Fastguy

Fronts only? Bigger rotors AND calipers? Different master cylinder?

bogus

I don't think the kit will clear your wheels... thats a problem...

the GS upgrade includes 13" rotors, brackets and GS calipers. The GS calipers are stronger than the regular ones... but use the same pads.

I did the upgrade, and also added SS brake lines. They have a nice firm pedal and stop great! I also used EBC Greenstuff pads.

Springer's LT4

They say the calipers are stronger, but if you do a side by side comparision.. the J55's look stronger to me. (And they also look as they offer more cooling on the J55's) See if I can dig up that post..

Springer's LT4

Here is a side by side comparision of the all the C4 calipers. GS looks as it has more metal in areas, but notice the fins on the top... J55 has more.
http://www.superchevyperformance.com...4calipers.html

Thanks 18carfan for the comparision!

vader86

the brakes will clear only 17" wheels, which i think you have, i'm looking at the upgrade myself.

BBA

Will the JL9 ( two piston calpier for 12" rotor ) bolt on to replace the single piston caliper on an '87?

scorp508

He's got the 16s. They might still clear. I am unsure exactly which wheels though. Rumor has it (can anyone confirm) that the 16" wheels made by Enkei will clear a 13" brake upgrade.

John Row

A GS upgrade includes: (front brakes only)
.New Calipers (and associated pins and clips to hold the pads)
.New Rotors (13" dia about 1.25 thick and directional vanes)
.New Caliper mounting bracket
.New Pads
.Bleed

Some good things to do as well:
.Flush with good quality high temp DOT 3 or 4 fluid
.new brake lines (required if they are abradded or cracked) (there's a lot of disucssion whether braided Stainless Steel is anything more than cosmetic)

Cheers,



[Modified by John Row, 5:40 PM 1/3/2002]

snaketr

The GS caliper mean Grand Sport and the only difference between them and the J55 is they are smoothed and powder coated black with Corvette written in the side. That is the only difference, other than eventually the black will chip off like mine are doing. They fit under some 16" wheels and not others. I had aftermarket 16" wheels and they would not work, so I bought new 17" GS wheels. The kits come for just the front, the rear calipers for the GS and all other 17" suspension are the same, they just powder coated them black and they do not say Corvette.

GlockLT4

There actually is a GS rear brake kit.. but I'm yet to see many people with it. Almost everyone just goes with the front. The GS rear stuff I think is nearly the same.

vader86

yeah theyre supposed to clear only the 16" Enkei's but i havent seen anybody with them.

dgoodhue

They are suposed to clear the Enkei rims, but I heard one guy who had to file the caliper a little. I have also read about others who have fit the regular 16x9.5 rims with some grinding of the calipers.

Cory@LS2PortWorks

The ZR-1 and GS calipers will clear the Enkei 16 inch wheels common on the 85 Corvette. I've done it. The 17's, of course, offer much better brake cooling.

Cory

johndezman

i've seen most addressing 85 16" wheels in this thread. would they (16" '85) be the same as those used in '84? thus possibly making this upgrade possible on a '84?

scorp508

I would like to know this also. My '87 wheels are 16x9.5" Enkei.

snaketr

Glock you did not read my whole post. Yes there are GS rear brakes. They are the same as the rear brakes on all 88-96 Corvettes, they are just powder Coated black. That is the only difference they do not say Corvette in them.

Fastguy

I have 16"'s but I think they are 88 base coupe only as I have never seen others with these wheels. Maybe at the next autocross I'll swap one on LT4SilverEagle's car and see if they fit.:)

Rick93Z07

Springer,

The front J55's are much thinner in critical spots and they definitely bend under severe duty. Mine bent open like a Chinese C-Clamp...by 0.2", about the thickness of one pad! The pads had to wear half way out before they would make complete contact with the rotor! Weakness is in the area encompassing the outer pad. The front GS calipers do not bend. PBR recognized the shortcoming of the J55 design in 1992. They re-designed the calipers in 1992 for use on the Cobra and GM had PBR change the logo for the 1996 Corvette GS caliper. I can not comment on 16" Enkei fitment with beefy GS calipers. I hope other's here are not making statements based upon assumptions. If I did not have J55 and wasn't concerned about legality in stock SCCA calsses, I'd convert to C5, not GS. The cost is close and the C5 setup is significantly better.


[Modified by Rick93Z07, 2:58 PM 1/5/2002]

Kevin 88

I had the same '88 16" base wheels you have. They will NOT fit over the GS calipers. I showed my wife the problem and said, "Gee Honey, I have no choice but to spend money on ZR-1 wheels."
I actually got away with it.


[Modified by Kevin 88, 2:51 AM 1/6/2002]