When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I just assumed since Porsche was using the ABS sensors to activate the PSD that they would activate the breaking on an individual rear brake. I guess at the time the main interest in ABS was to keep the front wheels from locking up for better directional control and stopping distance.
It's pretty obvious that there is something "missing" with an ABS system that only has one brake line going to the rear, which also has a rear proportioning valve, in line.
When the "American 964 Cup Cars" were built up by Porsche Motorsports USA (from the kits that Porsche sent over) one of the changes was a brake line that eliminated the rear proportioning valve.
It didn't take us very long to give this a try, on my RS America track car.
The rear brake pads went from lasting 3X as long as the front pads to needing replacement at the same time the front pads did.
Stopping distance, on the track, decreased by over 20%...simply by getting the rear brakes more involved in the stopping process.
This, obviously, allowed us to get much deeper into a corner.
Combine that with a higher percentage trailing throttle limited slip (allowing very deep trail braking) and our lap times dropped over 3 seconds a lap, at Willow Springs.
Radical difference!
Probably the same generation as a 928.
Porsche didn't bother running two brake lines to the rear wheels on a 911 until a 1995 993 Twin Turbo....everything before that was still 3 channel, with the rear wheels hooked together.
Pretty crude, by today's standards.
I think that, at least until there was an electronically-controlled rear center diff that could be integrated with ABS and the traction controls, the rear brakes had to be treated as one. Else the mechanical diff would be fighting the brake-actuated traction control or the ABS. The PSD systems on our 928's are a step in the right direction but obviously had a long way to go. Common-today road car systems look at a ton of data to decide where and how to apply corrections for driver assistance. Even then, the options for correction are often limited to throttle controls (drive-by-wire throttle only) or trying to reduce available engine torque with timing or fuel cutoffs. Systems add selective brake applications via more active ABS system capabilities to reduce drive to slipping or yawing wheels. The not-for-highway-use ABS pump that Greg shows is a gem, but still wants a lot of controller data inputs beyond wheel speeds. Like steering wheel angle, throttle input, accelerometer-based pitch and yaw angle calculations, suspension loading, and more. This will be an interesting exercise!
I stopped by Greg's yesterday, he was chained to the lathe turning out pieces for this GTS, including this bit here. Any theories as to what this is for?
Although the part that Rob took a picture of is already in the trash can....as a developmental piece that didn't work correctly (when you're developing new pieces this happens), this picture will help everyone know what I was working on, this weekend.
Given Greg's understandable concerns about intellectual property and piracy, I'm gonna guess he's taking pics of random pieces & parts so that 'certain people' will try to copy them.
Given Greg's understandable concerns about intellectual property and piracy, I'm gonna guess he's taking pics of random pieces & parts so that 'certain people' will try to copy them.
The people that copy my designs/products are pathetic.
There is little I can do to keep these people, with absolutely no ideas of their own, from copying my stuff.
I can only encourage people to not do business with these slimeballs or buy the copied products.
However, this part is not a "joke", but something I've been working very hard on.
The part that Rob took a picture of was just one piece from the assembly shown.
I'm comfortable showing the outside.....that's a visible piece of metal.
The inside is where the engineering takes place!
And, yes, this will become a new product, for the "higher end" street cars and track cars.
12-02-2020, 03:50 PM
