jpurban

I've been sitting on a wavetrac for quite some time, waiting for my OEM clutch to give out to "justify" the upgrade. I think I'm getting close. So, I'm starting to think about the install...

Is the Wavetrac install straightforward? Anything other than a "part swap" exercise?

Can I trust a local indy to install it? Or, should a transmission specialty shop, like GBox or CMS, do the work?

CMS's website says the axle flanges need to be cut down for the G96/50 in the P996TT, but I have no idea what that means.

Would love to hear from folks that had one installed in their P996TT!

trendy996

TheDeckMan

Have not got around to doing mine yet, most likely will this winter. Guessing the inner ends need to be turned down to prevent from bottoming out?

32krazy!

You have to shim the d/s bearing. You need a new bearing to start. No need to cut anything. Install it fully against the pass side and measure the shim stack so the ring and pinion line up. There's multiple shim packs available from porsche. The mounting bolts change due to the wavetrac vs the oem diff

"02996ttx50

mine was done once and correctly by a pro. by far best mod ever, that and going RWD. there is some question as 32 says re setting the gear lash, but a pro will "know". a guy like roger at CA motorsports for example. or the guy that did mine in SoCal.

GTgears

People seem to be talking about two different grinding operations here. The first one, is the axles flanges. Early 2 spider open diffs used circlips to attached the flanges to the diff. A later 4 spider diff will have bolt in flanges, like have always been used on the LSD cars, and no modification will be required. If you have the circlip flanges, either you need to find some G50/GT3 bolt in flanges in the used market, or pay someone to machine yours down in the way that CMS describes on their website. They need to be shortened and through drilled

Someone mentioned a case modification. Again, this is an early vs late thing. Some of the early cases have a little internal rib that needs to be machined down to clearance for a diff. It was only the first year or so, to my recollection. As he said, you'll know if when you see and test fitting the diff will hit it. You just take a dremel/grinder to it and knock down a few mm until the diff is clear of it.

The bigger issue is the installation and set up itself. Personally, I don't know why anyone would do their own install on one of these cars. Ring gear backlash is measured to 1/100th of a mm. It uses a $3000 tool to do. Some people make their own. Some people use a flat plate and geusstimate height of original diff versus replacement. If you think your eye or tools are that good go for it. But if the backlash is wrong, it will only take a year or two until the ring and pinion eats itself. That's if you get it close enough. It you get it way off, it will go in a matter of months.

A ring and pinion is around a $3000 part. It is NOT something you will install yourself. You will pay someone $2000 labor to do it for you. If it fails in a grand fashion it may do thousands of additional damage. It could require a whole new gearbox. If this were a Golf or Civic where one can find used gearboxes all day long for $1000 or less, go for it. But do you really want to make a $5000 mistake.

And lest anyone thing I'm just saying this to drum up business, I would remind you that I am not a shop. I am a competing manufacturer with Wavetrac. I only make parts. And why I only sell them to wholesale shops is because I know what it takes to do the job right. I don't want my product anywhere near a self destructing ring and pinion because in my experience when that happens the first thing people do is blame the part, when nine times out of ten it's the monkey who installed the part.

coffeehead

Very helpful, GT.

When you say "early" versus "late", do you mean in G96 production, or pre/post 2001.5 996tt?

GTgears

trendy996

GTgears

"02996ttx50

THIS ^^. When I had mine repaired the FIRST time ( while under factory warranty ) Porsche ( TRIED ) to claim to me, that they had "never" heard of this issue. This was in '09. i KNEW they ( the service manager @ major dealership ) were lying to my face and I quickly elevated this to PCNA, armed with a ton of info they already had, but hoped that I did not. sometimes the internet is just "right". and that's how I got them to acquiesce to my demand they repair it. Their original quote to repair 2nd gear pop was $8K. I was going to fight them to the death but i "knew too much". After some heated exchanges, they relented and repaired it under warranty. THEN, they had to repair it AGAIN per my personal nightmare ( per above ) of them replacing the parts to the ORIGINAL ( rather than amended re-shimmed ) specs.

add; sorry thought this was the 2nd gear thread..ha

jpurban

Thanks for all the replies. Matt (GTGears) and Roger (CMS) have been very helpful, here and via e-mail.

I know a lot of folks install a differential as part of the process of converting to RWD, but I'm thinking of staying AWD. I know the non-open differential *can* limit the torque transferred to the front differential (in one wheel slip scenarios), but you still transfer at least 5% to the front, maybe up to 15%... and more traction is more traction, right? One of the main reasons I was thinking of installing a non-open differential is the rear wheel spin that shows up on tight corners after you stiffen up the suspension (stiff rear ARB to dial out some of the factory understeer). So, I see some benefit to having a non-open diff AND keeping the AWD -- kind of a shift towards more RWD feel, but retaining some of the benefit of 4 wheel traction. Am I missing something?

Sure, the AWD adds 70 or so pounds to the car, but that extra weight (and driveline loss) seems to be offset by the improved traction, especially in the wet, and the extra weight up front helps with the car's F/R balance, albeit in only a small way -- we're still 38% front/62% rear, or so. Of course, RWD is still RWD -- many prefer it and I'm not knocking anyone's preference.

"02996ttx50

yes. what you are missing is real time experience with rwd and a lsd. whether plate type or a wavetrac tbd. open diff and rwd, is essentially "one wheel drive" and utterly useless for the reasons you cite.. however, rwd in concert with a properly locking lsd ( again whether a torque biasing diff? or a "true plate type" lsd ) will tell the tale of the wag. i am not sure what the point of an lsd affixed to an awd 96t might be? perhaps you'll be able to let me know. the advantages of an rwd car w/ lsd, however, are instantly apparent. once installed.

and yes. matt and roger are incredibly helpful. whether they get your business or not? they remain, seriously helpful folks.

s65e90

Should be good with the AWD though I don't think 100% necessary. I for one like the mechanical AWD setup. Simple and works as designed w/out fault. I am certain there was even a rare option for an LSD in the 996 turbo.

T10Chris

Im RWD and my weight distribution is 39/61 after corner balancing. The weight difference is able to be balanced out with a good suspension set up. Traction wise, straight line traction I don't notice any difference, but I am not a drag racer and don't launch the car- cornering traction/grip is better with RWD and LSD than AWD no LSD.

As far as everything else, AWD with LSD is better than AWD with no LSD. The LSD isn't going to fix the short comings of the AWD system (most of which you will probably never come up against without hard track use), specifically the lack of power actually transferred up front and the inconsistency in how it does it, and the instability in cornering. You can always try AWD with LSD and then drop the AWD unit later if you want, which was my plan until I started tracking harder and ran into the point where the AWD was a pain in the *** and unpredictable rather than being a benefit.