Jon_Valjean

Just the front - custom hubs, wilwood rotors and calipers, brake pads and bearings.

I'm using a Ford 8.8" rear end with factory 10.5 solid slotted disks, those were about US$100 each.

Hyper4mance2k

iTrader: (40)

First off your breaks are only as good as your tires! Most people never run tires that are good enough that good working new stock FB brakes cant over work. But I tell you what I look like I'm about to pay for some shipping from AuZ!!! I want to keep the stock 110x4 cause I've allready got a few sets o' rims.

Dan_s_young

iTrader: (1)

Ya, im going to be running 275/40/17's in the front so I can use all the braking I can get, but 2000 US, it out of my price range....

Hyper4mance2k

iTrader: (40)

They Auzzie ones are 1200 AUD. Aka $980 US.

Jon_Valjean

Well you're obviously using a widebody. My concern would be your bearing strength on the spindle. That's a massive increase on width over the factory, and the factory spindle size isn't exactly great.

Besides which, you can afford 275 tyres, but you don't want to spend money on the brakes? I'd rather over-brake it and have narrow tyres. Hell, I can't even fit 275's under my rear guards, and I'm pushing 500RWHP.

Re-Speed.com

iTrader: (3)

FC Bearings are used.

The FC and FB outer bearing is the same part number.

-billy

Re-Speed.com

iTrader: (3)

[QUOTE=Jon_Valjean]My concern would be your bearing strength on the spindle. That's a massive increase on width over the factory, and the factory spindle size isn't exactly great.
QUOTE]

Doesn't your setup uses the factory spindle. The SA spindles were a weak link, but the FB spindles seem to hold up.

-billy

elwood

iTrader: (1)

I've been reading all the info on big brake packages, and by my calculations, the bore sizes on all the 4-pot upgrades are too big. Somebody check my math because something doesn't seem right. When you change from the stock brake setup to a big brake setup, you want the same amount of brake torque you had beforehand. Do this and you will maintain OEM front-rear brake bias, which will give you the shortest stopping distance. Don't do this, and you will end up with way too much front brake, which will hurt stopping distances. I think this may be one of the reason that so many tuner cars with big brake kits have longer stopping distances.

At any rate, here's the math:

To maintain OEM Front Brake Torque before and after the big brake swap,

(OEM piston area) X (OEM Friction Coeff.) X (OEM Effective Radius) = (Big Brake piston area) X (Big Brake Friction Coeff.) X (Big Brake Effective Radius)

Note that piston area = the area of one piston for a single piston caliper = the area of two pistons on one side of a 4-pot caliper.

We will assume that the friction coefficients are the same for both setups, so that drops out of the equation.

The effective radius is the distance from the centerline of the rotor to the middle of the friction surface.

For a GSL-SE, the OE caliper bore is 50.8mm, for a 2026.8mm^2 piston area. The effective radius is 101.2mm.

If I upgrade to a 298.5mm (11.75") diameter rotor, its effective radius is 127.5mm.

If I plug into the above equation and solve for Big Brake piston area, I get a 28.5mm bore size for a 4-pot caliper (assuming leading and trailing are the same size -- if not, just average the two). This is a 1 1/8" bore size -- not 1 3/4" or 1 7/8" that I see many people using.

Dan_s_young

iTrader: (1)

ok, thats alot of math...

But, won't bigger tires = require more stopping power? and the brake bias will be completely fubared anyways because im going to be running larger rear brakes as well in the future....

trochoid

iTrader: (6)

Brake bias can easily be changed with an adjustable proportioning valve. Hell with all the math. Take some runs, make hard stops, adjust bias accordingly until shortest stopping distance is achieved. Real world results.

NTRX7

I hope you seriously dont think that was at the finished stage. LOL

Paul

Dan_s_young

iTrader: (1)

I honestly am still thinking I should go with some TII rotors for the time being, and then the bolt pattern is changed to the 5 lug. Then after that if I NEED bigger, badder, meaner brakes up front ill go all out with wilwoods/brembos.

But my goal for this car is to be a fun, well performing street machine, but 2000+ dollar brakes are a little out of the budget at the moment (working only part time, at the worst job ever)...

FIBREMAZ

I have FD calipers with slotted FC discs. Stud pattern redrilled to 4x110. If you do this to new discs will be ok but wouldn't do it to used discs. FD/FC calipers are plenty for an SA/FB Brembo/Willwoods are overkill for such a light car IMO.

elwood

iTrader: (1)

A prop valve should only be used on the rear brakes and it is only used to reduce pressure. Therefore, if you have too much front brake, no amount of proportioning will fix that situation. It's like a carpenter trying to cut the board to make it longer.

Also, I've set bias on a few racecars -- it requires you to lock up the wheels, which wil flat spot your tires. It's a very time-consuming and expensive proposition. Better to get your caliper bore sizes correct before beginning.

elwood

iTrader: (1)

Bigger tires may require more stopping power, but the difference will be minimal. I'm sure your stock system is sufficient to lock up your bigger tires at reasonable pedal force. I doubt you'll need or want more brake power. (At least I don't) What I'm after is more brake fade resistance for track days.

As for the larger rear brakes -- that would fix your bias issue, but only if you run some calcs and know what size rears to get. Remember, however, that the rears don't do much work, so GSL-SE rears may be OK from a fade standpoint -- at least that's what I'm gambling on.

Go to www.stoptech.com and read through some of their technical stuff. Very good website.

elwood

iTrader: (1)

I agree. FD calipers have a bore size of about 36mm (assuming you don't have the differential bore ones). Since you didn't increase your disc diameter, you should have perfect bias.

For those that want to run wider discs for a larger heat sink, Roger Mandeville used to offer a kit to widen FD calipers by inserting an aluminum spacer between the halves then offering longer bridge bolts, etc. He no longer offers the kit, but he says it's relatively easy to do with some 3/8" aluminum plate.

dbragg

iTrader: (7)

13 BEEF- will the FD and T2 calipers mount the same. i have an adapter to mount the T2 calipers to my SA but if the FD calipers will mount on the bracket then i may go that route

steve84GS TII

I widened the TII calipers I used on the front of my Samurai rock crawler's Dana44, with a dremel tool.Very simple to do,just trim away some material,but dont go overboard.
I got the calipers to fit over some F-150 rotors that had been turned one time.

Elwood is correct,a prop valve is not a bias control valve.Rotor size and caliper leverage determines bias.Check out this months SuperStreet or SCC...whatever one it is....They do a brake upgrade on some car and explain the differences quite well.
FWIW,along with my big front brakes,I run SE brakes in the rear,which are only a tad smaller than stock TII rears.All 4 are controlled by a stock TII master,booster and prop valve.Braking is stellar and bias seems right on.The car doesnt pitch or squirm at all and rear lockup is quelled by my slightly larger rear tires.225-17 in the front and 245-17 in the rear....Falken FK451

elwood

iTrader: (1)

Steve,

I once had SE rear brakes and FC rear brakes together in my garage, and I used some of the FC parts to rebuild my SE rear calipers, including the pads. It seemed they were the same size, just with a different casting design for mounting. Do you have any info on their relative sizes? Were the TII rears different?

elwood

iTrader: (1)

Folks,

I give you a simple experience that illustrated the effect of proper bias:

I had a '62 Chevy that sat in my Grandfather's garage since his death for 15 years. The car was in Connecticut, and I decided to fix it up and drive it to my home in South Carolina. I got it running and set off on my drive -- oblong tires and all. My friends and the auto parts store clerk all thought I was crazy, but the drive went fine. Aside from minor overheating if I was stuck in traffic and the bumpy ride from the dry, flat-spotted tires, things went flawlessly. The car accelerated fine and stopped fine.

After I got to SC, I tore down some of the basic systems to make sure the car would be a reliable daily driver -- I got some good round tires, replaced the distributor with an HEI unit, and did a full brake job. When I pulled the brake cylinders off the car to inspect them, I found that the rears were so corroded, they were non functional. I was ONLY braking with the fronts. I was amazed that I had survived the trip (not knowing at the time that the fronts do most of the work).

After I fixed the rears and had 4 working brakes, the car stopped shorter. Pedal efforts weren't noticeably different, it wasn't more or less stable under limit braking, and there wasn't a huge difference in stopping distance -- it just stopped a little shorter. (As gauged by my non-scientific tests on an access road)

The point is that oversized front caliper bores and/or rotor diameters will put you in a similar situation. You will virtually have no rear brakes.

Having too much front brake is a safe condition. This may be counterintuitive, but it's true.

Having too much rear brake is unsafe -- it will cause your car to spin. Think of a parking brake turn.

Having the correct front/rear balance is best. It is still safe, but will give you slightly better stopping distances, since all 4 tires are allowed to do the most work possible.

FIBREMAZ

Yes, they are the same bolt spacing and I'm fairly sure take the same pads. The FD calipers are made from basically an updated TII casting

ntech

Yes, the TII and FD front calipers use the same pad, and all the fuel injected RX-7's use the same rear pad.

ntech

Elwood, I agree with your assessment of the caliper piston sizing. I'm working on this for a customer with a GSL-SE using a 3rd gen engine. I have come up with some numbers, and will be giving him three basic routes to take. If he chooses the perfect solution, door number three, I'll have the opportunity to create a properly designed front system that will work with any 1st gen using the SE rear brakes, and possibly the rear drum cars too. If the big rotor/piston kits are being accepted in both applications, mine would certainly be better for both. They would allow use of the standard or SE lug patterns, too. But, time will tell what becomes of this.

Nick

dbragg

iTrader: (7)

13 beef-- i know they use the same pads. when i was trying to find EBC pads for the T2 calipers the part numbers were the same. so youre saying i can mount an FD caliper on an T2 bracket right?

FIBREMAZ

Yes