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Stoptech 14" 6 piston and 13" 4 piston rear kit?

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Stoptech 14" 6 piston and 13" 4 piston rear kit?

Old 08-13-10, 03:54 PM
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Question Stoptech 14" 6 piston and 13" 4 piston rear kit?

I've been running the Brembo 13" front Gran Turismo kit with the Racing Brake rear kit this season on our Rx7 road race car. Unfortunately it has proven to not be enough brake for the speeds our car is going.

I'm thinking of having a 14" Stoptech (355x32mm) and 13" Stoptech (332x32) rear kit custom made.

I've priced it out and I think I can get it done for for around $2250 front and $1850 rear.

Anyone else have a kit like this already out? I'd rather buy it than make it if I can, but I couldn't find one, especially in the price range.

Anyone else interested?
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Old 08-13-10, 06:36 PM
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I would not use Stoptech if they gave me the product for free.

What exactly are the issues you are having, what is your specific setup (car weight, class, etc) and which tracks are you running?

The Gran Turismo kit is not an actaull race kit, so my first thought would be to upgrade the kit you have. Running a 14" rotor is good if you have the wheel clearance and do not mind the extra weight. Can make more specific recommendations once I know more about your setup.
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Old 08-13-10, 06:46 PM
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I have always heard good things about stop tech, has that changed? For a long time I have heard that willwood makes not so good brakes at the low end of their product line, but they make ok stuff at the top of their line up of brakes.
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Old 08-13-10, 06:51 PM
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Not sure what the specific issue is with StopTech. It's a fairly proven package.

I'd be interested to hear what sort of speeds you're running and details on your car that are making the existing kit not enough, and what ST might do w/ regard to a 14" kit. There would be the issue of what to do with the master cylinder with that much piston, and what you might do about an e-brake if you use ST rear calipers.
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Old 08-13-10, 07:15 PM
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I have had issues with StopTech and thier "engineers", going back a few years that I will not get into on a public forum. I am aware some things have changed there but I still consider thier product standard at best if not substandard.

In order I choose to use:

AP
Brembo
Wilwood

I have a set of FSL 6-pistons here for my car, but may never use them, as a set of AP calipers may have come available.
When racing Porsches in the past I have noted:

Brembo - Race calipers vs street calipers are very different, although most street calipers can be upgraded.
Wilwood- work well, only issues I have ever had has been with the older Dynalite style calipers using serious slicks (10"wheel fnt, 12 or 13" rear) after a season or two the caliper would have flexed to the point we replaced them out of hand. At 110 or so a caliper at the time, it was almost as cheap as replacing pads. The newer calipers are much improved and have used several sets of FSL calipers and they also work well.

I think too much emphasis gets placed on the caliper or brand of caliper or size of rotor and not the actual job the brakes need to do, so most brake systems are less than optimal.
I have a friend who is using the D2 purple 6-piston calipers, which are clones of AP Racing calipers (co much in fact the D2 parts can be uses in the AP calipers and vice versa) and other than the anodizing turning brown from the heat they have worked flawlessly despite being a "lesser" caliper.
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Old 08-13-10, 10:44 PM
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Stoptech has been used in a lot of forms of racing. http://www.stoptech.com/proven_techn..._success.shtml While I agree Brembo Race and AP are good calipers I think Stoptech is as well. Individuals can have issues with any of the manufacturers. AP is owned by Brembo FYI. The big issue with Brembo and AP is the cost of consumables (rotors, etc...). Figure about $1000 a set for new rotors. Stoptech can be done for half that. We'll size the pistons to be used with the 15/16" Mazda 6 master cylinder.

Our car is a bit extreme. It's LS V8 powered (about 460 at the wheels - soon to be close to 600) and weighs about 2600. We run 12" wheels all four corners with 315 fronts and 335 rears. We can reach about 150 at Thunderhill, 145 at Laguna, and 130 at Infineon.

We're running SCCA ITE this season and have won 6 of the first 8 races. Only races we haven't won are one where we had an electrical gremlin while leading and the season opener which we blew up the stock diff before putting in the Ford 8.8.




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Old 08-13-10, 11:11 PM
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Rotor costs are what you are willing to pay I suppose. I tend to use Coleman or PFC rotors. Last I checked Coleman 12 1.1 rotors were 140 per corner, fairly economical really. Not sure about Brembo rotors BUT they are likely to become insanely hard to come by now that Brembo has turned pissy and are only shipping containerloads. I use PFC pads, and while not cheap, tend to last very very well.
As always YMMV, but I would think your streetcar Brembo Calipers with drilled SS pistons, TI heat sheilds, PFC 97 or 01 pads and Coleman or PFC 1.1 rotors with adequate cooling should do you very well. On the SWC C5R Vette running 500whp, 2800+lbs, using PBR (OEM Vette) rear brakes and 13" 1.1 rotors with AP calipers worked perfectly.
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Old 08-13-10, 11:16 PM
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Have you got any from Coleman lately? I've tried e-mail and phone call and can't get anyone.
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Old 08-13-10, 11:21 PM
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Actually no I havent, but maybe I should call over there and see whats what
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Old 08-14-10, 07:03 AM
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So what about the brakes isn't working?

Are you looking for more brake torque/stopping power, or are you having trouble with rotors lasting? You're making a lot of power w/ a lot of tire for sure, but those aren't insanely high speeds (maybe they are for those tracks)—But It's not uncommon to see 150-160 at VIR, WGI, and SPR in a street car.
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Old 08-14-10, 01:38 PM
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This photo of clearly shows the limitations of Bill's current brake setup.



So Bill, what's in the works for the motor? Turbo, turbine, supercharger a V-12 swap from a P-51? Will you be achieving escape velocity before T1 at Thunderhill?

Sarcasm Saturday...

Guy
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Old 08-14-10, 06:26 PM
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No the motor is ten years old and it time for a refresh. We'll probably put an LS3 in it for next season.

That along with a Racing ABS system and bigger brakes should put us in good shape for the NASA Nationals.
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Old 08-15-10, 11:52 AM
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Bill, I look forward to seeing how the new brakes work out for you. I've ran all of the current rear set up's(99+, racing brake) and the results are negligible at best from the stock rears as I'm sure you already know. BTW, how is the S2000 ABS working for you?

Pete, you should check out Bill's car. You would really appreciate his set up. It's similiar to my car, but 10x nicer and about 150 more rwhp. He is also running JRZ's, so you might hit him up for some realworld feedback. His car is def. a sub 2's car at VIR.

Awesome video of Bill's car from Laguna Seca: http://www.norotors.com/index.php/to....html#msg14063

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Old 08-15-10, 05:16 PM
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Bill,
You have a PM :-)
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Old 08-16-10, 10:30 AM
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Is this the blue FD? Scott/2mchpwer's car from NJ?

FWIW, Chris/Hyperion, another very fast LSx powered FD in the Bay Area, has had challenges getting his car slowed down in an acceptable manner at track days. He is on the RacingBrake kit.

It seems that once you get to those power levels on the FD chassis on a road course, the regular off the shelf stuff doesn't seem to be sufficient. I pitted next door to Jack Mardikian a couple of years at a NASA event/race when he was running his Civic in H1. He is a very fast driver and has a very nicely setup turbo rotary FD that is very fast. The build thread is on here somewhere in the Twins Turbo thread. He advised me that none of the "street car" big brake kits would work well enough once you reach a certain level of speed and talent. He recommended AP Racing Brakes.

Hope that helps.
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Old 08-16-10, 03:45 PM
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Guess I'm wondering how everyone is making the distinction between "racing" brakes, and "Street" big brakes, and what sort of speeds (not power levels) are dictating what need (is it cooling/heat resistance, actual stopping power?)

Most of the calipers and rotors used in "street" big brake kits are racing calipers and rotors with dust shields and anti-rattle hardware.
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Old 08-16-10, 07:53 PM
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I think the Brembo kit I have would be fine for 90% of the guys out there. The problem I think I have is balance. The rears have very small pistons. This pushes the balance to the front. I think what is happening in my case is just the rears are not up to the task. We upgraded the rear rotors to the "Racing Brake" (Racing brake is an actual company FYI) version, but the caliper is just too small to do anything. We went as far as to remove the proportioning valve to get more rear brake, but it really doesn't matter. Now we are no where near stock, so take what we have almost as a different car. In order to balance the rear brakes I need a bigger rear caliper. Since the Brembo's are just marginal in the front (rotor cost / replacement - not braking force) it seems like a good idea to design a good front and rear kit complete. I'm setting the rear brakes at about 58% of the total braking force which will be a bit high. I can then dial them down with a proportioning valve.

Bill
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Old 08-16-10, 08:50 PM
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At the level you're talking about it's time to consider dual masters with a balance bar, not a factory master with prop valve.
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Old 08-16-10, 08:53 PM
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Yea, agreed. I'm hoping Howard is going to start making them, otherwise over the winter we're going to do a pedal box. I'll still have them set up about the same though with 58-60% on the front and 40-42% on the back to start with.
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Old 08-16-10, 11:55 PM
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Originally Posted by ptrhahn View Post
Guess I'm wondering how everyone is making the distinction between "racing" brakes, and "Street" big brakes, and what sort of speeds (not power levels) are dictating what need (is it cooling/heat resistance, actual stopping power?)

Most of the calipers and rotors used in "street" big brake kits are racing calipers and rotors with dust shields and anti-rattle hardware.
And rubber dust boots and "solid" pistons. Usually easily upgraded to no dust boots and drilled/vented pistons.
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Old 08-17-10, 07:40 AM
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This all makes more sense.

Agreed, the stock rear calipers have their limitations, not the least of which being tiny pads (particularly compared to upgraded fronts), and the availability of those pads in good compounds (no PFC's). Usually the reason everyone sticks with them is to retain e-brake function, which may not be a concern for you guys with pure race cars.

I'd love to upgrade my rears to even a 2-piston StopTech, with bigger pads, easier to change, more torque, etc. Wondering if some sort of hydraulic e-brake would be easy to adapt and solve that issue once and for all.
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Old 08-17-10, 10:10 AM
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I'm running the Brembo GT BBK up front (thanks Fritz!) and I just upgraded my rears to four pot Wilwood calipers and the 1" bore 929 master brake cylinder. This is the same rear set up that Shpnout runs. These calipers work with a Widefoot bracket and the 99' rotors. Finally, I'll have a decent selection of pads available!
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Old 08-17-10, 04:16 PM
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Now you tell me Guy. Where did you get them? How did they work? Did you run the Brembo's without the bigger rear kit first? Did it make a difference?
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Old 08-17-10, 07:24 PM
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Bill,

I sent you a PM with my contact information.

Guy
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Old 08-17-10, 09:53 PM
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Gee whiz Guy, your giving away all the secrets!!!.......... I'll never catch Bill now!

:-)
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