round tube framing under the cab do you think that will make the frame stiff enough? The frame will be 2x4 3/16 square tubing. Any suggestions will be greatly appreciated.

 

[donsrods]

I think you have too much kickup in the back and it will sit on the ground.

Don

 

[Dirtyrat]

I really like the look of the front of the truck, looks good in the front as long as nothing is below the scrub line and you are happy with things like oil pan to ground clearance, etc. On the rear section, I am with Don on this one, how high is the centerline of the wheel now? Not only will it compress the springs, but the tires will deform some as well from weight.

I think with an engine crossmember, and a trans crossmember you will be plenty stiff enough on the frame at 3/16 wall...

 

[bruno]

Dirtyrat, the centerline is 14" on the rearend. I'll take 6" out of the kick up and take some more measurements. The rear springs are extremely stiff, how much do you think they will compress. The only weight on the rear will be a 4' bed and a 16gal gas tank.

 

[Old Iron]

Bruno, I'm glad to see ya going forward with your 35 Dodge project !!!!!!!!!
This rig is gonna be a hit.

 

[bruno]

Thanks Old Iron, I would have liked to own the 47, wish things could have worked out. Did you ever sell it?

Guess i need to start a build thread after i get the frame.

 

[donsrods]

Bruno, do you have it blocked up at what you want the final ride height to be ? If so, you do need to reduce that kickup a little. The car should only settle about 3 inches, but I always find the rear settles about 4 or so once you start driving it and put some power to it.

Don

 

[Dirtyrat]

Dirtyrat, the centerline is 14" on the rearend. I'll take 6" out of the kick up and take some more measurements. The rear springs are extremely stiff, how much do you think they will compress. The only weight on the rear will be a 4' bed and a 16gal gas tank.

Dont forget you have the weight of the frame, and some of the cab... 100# in fuel as well.
Frame 3/16" 2x4 is like 7lb a foot...

I'd guess 1" of compression on the tire is probably about right?
No idea on spring rate then?

 

[bruno]

Don, the body is at ride height. I had the full weight of the motor and trans sitting where it will be in relation to the spring and the spring compressed 1 7/8" so i figure, as you said ,that it will probably settle to 3". The front axel is sitting at ride height, so i'm thinking when the spring compresses i might not need a Z in the front at all. The rear end is at ride height so maybe 4" out of the kick up would set it c
lose to level. What do you guys think. I'm a newby at setting up frame


Dirty rat, I have no idea what the rear spring rate is. I bought it from Total Performance and they called it their pro street set up.

 

[Dirtyrat]

I'd try to get some info from them on rate, I didn;t have a rate for my rear coils, but I stood on one and had someone measure the deflection with my 200lbs on it =) Better than nothing for estimating!

This is going to be a really cool build, love the powerplant...

 

[bruno]

Dirty rat, Total Performance is out of business, bought out by speedway, and speedway has never offered them. I went to Eibachs web site and couldn't find out anything, i'm going to call them tomorrow. Thanks.

 

[bruno]

Well i called Eibach and hit a dead end. They said TP kit# told them nothing and that their leaf springs were made by an outside source. FWIW The leafs are 1 3/4" wide, 1/4" thick, 4 leafs, 6" arch, and 30" eye to eye. I stood on the spring (206lbs) and it deflected 3/4 of an inch. As dirtyrat said, not very scientific, so i guess i'll err on the side of caution and drop the kick up 6". I don't want to, but can use lowering blocks to level it out if its to high.

 

[Dirtyrat]

Well, thats a starting point, have to start somewhere!

I'm sure you will work it out!