porschejonno

Hey guys,

I am about to get my coolant lines pinned. Since the car is getting it's engine taken out I was hoping to get some opinions if I should upgrade to a Guard LSD while I am at it or just leave the stock lsd as is. The car will be 100% driven on the street, and 90% of time driven spiritedly.

Spyerx

Just rebuild what you have with guard kit. On street? Likely not really.

MJSpeed

At the very least, upgrade your diff’s ramps and clutches with Guard bits.

OTOH, Guard GT2 Pro+ diff is a thing of beauty. It’s better in every way compared to the OEM. It’s lighter (iirc it’s 7.5lbs lighter) and stronger than OEM. Great place in the car to go lighter.

The housing is billet, and I’ve seen stock housings break on tracked cars, which is why Porsche Motorsport has been using billet housings since 2009.

Besides all of this, the GT2 Pro+ has 6 plates not the usual 4, which gives you more configuration options.

noro78

I personally enjoy the "loose" stock LSD on the street.. it gives it a fun personallity if you are fast but smooth with your hands... but I know for a fact it would equiate to slower lap times compare to having more pre-load. People understimate the positives of no pre-load in regular street driving while making tight turns at slow speeds.

TB993tt

Having gone the Guard Pro 40/60 route and (following a problem) now using a 40/60 Drexler unit I am now heading towards trying to achieve stock like LSD behaviour.

I have memories of how easy my GT2 changed direction on the street, the steering was superb and the electronics did their thing, the car felt super stable even on a 4 mile 200mph attempt on a German Autobahn. I put the Guard in when I increased the torque to 900+NM, immediately the drive changed gone was the loose chuckable, flowing driving style, in came a rear end dominated uber controlled grip fest with understeer being the main thing on the menu.

The new Drexler felt the same as the Guard and maybe even tighter, the drive is dominated by the rear end...... for straight line driving this is great, virtually no loss of traction in second and third and arrow straight on deceleration but I find with a bit of camber on the road the directional control is fidgety both on acceleration and deceleration. The steering feels totally dominated by the rear end has been highlighted hugely to me when driving my Mclaren with its open diff.... I want my old car back but with the traction of the Guard/Drexler......

CosmosMpower

Whoa, so with the upgraded LSD the car went from oversteer prone to understeer prone? That has to be super frustrating and for me would probably equate to slower lap times. A lot of the speed in the GT3 is being able to rotate the car with throttle and trail braking, aim it and then blast out of the corner.

limitedslip

​​​​​​​FYI you do not need to take the engine out for either of these jobs.

point2point

I had the stock LSD on my GT3 rebuilt with Motorsport clutch plates. I wasn't looking for a feel or performance change. I just wanted a working LSD that wouldn't become non-functional again after a few track days.

Jrtaylor9

If you just do the GT LSD rebuild “kit”, does that materially change the “feel” to what is being described above?

Spyerx

a WORKING LSD will feel different than a car with a worn LSD. I've had a guard pro in my car for a long time now, and yeah it still works great with lockup in spec.

But, when I first put it in, I had to adjust my driving style and made a few tweaks to setup to adjust. on power it was locking up, before it wasn't.

Harder trail into corners to get car to rotate and once you got it you could absolutely get on power harder. further, braking was MUCh better and controlled, no tail wag under hard braking. Driving it like I did prior it would push on throttle as I didn't drive in hard enough and rotate.

Keep in mind a car in motion is basically a pendulum rotating weight and traction between the tires, if you get that you'll see why a working LSD will behave differently.

But, its very much for the better.

Tom@TPC Racing

The performance feature of a more effective diff is more "locking", which improves corner exit grip by locking both driving wheels to put power to the pavement when on the gas pedal. By the same token more locking can make the turn-in a little lazy with both driving wheels are locked at the same rotation speed, that is, until the breakaway occurs, hence the term "breakaway torque". This is why often you hear of drivers softening the front sway bar or stiffening rear sway bar to get the turn-in better, as well as trail braking more aggressively to balance the car after a highly effective diff is installed. These adjustments are no big deal, IMO. And for most track drivers the benefits of a highly effective diff certainly outweights the small hassle of making these adjustments. The overall effectiveness of a clutch-type diff can be tuned by breakaway torque/preload. Gear oils having different percentage of friction modifier(or none at all) is also a tuning device to change the locking efficiency. The effectiveness specifically at acceleration and at deceleration is a function of the built-in ramp angles. Some manufacturers offer different ramp angle options for tuning(i.e. 40/60, 50/50, 20/80, etc.). There are some good internet articles on this topic. Here is one article that's pretty good- http://www.intothered.dk/simracing/differential.html

CosmosMpower

What were the main improvement points? Better drive out of corners?

I don't notice much wheelspin or anything now with my stock probably worn out diff unless the track is super bumpy at corner exit. I also don't have high speed braking instability either. I'm going to have my breakaway torque checked this weekend, curious if I should upgrade the guts to GUARD

Astrix

Completely agree with you dudes... had to adjust driving style (and suspension), but the big one for me adding the Guard LSD is the elimination of the tail wag under heavy, high speed braking... the car is safer to drive fast now.

point2point

Most noticeable was less skittishness braking from high speed.

powdrhound

I've been using the Guard GT2 Pro 40/60 LSD for a number of years. Fantastic unit with zero down sides.