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I'm starting to put the '90 ZR1 track car back together and found out some interesting stuff this week...
First off a shout out to forum vendor Rich Willhoff @ Abel Chevrolet...I purchased my Z07 calipers from him last year and he gave me a killer price. They ordered the items in and had to re-order a few times to finally get the calipers in perfect condition, then carefully wrapped them all up and packed them up and shipped them out. The best customer service I've had from someone I've never physically seen.
So...when push came to shove I just couldn't see ordering the carbon ceramic rotors for the car (at this time). I found a vendor who makes iron replacement rotors for the C7 Z07's and they were 1/2 the price.
Giro Disc shipped them out in 3 days...
The calipers I got a hell of a deal on...looking in the GM catalog these '17 Addicted Red calipers were $200 cheaper (each) than the others, so we snagged them up.
I ordered the C6 Z06 caliper brackets from Van Steel...hoping they would work but not confident they would...
While I've been saving and ordering parts, I've been busy polishing the suspension components for the car...it's going to be strictly track/off-road use only, and it's just my time and some materials so I figured what the hell...
So now was the moment of truth...would this half-cocked hair-brained scheme of mine work? I've already invested some coin in parts not knowing if they would even work...nobody has ever attempted this, so it was a gamble.
The rotors look massive...because they are @ 15.5" in diameter...
So...I tried the Van Steele adapters, and they just wouldn't fit. They fit the steering knuckle but I couldn't get the holes to align on the caliper...so after looking at it for a few minutes and sipping a cold beer I figured "What the Hell..." and tried mounting the caliper directly into the original mounting holes for the J55's...and they fit! (Almost...)
The hole spacing is off by a little more than 1/16"...so the bolts started but they weren't "right". I needed to take the die grinder and oval the holes out a little bit to make it so they wouldn't bind up.
Comparing the rotor and caliper "placement" with my '19 Z07 Grand Sport...they are almost dead on in the right location. If they are off...it's only <1/8".
So...now I need to fabricate some spacers to center the rotor in the calipers...and get the right length bolts to secure them. The bolts should be here Thursday...
Next is the rear end...I have all new seals for the D44 coming. They should be here before the end of the week.
Here is the Street Shop , Inc. billet rear adapter so I can use the e-brake function of the C6/C7's (inside the rotor)...
Anyway...I was excited to see they WILL actually work, and so far it has taken minimal fabrication to get it there. Next week will be rear end work...
Awesome ! So happy to see that you are doing a real brake upgrade here and not someone wasting time/money converting factory j55 c4 brakes to ‘c5 brakes’ - under the guise that bc its c5 fhat must mean its better
Eastwood has a bare metal clear that would protect all that brightwork from corroding again. I am cleaning my suspension all up, but am not going to polish it. I will use the satin finish on mine.
Eastwood has a bare metal clear that would protect all that brightwork from corroding again. I am cleaning my suspension all up, but am not going to polish it. I will use the satin finish on mine.
I’ve already ceramic coated them...I don’t want to fuss with stripping clear coat off when it gets chipped. The ceramic coating should be good forever if I re-apply it at least once a year.
Awesome ! So happy to see that you are doing a real brake upgrade here and not someone wasting time/money converting factory j55 c4 brakes to ‘c5 brakes’ - under the guise that bc its c5 that must mean its better
My personal philosophy is brakes are the #1 most important item on a car. I've been to the point of brake failure before flying into a turn and it's NOT fun when you step on them and there isn't anything there. Undersized brakes in a track environment is a recipe for disaster...
I'm going to start out with a mild crate motor for this...just a Gen5 LT1 @ 460 hp...but it's easy to get them up to 700 HP without a blower or turbochargers. With the brakes I have I won't ever need to upgrade them...I'm good.
I can also step up to the Carbon Ceramic rotors and pads if I want down the road...I'll lose a ton of weight and the stopping power is incredible
My personal philosophy is brakes are the #1 most important item on a car. I've been to the point of brake failure before flying into a turn and it's NOT fun when you step on them and there isn't anything there. Undersized brakes in a track environment is a recipe for disaster...
I'm going to start out with a mild crate motor for this...just a Gen5 LT1 @ 460 hp...but it's easy to get them up to 700 HP without a blower or turbochargers. With the brakes I have I won't ever need to upgrade them...I'm good.
I can also step up to the Carbon Ceramic rotors and pads if I want down the road...I'll lose a ton of weight and the stopping power is incredible
Sounds awesome.
Going to a gen 5 lt1 makes complete sense - esp if in it to drop weight !
I ordered the C6 Z06 caliper brackets from Van Steel...hoping they would work but not confident they would...
The rotors look massive...because they are @ 15.5" in diameter...
Comparing the rotor and caliper "placement" with my '19 Z07 Grand Sport...they are almost dead on in the right location. If they are off...it's only <1/8".
So...now I need to fabricate some spacers to center the rotor in the calipers...and get the right length bolts to secure them. The bolts should be here Thursday...
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Joe - you didn't really expect C7 calipers to fit a C6 adapter, did you???
In the images, the position of the caliper looks to be outside the radius of the edge of the rotor. Have you installed pads to see if they will be fully biting on the rotor or will you have a "muffin top" pad?
Also, I'm curious what size wheels and tires you're planning to run on a C4 track car that has 15.5" brakes on the front. Have you checked your wheels to see if they will go over the calipers when bolted straight to the upright?
Joe - you didn't really expect C7 calipers to fit a C6 adapter, did you???
In the images, the position of the caliper looks to be outside the radius of the edge of the rotor. Have you installed pads to see if they will be fully biting on the rotor or will you have a "muffin top" pad?
Also, I'm curious what size wheels and tires you're planning to run on a C4 track car that has 15.5" brakes on the front. Have you checked your wheels to see if they will go over the calipers when bolted straight to the upright?
At the time I was going to go with a C6 Z06 configuration so I bought it...once I started to look at the Z07 stuff and how (relatively) cheap it is compared to the rest I changed my mind. I already had the brackets and Van Steel didn't know as they've never had a set of Z07 brakes in their shop yet. The said to give it a try...if it didn't work I could return them and get store credit (which I'll DEFINITELY use)...
The alignment picture wasn't with it shimmed and the bolts tight...it is now and it's centered where it needs to be both in plane on the rotor and radially. Pads are coming...it's a money pit! In the end...I'll have something I want and it'll be completely different from everything else on track days...everyone has a C6/C7 GS or Z06 or Z51, but VERY few C4's are at the CotA track days. My Z07 always surprises them...I'm outrunning them or right on their butts in the twisty infield bits but I get murdered by the Z06's on the straights because I'm 220 HP down on them. Eventually...I'll have 700 HP from the LT1 and we'll be all even in the power side. No more blowing by me on the straights...
I've got my 2019 GS next to it and can do a direct comparison between the two and I'm within an 1/8" of being in the same radial position on the rotors.
I COULD run the GS/Z06 Z07 rims on it...but they are too heavy for track use. I've been talking to John @ CCW...their C14's WILL clear the rotors & calipers in 18" diameter. I've got to test fit a front and rear before I buy them...but with it being an 18" rim I can still get cheap take-off race rubber for it The fronts are going to be 12"x18" flat-faced and the rears will be 12"x18" with a 1" lip according to John.
I found your info about the brakes facinating, I always wondered if the C7 brakes would 'almost' bolt up to the C4 spindles, thanks for being the pioneer on that upgrade.
Lool forqard to watching the rest of your thread as you build this unique car.
I've had a slight hiccup in the D44 rebuild...Rock Auto didn't have a good enough description on the web site with the seals...
The pinion seal I ordered was for a D44, but doesn't fit the D44-HD (which the 3.54 units are)...so, I had to re-order. I also ordered new "grease seals" for the stub-axles (last 2 they had in stock ).
I got the inner & outer axles all cleaned up and painted this weekend...and noticed someone had previously replaced one of the U-joint straps with some crap "Made in Taiwan" so I got online and ordered new straps and bolts from Denny's Drive Shaft for it. I should be able to get it in before the weekend if the stars are aligned right. Right now I'm trying to find the box with my Banski rear-end parts...it got moved when cleaning the shop and I can't find it .
Edit: FOUND the box with all my Banski parts buried behind a bunch of other stuff...3 garages, 2 barns and 3 pump-houses searched in 103 deg. heat.
08-14-2018, 10:55 PM
C7 Z07 Big Brake Upgrade
The fronts are going to be 12"x18" flat-faced and the rears will be 12"x18" with a 1" lip according to John.
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