openinverter forum

Hi all

I have an LDU with no subframe, but wouldn't mind finding one - just wondering if I find one that had an SDU in it, would it fit the LDU?

Also, has anyone shortened a subframe before? If so any links to see how it was done?

For background, I'm planning a project to put an LDU in place of a rear differential car with no IRS so need to think of suspension solutions.

Thanks in advance!

The attachment points of the LDU and SDU are the same, the subframe is interchangeable. Do you want to have a rigid axle again or convert to IRS?

muehlpower wrote: ↑Thu Oct 07, 2021 7:50 am The attachment points of the LDU and SDU are the same, the subframe is interchangeable. Do you want to have a rigid axle again or convert to IRS?

Contemplating options at the moment, though prefer to mount it in place of the rigid axle and convert to IRS. It's for a 1949 Pontiac Streamliner. So similar to your sled project, which is very influential! Amazing job you're doing there. I would love to do the same, but not sure if I can manage the same level of fabrication!

deadsled wrote: ↑Thu Oct 07, 2021 11:51 am

muehlpower wrote: ↑Thu Oct 07, 2021 7:50 am The attachment points of the LDU and SDU are the same, the subframe is interchangeable. Do you want to have a rigid axle again or convert to IRS?

It's for a 1949 Pontiac Streamliner.

You may have an issue with width if you use the stock Tesla suspension. The Model S is way wider than 40s era cars are.

For my '40 Chevy, I ended up using 2004-2006 Pontiac GTO suspension that I narrowed 3-inches, because the swing arm is entirely in front of the axle line. A-arm type IRS tends to want to mount right where the inverter and motor are on a narrow car.

I'm not sure I would recommend the GTO suspension, because there was lots of fabrication and modification involved, but it is an option, and since those were built by Holden, it might be easier for you to find the parts than it was for me.

Yes, width is a problem, hence my 2nd question in opening post about shortening a Tesla subframe.

The Pontiac's track width is 59" compared to the massive 67" on the Tesla.

I'll see if those Holden made suspension parts are available easily in Australia. But am a bit wary of lots of fabrication... I do really like the look of @muehlpower 's De Dion solution.

deadsled wrote: ↑Thu Oct 07, 2021 12:57 pm Yes, width is a problem, hence my 2nd question in opening post about shortening a Tesla subframe.

The Pontiac's track width is 59" compared to the massive 67" on the Tesla.

I'll see if those Holden made suspension parts are available easily in Australia. But am a bit wary of lots of fabrication... I do really like the look of @muehlpower 's De Dion solution.

If I had to go back and do my build over again from scratch, I'd be heavily inclined to go with his solution. It does seem far cleaner than mine.

I think it would be really involved to reduce the track width of the tesla subframe/suspension. Doing it would involve completely redesigning and fabricating the suspension and getting the geometry right would be a huge challenge.

Mojave wrote: ↑Thu Oct 07, 2021 4:49 pm I think it would be really involved to reduce the track width of the tesla subframe/suspension. Doing it would involve completely redesigning and fabricating the suspension and getting the geometry right would be a huge challenge.

When I looked at it, it seemed it might be possible to squeeze a couple inches out where all you would need is shorter axles, if you reinforced stuff properly after cutting. I don't think you could get it down by the 10-inches needed in this case.