antonhr

Hi all,

I've been looking at upgrade options for my diff and am not able to find much information on the 997 parts. As far as I'm aware the stock 997 GT3 unit is not much better than the one in the 996.
That being said, would the 997 diff be a straight fit to a 996? What about the 997 cup LSD, would that fit a 996 gearbox and do you think it would be a worthwhile upgrade? Based on the pictures I've seen the diffs look identical.

Regards,
Anton

Marv

Guard. Much, much better than anything you can buy from Porsche.

GTgears

997 street lsd is going backwards. It’s 28/40. You’ve already got 40/60 locking factor. The ONLY difference between your LSD and a 996 Cup LSD is the clutches. Put a set of cup clutches in there and you have a cup LSD.

Or better yet, as mentioned, you can use my clutches in your unit. They last longer, offer more progressive locking, and cost less than the PMS parts.

regards,

Matt Monson
Guard Transmission llc
gtgears@yahoo.com

Malloy

Hi @GTgears ,

I'm extremely new to this platform so please excuse my ignorance. Do you offer an OE or OE+ rebuild kit?

I won't track my car and I want it to be a stock as possible mechanically. I have 65k miles so a rebuild may be in my future. The beautiful CNC'd unit on your website seems like overkill for my use case.

Thanks!

craina

Yes they do, reuses the stock housing. That is what I have had in my car for the last 10k miles, many of them on track, and it is holding up nicely. No sense in rebuilding with OEM parts when the Guards rebuild is available.

ScottArizona

I have GT diff plates and they don't "feel" different than stock in any way other than better performance. And, at 65k miles if you don't already have guard internals, you need a refresh now...not in the future. The stock internals don't last at all! But most people don't know their unit is shot because they don't push the car hard enough on the street to be able to discern that the Lsd is doing nothing! Main symptom on my prior gt cars was a very wiggly rear end at threshold or near threshold braking. That's a tell-tale sign in my experience.

black04

WHOOOA You are going down the wrong path, man.
Do NOT, I said DO NOT "UPGRADE" to anything, just REPLACE your plates with Guard plates
I can walk you "down the path", but that would be a lot of work and ....

I replaced my stock LSD plates with OEM. Was I sorry.
Guard replacement plates are the way to go.

• Last longer...WAAAAY Longer.
• Work Better
• Most economical and cost effective

DO NOT REPLACE your diff...unless you like to throw money down the toilet or unless you are a serious, I said SERIOUS, Track-meister
I can go on, and on, and on...but I will stop
You will thank me

black04

there is Much information and misinformation about LSDs on this and most all forums. Separating it all out is difficult.
And apologies, I didn't read all the posts here, so I might have missed something and am shooting in the dark. If I am wrong, I apologize.

Further... I lied when I said I would stop.

You talk about "upgrade"...WHY? What is the problem? IF THERE IS NO PROBLEM DON'T FIX IT.
If you don't feel a problem there are two possibilities:

• You are not pushing hard enough to feel a problem
• OR you are pushing hard, but your diff is effectively "Open"
• I have no way to know your situation, but it is probably the latter

Most Porsche of that era come stock with open differentials and they corner like stink, so a worn, so-called open diff is not a problem
So I will double down on my "...if you like to throw money down the toilet", don't bother to do either. i.e. don't "upgrade" OR "replace"... you don't feel a problem. FULL STOP (that said, with that mileage I can guarantee that your diff clutches are worn out)

That said, if you want to learn to drive hard. Learn...and then spend the money to repair your diff.

Marv

The OEM plates come with a "blacktop" warrantee. Once you drive it off the installer's lot they are effectively shot.

Okay, not that bad, but not far from it. You would be very lucky to get 30K out of OEM plates. Put the Guard plates in and it will drive like a different car. Really a superior product.

spiller

My 996 GT3 that I purchased 3 years ago had 0 track miles and around 17,000 road kms. In that time I have done 5 track days with the car, each consisting of approx 1 hour of track time. In the first few events, the diff performed satisfactorily. At the end of the last day I could progressively feel the rear end becoming less stable under braking. The clutches are not yet toast, but getting there. It was interesting to be able to go “back in time” by starting off with a fresh 996 GT3 and experience the rather rapid decline of the differential, given that it’s a known issue.

black04

not sure what ”toast” means

if you feel rear instability it’s likely the worn plates are degrading your handling. More wear and rough pavement could result in a skid You would be foolish to push to the limit in that condition

spiller

toast = done/worn out/kaput.

yes, that’s correct, it was the LSD causing the rear end instability. Not really a major concern for what I am using the car for.

mehoff

Order of what you should do:

1) Guards LSD
2) Motorsports LSD w/ Guards clutches
3) Nothing

The cost of install makes putting a less than perfect LSD in a complete and total waste of money. Better off waiting until you can afford to do it right, because eventually you will regardless.

I just changed from a 997 Guards to a 996 Motorsports with Guards clutches. Both have similar performance under braking, but the Guards LSD is substantially better in high speed corners.

pete95zhn

997 (or 996) Cup LSD will bolt on. BTDT. Forget street car parts.

996 Cup: 40 / 60 locking value
997 Cup: The locking torque of the differential is 40 % (power) and 60 %
(braking) (Dynamic locking value).

^Both quotes from respective Technical Manuals

black04

What you are "using the car for" where the handling is not an issue?
I don't understand why you say the plates are not worn out when they don't do their job and are ruining your handling.