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SN95 When do you need a brake proportioning valve

21
21
Exp. Type
Autocross
Exp. Level
5-10 Years
Virginia
I have a 94 Mustang that used to be a base V6 car. Current brake setup is cobra front with G-Loc R6, cobra rear with Carbotech AX, and cobra master cylinder. I can easily lock up the front wheels, so I need more rear brake. Usually I hear about the opposite being true, that people are locking up the rear before the front and then need an adjustable proportioning valve.

Would an adjustable proportioning valve help in my situation? I'm thinking the stock V6 proportioning valve may be different enough and causing my issue. Just wanted to hear from someone with more brake experience.
 
458
420
Exp. Type
Autocross
Exp. Level
10-20 Years
Kansas City, Missouri
You want the maximum amount going to the front brakes because they do the most work. You don't want a proportioning valve on the front. I'd try swapping to a GT master cylinder. I assume you're running the same pads front and rear?
 
21
21
Exp. Type
Autocross
Exp. Level
5-10 Years
Virginia
I'll add the car is an autocross car so the fronts lock up under hard braking into a turn. I'm not trying to lock up the rears just trying to get them to do more of the work.
I would look at a part swap before spending money on hard parts.
What parts are talking about swapping? I actually have all the parts to add an adjustable proportioning valve, except the parts were for another car.
You want the maximum amount going to the front brakes because they do the most work. You don't want a proportioning valve on the front. I'd try swapping to a GT master cylinder. I assume you're running the same pads front and rear?
The pads are in the first post. They were the same until last weekend, but the two now are equivalent. The adjustable PV would go in the rear in hopes of sending more pressure to the rear. I thought I had a cobra master cylinder but it might be a GT. It was a long time ago I did the brakes.

After reading the instructions for the adjustable PV I think it will do what I want.

I tried searching if the V6 proportioning valve is different than the GT, but was inconclusive. Since I have the parts I think I'm just going to do it.

But I also have the parts to add ABS which doesn't need a proportioning valve. But that's a lot more work.
 

TMSBOSS

Spending my pension on car parts and track fees.
6,225
3,211
Exp. Type
HPDE
Exp. Level
5-10 Years
Illinois
Sorry. Typos are my speciality. You have to specialize in something.:banghead:

Pad Swap. Call the folks at OP Mustang, or direct to G-Loc and see what they can do to increase rear bite with different pads.

Again, sorry for the confusion and typo.
 
21
21
Exp. Type
Autocross
Exp. Level
5-10 Years
Virginia
Sorry. Typos are my speciality. You have to specialize in something.:banghead:

Pad Swap. Call the folks at OP Mustang, or direct to G-Loc and see what they can do to increase rear bite with different pads.

Again, sorry for the confusion and typo.
Ah, that makes more sense. I already have autocross pads front and rear. Next step would be race pads. I think race pads need more heat than autocross can provide. But talking to a brake company is a good idea.
 
458
420
Exp. Type
Autocross
Exp. Level
10-20 Years
Kansas City, Missouri
I could be wrong but I didn't think there was a proportioning valve separate from the master cylinder. I removed all my hard lines when I deleted my ABS and I don't recall a proportioning valve anywhere. I added in a Baer proportioning valve to my rear brakes.
 
21
21
Exp. Type
Autocross
Exp. Level
5-10 Years
Virginia
I could be wrong but I didn't think there was a proportioning valve separate from the master cylinder. I removed all my hard lines when I deleted my ABS and I don't recall a proportioning valve anywhere. I added in a Baer proportioning valve to my rear brakes.
Correct ABS cars do not have a separate proportioning valve. It's funny you removed your ABS and I want to add ABS. I feel I could brake later with ABS. But this all theoretical as I've never raced with ABS.
There's a reason why American Iron limits tire size for cars that have ABS, it gives an advantage.
 
Correct ABS cars do not have a separate proportioning valve. It's funny you removed your ABS and I want to add ABS. I feel I could brake later with ABS. But this all theoretical as I've never raced with ABS.
There's a reason why American Iron limits tire size for cars that have ABS, it gives an advantage.
You don't have the brake pressure control valve on your car? It's normally located on the left hand shock tower underneath the master cylinder. It is designed to regulate pressure in the rear brake system.

img017.jpg
 
I am excited to hear how the proportioning valve works out! I also have issues with front locking up too easy and am looking for better braking. My iphone track addicts telemetry is neat - not sure how much to trust it - tells me i am hitting .8 to .9 g on hard braking before i lock up. Do you know how many g of braking you are hitting?

My sn95 is v6 with carbotech rp2 pads all the way around, Cobra front brakes, gt rear, master cyl stock v6, no abs. During 24 hour race doesn’t matter if its lap 1 or 300 it acts the same - brake temp not changing performance.

in my very limited track experience abs is big advantage. I kind of wish my car had it. My dads track car has abs and i can wait very late and then just stand on the pedal. I have no talent but that doesn’t stop me from enjoying the g forces of braking late!
 

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