Beaky

I know this can be a bit of a subjective and emotive question, but who chose which and why?

sig_a

I decided on a KAAZ SUPER-Q because:

1. Quality per dollar value for stock horsepower/torque 3.2 liter. No need for a much stronger Guard chrome moly housing. SuperQ for my 911 was $1575. I think Guard is roughly $1000 more.

2. Professionalism of Ray, president of KAAZ US, who does not run down the competition. Personable to work with.

3. KAAZ web site is a plus; up-to-date, comprehensive and educational.

4. Performance and handling is a dream.

KAAZ manufacturers SuperQ limited slip differentials at their Japanese factory, then distributes them throughout USA, europe and asia. I may be wrong, but I believe they manufacturer more LSD units than any other after-market manufacturer in the world.

Guard is one of many heavy - duty LSD suppliers. For all but superpowerful cars, KAAZ offers a wide variety of configurations for drag, drift or road course sportcars.

You be the judge.

Ed Hughes

I'd contact Matt Monson at GT Gears in Boulder, CO. He is the Guard guy. He does a lot of racing boxes, and I believe will give you good counsel-he's been on the Porsche forums a long time.

Beaky

Thanks folks

Beaky

For fast road use and perhaps the odd occasional track day how many clutches/plates per side (2, 4 or 6) and what ramp angles would be the right and is the latter changeable or a once machined when built setting?

Steve Weiner-Rennsport Systems

Guard only for me & my clients,...

Super durability, excellent adjustability and "tuneability", along with 24 kt support makes these our first & only choice for street and competition use.

IMHO, you'd want a 4-plate, 40/60 unit for what you will do with car.

Droops83

Count me into the Guard camp as well, ask anybody at a POC or PCA club race what they are running and that will likely be the answer.

If you are on a budget and cannot swing the fancy billet unit (like me!), try to find a used factory LSD and send it to Matt at Guard and he will rebuild it to your specifications. It will function virtually the same as the top-of-the-line unit, only downsides being that it will be slightly heavier and maybe not quite as bulletproof, but that is perfectly OK since you are not building an all-out race car. My wimpy 40/40 LSD that my 951 came with from the factory (which I rebuilt with Guard components last year) has stood up to 4+ years of my drifting shenanigans at 12+ track weekends each year, all the normal street driving in between ;-)

sig_a

KAAZ SuperQ in my 1987 911 uses 12 plates each arranged opposite the other. I'm unsure of the exact degree of ramp. One side is approximately 45º and the other is much flatter, requiring added torque to engage clutch plates. This is an asymmetrical (1.5 way) ramp configuration. Pressure rings are reversible and changeable, as is the thickness, material makeup and number of clutch plates. Cone spring strength can also be modified.

All SuperQ KAAZ plates are surface metal treated by this outfit:

http://www.wpctreatment.com/

Beaky

Thnaks for the info folks

burglar

Sorry to bump an old thread, but just want to throw in my $0.02.

I went with KAAZ for my AX car. Mostly because I was watching my budget.

I did talk with Matt at Guard, and he's everything his reputation says - extremely knowledgeable, friendly, and patient. If you have the means and either don't know what you want or really know exactly what you want, I believe you cannot go wrong. Guard will steer you right to the correct diff type (biasing or LSD) and also custom set you up for your use. Plus service your diff post purchase.

That said, I've had my KAAZ in for about a year now, and I'm very happy with it. Ray at KAAZ is a real delight - after some chat, he set my diff up similar to the factory LSD - reverse 1.5 way, aka more locking on deceleration to stabilize the car. The 915 KAAZ has three pair of plates (iirc the Guard has more,) since my car is an AX car, Ray suggested disabling one pair of plates to reduce the total lock slightly. Here's the KAAZ ramps:

Accel:


Decel:


I did my own install without removing the trans from the car. The dimensions of the KAAZ were slightly different from the OE open diff that came out, so I had to get creative with shims (Hint: 996 shims work fine, are easier to find, cheaper, and are available in finer increments than 915 shims.)

The diff has held up well so far. It's smooth other than when reversing while turning. Inside wheelspin is eliminated, braking stability is increased.

And FYI I do lean on the diff pretty hard, not just a light cruiser here:

GTgears

How did you measure and set the backlash with the gearbox still in the car? That's a number that Porsche specs down the the 100th of a mm and makes a special tool for measuring. Get it wrong by much and the ring and pinion's days are numbered.

burglar

Get ready to cringe:

I measured my old one, and ordered the shims to put the KAAZ at the exact same width and lateral position.

The factory shims go down to the 5/100ths, not quite "to the hundredth." In fact, most of the ones I bought measured +/- .02mm of their stated spec. The new carrier bearings also measured 0.02mm thicker than the old 130k mile ones. In the end, the stack ups put my ring gear less than 0.05mm of total width and lateral position than when I pulled it out. It's nice to have full access to some really good measuring equipment.

Just to be extra sure, I also did two layers of sanity check - I used the side plate gap measurement method in the factory manual for total bearing preload, and I also used gear paint to check my mesh in both directions. Both read out real good. The paint was especially comforting - matched the wear pattern on the gears exactly.

If you have a weak stomach, do it the factory way. But a sheet of paper is 0.1mm thick, so half that away from what worked before was good enough for me, especially with the two backup checks.

So far it's worked great for 5,000 miles with no change in noise from before I took it apart.

Duc Hunter

I have heard Wavetrac's are great. Some guys from Quiff left or something, to start their own co any and build a better LSD?

GTgears

Wavetrac is a TBD, not an LSD. It was brought to market when Autotech lost the US distributor ship for Quaife, another brand of tbd.

Burglar,
Your shade tree method is more diligent than most. But most don't have the ability to measure things well.

KevinGross

Further to Matt's point, unfortunately in practice measuring and doing the math doesn't work well. As you note, the factory shims are not always exact to their nominal thickness, and it's not possible (at least without some very expensive equipment) to accurately measure and compare differential dimensions, for example. You can use those measurements as good starting points. But getting the transmission out of the car, and following the procedures in the workshop manuals is the only way to accurately set up preload and backlash. Which are critical to pinion gear longevity.