Question: C5 brakes on an 88?

[vdogamr]

So I have read that it is possible to replace the C4 brake pads and rotors with the C5 version on 1988s or later. It would seem that you also need conversion brackets.

My question: If I need to replace all 4 rotors and pads, would it be much more expensive to upgrade? Is there any reason not to upgrade? And, if I am not a racer, is there any reason to upgrade? Is there anything I should know before I tackle this adventure?

Thanks

 

[twiget]

From your avatar, it looks like your 'Vette has the stock 16" saw blade wheels. C5's have 17" wheels in the front and 18" in the rear. If you upgrade to C5 brakes, you might be forced to change your wheels and tires too.

Another option, if you want to improve your braking system, is to upgrade to the '88 Z-51 brakes. They are bigger brakes, but you'll probably have to go with a larger wheel/tire combo with those too, but at least you'll know the Z-51 brakes will go on.

Good Luck!

Jason

 

[GO_VETTE]

hey, dont buy into the ads you see in the magazines.
they read like this....
wow wow wow
you can now buy $$$$$ c5 red calipers and pads"
****if one has to modify*** hell I might as well build a real brake system*****
check this out 4 piston caliper * no need to go bigger RIMS/TIRES
just modify rotor, build a bracket and weld to knuckle.
*****************************************************
The problem with most big brake kits is that you can not use the stock 16" rims.
I did some research and bought rotors from a BMW E39 540i (2003-). The BMW rotors are 324mm x 30mm, almost exactly the same as the Corvette C5 rotors, 325mm x 32mm.
The differance compared to the C5 rotors is that they have much more 'backspace'. The C5 rotors are almost flat.
The extra backspace makes room for Wilwood Forged Superlite 4-piston calipers in the stock 16" x 9.5" rims without any spacers.


see image:
My Photos Photo Gallery - Photo 167 of 167 by NY - MySpace Photos

 

[vdogamr]

That avatar is of my car. But I think I have 17inchers.
My tires are :
- P275/40ZR17
and I have RPO code:
- QA1 : WHEEL, 17 X 9 S, ALUMINUM, STYLED

Is this one of those cases where the numbers don't mean what they say? (like wooden 2x4 ad)

GO_VETTE are you saying I should or shouldn't get larger brakes? And your post mentions welding. If there is welding involved, I will think twice, because then in means taking it to a professional. I don't weld and I don't think I should start on the Corvette .

Thanks

 

[GO_VETTE]

I am going to give you my honest opinion. I am not going to give you an advice of someone trying to sell parts, or earning labor.
you will know if you need bigger brakes. by reading this.
========================================
1.do I need bigger brakes for my stock engine?
No, your factory motor and brake system were designed to work w/ one another. no point in wasting money.

2. are drilled and slotted rotors better than the factory?
No, not necessarily, drilled rotors can crack easily- are more a cosmetic than performance.
Although slotted ONLY rotors are good for heat ventilation.

3. the claim is that the drilled rotors can cool better than non cooled?
first of all, this is true for stock car racers- not street cars. but if this is a concern,
you can add a duct under bumper and center it in middle of rotor... that would really cool off a rotor.

2. to what extent or mods would you recommend doing brakes?
if your factory engine came w/245 HP, and you did some exhaust, intake, biger TB and injectors...say roughly under 300HP range.
You can still use factory brake calipers and rotors.

3. how about if i am doing a serious motor w/ a camshaft, cylinder heads, spraying a bit of nitrous or may add a supercharger?

yes, one can upgrade to bigger brake system.
most upgrades do require some level of modifications.
Yes welding brackets to knuckles, cutting rotors partially to fit stock rims and or may have to increase rim size.
4. will it cost money?
absolutely, if especially welding parts, and experienced tech and tools.
5.what do you think, do I need it?
I cannot answer this question b/c I dont know much about your PURPOSE for car, engine type, current HP or desired modifications.
6. Can upgrades enhance my braking?
yes, but does the cost to upgrade justify your horsepower level, and stopping requirement?

 

[GO_VETTE]

hey VDOGAMR, I personally think a stock street driven car DO NOT requires bigger brakes.
but just in case you do decide to do em, here is bit of 4 piston brake conversion,
==========================================================
The problem with most big brake kits is that you can not use the stock 16" rims.
I did some research and bought rotors from a BMW E39 540i (2003-). The BMW rotors are 324mm x 30mm, almost exactly the same as the Corvette C5 rotors, 325mm x 32mm.
The differance compared to the C5 rotors is that they have much more 'backspace'. The C5 rotors are almost flat.
The extra backspace makes room for Wilwood Forged Superlite 4-piston calipers in the stock 16" x 9.5" rims without any spacers.


My stock rotor compared to the BMW rotor and mounted on the Corvette
see images:

-----------------------------------------------------------------------The bolt pattern and 'backspace' of the rotors are perfect.
The center hole is a bit too big so you must make an adapter ring in a lathe to center the rotor on the hub.
You also have to modify the rotor in a lathe. Remove the inner rotor near the center to clear the caliper bolts on the knuckle.
The outer diameter on the Corvette hub was slightley too big and the rotor got a bit narrower near the hub mounting surface, so I removed some material from the rotor there too.
The removed areas are marked red in this picture and you can also see both modifications on the picture:
see image:
----------------------------------------------------------------------
A bought Wilwood Forged Superlite for 1.25" wide rotors.
http://www.wilwood.com
They are available with different piston sizes.

This is a mock up caliper bracket I made.
The real bracket will be made from thicker aluminum.
As you see in the last picture the caliper has to be moved out slightly.
For extra support I will use distances and bolt the bracket to the original caliper mountings too.
see images:


***** a bit busy, I will load up images shortly*****

 

[vdogamr]

Thanks for all the info.

So after all that, I have decided that I do not need to do this conversion now. Possibly never, but in the future it may just be a fun thing to do. So for now I will just get new rotors and pads for the whole car and call it done until they need replacing again. Maybe by then I will be more willing to spend money on cosmetic brakes to go with some new, cool looking, wheels.

Thanks again. This was all valuable information. GO_VETTE, if you will still put up pictures, I would still like to see them.

 

[GO_VETTE]

The problem with most big brake kits is that you can not use the stock 16" rims.
I did some research and bought rotors from a BMW E39 540i (2003-). The BMW rotors are 324mm x 30mm, almost exactly the same as the Corvette C5 rotors, 325mm x 32mm.
The differance compared to the C5 rotors is that they have much more 'backspace'. The C5 rotors are almost flat.
The extra backspace makes room for Wilwood Forged Superlite 4-piston calipers in the stock 16" x 9.5" rims without any spacers.


My stock rotor compared to the BMW rotor and mounted on the Corvette

My Photos Photo Gallery - Photo 177 of 185 by NY - MySpace Photos

My Photos Photo Gallery - Photo 172 of 185 by NY - MySpace Photos

My Photos Photo Gallery - Photo 178 of 185 by NY - MySpace Photos



-----------------------------------------------------------------------The bolt pattern and 'backspace' of the rotors are perfect.
The center hole is a bit too big so you must make an adapter ring in a lathe to center the rotor on the hub.
You also have to modify the rotor in a lathe. Remove the inner rotor near the center to clear the caliper bolts on the knuckle.
The outer diameter on the Corvette hub was slightley too big and the rotor got a bit narrower near the hub mounting surface, so I removed some material from the rotor there too.
The removed areas are marked red in this picture and you can also see both modifications on the picture:
see image:

My Photos Photo Gallery - Photo 173 of 185 by NY - MySpace Photos
----------------------------------------------------------------------
A bought Wilwood Forged Superlite for 1.25" wide rotors.
http://www.wilwood.com
They are available with different piston sizes.

This is a mock up caliper bracket I made.
The real bracket will be made from thicker aluminum.
As you see in the last picture the caliper has to be moved out slightly.
For extra support I will use distances and bolt the bracket to the original caliper mountings too.
see images:
My Photos Photo Gallery - Photo 179 of 185 by NY - MySpace Photos

My Photos Photo Gallery - Photo 180 of 185 by NY - MySpace Photos

My Photos Photo Gallery - Photo 182 of 185 by NY - MySpace Photos

My Photos Photo Gallery - Photo 184 of 185 by NY - MySpace Photos

My Photos Photo Gallery - Photo 175 of 185 by NY - MySpace Photos

My Photos Photo Gallery - Photo 176 of 185 by NY - MySpace Photos

My Photos Photo Gallery - Photo 181 of 185 by NY - MySpace Photos

My Photos Photo Gallery - Photo 183 of 185 by NY - MySpace Photos

My Photos Photo Gallery - Photo 185 of 185 by NY - MySpace Photos

 

[Toms007]

vdogamr, If you should choose to upgrade your brakes, you can do so by finding the J55 brake system from a Z51/Z07 or optioned car or any 95-96 (J55 became standard in 95). These brakes will readily fit on your 88 without welding anything. But, if you choose to do this conversion make certain that you obtain all the parts from the donor car, which includes the calipers and caliper brackets (these are not the same as the 12" standard brakes. These parts will upgrade the FRONT brakes to 13" units and they will fit those stock 17" wheels. If you choose to do the C5 upgrade, standard C5 calipers will not fit on the J55 bracket, someone out there makes a bracket that will bolt on to the existing C4 mounting holes and attaches the C5 caliper. I believe that the sawblade wheels will not work with this set up and that you need to upgrade the wheels to the A-molds (ZR-1 style if you want to stay with C4 looking wheel) or go to a C5 17" or larger wheel.

With all this said, if you are stock, don't race or autoX, your standard 12" brakes will do the job quite well. If you so desire to upgrade for what ever reason, you have some options, either my way or GO_VETTEs.

 

[Black Bart]

The problem with most big brake kits is that you can not use the stock 16" rims.
I did some research and bought rotors from a BMW E39 540i (2003-). The BMW rotors are 324mm x 30mm, almost exactly the same as the Corvette C5 rotors, 325mm x 32mm.
The differance compared to the C5 rotors is that they have much more 'backspace'. The C5 rotors are almost flat.
The extra backspace makes room for Wilwood Forged Superlite 4-piston calipers in the stock 16" x 9.5" rims without any spacers.


My stock rotor compared to the BMW rotor and mounted on the Corvette

My Photos Photo Gallery - Photo 177 of 185 by NY - MySpace Photos

My Photos Photo Gallery - Photo 172 of 185 by NY - MySpace Photos

My Photos Photo Gallery - Photo 178 of 185 by NY - MySpace Photos



-----------------------------------------------------------------------The bolt pattern and 'backspace' of the rotors are perfect.
The center hole is a bit too big so you must make an adapter ring in a lathe to center the rotor on the hub.
You also have to modify the rotor in a lathe. Remove the inner rotor near the center to clear the caliper bolts on the knuckle.
The outer diameter on the Corvette hub was slightley too big and the rotor got a bit narrower near the hub mounting surface, so I removed some material from the rotor there too.
The removed areas are marked red in this picture and you can also see both modifications on the picture:
see image:

My Photos Photo Gallery - Photo 173 of 185 by NY - MySpace Photos
----------------------------------------------------------------------
A bought Wilwood Forged Superlite for 1.25" wide rotors.
http://www.wilwood.com
They are available with different piston sizes.

This is a mock up caliper bracket I made.
The real bracket will be made from thicker aluminum.
As you see in the last picture the caliper has to be moved out slightly.
For extra support I will use distances and bolt the bracket to the original caliper mountings too.
see images:
My Photos Photo Gallery - Photo 179 of 185 by NY - MySpace Photos

My Photos Photo Gallery - Photo 180 of 185 by NY - MySpace Photos

My Photos Photo Gallery - Photo 182 of 185 by NY - MySpace Photos

My Photos Photo Gallery - Photo 184 of 185 by NY - MySpace Photos

My Photos Photo Gallery - Photo 175 of 185 by NY - MySpace Photos

My Photos Photo Gallery - Photo 176 of 185 by NY - MySpace Photos

My Photos Photo Gallery - Photo 181 of 185 by NY - MySpace Photos

My Photos Photo Gallery - Photo 183 of 185 by NY - MySpace Photos

My Photos Photo Gallery - Photo 185 of 185 by NY - MySpace Photos

man that is scary that thin piece of aluminum will not hold under hard braking.

 

[JohnyH]

Brake upgrade

Your 17" wheels will accept the C5 upgrade. I don't have any pictures here (i'm at work) but I track my car and felt that a little improvement would help in being able to get into the corners a little faster.

It was just a remove and bolt in procedure after I had acquired all the parts!

slotted front C5 Rotors, C5 Z06 calipers for the front, slotted C4 rear rotors, steel braided brake lines, Hawk HPS pads all around and finally the famous C4 to C5 adapters for the front calipers. Also a DRM master brake cylinder bias spring to put a little more pressure on the rear back brakes!

1/2 a day to unbolt, replace, torque all the bolts and bleed the brakes, good to go!

John

 

[vdogamr]

Your 17" wheels will accept the C5 upgrade. I don't have any pictures here (i'm at work) but I track my car and felt that a little improvement would help in being able to get into the corners a little faster.

It was just a remove and bolt in procedure after I had acquired all the parts!

slotted front C5 Rotors, C5 Z06 calipers for the front, slotted C4 rear rotors, steel braided brake lines, Hawk HPS pads all around and finally the famous C4 to C5 adapters for the front calipers. Also a DRM master brake cylinder bias spring to put a little more pressure on the rear back brakes!

1/2 a day to unbolt, replace, torque all the bolts and bleed the brakes, good to go!

John

That almost sounds too easy to be true. So it sounds like extra costs are in the calipers and the adapters. Is the bias spring required? Did you replace the brake lines in the 1/2 day as well?

My current plan is to buy some of the cheapest pads I can, and then save up money to replace the rotors and pads at the same time. I still haven't decided if this conversion is something I need, but it does sound less scary now.

 

[ZumZum]

There's been more C5 brake conversions done than you can shake a stick at.

I believe several companies offer conversion kits.

 

[JohnyH]

That almost sounds too easy to be true. So it sounds like extra costs are in the calipers and the adapters. Is the bias spring required? Did you replace the brake lines in the 1/2 day as well?

My current plan is to buy some of the cheapest pads I can, and then save up money to replace the rotors and pads at the same time. I still haven't decided if this conversion is something I need, but it does sound less scary now.

It really depends on what you want to do with the car and how handy you are. The bias spring isn't required and the brake lines are the ones from the steel lines to the caliper. They are rubber now and replacing them can give you a little more firmer feel in the pedal, they do not expand like the 22 year old rubber ones you have on your 88 do! Just replacing the rotors and pads will give you some satisfaction but if you upgrade to the C5 you will need new front rotors again! I bought most of the stuff on sale or used when I found it, it took 2 years to acquire the parts and I spent probably around $600US. The kits are available but not cheap! Good luck and happy searching!

John

 

[vdogamr]

QUESTION?

That avatar is of my car. But I think I have 17inchers.
My tires are :
- P275/40ZR17
and I have RPO code:
- QA1 : WHEEL, 17 X 9 S, ALUMINUM, STYLED

Is this one of those cases where the numbers don't mean what they say? (like wooden 2x4 ad)

So I posted this a little while ago. If I understand how these numbers work, the P275/40ZR17 means:
Passenger Tire, 275mm wide, 40% of that in height, Radial for 140+mph, that fits on a 17in rim
Correct?
Well 275mm is ~10.8in not 9 :confused. Does that mean that the previous owner of my car changed the rims, or (like I said) do these numbers never add up like they are supposed to? With the Corvette Logo, I would assume they are the stock wheels. I measued, and the tires are wider than 9in. Is the 275 measured at a different point than the 9?

This isn't too important, I am just trying to learn. And if I ever decide to make my wheels look modern, I will need to know what size to buy. (My guess is 10.5x17)

Also do I need ZR's . If my tires are rated for 140mph, I would feel really bad letting it go to waste. And that is how I will explain it to the cops :cool.

 

[Hib Halverson]

275mm is the section width not the wheel width.

OE 17s for 88s are 9.5" wide.

 

[JohnyH]

The above post is correct 9.5" are stock 17" rims and if you go with the 10.5" rims they may stick out 1/8" out of the wheel well if you do not adjust the backspacing properly. Now there is another can of worms openend up for you to research!

 

[vdogamr]

If 9.5 is stock, is the RPO code I looked up labeled wrong and 17x9? If I remove the tire and measure the rim will it be 9.5in?

Thanks for all the help

 

[Toms007]

Yes, they should be 9.5" between the beads. In 1993 they went to a staggered configuration 8.5 fronts 9.5 back, with 255/45 front tires and 285/40 rears. This was done in order to help divert the issue of "tracking". There are some notable exceptions to this 1993 change....the first was the ZR-1, it had a staggered set as well, but they were 9.5 front and 11 rears 275/40 and 315/35. The other exception is the Z07 optioned cars, they had 9.5 all around with 275/40 tires at all four corners.

 

[vdogamr]

It really depends on what you want to do with the car and how handy you are. The bias spring isn't required and the brake lines are the ones from the steel lines to the caliper. They are rubber now and replacing them can give you a little more firmer feel in the pedal, they do not expand like the 22 year old rubber ones you have on your 88 do! Just replacing the rotors and pads will give you some satisfaction but if you upgrade to the C5 you will need new front rotors again! I bought most of the stuff on sale or used when I found it, it took 2 years to acquire the parts and I spent probably around $600US. The kits are available but not cheap! Good luck and happy searching!

John

So I recently bought some parts from Ecklers, and while I was at it I had them send me their parts catalog. Inside is a C5 upgrade kit. The kit mentions everything you said except the Bias Spring and it cost $1800:eyerole. However, when I look at buying parts individually, I can't figure where all the money is going. Granted in front of me is only C4 parts, but looking at the most expensive parts I only get to about $700. I doubt that all the C5 equivalant parts are more than twice the price.

Its like the other day. I was at a fast food place and because of a sale they had, their combo was actually a worse deal (by only a few cents). But I guess it shows you need to take the time to add it all up when buying a "deal".

Thanks for setting the goal at $600. Without it, I may have just looked at the $1800 price tag and given up. I am still impressed by your shopping ability and I know I probably can't do as well, but at least now I won't get ripped off.