No PSM and Open Diff???

[Danimal]

Yesterday, I realized that I don't have a PSM switch. I thought PSM was standard, but apparently not!

Then I thought no big deal at least I have a LSD....and then promptly found out I don't have that either!

How in the world did they produce a sports car without some form traction control and an open diff?? My jaw dropped and I've been contemplating my existence ever since.

So what's the deal? Is the car so well balanced or underpowered it doesn't need a LSD? I did a quick search and it doesn't look like many people add one.

[JFP in PA]

PSM is not traction control, it is stability management. You want limited slip, be prepared to spend money................

[Danimal]

I guess my question is: Does anyone know why it was nto included for these cars? Supposedly it was offered, but very few have it?

Most somewhat sporty cars before the whole "e-diff" thing took off had a LSD.

[986tate]

Most of the 200 bhp Porsches (911, 944, 914, 928) up to Boxster did not have LSD. It’s always been an option but rare.
I don’t know about all the newer stuff. What are all these other cars you’re talking about that have LSD as standard?

[tcoradeschi]

Originally Posted by Danimal

Yesterday, I realized that I don't have a PSM switch. I thought PSM was standard, but apparently not!

Then I thought no big deal at least I have a LSD....and then promptly found out I don't have that either!

How in the world did they produce a sports car without some form traction control and an open diff?? My jaw dropped and I've been contemplating my existence ever since.

So what's the deal? Is the car so well balanced or underpowered it doesn't need a LSD? I did a quick search and it doesn't look like many people add one.

PSM was always a checkbox on the order form.

WRT the LSD question, is there a problem you’ve identified which one would solve? I DD my 986 year round, with winter tires in the cold & snowy months. The biggest traction related problem I have then is that the chin spoiler tends to act like a snow plow. So I don’t drive it when there is more than 5” of fresh snow on the ground.

[Danimal]

Originally Posted by 986tate

Most of the 200 bhp Porsches (911, 944, 914, 928) up to Boxster did not have LSD. It’s always been an option but rare.
I don’t know about all the newer stuff. What are all these other cars you’re talking about that have LSD as standard?

In terms of cars I guess I'm thinking mostly BMW 325/328is, M3s, Z4 M roadster, 350z (other than base), S2000, Miata clubs....even a good number of muscle cars. With those cars there are at least enough units out there you can source a used unit and swap in fairly cheap.

However these cars are all front engine RWD and I guess may have had more of a need for LSD having a lighter rear end.

[Danimal]

Originally Posted by tcoradeschi

PSM was always a checkbox on the order form.

WRT the LSD question, is there a problem you’ve identified which one would solve? I DD my 986 year round, with winter tires in the cold & snowy months. The biggest traction related problem I have then is that the chin spoiler tends to act like a snow plow. So I don’t drive it when there is more than 5” of fresh snow on the ground.

You bring up a good point. I probably won't ever need it in a big way. I guess I'm just thinking about spirited driving on less than optimal roads (patches of water, dirt gravel, etc.). But so far the Boxster feels very solid traction wise.

I felt like it may have bailed me out driving my BMW like a hooligan back in the day, but who knows.

[tcoradeschi]

Originally Posted by Danimal

You bring up a good point. I probably won't ever need it in a big way. I guess I'm just thinking about spirited driving on less than optimal roads (patches of water, dirt gravel, etc.). But so far the Boxster feels very solid traction wise.

I felt like it may have bailed me out driving my BMW like a hooligan back in the day, but who knows.

I feel very much the same way. You can put a Boxster sideways (or so I've heard), but an LSD isn't going to change that - it will just help you to smoke both rear tires, rather than just one.

[Hasdrubal]

I see both sides here, if Honda can put a torsen in the Civic Si and keep the price down, Porsche should be able to do the same thing. I know, economy of scale and all that, but the numbers of 986 produced is quite large and the Si was a small fraction of Civic sales.

Probably makes more difference on a FWD car with its inherent traction issues, but it makes a big difference to me- I used to daily a Fit with mild suspension upgrades, and even with far better tires than stock and quite low power, it really could have used one.

Mind you, I'm not claiming to be an exceptional driver, and I haven't suffered any serious lack of grip in the Boxster. Just that with everything else on the car at the level it is, it seems like an obvious omission.