BGB Motorsports

If I can pop in and add my $.02, we were just talking about this here in our shop. I assumed that the "bridge" is for caliper flex. For the longest time, Porsche has been concerned about caliper flex and I think that this attempt was to reconcile it. However, given that the new 991 Cup car comes with PFC everything, it's clear that the Motorsport groups switched calipers for endurance racing reasons i.e. being able to drop pads in.

Can I see a show of hands from someone that wants me to try and hang a 996 GT3 Cup 6-piston caliper on a 991 upright and see if it lines up?

Ultimately you are going to have to remove your calipers to change your pads. I think that the best advice to you guys is, while it's really hard to do, find a disc/pad combination that wears similarly so that you change pads when you change discs. I know this doesn't help but I also know that no one is going to want 7 year old Cup car calipers on their new 991 GT3.

Our 991 GT3 "harness bar" will be done Monday. It's called a "harness bar" but it is really a 4-point bolt in hoop that attaches to the OE seat belt mounting holes (RSS style) and to the rear shock towers.

Given the 991s aluminum nature, we designed a roll hoop that requires no drilling of any holes AND (READY FOR THIS), retains the use of the back seat so that you can maintain the 2+2 nature of your $150K street car.

Cheers.

ShakeNBake

There are some interesting points in this blog post from Stoptech about materials:

http://stoptech.com/technical-suppor...s-2pc-calipers

Dr.Bill

This quote from the Stoptech article may explain all - "In the case of monobloc designs made from billet, once the machine tools have been paid for, monobloc calipers may actually be cheaper to produce than two-piece units. As in the case of billet, in the case of designs made from squeeze or semi-solid forgings, once the foundry tooling and machine tools have been paid for, monobloc calipers are definitely cheaper to produce."

No big conspiracy after all, just the bean counters again.

As an added bonus, they get to sell more caliper bolts. If you read the manual, they are one-time-use items. So, for those insistent of following Porsche guidelines, the caliper bolts need to be replaced with each pad or rotor change.

orthojoe

Great link. Thanks!

montoya

With my manufacturing experience, early on with this thread I thought to myself "oh, that's just a cheaper caliper", it seemed so obvious. But then the thread speculation regarding flexing and I paused. Now it really is obvious. While performance might be improved marginally, which is obviously a plus, maintenance suffers but cost is definitely improved- bean counters (particularly bean counters with VW on their sleeve) rule. I can imagine the advanced planning meetings on the 991 GT3 with VW: Porsche lays out all the performance and marketing goals- increased performance parameters, more accessible performance to the masses etc, and VW closes out the meeting with one comment, "This project is approved subject to a 10% cost reduction and elimination of special assembly plants".

Just say'in, having worked for a large mult-national, been there, done that.

Mike in CA

Interesting perspective, but I'm wondering, what makes the new monobloc 6 piston cast caliper with a bridge on the 991 GT3 more cost effective than the old monobloc 6 piston cast caliper without a bridge on the 997 GT3?

If we were comparing forged monobloc race calipers to cast monobloc calipers your argument would carry more weight but I don't think we are; TTBOMK, both the old and new GT3 calipers are cast not forged.

The performance versus maintenance argument is valid, but I don't see how a reduction in the cost of manufacturing figures in the discussion. What am I missing?

frayed

I'm w u mike.

montoya

Less machining, less parts. Yes they are both cast, but one requires fewer machining operations, is easier to build, has fewer parts and is faster to install on the car. It all adds up even if the machine time is just a few operations and assembly time is just a minute or so faster overall for both calipers.

Edit: Looking closer at the caliper I see that the bridge doubles as a locator for the anti rattle clip and eliminates any locating pins and bolts. Definite savings.

eurotom

I'm in MFG and a big +1. Operations require jigs/fixtures that are amortized across pc parts. Great"value engineering" effort Porsche.

Mike in CA

Ok, I see your point. Still, it depends on how you look at it. When I engineer a telcom fiber/electronics project and in most engineering and design applications, being able to achieve superior performance with fewer components and at lower cost in less time, is considered a win. Granted, in this particular case ease of owner maintenance is also apparently a factor, but on balance I'd suggest there are more pluses here than minuses.

jumper5836

Major minus is not being to change pads easily. Big fail just like the CLs.

orthojoe

Mike, is it even possible for you to accept that the GT3 might not be perfect in every way?

I don't think anyone can trust your review at face value once you get your car. LOL.

I'll follow-up with any faults I find once I get mine.... but that won't be for a while after you get yours.

wanna911

ROFL

My first instructor was a woman who continuously yelled at me not to touch the throttle. Worst experience ever. Even 30% throttle she was yelling. My nerves were shot when I got out of the car. Took me a couple more track days without her in the car to get that out of my head.

People like that should be banned from instructing. If you are scared of the car and anyone else's driving but your own, you are not cut out to be an instructor.

I realize there ARE limitations to that statement. 2nd scariest moment was riding shotgun with a woman instructor who just threw the car into the turn and waited for TC to kick in, and TC always waited until the last second. Nerves shot.

orthojoe

OMG it was the worst experience ever. Not even close to the limit and she was freaking out. They had video cameras running, so I'm waiting for the video to be emailed to me that shows the sheer boredom and disgust on my face. I didn't know what to do. I didn't want to be 'that guy' that starts arguing, touting my experience, and making a scene, so I just kept quiet and stared forward while nodding my head. I don't know if there was a better way to handle the situation. I just got screwed.

Mike in CA

That's BS, Joe. The upside to the bridged brake calipers is that they are more rigid, apparently use fewer parts, and if Montoya is correct there are cost savings which help keep down the price of the car. The downside is that changing pads will be more difficult for the owner.

That's a balanced real-world view, not a suggestion that the brakes or car are perfect. It's a view that's certainly less biased than one which believes that Porsche redesigned the brakes as part of a conspiracy to squeeze more maintenance $$ out of the customer, which I believe was your premise at the beginning of this thread.

Honestly, I'll spend very little time worrying whether anyone will trust my feedback about the car. I'll be too busy driving it.