E-man930

I posted the links to Pacific and Gear One on the prior page. Eric we need to chat about Gear One.

URG8RB8

Just saw the Gear One link, looks like top notch stuff there, but again if not drag racing breaking the EMPI axles would be near impossible for most 951's on the street except for a select few. Tom has over 500 to the wheels and is in a rare club there. If they are holding up well for him, I am sure they will be just fine for most everyone. Especially with the proper HD clips and grease. Now, after I drop in Frankenmotor and switch to 305's I might snap one at the circlip groove like Sid did. Time will tell, but for the super cheap price of entry I am not that worried. My whole set up installed cost less than the two axle blanks from Pacific Customs.

Tom M'Guinn

I do hope the combo of the tranny mount and these axles/joints will hold up great, and they seem to be doing fine, but I don't have enough miles, boost, or aggression on them yet to say for sure. I did a rear seat delete recently and the combo of that and the semi-solid mount have created pretty lively (i.e. loud) driveline noise in the cabin. Am going to try a little sound insulation and, if still loud, I might try the urethane-filled mount instead, maybe with a stabilizer bar.

V2Rocket

I've asked this a few times over the years but never get any answer.
Is there a reason why it wouldn't work to whip up some custom U-joint-ended (C4 corvette or Jag IRS-style) shafts, vs the 944 CV joints?

Big U-joints should be able to take a big punishment and you can just use an inner/outer shaft for plunge travel.

944 CV flanges are what, 100mm? You could use some regular driveshaft type U-joints made for big torque loads there.

333pg333

It's something we considered Spencer. Never got very far with it but I'd think this is a good idea for those cars that are having ongoing problems with the standard or modified versions.
Didn't the LeMans 924 have something like this? I think I've got a pic of this at home.

333pg333

Working on the theory that the weakest part presents a fuse of sorts, do we assume that if we can find 'indestructible' Axles / CV's that it might transfer some unwanted extra force back into the transmission?

Ifly951

I dont race my car yet, but have had very high Horsepower cars before. (800 hp Viper) And the challenges of High TQ+Power.

I do know this, I would rather have an axle break, or a slipping clutch (power reasons) than Transmissions that grenade.

It's a path of less $$ resistance if you will.

Tom M'Guinn

Do I get extra credit points for having all three?

333pg333

Yes, you win 11 billionty Internet points!

mikey_audiogeek

Absolutely. On our race car our chassis builder got sick of blowing CV's (long story but not the CV's fault) and made up UJ axles.

Absolutely ruined the cars handling due to the splines locking up under plunge and torque.

I did the math and under full power it would take 1000kg of force to overcome the static friction of the splines. Luckily (!) we were using a bulletproof diff.

Of course that stiction ruined the suspension compliance in nasty and unpredictable ways. Never want to see that combo of mid-turn push and exit oversteer again...disastrous. CV's all the way for this guy.

Did the Le Mans 924 use rubber donuts because of the locked diff? The donuts solve the plunge issue but aren't the most effective solution. However they do provide some torsional compliance which is useful with a locked diff. Believe this arrangement was pioneered on the 935's.

Locked diff is/was common on LeMans cars so you still had drive to one wheel if you lost a halfshaft, hub, wheel or tyre. Not elegant but one of the practical strategies for endurance racing...to finish first, first you must finish!

Cheers,
Mike

333pg333

Good info Mikey, thanks for that. I think I'll just get a backup set of what I have now on the 'Just in case' principle. Sort of like taking an Umbrella out and it doesn't rain...well that's the hope. Not sure if I will chase a different version from one of the other links in this thread. But with the expected higher tq/hp levels perhaps we should...hmm...

URG8RB8

That Gear One stuff looks right up your alley Patrick. Then maybe the PC stuff but definitely not what Tom and I are using. This is bargain basement stuff that happens to be strong. This stuff is made in China, which should never be used on a quality race car such as yours. However, since I am in China right now, this place is getting much much better in terms of quality. They are starting to "Get It".

Tom M'Guinn

Well here's an interesting discovery. I was going to try replacing the semi-solid mount with a urethane-filled factory mount, so I got a spare mount from Lart. It arrived in 2 days (thanks Lart) and had been cleaned, but I went to super-clean it (as is my way) and I discovered both of the end pieces were cracked.

Kind of hard to visualize here, but these pieces act as a hard-stop on movement, and it's pretty clear they'd been put to the test. The tranny movement essentially pried the C shape open more than intended until the corners cracked open. The result is a tranny that can move more than Porsche intended!

It's worth nothing that this was NOT the cause of my blown CV joints, as I went back and confirmed the mount that was in my car at the time was not cracked like this. Still, it's one more thing to check for sure if you're having issues.

Tom M'Guinn

By the way, even though new mounts are back-ordered, Sunset Porsche told me they are not discontinued. The guy I spoke to said Porsche was probably just looking for a new supplier because it is still listed as an active part. He said when Porsche discontinues a part, they promptly flag it in the system as discontinued, which isn't the case for this part. Here's hoping!

Edit: I barely finished typing this before Lart sent me a note promising un-cracked brackets on Monday. I didn't want to nit-pick, but he stepped up anyway. Hat's off to Lart!

333pg333

Lart's always backed up his products with me.

On face value that part just doesn't look quite up to the task (even in new form). Wonder if a pretty simple alternative that is stronger couldn't be whipped up.