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IRS in an Alpine?

Discussion in 'Modified Alpine' started by shapeshaver, Jun 5, 2014.

  1. shapeshaver

    shapeshaver Donation Time

    I need to put a rear differential/suspension in my car. Have there been many Alpines or Tigers that have had an IRS installed? Was it heavier than an 8" or dana 40?

    I posted this in my "LX9 Alpine" build thread, but I think more people will see it and chime in if it's in it's own thread.

    I was given an IS300 IRS from a wrecked car and It looks like it could possibly be a good match for the alpine. I would build a subframe to install it into the car, possibly by using the four spring mounting points.

    Here is a picture of the IRS http://www.lx9alpine.com/rear-suspension.html
  2. alpine_64

    alpine_64 Donation Time

    I now of 3 Tigers with IRS that have been done in the last 5 years.. 2 in states and 1 in Uk.. The factory did prototype Tigers with IRS too.

    Of note.. its easier in a later car .. requires less cutting of the body.
  3. bashby

    bashby Donation Time

    I looked into an IRS for my SV, I did not want to cut the trunk floor. rear shelf at that time make so many changes. But, it would be nice. probably add 100# though. ERA Cobra make a very nice IRS if they would sell you without the rest of the kit (they might). I would definitely make my stud 5x4.5 if I did it again.
    Last edited: Jun 6, 2014
  4. impster

    impster Donation Time

    It's been about 30 yrs and consequently, I don't recall the details but I modified an IRS out of an early rear wheel drive Maxima to fit my now long gone SV. The beauty of the Nissan system was that the half shafts utilized two U-joints each with a sliding joint in between; no constant velocity joints to mess with. At the time, I found a shop that had shortened similar half shafts and they merely cut the U-joint yoke from the shaft, shortened the shaft, then welded the yoke back on. Don't remember what the rest of the assembly looked like but it was easy to then cut, narrow, and weld the subframe. I was even able to use the existing Sunbeam's leaf spring mounting points to attach the whole thing. I then built spring "towers" that projected up in the interior behind the seats and in front of the folding top space. Steel cylindrical things that looked rather hideous but the car had a roll bar, so I then enclosed the area behind the seats to cover the spring towers, which then created a nice space for a pair of stereo speakers.

    I used a pair of coil over spring/shock assemblies from somewhere like Jegs so that I could play with spring rates until I found the best match. Tried a couple of spring sets but sold the car before I dial it in.

    Would I do it again? Probably not. It's hard to engineer such a system in the shade of the back yard tree and have it work better than anything the factory designed. Nevertheless, it was a fun experiment and provided a ride quite different from the solid axle. Its strength was ride comfort, not handling as I found out after autocrossing it once. Which, by the way, was why I had to replace the original axle as I tore it up while sliding between the cones.
  5. shapeshaver

    shapeshaver Donation Time

    Lexus IS300 IRS in an Alpine - Measuring and cutting it up.

    Since I have been posting about this in my build thread HERE, I'm not going to post about it here anymore. If you are interested in this swap possibility or if you have something to contribute, please join in and participate there.
    Last edited: Jun 23, 2014

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