Did the same upgrade on my 84. C5 fronts with home made adapters using stainless steel. DRM bias spring(not as easy to do as instructions let on), and stock rear brakes. Russell SS braided lines. Works great. Althought the latter year C4's went to the disc brake style Ebrake, the C5's went back to using the drum style separate E brake.

 

I was thinking of the GS upgrade, thanks for your info :cheers:

 

Trixie,

If you pull your wheels off they may of been made be Enkie. If you have an Enkie stamp inside of your rims then the C4 big brake J55 upgrade will supposedly fit behind them. I have not personally tried it, but I've been told that over and over.

 

Now, that is something good to know- What are the odds that my 9.5's are Enkie?

 

Very good. If memory serves me right 1986-1987 where made by Enkei. Don't take my word for it though, yank them off and look inside.

 

On my '88 Fiero, the front and rear calipers mounted the same way and when I upgraded to larger calipers on the front, I moved the front calipers to the rear because the front calipers have larger pistons than the rears. Are the Corvettes like that too?

 

Dumb question but I gotta ask. What direction are the slots/holes turning in when mounted on the car. Is the first hole that catches the pad the one on the outside edge of the rotor or the inside edge. Looking at them I would think they would look like a pinwheel going clockwise. So that it looks like it moves from the inside to the outside. But the picture Jeffvette has looks the opposite? Does it really make that much difference?
Confused.

 

The slots and the cross drilled pattern do not matter at all. It is the direction of the vanes inside the rotor that matter. There was a thread last week started by yoslambo regarding this. Each manufacturor places holes and slots in different places.

 

Unfortunately my 9.5"s were not Enkei. I wouldnt have kept them if they had been though, GS rims look so much better.

 

I don't want mine either. :)

 

Thanks Jeff I'll go find it. I have them mounted the way your look and the ones on Baer website. Figured I'd ask while I had everything apart...
Graham

 

I posted a pic in my reply...but for whatever reason it's a no-show. :confused: Not even a red X. I'll try again.

 

I did the J55 upgrade on mine using Baer/PBR 2 piston calipers in the front with the 13" Eradispeeds. I used new stock GM calipers in the rear with the stock sized rear Eradispeed rotors. I went Stainless lines all the way around with ATE super blue brake fluid. The bias spring was replaced with the DRM spring, and the pads are stock GM in the rear and PBR/Baer in the front.

It rocks! I'm very happy with not only the looks but the performance is stellar.

Hope this helps. Feel free to mail if you have questions. I can probably post some pics if you're interested in seeing them.

Ron

 

I did the J55 13" upgrade on my 86 (11.9" rotor). The early C4s need an extra bracket for either the J55 (C4) or the C5 upgrade. I left my rears stock for right now and don't have a problem with them. That said, here are some of my observations.

The '87 Enkei 9.5" wheels rub (just barely). I run my car at HPDE track events (20 minute sessions) and the braking is great. I would toast the OEM pads in a single day at the track. Now with the J55s and Performance Friction pads, I can get 4 track days out of a set of pads.

Turning off the ABS with this setup is a real good way to 'flat spot' your front tires in a heart beat.

IMO the geometry of the additional bracket needed to mount the big brakes is what causes the differences. The OEM 16" Enkei wheels that I have fit on my 96 (J55 was standard equipment) without rubbing. The 17" sawblades from the 96 fit the 86 (big brake mod) without a problem.

I run the AFS 5 spoke with the 38mm, 6.7" backspace fronts and the 36.5mm, 7.397" backspace) rears and the fit perfect. On the 96 they stick out just a bit. This is due to the change in geometry on the 88-96 cars.

I haven't tried it, but I would be willing to bet that wheels with that offset would work on the 88-96 cars that have been upgraded to C5 brakes without the need for an adapter.

Here is some food for thought...

ZR-1 wheels: 56mm offset, 7.4" backspace front and 36.5mm offset, 7.397" backspace rear
88-96 (GS/CE) wheels: 56mm offset, 7.4" backspace front and 50mm offset, 7.93" backspace rear
84-87 wheels: 38mm offset, 6.7" backspace front and 36.5mm, 7.397" backspace rear

I like the performance I have with the J55 upgrade but the C5 upgrade wasn't available when I did mine. If I was to do it now, I would go with the C5 upgrade.

Good luck with your decision.

 

I too want to upgrade my 93. I am very close to getting GS calipers. Although I'm debating the C5 upgrade too. I wasn't interested in that because the brackets cost more than all the other parts added up. If someone can nudge me in the direction of cheaper C4-C5 caliper brackets, it would be greatly appreciated.

 

Doug Rippie looks like he has brackets for 185.00. Anybody else?

 

DRM installed their C5 brake package on my 94 and I stilll have the stock wheels.

 

9T,

Try http://www.car-vette.com. They have them for about $150. I like their design also since the bracket cross section is thicker except for the mounting points.


[Modified by Dominic Sorresso, 8:59 AM 6/3/2003]