Should I put Guard LSD in a 2.2??

nhs15 · nhs15's Garage

Question for the experts - 1970T coupe currently being restored. Stock 2.2 engine is being upgraded to S specs. Transmission is being rebuilt as well and wondering if I should put in a Guard LSD. Stock fenders so tires will be 205 width for now. Suspension hasn't been touched but will next year funds/wife permitting. I will be driving it regularly on the street and occasional track days. It will never be a race car but will enjoy track day events. So is the cost of the LSD worth it? I figured now would be the time but if I'm not going to notice it enough then maybe use the funds elsewhere on car. Thanks in advance for any advice.

kenikh · 10-11-2017, 05:23 AM

I would. The occasional track nails it.

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Driven97 · 10-11-2017, 05:43 AM

A question only you can answer. You're technically not going to win or lose a track day so it doesn't matter. However an LSD can improve your experience on track.

Not a cheap decision. FWIW, I installed my LSD with the trans in the car. So you really don't need to decide now. If you button your car up with an open diff, get the track day bug, and are peg legging all over the place you can decide to upgrade at that point.

You may find that your track day dreams are just dreams, and the car ends up too nice to drive on track. At that point the LSD would be nice to have, but not really being utilized.

The one good thing is that unlike a lot of mods, an LSD has very little negative effect in everyday use. A 911 style clutch diff can occasionally be a little grumpy when reversing out of a parking spot but that's it. A torque biasing diff is virtually invisible day to day.

nhs15 · nhs15's Garage

Great comments, thanks. Honestly I see 4-5 track days per year max. Not restoring to concours level so I don't feel bad about thrashing it. Crazy how costly even driver level is to get to.

I take it if you had to decide between an LSD now, or upgrading shocks/struts/tbars through Elephant, most would take the latter?

kenikh · 10-11-2017, 06:32 AM

That's a hard one. Do you not like your current suspension? You can do great work on a track with a stock really suspension. I would probably do they latter first, but it is close. My LSD has saved me enough times I won't do without one in any car now.

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nhs15 · nhs15's Garage

I don't really "know" my current suspension as I only drive it for few times on the street prior to deciding on the restoration. It was bouncy in the back but shocks/struts only can be changed easily. Car wasn't driven regularly for several years prior so lots of catching up to do.

Elombard · 10-11-2017, 06:58 AM

How much is the Guard?

nhs15 · nhs15's Garage

Should be around $2200 I believe.

Matt Monson · 10-11-2017, 07:04 AM

Quote:

Originally Posted by nhs15

should be around $2200 i believe.

$2595

KillerDynoSoar · 10-11-2017, 08:06 AM

What type of LSD is the Guard?

I have a spare 915 LSD transmission, which I was thinking of putting into my 77 911 running a 3.2 but its an original Porsche item and measured within the tolerance.

Personally once you have had a LSD its hard not to appreciate the extra traction control you gain from it under acceleration and deceleration.

Well that what I found.

Driven97 · 10-11-2017, 08:12 AM

Not that I should speak for them, but Guard sells both a Salisbury (clutch) LSD and a torque biasing diff (don't call it an LSD or you'll trigger some people.)

Talk with Matt and he'll recommend the best Guard product for your application and goals.

nhs15 · nhs15's Garage

It would be this
Limited Slip Differentials | Guard Transmission

Good to know its not a hassle to install later once drivetrain is back in.

darrin · 10-11-2017, 12:05 PM

I was under the impression that, while great for track driving/ultimate limits, adding a LSD would significantly change a 911's "feel" in day to day spirited driving. Would appreciate clarification/elaboration of what differences one would/could feel day-to-day after adding a LSD

Matt Monson · 10-11-2017, 12:16 PM

Quote:

Originally Posted by nhs15

It would be this
Limited Slip Differentials | Guard Transmission

Good to know its not a hassle to install later once drivetrain is back in.

We don't recommend leaving the gearbox in the car. It should be done on a stand with the factory set up tools. Backlash is set to .01mm tolerances.

The people who use the guesstimate method of install rarely come back a few years later and post about how their ring and pinion failed. Its not gonna break the first time out driving. If done wrong it takes a while to fail.

Matt Monson · 10-11-2017, 12:17 PM

Quote:

Originally Posted by darrin

I was under the impression that, while great for track driving/ultimate limits, adding a LSD would significantly change a 911's "feel" in day to day spirited driving. Would appreciate clarification/elaboration of what differences one would/could feel day-to-day after adding a LSD

That is easily address with lsd tuning.

Trackrash · Trackrash's Garage

I'd say, if you have the funds AND you will be upgrading to a larger motor, AND you think that maximum braking at a DE is your thing, go for it.

In my case my '71 has a warmed up 3,0 and a 915 and an open diff. I regularly autocross and do a couple of DEs a year. I don't feel a real need for an LSD. I'm not having any problem getting the power down or in braking. YMMV. See my garage for all my car's mods.

unclebilly · unclebilly's Garage

Grady Clay advised against putting an LSD into a low power car (under 250 HP) when Andrew15 and I were building our track cars.

Bill Verburg · Bill Verburg's Garage

Quote:

Originally Posted by darrin

I was under the impression that, while great for track driving/ultimate limits, adding a LSD would significantly change a 911's "feel" in day to day spirited driving. Would appreciate clarification/elaboration of what differences one would/could feel day-to-day after adding a LSD

Even an oe ZF 40% is only really noticeable in tight parking lot kind of turns, the later asymmetrics generally run lower preload and are less intrusive in parking lots.

But as Matt says tuning is a factor.

Once on the road most lsd are going to be mostly transparent

darrin · 10-11-2017, 02:17 PM

Thanks Matt and Bill -- another factor to consider when I start my upgrade journey!

Matt Monson · 10-11-2017, 02:54 PM

Quote:

Originally Posted by Trackrash

In my case my '71 has a warmed up 3,0 and a 915 and an open diff. I regularly autocross and do a couple of DEs a year. I don't feel a real need for an LSD. I'm not having any problem getting the power down or in braking. YMMV. See my garage for all my car's mods.

I 100% agree with this logic. It's what I used when deciding for my old 914. I would suggest the OP drive a few cars with various diffs if possible. As someone mentioned above ANY performance differential will be a night and day difference. For the $1000 savings off of our LSD, the TBD leaves a good chunk on the table to spend on other things.