157 inches of crazy!

[BenE64]

Hello, I have been snooping around here for a while gleaming bits of information off of some of the awesome threads on suspension mods so I thought I would say hello and thankyou for sharing your knowledge with people like me.

I found this forum while researching possible designs for the rear suspension of a couple of my projects and found an excellent thread started by "Exwestracer" which eventually inspired me to start building my own torque arm rear for my main project truck.

Not sure if he is still around here but I would also like to thank Norm Peterson for sharing such a large amount of info across this and other forums, I have been searching different info on suspension everywhere and whenever his name pops up on a search or in a thread I learn something, If I ever get a chance, I'd like to buy him a beer or three!

Anyway on to my project, its a 1970 IH truck, which I am in the process of turning into.... well as much as possible a pro touring beast. It is the biggest ugliest worst handling slowest piece of junk I've ever come across! Which means every thing I do will be an improvement. As it currently sits I have stripped it down to a bare chassis, I blasted it to bare metal and have began planning the suspension mods and engine placement. I have cut the rear off the chassis and flipped it which gained me 4 inches of drop on the frame.

A run down of driveline.

Cummins engine, 4r100 auto (not exactly light weight corner carving base, but it needs to be able to push 6000 pounds of un aero dynamic brick wall around)

Front independent conversion, C20 chevy IFS needs to be majorly cut and shut to fit.

Rear is a F350 diff with a home made torque arm

Hydroboost conversion

Front power rack and steer conversion

Air bags all round.

As the wheel base is 157in long it is not going to break any track records but if I can get it to go fast stop fast(ish) and go around a corner with out putting me into a tree I will be happy, think of me as the slow kid out the back field digging a hole with a stick, tolerated even if it is just to fill numbers!

I bought Perf trends susp analyser a while back and have started mapping all the front and rear into that and have a rough base to start from. I have also began learning Inventor to try and draw it all up but that is proving rather difficult form so its slow going. Keep plodding along!

Cheers

[andrewb70]

Welcome!

Looking forward to updates!

Andrew

[DreamRyder1963]

I am looking forward to this. I love the old intenational trucks and drive a 71 c10 as a de so I get where you are coming from.

[BenE64]

Here is a photo of ugly before treatment began.

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And as it sits now. All I have done is cut the rear chassis of trim it and flip it 180* so I lowered it by 4in. About as low as I can go really with where the rear sits with out going nuts, plus a 20ft long truck 4in off the ground is not going to be fun to get around in, I would get hung up on everything. 10in is as low as it gets.

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I have mapped out the suspension and put it into susp analyser, Pretty happy with the rear torque arm results as it is now. Anti squat is roughly 100% and no roll steer, although I may tune this a bit for a bit of roll under steer yet. I am concerned on what the loads on the arm will be as the rear air bags will need to be mounted low and behind the axle, which in my mind will cause the axle to try pivot around the centre line and will load up the torque arm, initially I had the LCA's at centre line as in the thread I referenced in my first post but I have decided that by moving them down 5inches I am not sacrificing much handling but they "should" counteract the pivot force from any weight in the back acting on the springs. After playing around with converging the front mount points I got it to basically neutral understeer/oversteer again. I am going to need some seriously beefy brackets welded onto the diff!!!

The front is untouched from standard so far, I am hoping I have got the measurements fairly close, it was an elaborate set up of string lines plumb bobs and levels to try and get it as accurate as possible, but there is still a bit of guess work in it.

I plan on modernising the C20 geo a bit, at the moment it has very little caster at static ride height 2.5*
I am going to try and aim for 7- 7.5
-.6* camber gain per inch of bump
0.6* caster gain per inch
1:1 vertical RC height to chassis height movement ratio
Less than 2.25" lateral RC migration
Minimise side scrub

All sounds good in theory but in reality may be impossible. Good practice though for when I do build a faster car on a better platform. And the fact I have never built a car before means its all going to be a learning curve.

Anyone have a C20 they can look at and see if the front looks like the diagram? I got hold of a front subframe but never saw it on a truck at ride height.

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Thanks for the comments. Cheers

[Bonehead]

So epically bad ass.

[BMR Sales]

Welcome!

[BenE64]

Holy #$^@! its been a while, had to Google search just to find my own thread! Well I am finally back into it, I have been collecting bits and pieces for the past few months, I sourced a power steering rack from a ford transit van that measures up perfect so I should be able to use it with little to no bumpsteer, I have found a full set of steel rims to suit the ford diff and to dished steelies to fit the chev front. Even got some chrome dress rings to fit so I will be flasher than a rat with a gold tooth:jump:

I have spent a stupid amount of time on the computer for what is supposed to be a shed job. I have come to an end result with my front suspension design. Has proven very difficult to first draw in CAD and then transfer into Perf trends. I have spoken to the engineer and it is going to be harder to approve with aftermarket components rather than the OEM parts so I have basically used all original arms, spindles etc in my design and arranged them to what I think will give me the best ride and handling.

So front end specs are now

RCH 9.26cm and move about an inch per inch dive. Lateral is a bit more than I'd like but its the best I can get with standard arms.
Caster static 7.5degrees
Caster gain .79 degrees per in dive
Camber static -.5
Camber gain -.58
Scrub radius is 9.7cm
Antidive is about 40% with a bit of gain in dive.

Had a heap of good results and then would go out and mock it up and find something wouldn't work, the biggest drama has been the ball joint angle in the arm has been too tight and not allowed enough articulation, I haven't been able to get the perfect result I would like but I tell myself its not going to win races it is going to carry 2 ton in the back :smoke:

So I started building a jig to mock it up
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I machined up some little cones to centre the rod in the ball joint tapers and set the camber to 0* then adjusted the caster, it was a lot easier with the threaded rod adjustment to get accurate results.

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Hope to start cutting the front subframe this weekend (kids permitting) and get a bit more to look at than 2 slowly rusting rails! Hope someone finds bits of this interesting....a lot of old rusty stuff being re used rather than all flash brand new gear.

Cheers Ben

[BenE64]

Front Sub frame sectioned and LCA pivots set in correct position. Got the sub frame in the chassis rails and got a little excited and welded the top out, hopefully it doesn't bite me in the arse later. a few pics of progress

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Upper and Lower control arms fixed in position so I could use it to position the Sub frame....pita to do! drilled all the rivets out of the UCA bracket and bashed them out.
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Smashed 2 stubbies down for courage and took to it with the cut off disc.
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About 3 dozen measurements, another hour of grinding and re-measuring and got it tacked in to see if it fits.
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And welded in. Started experimenting with boxing in the sub to the chassis rails, I have another set of rails of a buggered truck as spares. Finished up and started checking steer rack position, this next bit may result in cutting the sub back out :pat: In any case the sub frame is going to have a tough day with the plasma cutter!

[Poopy]

Well that's pretty cool, hurry up and get us updates!

[cornfedbill]

Looks very intense. This is definitely out of the box and the type of project I really appreciate.

Keep the updates coming.

[wfo guy]

Interesting project. I grew up on the farm with binders. I know what you're starting out with. :)

[BenE64]

Well that's pretty cool, hurry up and get us updates!

Thanks, I'm working on it as much as life allows me! Thanks also for the tips on the panel work, there is not much to work with on the old girl, I need all the help I can get!

[BenE64]

Looks very intense. This is definitely out of the box and the type of project I really appreciate.

Keep the updates coming.

Cheers, intense is not the word my mates use!

[BenE64]

Interesting project. I grew up on the farm with binders. I know what you're starting out with. :)

Yes they didnt go over board on extras or even steel on the panels did they, door gaps vary 3/4 inch over the length of 1 door. But they do have a brick like rustic charm that I just couldnt resist, or it may have been the goat crate it had on the back when I first saw it, I'll never know:jump: