I am in the midst of installing a 2nd gen front subframe with all the associated parts into my '85 RX7. Other than the intended results - rack & pinion and 2nd gen motor fitment - I will have either 2nd gen 4 lug or 5 lug hubs.

There are several ways to achieve the same lug patterns on front and rear - but I am wondering about installing a 2nd gen rear assembly into this car.

Are there any significant advantages to a 2nd gen rear suspension compared to a 1st gen - for a car that will only be used for public road travel. The car will have a 2nd gen 13b with a 5 speed.

Thanks for your thoughts.

 

First, if you want to have the same bolt pattern and offset F & R, you can select the 4 lug front hubs and use GSL-SE rear axles. This will get you the 4 X 114.3mm bolt pattern at both ends.

As for the advantages of the 2nd gen IRS for "public road travel" -- it all depends on your definition of "public road travel". If you are engaged in limit handling and you have the capability to successfully install the 2nd gen IRS, you will potentially have a rear end that sticks to the road a little better.

Advantages of the original setup include lighter overall weight, simpler alignment (none required in the rear), and wider selection of internal components. Lastly, the adhesion problems with the first gen rear axle can be corrected with some aftermarket parts.

Bottom line -- for most street driving conditions, you will realize little benefit from the 2nd gen rear suspension. But it looks like you enjoy tinkering, so you might want to do it anyway.

 

Not to be too nit-picky or anything but I feel compelled to say something. The rear end of a 1st gen still needs to be aligned. Not toe or camber angles but the thrust angle needs to be checked.

Just do the front and be happy. The original setup is great for most everything you'll see out there. A 3 link setup will be even better than the stock links that bind up. You can always get the rear hubs machined to have the five lug setup to match the front.

If you can, try to use a nice GXL or equivalent front end for the donor parts. If you are going to go through all that trouble you might as well use the best the FC can offer.