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Author Topic:   brake pressure gauges
ss#4
Member
posted February 17, 2004 11:19 AM
What size gauges? I see both 1000psi and 1500psi are used. What is a realistic number on the brake pressure front and rear???


rexalott
Member
posted February 18, 2004 05:12 AM
Pressure will depend on the master cylinder bore size, the pedal ratio and how hard you can push the pedal.
One example I know of is a Tilton 3 pedal setup with a 7/8 and a 1" MC, metric calipers on both ends, would show bout 400 # on both gauges.
I used to start here just for reference, with both gauges showing the same pressure, and adjust from there acccording to the track.
I always set mine up so that turning the adjuster to the right shifted the balance from the rear to the front...Making it simple to remember.."Righty Tighty Lefty Loosey" just like turning a wrench on a bolt.
You cant adjust with your foot on the brake.

Remember that the smaller MC develops the higher pressure, and the MC that is closest to the pivot point will too.
I got a little long-winded here, but the 1000 # gauge will give you a little better resolution, I think.
Hope this helps


ss#4
Member
posted February 18, 2004 05:33 AM
thanks for the response. So should the fronts be on the smaller diameter/higher pressure?


Dennis Krause
Member
posted February 18, 2004 07:05 AM
Forget the gauges. You adjust the brake bias to what feels right for the track condition and set up anyway. Besides they make bleeding the system more difficult and add unnecessary weight and expense. My 2 cents.


NJantz
Member
posted February 18, 2004 07:12 AM
I don't disagree regarding adjusting to a specific pressure during a race. But it would be nice to preset the pressure at least in the ball park going out.


dirtbuster
Member
posted February 18, 2004 08:07 AM
When you are on the track youll never even know or care the gages are there. They can cause trouble at times. What we use them for more than anything is to make sure the system isnt bleeding off somewhere. Use a board or something to keep the pedal depressed over night and see how much pressure we lose. Other than that we never use them and driver never see them.


rexalott
Member
posted February 18, 2004 09:24 AM
I dont know anybody that looks at the gauges while they're racing.
If the track's sloppy wet when you start,put the bias to the rear. This will keep you from hitting the outside wall with the wheels cut to the left and the front brakes locked up.As the track dries out start turning to the front.I usually go two rounds at a time.
You shouldnt have much trouble with air,crack the fitting feeding the gauge with a little pressure on it until you get the air out.
I have run the small MC on the front and the rear at different times.A lot depends on the driver and the track and what they like.In general dry tracks need front brake and wet ones need rear.


jws
Member
posted February 18, 2004 09:37 AM
I started using the gauges a couple of years ago and like them a lot. Sometimes in the thrash of the moment, I forget where they were set or maybe I forget to reset them after the last night out. Besides, it gives me something to do in staging. I never look at them while racing and adjust by the feel of the car.


ss#4
Member
posted February 19, 2004 12:15 PM
bkap, so what are the pressures you are seeing???


bkap
Member
posted February 21, 2004 01:03 PM
SS#4, it's been a while since I've been in the car, but I'm thinking it's in the 600-700 pound range when dialed in for mostly rear brakes. The front, in that situation, is around 300 pounds. I've got the 1500# gauges, which is overkill for my brake setup. I'm running a 1" front cyclinder and 7/8" rear. Hope that helps.


24mod
Member
posted February 24, 2004 01:37 PM
1000# pound gauges will be plenty but what the amount of pressure is always stipulated by brake bias and how many rounds the MC rod is into the bias assembly. For me, gauges are mainly used when setting the rods for the dual MC's so I can get the correct pressure split I am looking for. Everyone will have a different preference but all work the same.


cozmo
Member
posted February 24, 2004 02:33 PM
Without guages, you have no baseline or hard numbers. "Feel" only takes you so far.

Anyone looking at brake bias guages during a race probably will wreck in about 846 other ways because that aint too smart. They're just for set up purposes. Thats why they don't have lights in them.

On my 3000lb street stock, they're both between 400 and 600 with 1" MC's, dependant on the bias.

[This message has been edited by WesternAuto17 (edited February 24, 2004).]

racerwilson
Member
posted February 28, 2004 03:52 PM
I thought IMCA allowed you to limit pressure to the RF but not shut it completely off.


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