will mounting a rear end this way work??

... anyone ever seen something like this done before??? Im wondering if it will work?... Im trying to put together all of the plans for a bubble top rod Im about to start and this is what Ive come up with... the basic problem im looking at is that it will not have a drive shaft, but I would like it to have at least a little suspension movement... My thought is that if I make the pumpkin stationary on the same axis line of the transmission, but allow movement at the ends of the axle I could get a few inches of suspension movement.. Its a see-saw which I know isnt going to be the best, but with heavy coil overs I think something like this would be better than a solid mount dragster style for something I want to be able to drive a little.... I have sketches of the rest of the car posted on the art show too, if anyone wonders why it would need this ....
So, anyone ever seen anything like this??? and will it work??? Thanks

 

Why not just install a Jag IRS and be done with it?

 

I'll start by saying that I'm no engineer.....BUT that doesn't look like it's going to work....and here's my reasoning.

If you hit a bump on the right you need to have a divot on the left the same or larger for it to move at all or it's going to force the left side of the car up.....in addition to the fact that you'll be creating all sorts of sheer/double sheer points in which shit will fail and you'll die (potentially).

That said why not use a IRS, same principal of no driveline, old jag rears are cheap and use dana 44 (I think) pumpkins and you'll actually have suspention that wont put you in a tree.

Edit....that guy above me is fast!

 

How does it move straight up and down? don't think it would work to well at all.

 

I can't see any way it would possibly work, something is going to crack . The Uncertain T had pretty much the same setup as you pictured, but I bet it only got driven from the trailer to the show floor.

Like Pasadenahotrod suggested, just put a Jag or Vette indepenent rear in it and that will solve your problem. Or maybe go with a shortened Powerglide like the drag cars use and then you can fit a short driveshaft in there.

Don

 

Study the dynamics of u-joints and you'll understand why this won't work. You need 2 joints in phase, and the angle of the trans and rear axle within 2 degrees or it will vibrate bad. You only option to have a vette-jag independent suspension or mount the engine-trans-rear axle in a separate frame acting like a swing arm. It would act a little funny because over half of the weight of the car would be sprung weight. Depends on your application.

 

Irs would be great, but just wouldnt work in what Im building.. and it doesnt move up and down at all, in fact the coils will be so heavy it will seem like no suspension at all.. it will have super tall sidewall tires on it that I think will help but basically it will be like its a solid mount rear end.... except it will be able to move in an extreme case if it needed too.... the car is pretty much a dragster style frame..
I know this isnt the optimal idea at all... but, Im not sure what else I can do except solid mount it??.....
how about this question... if I was going to allow the rear end to move normally, what would a minimum draft shaft length be?? could I get awat with one say 5 inches long?

 

Yes, I wondered what uncertain T had in it, and thats actually pretty close to the wheelbase im trying to get..... my problem with the jag or vette stuff is that its going to be too narrow... and modifying it beyond what I think I can do

 

actually, you guys are right... what am thinking?? I was just looking at jag and vette rearends and thats what I need to get... I think the vette one reworked will do what I need it to do.
Thanks

 

Nope won't work. The main pivot in the middle and the shock/spring mounts arnt enough to actually hold the dig any torque and it will just bend/snap all that

 

Blow out the pivot point idea and replace it with a Watts link (best) or Panard bar. Gary

Just noticed... and a driveshaft!!

 

what about a de dion axle

 

Thats what i was thinking. Is,nt that one of those setups with the gearbox built into the rear end and independant suspension as well. Alfa or old 1950s Peugeot i think.

 

From your drawing, your "slingshot" design is a dangerous deal with any suspension movement !Rear end housings in front engined dragsters are a highly stressed member of the chassis , any chance for movement or rotation is a no-no .

 

Years ago I built a trailer with somewhat the same principle only on each side. No springs, just a walking beam that pivoted in the center and a wheel on each end, It worked great and is still in use some 30 years later with no problems.

 

Don't forget about the Ford 8.8" IRS from the 90's V8 Thunderbirds; a lot of kit car guys use them.

 

sounds like you're happy with the Jag or Vette rear end ( & in my mind that's really the best option if you're trying to avoid a traditional drive shaft )

but you asked about how short a drive shaft... I have a competition built Jeep CJ-5 ( ya... the short one ) with a 350, Turbo 350 transfer case & Dana 44 rear axle... my rear drive shaft ( actual shaft ) is only 5-6 inches long, but it also has 5-6 inches of slip spines, & a pair of U joints... total length is like 14" from tranny to diffy... this set up worked well for many years, of some pretty stupid twisty stuff... more than a normal street or strip vehical would be exposed to... you may be able to trim several inches off of that & still have 4-5" or rear suspension travel

 

Yep, solid mounted differential eliminates your drive shaft troubles
IRS let's everything else work.

A jag is about the easiest to fit and cheapest to get.
If you had the gumption you could procure the whole jag, use what you needed and part the rest. Come out with a free rear end and some extra cash

 

Uncertain T

( I don't endorse any of this,.. other than for a static display)

 

As a "mitigated solid rearend" it might work. The pivot would halve the effects of single-wheel bumps, but not eliminate them as actual suspension would. The thing is not to expect it to be actual suspension. One would have to support the front of the rearend, though, and not rely on the pinion shaft to act as a front pivot.

A DeDion as per english rob's suggestion is a possibility, especially if it runs over the snout of the rearend rather than behind the back of it, as is more common. I like DeDion axles; I even started a thread on them. They have the great advantage that they keep the wheels parallel to each other and pretty much perpendicular to the road, as a solid axle does.

I've been looking at ways to locate a DeDion axle so that it rotates about longitudinal and lateral axes at different heights, so as to optimize launch and cornering behaviour separately: see here. One advantage to having a DeDion rotate about an axis near or through the tube is that the tube then counts very little towards unsprung mass in pure bump. It can be tricky if the brakes aren't inboard, though.

 

It'll work from the trailer to the show and from the trailer back to the garage.

 

think of a rigid frame harley. ever ride one and hit a pothole? ouch!!!!!!!!!

 

If the idea is to mount a V8 as far back as possible.... how about the drive train from a Cadillac Eldorado, Olds Toronado or Buick Riviera from the 70s - early 80s?

They had a small V8 of about 350 cu in mounted conventionally, with a transaxle and the axle line just about the middle of the engine.

 

A good read if nothing else:

http://www.jalopyjournal.com/forum/showthread.php?t=365622

 

want a dash of odd, how about a Mercedes Swing axle!

 

How about tying the eng,trans and rear axle as one and build the engine mount on a hinge point. It probably wouldnt be any good for other than loading and loading on a trailer, but a little out of the box thinking.

 

Ive thought of all of these ideas, all good ones.. didnt even know about that crazy Mercedes rear end though, thanks.... I think I've found another solution that lets me get the engine where I want it... came across a really short tail shaft that would let me run at least a short drive line... problem solved maybe.... this idea I had was perhaps just 2am wishful thinking.

 

Here is a curveball for ya....
build the frame in a monococh[sp?]fashion surrounding the engine trans and incorporating the rear axle solidly mounted to monocoche chassis spine with no movement at the rear of trans/pinion joint....
Then the "spine surrounding the drivetrain would pivot on two large urethane bushings at the connection point of front frame rails[frt suspension crossmember.... at a point near front of motor....ON TOP...
at this pivot joint-use two horizontal coilovers[BOTTOM// much like the rear of a Harley softail uses....
as this whole post is insane..... so is this.Ha!!

 

Trailers don't produce loads of torque/stress on rotating components, plus your suspension technique (walking beams) has been used on trailers for years and are suspended parallel to movement. Whole different world from what is being discussed here.

JayD

 

Some where 455s