yes, you can fit C5/Z06 calipers with LS1 rotors under stock rims. the benefit over the LS1 caliper is you will never have to worry about it spreading. the stiffening ribs make it a tight squeeze but as long as you clearance your spindle adequately there is no problem. there is about a 4mm clearance between the stock pontiac rims and the C5 calipers. here's the proof:

btw thanks to ed for some very high quality parts at a reasonable price. i'd recommend him to anyone upgrading their brakes.

Tell that to the C5 guys. They may be stronger, but they will spread if you go racing.

you're the first one ive heard say that. maybe you could be more specific and link us to the thread you are talking about. if you do a search here seems the consensus is the ls1 calipers spread under heavy racing but the c5 calipers hold up ok from what ive read.

Sorry, no thread to point to when your at a race and see the results.

I'm sure most of the dual piston calipers would spread over time if you use them hard enough, it's just that no one has complained about the C5 calipers doing it yet. It's a good thing to know they'll fit under that wheel too.

Ed

Sweet! Good to know that you can use a c5 caliper and clear a 16" rim.....looks awesome.

Looks to me like you are running a wheel spacer to make it work. The wheel studs look pretty shallow in the lugs.

nope, no spacers necessary. fits perfectly as is. the motormite lugs that ed supplied with the hubs come right about to the top of the lugnut which is all you need.

Has anyone here experienced caliper spread? A race car team I worked for use c5 calipers on the rear brakes for a 06 zo6 we were racing and never ever experienced a problem

well i had to dig but i did find this:

http://frrax.com/rrforum/index.php?a...ter&f=2&t=1300

apparently they will spread but its rare.

btw heres another pic with the wheel off

really...

cormyr: Where did you buy your C5 setup from?

link?

got alot of the conversion parts from our very own ebmiller88 right here on this board. great stuff, everything was perfect and the price was good. i got the calipers and rotors from autozone, they are pretty cheap there plus i have a connec. earl's ss 1le brake hoses from summit and axxis ultimate ceramic pads from www.mr-auto-parts.com but you can choose whatever pads and source you prefer.

...

what did the swap set you back?

all new parts, about $600 including pads and stainless hoses but i modded my own spindles

I think I already know the answer (won't fit), but has anyone tried GTA wheels over this setup?

I doubt it...you need a spacer to get the LS1 calipers to clear anyway, and I think the ribs may hit also. If I can get the chance I'll try to fit it up soon, I have an LS1 kit ready to go out but if I can find a GTA wheel close I'll try to fit the C5 caliper on it to see.

Ed

Ok so it wasnt a really c6 zo6. It was a c5 zo6 with c6 body pannels. The c6 frame is made out of aluminum so its doesnt make for the safest race car. But we use stock c5 front brakes on the rear. Up front we use apracing 6 piston calipers.

Thanks Ed. I'm trying to find someone local that has them to help. I'm going to run a spacer for track width anyway, but I'm guesstimating it's going to run out of room radially first.

What exactly is the reason for them not fitting under the GTA wheels? Will this work for the stock 91 Z28 16" wheels? Sorry if I'm asking a stupid question, but thanks for the help.

ED - I've got a 16x8 GTA wheel with a bent lip (looks like someone rammed a curb with it) that I'll send you FOR FREE to check the GTA fitment issues. Sounds like the only way I can be sure I get the right stuff to up grade my fronts to LS1 or whatever you think is best. Don't need road racing capabilities, just want a better "stopper" and better looking rotors size-wise.....

Sounds great, Vern, I'll take you up on that. I'll send the info in my e-mail response to you tomorrow..today was too hectic and I didn't get to it.

Thanks!

Ed

I thought the C5 and LS1 calipers were identical gravity cast units. I was under the impression that only the Z06 calipers were different (pressure cast).

Nope...LS1 and C5/ZO6 are different. It's the C5/ZO6 calipers that are identical except for the "paint job".

Ed

Oh, I suppose I got them mixed up a bit. Thanks for straightening me out.

Cormyr,

Did you have to grind the lower cast vane off of the C5 caliper? I'm trying to fit my LS1/C5 combo setup and it won't fit due to that last fin on the back side, it contacts the lower part of the spindle where the bracket bolts on. Please advise..

Thanks!

Ed

OK, here's my pics of my LS1 rotor setup using a C5 caliper. I'm using a standard LS1 bracket and the LS1 carrier. I had hoped to use the C5 carrier for a few reasons..one being the price. An LS1 carrier is $60, a newe C5 carrier is $35. The second reason is the fact that you may need to grind the head of the lower spindle bolt to get it to clear the LS1 carrier, the C5 carrier has more clearance in that area and it's not an issue with the C5 carrier. I have a different design and it's not an issue with my setups either, no grinding required. THe problem is that the C5 carrier simply wouldn't bolt up as easily and doesn't fit between the rotor and bracket as well as the LS1 carrier does.

Here's the interference I have, I've had to totally remove the lower two ribs on the C5 caliper. No big deal, just a little time to cut it off. With those two ribs gone, it fits up very well although I will be moving the carrier holes a bit on the bracket to get it to fit like I like it to.

Ed

Closer view of the ribs to be removed. Notice how the caliper slider bolt is not installed in the top hole as pictured, it won't line up due to the ribs. I have taken them off and I'll have more pics later.

Ed

Ed,
Are those the C5/LS1 brackets Serpent99 makes? I'm ready to bolt mine up as soon as I have some time and these are all that I need now!

That's just a test LS1 bracket I have on hand.

I'll have more pics up in a bit.

Ed

OK, here's how I got the caliper to fit. Please note that I don't like modifying stock parts in any way but in this case, considering the options, I feel it's necessary to get the caliper to fit with the least amount of hassle: remove the two lower fin castings on the back of the caliper, easy. I still need to massage a new bracket since I don't really like how the LS1 bracket locates the caliper so I'm working on a new one. I'll post pics of that when I have it figured out.

Ed

Ok fellas, my setup is done. The bracket I made for it is an all new bracket so to speak, patternted after a modified C4 bracket. I rotated the caliper a bit for clearance on the caliper piston bores and to make it fit better in my opinion. Here's pics of my finalized setup. First off is a pic of the bracket I made compared to a standard C4 bracket. I trimmed the new bracket for better clearance and a better fit:

Next is a pic of how the bracket and carrier look with the inner pad installed:

Oops..

Now with the trimmed up C5 caliper installed...no clearance issues whatsoever:

Now for the wheel fitup issues. This setup will fit into 16" Formula wheels (pictured) and 16" Iroc and Z28 alloy wheels with no problems and plenty of room, about 1/4" between the caliper and the rim. The GTA wheels however, still have interference. The stiffening ribs on the back of the C5 caliper contact the wheel and will need to be ground down to get them to clear the ridge on the back of the GTA wheel. Other than that they seemed to fit fine but once I ran into that interference, I didn't go any further with the GTA wheel today so I don't really know if they'll need a thin spacer behind the wheel or not.

Ed

While Ed is busy fitting up parts, I'll throw in a comment or two about brake bias with this setup.

If you sit down and do the math with the piston area and lever arm length, you'll note that the C5 calipers will shift the brake bias about 5% more to the rear, compared to LS1 calipers, all else being equal.

What that means is, this brake setup should go together well with either the 1LE/LT1 PBR rear discs, or the old Delco-Morraine iron calipers. However, if you already have LS1 brakes on the rear, and mount the C5 calipers on a 12" front rotor, you'll end up with a LOT of rear brake bias.

Just to throw out some numbers, here's the approximate % of brake force on the front wheels with some common combos.

1LE front & rear = 65%
LS1 front & rear = 65%
LS1 front, iron rear = 71%
LS1 front, 1LE rear = 72%
C5/12" front, iron rear = 66%
C5/12" front, 1LE rear = 67%
C5/12" front, LS1 rear = 61%

(figures neglect proportioning valve effect and weight transfer, also assume same pad cf on both ends for simplicity. The point of the exercise is to look at how the figures compare to one another, rather than worrying about the absolute values.)

So IMHO, if you have LS1 rear brakes, and want to use the C5/12" setup up front, you'd better plan on adding an aftermarket proportioning valve to dial out some rear brake. (EDIT: I consider that the 65% F/R setups -- 1LE and LS1 pure -- as being about the max permissible rear bias, IOW *just barely* OK. By that I mean that people occasionally have problems with either rear wheel lockup or wheel hop, with those setups. Not saying that everyone experiences that, since it can be avoided or cured by the right prop valve, suspension setup, or pad selection -- but it happens often enough to indicate that's about as much rear bias as most F-bodies can effectively tolerate, IMHO.)

Also, if you prefer less pedal effort, especially on a non-track car where caliper spread isn't a concern, the LS1 calipers might be a better choice. I'm pointing this out, since some people seem to complain that the 1LE setup requires too much pedal effort -- if you're one of those people, you'd probably be happier with the LS1s than the C5s, since the larger piston on the LS1s provides much more hydraulic assist.

All IMHO, and YMMV of course

Good info, thanks, John!

The C5 caliper pistons are very close in diameter to the C4 caliper pistons. The LS1 pistons are larger, therefore will have different pressure than the C5 and C4s will.

Ed

Will the C5 caliper not work with the C4 rotor?


thx
RP

Will the C5 caliper not work with the C4 rotor?


thx
RP

Yes, a C4 front rotor can be used with a C5 caliper. There's a bit of room to be taken up by the pistons and pads but it works. Here's a setup I did for a MCSS using a 13" HD rotor and C5 caliper:

OK, here's pics of the final setup going to Chris B. up in 'Sconsin:

One thing I learned doing this setup for him is that C5 pads WILL NOT work with Ls1 carriers..they are a tad too long, the pad material is too tall and will hang over the top end of the rotor, and the lower side of the pad will interfere with the carrier should you decide to shorten them to get them to fit. I didn't get a pic of that but I will in the future. Here's the pad fitup:

New coated bracket and carrier fitup: