Brake Master

[e-rue]

I am making my brake lines now and had a few questions.
Coming out of the brake master does it matter which line is front and which one is rear?

From there I go to the ABS pump, then an individual line out to each wheel.
Does the distance traveled from the ABS pump make any difference? Some will be very short and others very long.

There is a stock cast iron proportioning valve that I was going to reuse to tone down the rear bias a little. It is installed after the ABS pump and has 2 ins and 2 outs. My assumption is that I can't use the wilwood adjustable valve since it only has one in and out it would have to be installed upstream of the ABS pump and I believe that would mess with the functionality of the ABS system?

I used a brake booster from a JDM Miata. I wanted power brakes after driving another persons 818 with manual brakes. I chose the Miata booster to hopefully keep the brakes from being overly sensitive due to the weight of the car. My car should end up being a bit heavier than most 818's because of the hard top. I used the JDM booster rather than the US version because the brake lines point towards the passengerside of the car rather than come out pointed directly into the frame rail (problem with most US booster options in the 818)

Thanks guys,

Puma

[Bob_n_Cincy]

I am making my brake lines now and had a few questions.
Coming out of the brake master does it matter which line is front and which one is rear?
The 2 ports on our OEM Subaru MC are equivalent.


From there I go to the ABS pump, then an individual line out to each wheel.
Does the distance traveled from the ABS pump make any difference? Some will be very short and others very long.
Length differences don't seem to matter. It is not unusual for brake line length to be all over the map.



There is a stock cast iron proportioning valve that I was going to reuse to tone down the rear bias a little. It is installed after the ABS pump and has 2 ins and 2 outs. My assumption is that I can't use the wilwood adjustable valve since it only has one in and out it would have to be installed upstream of the ABS pump and I believe that would mess with the functionality of the ABS system?
I did not use the OEM rear brake bias. Our rear heavy cars need more power to the rear brakes. Not less.



I used a brake booster from a JDM Miata. I wanted power brakes after driving another persons 818 with manual brakes. I chose the Miata booster to hopefully keep the brakes from being overly sensitive due to the weight of the car. My car should end up being a bit heavier than most 818's because of the hard top. I used the JDM booster rather than the US version because the brake lines point towards the passengerside of the car rather than come out pointed directly into the frame rail (problem with most US booster options in the 818)

Thanks guys,

Puma

[Kiwi Dave]

Hey Puma

The ABS computer negates the need for proportioning valves as it is basically a smart proportioning valve. Secondly, the Subaru ABS system is a "diagonal" setup where the front right and left rear share one of the master lines and the front left and right rear share the other, so if you end up putting in the proportioning valves you'd need two of them - one on each of the rear lines after the ABS unit. There are a number of discussions on this forum about this.

Cheers

Dave