I'm upgrading my 308gt4 brakes

Hi Grahame..... are you doing all for wheels or front only

 

Consider the 4-piston Hi-Spec kit as sold by Superforce in the U.K.

Did this one several years ago - WAY better than stock, especially for track day use.

Reasonably priced as compared to other kits on the market, perfect fit, easy install, two big thumbs up.

Second pic shows old OEM rotor on top of new, for size comparison.

You obviously need 16" wheels.

Probably not cost effective for strictly a street car, though.

Cheers - DM
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Have extensively dealt with Eric and Martin at Gyrodisc during a brake upgrade on the street/track 308 and they would be my #1 go-to guys for sure. They REALLY know the car and remember they are highly experienced and qualified to know exactly how a 308 brake upgrade should be done. In fact they even helped crunch numbers to recalculate brake performance as i also played around with difference brake pad compounds. if a company can provide the below (see attached pfd), they surely know what they are doing. So yes, Gyrodisc would be my #1 choice.

And yes, during HPDE days in the 308 i would regularly outbrake guys and never had brake fade
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Also maybe talk to QV in the UK - they do an upgrade using 355 disks & modified 355 calipers.

 

Upgraded my '74 GT4 with the HiSpec Superformance kit over the winter. Now doing 40 min. races with the Classic Sports Car Club as well as being still driven on the road. Very pleased with the performance - feels the same at 39 mins as it does at the start. Using Pagid RS5 pads which are a newer arrival and better suited to my use than the Mintex ones supplied with the kit. Rears we just stuck with refurbing the std. calipers.

 

Hi Grahame,

I installed Giro's on all four corners.

Check out the last pictures of this thread.


http://ferrarichat.com/forum/showthread.php?t=146296&page=2

Cheers,
Roo the Pizzaman

 

Grahame... what size wheels are will you be running

 

Hey pizzaman ...... how is your car going ..everything good with the rebuild ?

 

If you go larger piston the pedal goes a bit deeper, yet also has a bit more ability to control them due to needing a slight bit more pressure/pedal. So yes slightly deeper peal yet the plus is that it gives the driver a bit more control due to pedal pressure difference too.

Gyro does a 4-wheel system too. If you did not know, Eric ar Gyro was the guy who originally designed the 308 brake upgrade kit when he worked with Brembo. So he REALLY knows his stuff. He is a TRUE brake PROFESSIONAL engineer. Am sure the other packages may work, yet for my car i want a professional 'by my side.' This is why Gyro can produce proper brake analysis, they are real pros with real knowledge about many brake systems from racing Porsche to Ferraris and many others.

In the 308 that as here it had uprated fronts calipers and stock rears were fine with pads that had a highish grip coefficient. The rear brakes rotors were uprated to Gyrodisc and were alu hat floating/slotted like the fronts. Unsprung weight is your enemy!

 

Yes, very happy with them. Most folks don't like the drilled discs, but i like them.

I had them for two months and they worked great. You could feel the difference. But she had to go under the knife. So she's out of commision at this time.

Here's another shot before i installed them.


PS Make sure Martin wraps them up real good. A couple of mine got all banged up.

Cheers

Roo the Pizzaman
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A few thoughts jump out at me:

1. The big brake kits will generally require a larger MC if you want to avoid a longer stroke on the pedal. Why? Because with multiple (4 or even 6) piston configuration v. 2 piston configurations you have to pump more volume of fluid to get the same relative motion of the piston/pad. If the total piston area is increasing 25-50% then it's wise to increase the MC size proportionately. Not doing so will give you the feeling of a slightly soft pedal.

2. Be aware of fore/aft balance. The front to rear balance should be maintained. Putting huge brakes on the front and not balancing them with the rears so you have lock up happening at a dramatically different times is going to produce a funky driving experience. You can use a proportioning valve to do some compensating here but there's a limit.

3. If your car is not going to spend much, or any, time on the track then you might find that the extra rotating mass of heavier/bigger rotors and tires/wheels diminishes the ride quality somewhat on the street. Remember, both heavier rotors and tires, and, rotation father away from the axis point is going to negatively affect the ride quality.

 

I would still talk to someone like QV - they have done dozens of these upgrades & don't use off the shelf kits like this - there is probably a reason why.

Maybe the Girodisc stuff now supercedes what they have been doing or maybe its that what they do is way less expensive but no less effective. I have no idea, but in your position I would ask them.

I.

 

Hi Graham,

Girodisc has best set you are going to get without spending really serious bucks. It uses a larger than stock front caliper that provides the proper F/R brake torque. I believe that Eric, (Martin's partner in crime), the engineer who while working for Brembo said of the 308 kit that the 36-40mm piston caliper was a bit too large to provide the proper balance but was the closest that was available in the brembo line up. You can sort of compensate for this hydraulic inbalance by suing rear pads with a higher coefficient of friction. They have not only got the balance right but have increased the cooling efficiency of both front and rear in a much lighter than stock system. They have really got the best set up.
I have no knowledge of the High Spec piston size or the F/R torque balance.

I have some experience in upgrading the 308. I realy wanted to do a big brake upgrade. I bought a set of 355 calipers, a set of 360 front calieprs, called Martin at Girodisc and went through all of the calcualations and co-efficients with with him and decided these would have too much front bias. I finally scored a set of F-50 brembo fronts, including 355-32 mm discs for $700 on ebay.
Martin machined caliper adaptors and front hats to mount these monsters. We figured that a 36/40 rear caliper would be as close to balanced as we were likely to get on the rear and he found a set of used calipers, made the adaptors and hats to fit the 360 rear disc, 330/28mm.
One of the major difficulties trying to upgrade the 308 is that the rear caliper incorporates the parking brake and there are no good, larger calieprs with parking brakes to be had, SO, I looked at a few seperate parking brake calipers and settled on the 360 unit. To make this work, i had to remove the uprights, have the front ears machined and tapped to mount the main brake caliper, then have a pair of adaptor brackets cnc machined to mount the 360 parking brake caliper in the same position as the original stock caliper. The cable araingment was nearly the same but a bit longer.
The next major hurdle was the master cylinder. I bought a Wilwood 1-1/16th tandem unit, had an adaptor made to mount it, made a new pushrod and guide tube, ($1000.)
With the stock proportioning valve, the rears would lock just a bit before the fronts, so i installed a Tilton adjustable unit.
Total cost with all used calipers,front discs, new rear discs was right at $7k. The fronts weighed a bit less than the heavy stock cast iron, the rears were a bit heavier.
The result is brakes that are awsome.
Photos to follow, got to go off to work.

chris

 

So, here are photos of the end result:
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I now have more brakes than i can ever use - but they stop superbly and i never have to worry about them even under the hardest track driving i can muster.
I would improve the cars performance by installing lighter, (less rotational inertia & unsprung weight) discs of the same diameter & thickness, but less metal.
Doing this with new calipers and discs would be astronomically costly, it was 7k with a lot of used parts.
There is a slightly larger, (significant and worthwhile) master cylinder that i believe fits the testa rosa, that would work for "moderate" brake upgrades and would very likely reduce the longer pedal travel AND the slight softness associated with big front caliper, (Brembo) brake upgrade at a very modest price.

It is possible to do your own big brake upgrade, but be prepared to do a lot of pencil and calculator work. This is cool if you like this stuff, (and i really do) and if you are willing to devote a lot of time to research and seeking out a good machinist.

Even studying hard, i still need the generous advice of Martin at Girodisc. I am not a stockholder, but this firm knows brakes and is willing to go an extra 10 miles to help you and that is why i am such an advocate of their work.

It is really critical for you to get the balance right if you are to develop a better system. It does you little benefit if the fronts have killer grip and the rears are coasting / or conversely if the rears lock first. You can bandaid it with higher coefficient pads.

Brembo, High Spec and others have developed bigger brake kits for the front.

Girodisc has built a 4 wheel/ballanced/lighter than stock, quality system that will take thousands of dollars to beat.

I did and it was costly. I would do it again, because i'm a brake nut.

HTH,
chris

 

Those are some nice looking brakes you got there Chris.