Limited Slip or Welded Differential?, "Pros", "Cons", "How To Dos", and " Options

[Eddie914]

What are the "Pros", "Cons", "How To Dos", and "Been There Done That's" regarding reducing the slip for 914 sideshift differentials?

I have a rebuilt (or so said the PO) 914 sideshift 914 transmission in the 1971 3.2 conversion teener. It works well. It shifts well, all the synchros seem solid, it doesn't make any unusual sounds and stays in gear (after new engine mounts were installed).

Also in my inventory of used parts are a 1986 Carrera 915 Limited Slip transmission and a spare 914 sideshift transmission. The 915 came from a wrecked (nasty side impact with a tree at the B pillar) 911 Carrera with 85,000 miles. The spare 914 Sideshift was purchased on ebay and is of unknown working condition.

Option 1: Install the LSD from the 915 into the 914 SS transmission currently installed in the teener. The local Porsche transmission shop said that the 915 LSD will NOT fit in the 914/901 transmission. Grady Clay indicated on the Bird Board that he has done the swap. Are substantial modifications required? Has anyone BTDT?

Option 2: Weld the differential in the spare 914 SS transmission. Can the differential be welded with out completely disassembling the transaxle (removing the side cover and welding the spider gears while the differential is still installed in the case?

I use the teener mostly for track events. I have not yet autox'd the teener but may do so when my son turns 16 in about 4 months.

The 914 is currently running 944 Turbo CV joints with 914 axles. I also have a set of Sway-Away Slider axles with Carrera CV's that are compatible with the output flanges on the 915 LSD. I think I have all the parts required to utilize both of these options ( and a few variations ...).


Thanks


Eddie

[Heeltoe914]

(IMG:style_emoticons/default/popcorn[1].gif)

[Bleyseng]

I wouldn't weld the diff as I drove a 914 at the WCC04 and it was difficult to AX the car. Tight turns were interesting....

Sell off the extra 915 parts and spend the money building a Limited Slip 901 that will last for a long time with that 3.2L.

Down time isn't any fun as you well know.

[SirAndy]

I use the teener mostly for track events. I have not yet autox'd the teener but may do so when my son turns 16 in about 4 months.

my 2 cents ...

welded diff is only practical in a dedicated track car. and even then, you'll have to learn how to drive corners fast all over again.
but, once you get the hang of it, you'll be able to shave a second or two off your lap times.

however, if you still use the car on the street or for AX, a welded diff is *not* going to make you happy.
the car will *not* turn into tight corners!
the only way to get around a AX course will be to power-oversteer your way around the cones. not my idea of fun ...

of course, all this is just MHO ...
(IMG:style_emoticons/default/bye1.gif) Andy

[Aaron Cox]

KenH on this board mentioned how to do a 915LSD into a 901...

i remember something about ring gear bolts....

[brant]

I use the teener mostly for track events. I have not yet autox'd the teener but may do so when my son turns 16 in about 4 months.

my 2 cents ...

welded diff is only practical in a dedicated track car. and even then, you'll have to learn how to drive corners fast all over again.
but, once you get the hang of it, you'll be able to shave a second or two off your lap times.

however, if you still use the car on the street or for AX, a welded diff is *not* going to make you happy.
the car will *not* turn into tight corners!
the only way to get around a AX course will be to power-oversteer your way around the cones. not my idea of fun ...

of course, all this is just MHO ...
(IMG:style_emoticons/default/bye1.gif) Andy

(IMG:style_emoticons/default/agree.gif)
make that $.04

[Eddie914]

914(901) Transaxle upgrades?

- Billet intermediate plate
- Billet side plate
- Oil cooler and pump

How many cubic $$$$s


What are the best sources?

Thanks

Eddie

[brant]

914(901) Transaxle upgrades?

- Billet intermediate plate
- Billet side plate
- Oil cooler and pump

How many cubic $$$$s

What are the best sources?

Thanks

Eddie

lots of dollars.
do you need them yet.
its one of those questions about "while your in there"

I'm guessing that while your in there if you were doing all of that then you would also re-gear.

if you pay someone to do the work and buy the parts.
then you had better budget for 5grand.

so if your going to make that giant leap, you would need to seriously consider a 915 conversion at that point.

on the other hand..
do you have to do this or is your 901 sufficient at this time?

brant

[Bleyseng]

Eddie, if you locate the gear sets you want I can help rebuild/assemble a 901 for you.

I would start there and then look at the LS.

take advantage of the 3.2L hp/torque and gear the tranny for it.

You mostly track the car but if AX ing is in the future set it up accordingly.

I should let you try my car with the new gearing for fun.

[jhadler]

Why not just convert the car to a 915 transaxle and be done with it?

-Josh2

[Bleyseng]

$$$$$$

you haven't seen Eddie's car have you??

Its a good track car....lots of mods.

[Eddie914]

915 Conversion?

What is involved?

- Tranny Mounts? $$?
- Swapping the pinion? $$$$$$?
- Shifter: Cable? Wevo? Rennshift? OEM Porsche 916? $$$$$$$$$$$?

Help me out! Looks like only two of the three kids are going to able to go to college!

Thanks,

Eddie

[Bleyseng]

first ya haveto rebuild one you find to do problems in the 915 line, possibly.
then install a Wevo tailcover so its a midengine configure.

[groot]

Hey, Eddie. Check this out: Pinion Failure in a 901

I'm probably switching to a 915, but will not pay the cash for the WEVO shifter. I plan on fabricating a cable shifter and using an OEM shifter console from a Focus. I just need to find a 915 and then pull it apart to move the ring gear.

[brant]

Kevin,

got any pictures of the focus console?
cool Idea...

plus you have enough connections that you'll be able to pull it off!
I'm pulling for the company.
my last 3 car purchases were all foci!
(p.s. can you get them to put that mazdaspeed 3 drive train into next years focus SVT? I want one of those!)

brant

[groot]

Don't hold your breath on next year's SVT.... (IMG:style_emoticons/default/mad.gif) .... but that Mazda box will bolt right up (at least from the Mazda3, not sure about the Mazda3speed). It's a good way to get a decent set of ratios into a Focus. That powertrain in the 3speed is pretty awesome, but I don't think you'll see it in 4 cylinder form in any Ford products (that I know of at least).

I've been doing the damper tuning on the 2008 foci for the past few months and I've made some good progress trying to make them less "rental" and more fun.

No pics on the shifter setup yet... just thought it through the other day.

[Eddie914]

What is involved in swapping the pinion on a 915?

How many cubic $$$ (partial DIY vs full shop price)?

Thanks

Eddie

[Bleyseng]

read this thread http://www.914world.com/bbs2/index.php?showtopic=62553