[colin_e90]

What is the difference of helical compared to 2-way? I've noticed many members on here have been purchasing the helical lsd more so

[justpete]

Originally Posted by colin_e90

What is the difference of helical compared to 2-way? I've noticed many members on here have been purchasing the helical lsd more so

It's less expensive.

[94marcus]

Originally Posted by justpete

It's less expensive.

is that it??...

[justpete]

Originally Posted by 94marcus

is that it??...

Sorry.

It's less expensive.

Fergot the smiley...

OK, basically if you're going to track the car you'll want a clutch type LSD. Check wikipedia for Torsen and Salisbury limited slips, it's complicated.

On the street? Doesn't matter.

[631twentyeighteye]

Clutch type differentials eventually will wear out and require maintenance. Helical LSD's use gears that don't wear out , however don't always put down power the way most desire in a track application.

As Pete said, for street with occasional tracking you'll be better off with a helical and for pure track you'll probably want a clutch type LSD.

[justpete]

Originally Posted by 631twentyeighteye

Clutch type differentials eventually will wear out and require maintenance. Helical LSD's use gears that don't wear out , however don't always put down power the way most desire in a track application.

As Pete said, for street with occasional tracking you'll be better off with a helical and for pure track you'll probably want a clutch type LSD.

True enough, clutches do wear although not as much as you'd think as long as they're sized correctly for the transmitted torque and kept cool. This is where a differential cooler is critical. If the diff is marginal or undersized it can get overheated quickly and wear will accelerate. Routine maintenance is important as is break-in so yes they're a pita in comparison.

The number of clutch plates, static preload, and ramp angles can be changed with a relatively quick rebuild to suit conditions at each track if necessary, another reason they're preferred.

[ashmostro]

Fwiw I have a Quaife and wish I'd spent the extra $500 on a giken. Ymmv

[justpete]

Originally Posted by ashmostro

Fwiw I have a Quaife and wish I'd spent the extra $500 on a giken. Ymmv

Yeah, it's a buy-once-cry-once kinda thing.

[ashmostro]

I may still do the swap if I decide to keep the car at the end of the year! (contemplating a cayman)

[hassmaschine]

I'd rather have a clutch type personally, but $900 for the Mfactory one is tempting. Anything would be better than the stock peg leg, I can hardly put down the power I have now which is just a drop in filter and a tune. you guys with headers etc. must be hurting. The car would be so completely different with an LSD..

[ashmostro]

Helical is all that's needed for street and moderate track, to be honest. I only have been noticing the *slight* limitations of mine on the track as I've gotten much quicker in the last year (supporting the "upgrade the software first" philosophy).

On the street and given my car is a DD I'm glad I have a near zero maintenance unit.

[MFactory]

Just to put this out there, we do currently have a Plate type LSD available for the 188 diffs (non 335i's, and 335i AT's), and our new design will be ready in a few months time which will also be available for the 215's.

In Europe, our Plate type LSD's outsell our Helical as most of our customers track or drift regularly.

[justpete]

Originally Posted by ashmostro

Helical is all that's needed for street and moderate track, to be honest. I only have been noticing the *slight* limitations of mine on the track as I've gotten much quicker in the last year (supporting the "upgrade the software first" philosophy).

On the street and given my car is a DD I'm glad I have a near zero maintenance unit.

The only maintenance needed for the PG LSD is a fluid change (Red Line Shockproof and Friction Modifier) every 35K miles (same interval as Red Line MTL in the trans) and it'll last the lifetime of the car as long as the clutch plates aren't overheated or the 250 lb-ft torque limit isn't exceeded. This is one reason it's getting a diff cooler since the car gets tracked so often. And the torque limit is not going to be exceeded even with cams and a race engine rebuild. At the limit maybe but with the diff cooler (thermostatically controlled via a Stack gauge), not a problem.

The improvement in driveability of the car with the LSD was immediately obvious on the street and worlds different on the track. Couldn't have made any use of a Torsen given the way I tend to drive though. Nothing against one, it just didn't suit my needs. And man oh man does it ever let me know I just screwed the pooch on corner entry...yow...

[ashmostro]

Originally Posted by justpete

The only maintenance needed for the PG LSD is a fluid change (Red Line Shockproof and Friction Modifier) every 35K miles (same interval as Red Line MTL in the trans) and it'll last the lifetime of the car as long as the clutch plates aren't overheated or the 250 lb-ft torque limit isn't exceeded. This is one reason it's getting a diff cooler since the car gets tracked so often. And the torque limit is not going to be exceeded even with cams and a race engine rebuild. At the limit maybe but with the diff cooler (thermostatically controlled via a Stack gauge), not a problem.

The improvement in driveability of the car with the LSD was immediately obvious on the street and worlds different on the track. Couldn't have made any use of a Torsen given the way I tend to drive though. Nothing against one, it just didn't suit my needs. And man oh man does it ever let me know I just screwed the pooch on corner entry...yow...

Maybe the giken needs more TLC... the race shop I use informed me the right way to break in the giken is to drain and refill after 700 miles and the cost of specialized giken fluids was like $70 per fill, AND i would want to get a finned drainable diff cover if I was going to do that so the costs started to quickly spiral. Whereas with the Quaife I didn't need to worry.

That said, I am noticing under extreme lateral load corner exits where I may get compromised inside wheel traction that the Quaife can go into near freewheel condition which throws off the power delivery, which I know wouldn't happen with a plate type. One of the things I've done to combat that is go back to a thinner rear bar and lower the rear damping which has helped but it's only a matter of time that it happens again, at a higher limit.

I'm guessing this is close to what you experience with your "driving style"...

[justpete]

Originally Posted by ashmostro

Maybe the giken needs more TLC... the race shop I use informed me the right way to break in the giken is to drain and refill after 700 miles and the cost of specialized giken fluids was like $70 per fill, AND i would want to get a finned drainable diff cover if I was going to do that so the costs started to quickly spiral. Whereas with the Quaife I didn't need to worry.

That said, I am noticing under extreme lateral load corner exits where I may get compromised inside wheel traction that the Quaife can go into near freewheel condition which throws off the power delivery, which I know wouldn't happen with a plate type. One of the things I've done to combat that is go back to a thinner rear bar and lower the rear damping which has helped but it's only a matter of time that it happens again, at a higher limit.

I'm guessing this is close to what you experience with your "driving style"...

I can't recall what the break-in was, maybe 1000mi or so? Danged if I can remember but it wasn't all that much different. Neither is the cost of the fluid change but at 35K mile intervals it's negligible I think. Dunno what the maintenance interval of the Giken is.

Yeah, Torsens will do that but then the car shouldn't be able to tricycle so it's kind of a non-issue with a track suspension. I think a Torsen has to have both wheels on the ground in order to work correctly.

I couldn't get the car to tricycle if my life depended on it but it is very predictable in oversteer and does it ever power through and out of corners. Well except when weight transfer over the top of a rise in a turn gets both wheels spinning a bit. But even then it's very predictable and hard to notice. Basically why slow to street speeds for a corner when it's so much fun to power through? Well, ok, it scares the brownshoedsquares. Some might consider that a bug rather than a feature I suppose.

[justpete]

Originally Posted by ashmostro

I'm guessing this is close to what you experience with your "driving style"...

Forgot to mention that on rough track surfaces and turn six at ECR has gotta count (yikes...) the PG LSD helps maintain control as the wheels get choppy when going a wee bit too fast through it or trying to power out on a non-optimal line. Not sure a Torsen would be as predictable there but it's interesting to think about.

[ashmostro]

Originally Posted by justpete

Forgot to mention that on rough track surfaces and turn six at ECR has gotta count (yikes...) the PG LSD helps maintain control as the wheels get choppy when going a wee bit too fast through it or trying to power out on a non-optimal line. Not sure a Torsen would be as predictable there but it's interesting to think about.

That's precisely where I have issues and why I would love a plate type. I don't run on hoity toity tracks with perfect surfaces ;-)

[justpete]

Originally Posted by ashmostro

That's precisely where I have issues and why I would love a plate type. I don't run on hoity toity tracks with perfect surfaces ;-)

Heh. The track at MSR Cresson is smooth, hoity toity (it's a country club for driving, yeah) and it's sealed. Everywhere. After a lot of rain, like last Saturday, it's slick even when it's dry so perfect surfaces aren't necessarily preferable to non-hoity-toity tracks. Except ECR is also a country club for driving, just not as purty. Welcome to TX...

There is however a couple of turns at MSR that'll cause spins off-track for those who think punching the throttle on corner exit is the way to get around fast. No problems here but then the suspension deals with them nicely. Not comfortably and definitely not without serious pucker factor but absolutely no loss of line and we're talking about being thrown around at the limits of the Schroth harnesses. Yeah, the chassis is a tad stiff and harshly damped but it's hard to lose control. So far.

Honestly I've no clue how the top drivers get around MSR in the 1:20 range, that's just awesome to me. And it looks like the cars are just smoothly dancing through the turns. Must've been driving since they could reach the pedals in a kart.

[ashmostro]

That wasn't directed at you, but I enjoyed the read so good outcome anyway :-)

[justpete]

Originally Posted by ashmostro

That wasn't directed at you, but I enjoyed the read so good outcome anyway :-)

No worries, it addressed the fundamental difference between types of LSDs. And kinda makes it much more obvious why a Torsen is perfectly suited for the street but not the track, generally speaking. I think most will make a choice based on cost but probably don't track as much as we, and others, do. Anything to help, ya know?

[ashmostro]

Yep. Exactly why I brought it up!

So... Cayman or continue to mod my e92?

[justpete]

Originally Posted by ashmostro

Yep. Exactly why I brought it up!

So... Cayman or continue to mod my e92?

Cayman