smq42

I recently acquired a 997.1 GT3 and am considering some "light" mods to make the car more track worthy. I want to keep the car street-legal and only plan on doing about 10 track days / year. I have read that the OEM LSD doesn't last very long with track use. As the engine is coming out for coolant pipes, I was planning on upgrading the LSD at the same time.

Original plan was to go with Guard LSD but an experienced local Porsche indy shop suggested that the OS Giken LSDs were more reliable and didn't need to be rebuilt as often. Anyone here have experience with OSG LSD?

(Found this thread from 2009/10 but nothing more recent. . . . https://rennlist.com/forums/porsche-...d-to-have.html)

And to continue on the slippery slope, a LWFW seems like a reasonable next step! Any experience w Aasco light weight fly wheel vs OEM RS light weight fly wheel?

Thanks

HarmonyJim

I have a Guard unit in my 997 .1RS. So far so good. No noise, and the rear of the car seems more settled. May I suggest staying with the OEM 3.6 RS flywheel and pulley (to avoid problems, I would change both ends) since they are known commodities and hopefully you thus avoid any pulley-related problems as well as cam actuator issues.

voodoo

No experience with their diff, but I have the OS Giken clutch/flywheel and I am very happy with it.

I played on the Japanese side for 20 years and OS Giken is very well known for their quality.

Ryan

Jon H

If you go with the LWFW you must also change to the RS pulley.

MJSpeed

Guard's diffs are solid and Matt is beyond knowledgeable. Never had any issues with any of our clients' cars fitted with Guard diffs or their ramps (OEM diff rebuilt with Guard ramps). I have an oem .1RS diff available with the Guard ramps (zero miles since rebuild) if anyone is interested.

facelvega

Matt at Guard and his products are great. He knowledgeable AND accessible. What you are driving, and how you are driving affect what ramps you want. If you are driving autocross and short, tight, technical tracks, you want different ramps than big, high speed tracks like Spa. For a street car, mostly street versus mostly track can change what makes sense. Matt will have a conversation with you, and suggest EXACTLY what you need. He gets my highest recommendation.

powdrhound

PM me the price MJ. I have a friend looking for one. What are the ramp specs?

Johnb55

I've had a Guard diff in my 997 GT2 for 7 years / 35,000 miles. Still holds, no noise, zero problems.

MJSpeed

Thanks!

Still available if anyone's interested.

GTgears

This thread would be worth reading:
https://rennlist.com/forums/997-gt2-...sd-buster.html

I'm not sure where your indy gets his information. Our LSDs do not require frequent rebuilding, and especially so if you aren't racing on them. Our racing customers in IMSA rebuild their units once a season, only messing around with the tune mid-season to get optimum performance for a specific track. Our PCA club racers usually go 3-5 season between services. Of the quite literally thousands of rebuilds we have done on factory LSDs since that thread went up, I've had fewer than 50 repeat customers. Your indy may be just trying to sell you what he's got for sale. He might not even be a GT authorized installer with little actual experience with our product.

Here's the math that you need to think about. My rebuild kit and a Giken LSD cost about the same, just a tick under $2000. The Giken (or any replacement LSD) is going to be 12-14 hours of labor if it's done right. Shops who install LSDs with the gearbox still in the car are NOT doing it right. Backlash is something measured to 1/100th of a mm. You can't even get the tool in there to properly measure it with the gearbox still in the car. Rebuilding your existing LSD is about a 6 hour job. Putting a Giken in will be around $500 more expensive than rebuilding with my parts.

As for that good old thread you linked? That always was a funny way to try to market something. Didn't really work out for them in the end. What has happened since that thread?

GT Customers have won the following titles:

2012 Grand Am GS class 1st and 2nd with BGB and Rum Bum
2013 Grand Am GS class 1st with Rum Bum
2013 Grand Am GX class 1st with BGB
2014 Grand Am ST class 1st with Murillo
2015 IMSA GS class 2nd with Rum Bum
2016 IMSA ST class 1st with RS1
2017 IMSA ST class 1st with Murrilo

We produce the best performing Porsche LSDs in the world. We don't pay teams to run our parts. Every team above chose the parts and paid to have them in their cars. BGB Motorsports is the only one who even ran our stickers. The results speak for themselves. You can get a Giken, but it won't actually perform any better than what's in the car right now. If you want your car to get faster, rebuild it with a Guard.

Regards,

Matt Monson
Guard Transmission llc

smq42

Thanks Matt. I'll be going with one of your rebuild kits!

Polarcharger

I've tracked 996 and 997 GT cars with the OEM LSD, Giken and Guard. Giken has a particularly strong reputation with those coming from the BMW world - and shops with BMW racing experience. As Matt indicates above, Guard has a similarly strong reputation in the Porsche community. I expect you'll be happy with either LSD, and I encourage you to use what your mechanic prefers. I strongly disagree with Matt's comment that "You can get a Giken, but it won't actually perform any better than what's in the car right now." Both are superior to OEM. For what it's worth, I put OS Giken LSDs into two of my street GT cars.

MJSpeed

Listen to this man!

Our clients have sometimes complained about having to remove the gearbox to upgrade the OEM diff/install a new Guard diff. It's not the same thing!

If anyone is interested and since Matt no longer offers this, send me your OEM diff and we'll upgrade them with Guard discs & ramps, only after you've had a conversation with Matt and/or myself to best determine which ramps to go with. Guard diffs or their parts (ramps) are IMHO the only ones to utilize.

mooty

I have had many guards LSD. if you want LSD in a porsche, anything else is just failure

powdrhound

I run a Guard GT2 LSD in my car and it's been flawless under severe track abuse. I wouldn't run a Giken LSD if if was given to me for free.