Jump to content
SAU Community

Recommended Posts

Dedicated race car, the choice is between the standard type master cylinder, a booster and a proportioning valve, and, a non boosted system with one or two master cylinders. My main concern is that the non boosted system will require too much pedal pressure which will deaden brake feel, the boosted system on a similar car works well for me and is easy to modulate. I know that no booster is cool and offers more scope for balance with two cylinders but I don't want a heavy pedal. Experiences?

Link to comment
https://www.sau.com.au/forums/topic/473134-race-brakes-no-booster/
Share on other sites

I'm in our US office this week.  A day after saying unkind things about Porsches there has been a GT$ parked outside my window all day and I've had to pretend to ignore it.  Lovely looking thing from behind.

Back to the point at hand though.....Balance bar and 2 masters.  Do it right.  Pedal feel will be umpty bazzillion times better.  There is no reason to expect the pedal effort to be too high if you get the pedal ratio and master/caliper piston sizes matched properly.  This might take more than a guess to get right though.

  • Like 1
8 hours ago, GTSBoy said:

Balance bar and 2 masters.  Do it right.  Pedal feel will be umpty bazzillion times better.  

get the pedal ratio and master/caliper piston sizes matched properly.  This might take more than a guess to get right though.

The difference is night and day for feel.

Initial setup prep for M/C sizing is by maths to get the basic proportions in the correct ballpark.  And it's quite possible that you will need to trial one or two combinations.  You may not know that you've hit the best combination until you experience one that's not as "right".

My first go, the pedal wasn't terribly heavy, had excellent feel, but the travel was way too l-o-n-g.  Not a good feeling during a heavy decel event from 175 to 60 and that tyre wall seems very close.

Second go with different M/C sizes, the pedal length was where I felt it needed to be, but seemed WAY heavy.  After the first couple of applications, the driver becomes acclimatised to what's required, and you become aware that pedal feel is still sensational.

A few events later and I had a run in Mafia's 34 GTR (lovely car, 400awkW so pretty strong).  Boosted brakes were sensationally strong but devoid of feel and progression.

If you've got the time, budget, and a bit of perseverance, a proper balance bar setup that's actually set up is streets ahead and you don't notice pedal weight.

Some people will disagree and run with modern ABS setups and rely on the technology to do the stopping.  Each to their own.

  • Thanks 1

Have spent a couple of hours googling for a simple formula based on master cylinder sizes to total caliper piston sizes with no luck, that would be handy for both options. For the boosted option I do have some info on a MC size that should work, for the manual option nothing. Cost is not relevant, a new booster and MC is probably more expensive.

www.motorsportbrakes.com.au/

Consult with Marty, brakes is his day job and he knows this stuff inside out.  Far easier to get it right, and he offers great support.  It's not just about selling product for him.

You're going to need the piston sizes of your calipers to get any calculations done.

  • Thanks 1
  • 2 weeks later...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Yep, the closest base tune available was for the GTT, I went with that and made all the logical changes I could find to convert it to Naturally Aspirated. It will rev fine in Neutral to redline but it will be cutting nearly 50% fuel the whole way.  If I let it tune the fuel map to start with that much less fuel it wont run right and has a hard time applying corrections.  These 50% cuts are with a fuel map already about half of what the GTT tune had.  I was having a whole lot of bogging when applying any throttle but seem to have fixed that for no load situations with very aggressive transient throttle settings. I made the corrections to my injectors with data I found for them online, FBCJC100 flowing 306cc.  I'll have to look to see if I can find the Cam section. I have the Bosch 4.9 from Haltech. My manifold pressure when watching it live is always in -5.9 psi/inHg
    • Hi My Tokico BM50 Brake master cylinder has a leak from the hole between the two outlets (M10x1) for brake pipes, I have attached a photo. Can anyone tell me what that hole is and what has failed to allow brake fluid to escape from it, I have looked on line and asked questions on UK forums but can not find the answer, if anyone can enlighten me I would be most grateful.
    • It will be a software setting. I don't believe many on here ever used AEM. And they're now a discontinued product,that's really hard to find any easy answers on. If it were Link or Haltech, someone would be able to just send you a ECU file though.
    • Yes sir am asking is there possible way from aem tuner from wiring pins 
    • Have you checked cam to crank timing and confirmed balancer marks are correct?
×
×
  • Create New...