Limited slip differential

I'm thinking of converting my 915, and installing a Quaife differential, so that I get both wheels on the ground. The speedster will have a 3.2liter motor, so its light and powerful. Its an early 915 with coarse splines. Anyone ever done or have any comments. Its an expensive upgrade, but I will drive this car all year round.

Sorry Howard I have nothing constructive to say. I do however want to stop by in the winter and see you on your way to work in the snow.

Do it. Worth the money. Your 3.2 will make quite a bit of torque. Worth the money on resale also (even though you don't intend to sell). The speedster has less of a traction issue than the spyder (more weight to the rear) but the Quaiffe really makes driving on wet/slickery roads much easier.

I've driven the spyder in the wet with the open diff and with the Quaiffe. It was the difference between a sphincter clamping event of mortal terror and a relatively relaxed (but awfully cold) drive.

This upgrade on your car is a worthy improvement on an already extroardinary automobile.

angela

Angela, I was hoping that you would chime in. Since coming back from the BBQ, (what fun), touching my car and meeting wonderful people, I came back much reassured. Porsche ZF LSD unit or the Quaife is the way to go. Expensive, but woth it. I do drive all year round when I can and would want two feet on the ground. Bruce, I'll way as I go by!

seeya there

Quaiffe ??? do they smell?

Thak god I wasn't drinking my coffee---HAHAHAAAAA!!--Funny

This one seems reasonable...

http://cgi.ebay.com/ebaymotors/Porsche-901-911-914-Quaife-Limited-Slip-Differential_W0QQcmdZViewItemQQcategoryZ33731QQihZ019QQitemZ290136192278QQrdZ1QQsspagenameZWDVW

But its not for a 915. So Angela, you really think this would be a worthwhile investment? I've been thinking about it for years. Also looks at the Phantom LSD unit (a lot less $$) and they did have one for the 901 but now they say they don't.

Brian

Bruce -

If he had said "...my differential is making a funny sound" I would have been on the floor....!

Wouldn't the lsd make the car harder to drive in the wet? Especially with lots of power. When those tires cut loose, both of them, you've got no directional stability.

Hi Ron, No it dosent. In slippery condition, either in the wet,or of footing your foot into it, power is transferred to the wheel that has the most traction, seamlessly, so you don't lose complete traction. Once the other wheel bites , power is equilized to both wheels accordingly. Much better out of turns, compensates for wheels around a turn which are spinning at different speeds. With the power my car will be putting down,in the Northeast, its a must. By the way, Great meeting you guys at at IM tour, you did a great job, keeping us all pointed in the right direction. Hope to see you again when my ride is finished.

Howard, has anyone told you about the 911 pwr'd speedster in Ridgewood NJ.
Pics on this site under "Sewelli" (I think).

Right, power is equalized to both wheels, they both start to spin, and around you go.....

If only one wheel spins, the other one is able to continue on with it's job of keeping the back of the car behind the front.

Are you coming up to pick up your car Howard?

Ron, As soon as Henry tells me its ready, I'll be in Vancouver. There are a number of new friends that want to get together help "mid-wife" this birth. Lets have another BBQ on me!. Yes I have driven Marco's speedster 6 IM. 3.2/g50 LSD. Its is awesome, tight, refined and powerful. That is what convinced me to go with a 911 sourced car. Henry is making it happen as we speak. I'm giddy just thinking about it. I don't care if it drives in circles, I'll just hold on!

...and Howard, if you don't call me when you know the arrival date, I will hurt you!

Your PAL,

Tomm

Tomm, You'll have to give me a lesson on the Laws of Physics, because this bad boy will rewrite the book. If only I can keep my driving priviledges intact! See you in the Fall!

for sure, my friend! Perhaps we should get several sand tubes (used to weigh down empty pick ups in the winter) and load up your car, set up a wet skid pad in an empty parking lot and then start removing them as your lead foot becomes more and more precise, eh? Then we can go for the auto cross cones!

Tomm

Brian,

The speedsters have more rear weight bias than the spyder, so it they tend to "hook up" phenomenally well by their very nature. But with large torque engines, I really think the speedster would benefit from an LSD, especially a speedster with typical size tires (not flared). The spyder is pretty dramatically different with the LSD. That quaiffe reminds me of the killer deal Steve got on our tranasaxle... He paid $750 cashola for it, just a couple of hundred race miles on it (well driven) with the quaiffe already installed. Dang - that's pretty close to stealing, isn't it?

So Henry put a G50 in a speedster? Now that would been a tight fit - those transmissions are HUGE!

angela

Angela, Yes a G-50 fit with some "modification of the length' of the case. I don't know exaclty how it was accomplished. But I have driven that car, and its AMAZING. Its easily a sub 5 second 0-60 car. Good balance, rear end doesn't quiver under load. Fun to drive. I'm doing a Quaife for a 915 coarse spline tranny with aluminum case. Its been compleletly rebuilt, with stock gearing. I am wondering about doing a WEVO sport shifter, or should I do the upgraded Porsche sport. Or should I leave the damn gates alone?

Any thoughts about how a "Quaife differential" compares to a "Super-Diff" that some transmission builders are using?