I bought a complete front/rear kit of "performance brakes" on RockAuto. These are drilled and slotted. There was no mention of rotor size. It turns out the front discs in this kit are 355mm/13.9 inches while my 08 has 337mm/13.2 inch discs. I looked in the service manual and the general description for brakes states that the 4.4L version has different calipers and rotors than the 4.0L versions but does not say anything about performance brakes. A Google search does suggest there was a performance brake option of 355mm.

Looking on RockAuto I don't see a different caliper listed for the 4.4L and 4.0L versions. Is there only one size of caliper for NA cars? Is there a larger performance caliper or there just the one size?

I also did not see a larger size caliper carrier, something that would be needed in order to use the 355mm discs. Any source for these?

Thanks for any insights.
Gordon

 

V6 has 317mm front and 325mm rear while the V8 has 337mm front and 350mm rear. Both use the same caliper, the V8 just uses a different carrier bracket. It is strange that you would get a 355mm front disc, are the rears still 350mm? I don't see any 355s listed on Rock Auto, which package did you get?

 

It was a complete kit of front and rear discs/pads, sensors and hardware from R1 Concepts. I bought the kit because these discs were drilled and slotted. I thought they might work better on long downhill drives in the mountains. The info for the kit did not state the size of the discs.
I didn't measure my rear discs. My original fronts were 337mm. I put he R1 discs intended for the rear on the front and left my original discs on the back.
Since I paid for these 355mm discs I would like to use them if I could find the carrier. I will see if I can contact R1 Concepts.

 

OK, I have figured it out. I plead Seniors Moment. I just assumed the larger discs would go on the front. That is how it works with performance cars and my L322 SC. If I had looked closely at the invoice that came with the kit I would have see that the 355mm discs ARE for the REAR. Putting the smaller ones on the front was correct. Now I can go ahead and do the rears. 😆