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Posted by: zoomCat Feb 12 2022, 12:24 PM

There are different part numbers for the pressure regulators on the 4 and 6. Anybody know what the difference is?

Posted by: Superhawk996 Feb 12 2022, 01:44 PM

The difference is in the set point at which the "regulator" begins to proportion rear brake pressure.

914/6 has a lower pressure knee point due to larger rear caliper pistons 38mm vs. smaller 33mm pistons for /4.



I belive PMB can reset a /4 regulator to the /6 set point if need be.

There are also two types (early & late) for /4's where the inlet and outlet ports changed location to accomodate different mounting locations between early and late. If you were going to try to obtain and use a /4 regulator for a /6, you would want the early version.

Posted by: mlindner Feb 12 2022, 03:30 PM

Wow Superhawk996 that is great info again. This is just the best Porsche forum ever. Mark

Posted by: partwerks Feb 12 2022, 07:57 PM

Is this that part that is mounted in the engine bay, about 1/2 way up towards the driver's side with the brake lines hooked to it?

Posted by: mepstein Feb 12 2022, 08:16 PM

Yes

Posted by: zoomCat Feb 13 2022, 08:54 AM

The previous owner had changed out the pressure regulator for an adjustable proportioning valve, I'm going back to stock. Are there any visible differences between the two, or do I have to hunt down a /6 part to have Eric rebuild?

Posted by: mepstein Feb 13 2022, 09:12 AM

I don’t think there is a visible difference. I think it’s more of a setting on the part to achieve a different pressure release. I would think it’s a needle in a haystack to find the original six part. I would ask Eric directly but I bet he can achieve the exact same performance from an early 914-4 piece.

Eric did write up a thread that dives into this part in detail.