IRS upgrade report

[CraigS]

As you may know I upgraded my MkII over the winter. I have now run 3 autocrosses so have a few thoughts.
- The car is more stable than it ever was. It gets through turns in a rough section much better w/ one exception. At turn exit, full throttle accel I get wheel hop if the macadam is rough. Not sure the solution yet but am trying different settings on the QA1 DA shocks. May need to go to rodends on the LCAs
- Ride on the street is better. It is really nice when I installed 300# springs vs the 400# FFR supplied. The 400# are back in now that AX season has started.
- I am using the brakes that came w/ the salvage parts. Vented rotors means the donor was a V8 car. The brakes are very good. Surprisingly the pads that were in there were pretty good. HPS 5.0 were only a slight improvement. But the best part is this; NO pad knockback means I have the same brakes all the way though an autocross run. On Hoosier A7s, w/ the solid axle, the pedal was always lower at the end of a run. Also the front to rear balance would shift toward the front as the pedal dropped.
- Overall the IRS is definitely a worthwhile upgrade.

[wareaglescott]

Glad to hear your feedback. Thanks for reporting in!

[Jacob McCrea]

I was wondering how this turned out for you, Craig. I'm glad to hear that it was a success. Was it challenging to get everything fitted in place? I (dimly) remember comments from FFR to the effect that a retrofit was not easy fabrication work.

[scottiec]

That is great to hear. hopefully the wheel hop gets figured out!

[CraigS]

Jacob it wasn't too bad. FFR sends a front and a rear mount, each being tacked together. I finished the welding on them. I started w/ the front mount which just sits on the 4 inch tubes, kind of nestles between them and flush w/ the end caps. Welded that in and then bolted the LCAs to it. Used that to confirm distance back for the rear mount which hangs between the longitudinal frame tubes. Double checked that gave me the right distance between the diff mounts, looked at a bunch of pics to verify height of the tube that is welded to the frame, and welded it in. The front UCA mount took a little more thought but all in all it was tedious but not difficult.

[johngeorge]

Awesome!! glad its working out for you. Which diff/gears did you get? was it the 3.73 with Torsin? Very good news on the rear brakes resolving pad knockback. I will try something special by mounting a front 2011 mustang floating caliper on the rear, will see if that fixes my knockback with solid mounted wilwood calipers. Its more a cost thing as full floating rotors may actually fix issue but dont want to spend $800+ for 2 rotors.