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I'm upgrading my 308gt4 brakes

Discussion in '308/328' started by Grahame, Jun 2, 2009.

  1. Grahame

    Grahame Formula Junior

    Nov 9, 2005
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    I'm just about to pull the trigger on the Gyrodisc 308 brake upgrade, but I just want to ask those of you who have done this upgrade for your comments after living with this upgrade for a while. Many thanks for your help and advice.
    Grahame
     
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  3. rizzo308

    rizzo308 Formula 3
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    Hi Grahame..... are you doing all for wheels or front only
     
  4. dave80gtsi

    dave80gtsi Formula 3
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    #3 dave80gtsi, Jun 2, 2009
    Last edited by a moderator: Sep 7, 2017
    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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  5. enjoythemusic

    enjoythemusic F1 World Champ

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    #4 enjoythemusic, Jun 2, 2009
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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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  6. Iain

    Iain F1 Rookie

    Jan 21, 2005
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    Also maybe talk to QV in the UK - they do an upgrade using 355 disks & modified 355 calipers.
     
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  8. davidgt4

    davidgt4 Karting
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    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.
     
  9. Grahame

    Grahame Formula Junior

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    I don't want adversely affect brake pedal feel or pedal travel. I've read some of the threads about this and don't fancy going down the path of changing master cylinder to compensate. What is your experience with the feel and travel of the pedal with your converted brakes?
     
  10. Grahame

    Grahame Formula Junior

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    Also, I don't want to adversely affect brake balance. Did any of you convert both front and rear, and how is the front to rear balance as a result? I have a fear of swapping ends at high speed with unfortunate results. I did that once at high speed on the track with bad concussion and an expensive repair bill the results for the day - I want to try to avoid this, if possible!
     
  11. Pizzaman Chris

    Pizzaman Chris F1 Rookie
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  13. Grahame

    Grahame Formula Junior

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    Hi Chris,

    Your car look great! Drilled discs? Are you happy with these brakes now?
     
  14. rizzo308

    rizzo308 Formula 3
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    Grahame... what size wheels are will you be running
     
  15. rizzo308

    rizzo308 Formula 3
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    Hey pizzaman ...... how is your car going ..everything good with the rebuild ?
     
  16. enjoythemusic

    enjoythemusic F1 World Champ

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    #13 enjoythemusic, Jun 2, 2009
    Last edited: Jun 2, 2009
    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!
     
  17. Grahame

    Grahame Formula Junior

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    Hey Riggio,

    Yes - front and rear. The ******** kit is larger, lighter front discs and new callipers, etcetera plus larger, lighter rear discs using the OEM callipers. Wheels are 16"s
     
  18. Grahame

    Grahame Formula Junior

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    Hi Chris,

    Yes, I have seen their help in other threads and I also sent them an email a couple of days ago asking about an alternative using a combination of 2nd hand 550 and 355 components. Martin responded with comprehensive and analytical evaluation of the options. I am 99.5% there but just wanting to hear of the experiences of those who have boldly gone before!!

    Thanks, everyone, for your comments so far.
     
  19. Pizzaman Chris

    Pizzaman Chris F1 Rookie
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    #16 Pizzaman Chris, Jun 2, 2009
    Last edited by a moderator: Sep 7, 2017
    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

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  20. Grahame

    Grahame Formula Junior

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    Hey Chris,

    It looks a great kit. Remind me - the rear discs are also 310mm, like the fronts?
     
  21. CliffBeer

    CliffBeer Formula 3

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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.
     
  22. Grahame

    Grahame Formula Junior

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    Hi Cliff,

    Thanks for these thoughts. As far as I can see, the ******** system addresses all three of your points. Going for a customised alternative (which I have also been considering) using 2nd hand Ferrari 550 front and 355 rear components could potentially encounter all three issues you mention.

    Cheers,
    Grahame
     
  23. Iain

    Iain F1 Rookie

    Jan 21, 2005
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    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 ******** 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.
     
  24. chrismorse

    chrismorse Formula 3

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    Hi Graham,

    ******** 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 ******** 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
     
  25. Grahame

    Grahame Formula Junior

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    Thank you Chris. I'll look out for the photos when you can post them.
     
  26. chrismorse

    chrismorse Formula 3

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  27. chrismorse

    chrismorse Formula 3

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    #24 chrismorse, Jun 3, 2009
    Last edited: Jun 3, 2009
    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 ********. 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.

    ******** 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
     
  28. Pizzaman Chris

    Pizzaman Chris F1 Rookie
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    Those are some nice looking brakes you got there Chris. :)
     

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