Suspension on Mark 4 (IRS or Solid 8.8)

[seanbrown427]

Hey folks

I figured I would ask this quick question here. If I ordered a Mark 4 kit and selected Solid Axle now are the mounting points for the IRS on the frame when it's put together at Factory Five? Or would I have to add the bits to the frame later if I wanted to convert to IRS? Thanks!!

[rich grsc]

The frame is different, you can't add IRS at a later date.

[edwardb]

Completely different and not compatible as Rich said. One of the decisions you need to make up front. Yes there have been a few builders who have converted from solid axle to IRS. But involves cutting and welding and not officially a Factory Five mod. I've had both and the IRS is definitely a very nice setup. Highly recommended. Just to expand a bit more, this is the frame with the IRS mounts. Anniversary chassis so not the usual black powder coat. But you get the idea.

https://hosting.photobucket.com/albums/ab234/edwardb123/Factory%20Five%2020th%20Anniversary%20Mark%204%20R oadster/Delivery/.highres/IMG_3278_zpsol2zfovl.jpg?width=590&height=370&fit=bounds (https://app.photobucket.com/u/edwardb123/a/8550221c-c530-4637-816f-8b79fdfdfa2f/p/7f7710ed-ee44-4445-8ec3-edfbe40523aa)

[CraigS]

Yeah you can. I did it. But it is much easier to do it at the factory. Depending on whether you go for a new solid axle or a used one, and whether you do new IRS parts or a salvage rear suspension the up cost of the IRS isn't so bad. If you get a salvage IRS w/ the oem brakes you basically get free, and very good, rear brakes. BTW the IRS makes your car significantly more valuable when it's time to sell.