Wilwood big brakes, 914-4 brakes Options

[Freezin 914]

I figure some here will have more info on this, but Wilwood is advertising it has a big brake available for 914-4s. Just in case anyone would be interested. I haven’t even looked it up yet, but seen the ad in Excellence.

[technicalninja]

Maybe I have the rear pressure accumulator backwards...

A real proportioning valve (that has both front and rear circuits into the unit) hits a knee point that proportionally reduces the rear pressure. As the front pressure goes higher the rear pressure also increases but at a slower rate.

The 914 valve only sees rear pressure and it merely shuts it off at a spring-loaded point.
Once you hit that point the rear pressure doesn't change in any way, it doesn't drop or gain until you release the brakes at which point the pressure drops off and the accumulator section dumps its load back into the master.
This non-knee point is why I don't like them. It can be "tuned" with spring changes, but it is not proportional in any way.

The way I understand it is if you lower the spring rate on the accumulator section you lower the pressure it activates at and instead of the stock 525 you see something less.

OMG are you right on basic OEM brake set ups. They should always put heavy bias to the front.
Morons can deal with front lock up SO MUCH BETTER than rear.

As the CG of the car moves rearward this gets more important.

I just read your second post...
The puppy that Porsche installed looks like a simple accumulator to me.
I've worked with shitloads of these (automatic transmissions!). Normally they accumulate extra volume/pressure and are released to make something happen faster.
I don't think you will ever see any higher pressure in the rear system than what the valve operates at.
Now, I'm going to have to take one apart to investigate further.

A bit of search led me here.
https://tiltonracing.com/wp-content/uploads...ning-Valve_.pdf

That is COOL! the one line only Tilton valve definitely has a knee point. You can adjust when it happens, but you cannot adjust the percentage of proportion.
Still way cool!

The Tilton valve does NOT look like an accumulator, but the Porsche part does...

Thanks @GregAmy just the tidbit about how the Tilton valve works was worth it!
I'm big on balance bar dual masters but that link has shown a deficiency in my thought process. I'll be adding one of those to the 916 clone...