These Zuffenhaus brakes use 930 piston sizes front and rear, which means they can also use 930 piston o-rings and seals. Combined with their aluminum brake hats and Brembo floating rotors, you save a lot of un-sprung weight (but loose the stock e-brake). They look cool, too!
Last edited by smclaughlin; 02-17-2014 at 02:38 PM.
Aaron's attention to detail when fabricating and installing the brake lines is amazing!
Last edited by smclaughlin; 07-29-2014 at 01:03 AM.
Aaron said these were a LOT of trouble to install...
Zuffenhaus is working on their own version of the RSR e-brake, but last I checked they were not yet available.
Last edited by smclaughlin; 02-17-2014 at 02:55 PM.
I found these advertised here on the forum. They already had the RSR finish on them, reportedly done by Weidman many years ago.
They are standard Fuch offsets, and there are 25mm spacers in front and 15mm spacers out back.
Last edited by smclaughlin; 02-18-2014 at 04:02 AM.
Many of you know how hard it is to find a good 15" tire. Stock tires on a long hood 911 are about 25" in diameter, and that's what I wanted to stick with for various reasons including aesthetics. The choices available today are either too tall (26.7") too short (23"), too track-focused for my liking (Hoosiers) or too darn expensive (Michelin TBs). Actually, I would have bit the bullet and used the TBs but even there the only real option for this car would have given me rear tires over 2" wider than the fronts - more than I wanted. Soooo...it's Toyo R888s. Not exactly what I wanted, but I think the look is at least not completely objectionable and they perform very well, at least in the dry-weather street driving I've used them for so far.
Last edited by smclaughlin; 03-23-2014 at 02:47 PM.
I wanted an 8:31 ring and pinion for strength, and a magnesium case for light weight. The changeover from the 7:31 to the 8:31 happened during model year 75, and the change from a magnesium to aluminum case happened during model year 77. '76 was also the first year of an improved input shaft guide tube, so 1976 is the sweet spot, and Aaron found a good one to use as the basis of this build.
Last edited by smclaughlin; 02-18-2014 at 05:15 AM.
I don't have any close-up pictures of the machining that Wevo did on the 915 case, but you can read all about it here: http://www.wevo.com/Products/Transmi...aseSystems.htm, though we did not need the guide tube upgrade because we are using a '76 case. We also used Wevo's bearing retainer plate.
Last edited by smclaughlin; 02-18-2014 at 06:07 AM.
Nice piece of alu.
Last edited by smclaughlin; 02-19-2014 at 03:57 AM.
Matt Monson at Guard Transmission gave me great advice on gear ratios and I think they worked out perfectly. I bought three new gears, and used the stock 1st, as well as the stock 3rd gear as the new 4th gear. I bought a somewhat-shorter 5th gear - my goal here was not to have the ideal RPM drop between 4th and 5th which would have resulted in a far shorter 5th gear, but to be right at the beginning of the engine's power band when cruising at 75MPH. As you can see from the gear chart, 75MPH in 5th is at a comfortable 3600RPM at which point the engine pulls strongly. For me, it's perfect. Aaron had the same comment on 5th gear when he first drove the car, though he thought the jump between 3rd and 4th was MUCH too big...but that's because he accidentally used the stock 4th gear rather than the stock 3rd gear for the new 4th gear (if you follow me...) the first time he assembled the 'box...whoops!
One minor annoyance is that the new gears are somewhat noisy, though I only really notice in 5th. Matt explained that while these are still helical cut gears, they are optimized for strength and durability rather than noise and vibration like the stock gears. It's not bad enough to make we want to revert to a stock 5th...but it's something to consider.
8:31 ring and pinion
1st: stock 11:35 (3.18)
2nd: new 17:35 (2.06)
3rd: new 19:30 (1.58)
4th: former stock 3rd gear 23:29 (1.26)
5th: new 27:25 (0.93)
Last edited by smclaughlin; 02-17-2014 at 03:26 AM.
I did a lot of research on limited slip differentials and found many experts who dismissed the OS Giken diff without ever having used one, but many others using them on street and track cars who gave them strong endorsements. It automatically varies between 0 and 100% lockup on both acceleration and overrun (braking). After a few months using this diff, I am really impressed - it is very quiet and seems to be providing excellent traction out of turns and incredible stability under heavy braking, but is completely disengaged when puttering through town.
Last edited by smclaughlin; 06-14-2016 at 03:16 PM.
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