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What are you running for master cyl/booster?

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What are you running for master cyl/booster?

Old 09-16-09, 06:35 PM
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What are you running for master cyl/booster?

Are any of you guys running a stock booster on an FC or FD race car? Upgraded to aftermarket dual MC with balance bar? I'm debating which way to go, manual or power, dual or single.


Cheers,
Carl
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Old 09-16-09, 07:08 PM
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I run a 90 RX7 in SCCA E Production. I'm using the stock booster and mc with a tilton prop valve on the rear brake line to balance things. Hawk blues front and black in the rear with absolutely no problems at all. The front are ducted with 3" tubing.
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Old 09-16-09, 07:10 PM
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Awesome, you find there is enough rear brake to begin with to make the prop valve worthwhile?
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Old 09-16-09, 09:25 PM
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Yes, too much rear brake without some kind of bias adjustment.

My set up; dual tilton masters with bias bar with a modified stock pedal assembly. You have to change the pedal ratio to get into the range that you can pair up the different size masters that are available.
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Old 09-16-09, 11:45 PM
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I had been running all stock on the plumbing side until just now when I swapped in a 1" 929 MC and booster and replaced the stock prop valve with a wilwood lever style mounted beside the sifter. I haven't driven it yet as I've still got work to do on it. I did it because I too was having the characteristic FC rear lockup problem and I wanted a stiffer pedal to make fade less noticable.
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Old 09-17-09, 12:01 AM
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How big is the stock mc cyl size?

jgrewe, any pics of the dual mc setup? That's what I was thinking in the beginning.
Cheers
carl
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Old 09-17-09, 01:48 PM
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Here are some old shots I think I have posted before.

I'd have to double check but I'm pretty sure I have 5/8" in the front and .7 in the rear.

I also think the pedal shot is before I raised the hole the bias bar attaches to. I then had to lower the pedal itself to keep it in line with the masters. The stock pedal assembly usually uses one long bolt for the clutch and brake pedal pivot. Mine uses two now because they are different heights.
Attached Thumbnails What are you running for master cyl/booster?-rx7brakes2.jpg   What are you running for master cyl/booster?-rx7brakes3.jpg   What are you running for master cyl/booster?-rx7brakes4.jpg  

Last edited by jgrewe; 09-17-09 at 01:52 PM.
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Old 09-17-09, 02:25 PM
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I gotta say it again.. check your class rules before you go buying trouble

I ran the same setup as Don49, stock MC/booster with a inline bias adjustment to the rear, squeezed out just a little bit of brake force to the rears to get a good balance.
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Old 09-17-09, 02:35 PM
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Right now I'm leaning towards a NASA time trial or SCCA solo sprint car. It seems thats where I'd likely see the most action without breaking the bank locally. Also a couple of hillclimbs that happen within a few hours of here.
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Old 09-17-09, 02:42 PM
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The stock FC NA MC is 7/8", the TII one (well, S5 anyway) is 15/16". I believe the FD has a 15/16" MC.

But you really need to ask yourself why you want to change, what deficiency are you feeling that you're trying to correct before going down this path. Otherwise it's just money wasted that could have been spent making the car faster or safer.
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Old 09-17-09, 02:50 PM
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Totally agree w you on that one, its just that the whole car is being stripped down and rebuilt, so I want to get at the stuff that may be more difficult to change later on. It will be easier now to plan out whether im using the stock MC and booster or going with something like jgrewe is using.
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Old 09-21-09, 01:01 PM
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Understood However, those items wouldn't be super difficult to change out later, and honestly, brakes one of the last things I'd be concerned about in a ITS/PT type car with the power levels you can get in our cars.. Put in good new parts, and you should do fine.
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Old 09-29-09, 10:16 PM
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Mine is a fb

But I run dual tiltons (5/8 and 3/4 bore.... I believe, can't remember exactly)with the balance bar w/ indash remote, rear proportioning valve.
Dual brake pressure guages running t2 calipers and 11.75'' rotors all round.




Running 16 inch wheels minumum with this set up....
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