Homebrew rear suspension taking shape

beepbeep · 01:46 PM

These are details of "935-style" uniball rear coilover suspension that Mattias is putting together. "Swards" are cut by waterjet into appropriate shape and then cut to accept threaded rod that uniball fits into. We will fill this thread with more pictures as it starts taking shape.

There are also threaded rods epoxy-glued (!) onto shocks and coilovers to come.

Click to view:

Chuck Moreland · 08-16-2004, 01:50 PM

Not to throw a wet blanket on your (impressive) fabrication efforts, but have another look at the commercial products on the market. They fit inside the torsion tube such that much of the load is transfered to the tube, not the 4 mounting bolts.

The 4 bolt mounting bosses have a nasty habit of tearing, even when regular bushings are intalled in the torsion tube and delivering much of the load to the tube. There was a thread about this last week.

I would modify your design to fit into the tube, or plan to reinforce the mounting bosses. Perhaps you have already planned for this, and just not yet shown pics of your plan.

beepbeep · 01:13 AM

Quote:

Originally posted by Chuck Moreland
Not to throw a wet blanket on your (impressive) fabrication efforts, but have another look at the commercial products on the market. They fit inside the torsion tube such the much of the load is transfered to the tube, not the 4 mounting bolts.

The 4 bolt mounting bosses have a nasty habit of tearing, even when regular bushings are intalled in the torsion tube and carying part of the load. There was a thread about this last week.

I would modify your design to fit into the tube, or plan to reinforce the mounting bosses. Perhaps you have already planned for this, and just not yet shown pics of your plan.

Thanx for the input! Of course we're not offended by this sort of positive critique, what you are saying is (when you think about it) pretty obvious and probably true

We'll try to change mounting plate it loads the tube as well!

beepbeep · 08-16-2004, 01:57 PM

P.S. Do you have any picture of mounting bosses that fit into tube?

How do you attach them into tube? Is there just a rod behind them that kinda jams into turbe or what?

djmcmath · 08-16-2004, 02:26 PM

Goran, looks pretty neat to me. I'll ask the stupid question, though -- what are the potential gains to this massive and involved project? What's the completed end goal look like? Sorry if this is too elementary for you, but I'm really curious.

Dan

beepbeep · 01:16 AM

Quote:

Originally posted by djmcmath
Goran, looks pretty neat to me. I'll ask the stupid question, though -- what are the potential gains to this massive and involved project? What's the completed end goal look like? Sorry if this is too elementary for you, but I'm really curious.

Dan

There is no real goal. We're just wrenching along and having fun. We have loosely agreed to <2200lb weight (if possible), 400hp+ power (definatly possible) and suspension to match both. Project is actually not so massive as you could believe. It's just a hobby that we do in spare time and as we are manufacturing many things ourselves so it's not so expensive either. Project is quite odd as well, which gives lot's of publicity. Making Porsches fast is many times just a function of money, but we wanted to throw another variable (fun) into it

P.S. Real goal is to take finished car to PCS track meet and do some real hot laps, then open the engine lid and say: look, we bought it on the junkyard for 900$!

jpnovak · 08-16-2004, 02:47 PM

goran,

Here are some pics of a 935 rear suspension parts. Kurt Williams has these on his turbo 69 project

beepbeep · 01:18 AM

jpnovak: Thanx!

I still don't see anything else holding the blue uniball mount except four bolts?

Edit: I see it now, first picture, the round thing behind mount plate goes into torsion-tube I guess?

dickster · 08-17-2004, 03:46 AM

beep,

they LOOK great anyways. i hope you are good at welding!

coil springs are alot easier to work with.

i never would have believed that just using the four bolts wasnt strong enough.....i guess they just hold it all together.

beepbeep · 08-17-2004, 04:13 AM

But there is one thing I wonder about, which part of OEM torsion-bar plate is loaded? As far as i can see, OEM plate is hold there by just four bolts, right?

Should it be enough if we just weld a short pipe segment behind the plate that goes into torsion-bar tube?

djmcmath · 08-17-2004, 05:26 AM

That's outstanding! I love the idea; just wish I had the facilities to do the same.

My dream was actually more like a 550 Spyder (yes, I know they have cheap replicas available), with 250ish horses and an ultra-light curb-weight, like 1500lbs. So good on ya, I'll keep following this project.

Dan

Chuck Moreland · 08-17-2004, 06:31 AM

Quote:

Originally posted by beepbeep
But there is one thing I wonder about, which part of OEM torsion-bar plate is loaded? As far as i can see, OEM plate is hold there by just four bolts, right?

Should it be enough if we just weld a short pipe segment behind the plate that goes into torsion-bar tube?

With the OEM setup, the load is delivered through the bushings - Half to the torsion tube, half to the cover plate.

I would think a well-fit pipe segement could work.