69gaugeman

Well two days! That seals it. lol

How long did the original one last?

AO

I can't say much about 300m, but by making the shaft hollow you are removing the fulcrum (concentration point) where the shaft would "rotate" to twist apart and instead distributing that force across a larger section of material.

IcemanG17

Doc
??? for you....on the stroker racers you built (like anderson-fan) that run the race tilton race clutches which shaft did you use...the stock one or a custom one?

I would guess the stock one, but how did it EVER live with that kind of torque-slicks under race conditions?

James Bailey

Glad you recognized the humor in that post But it did hold up to that massive 220 HP !! The old one had been swapped in as good used one maybe 10 years ago. I did manage to wear out the splines on the stock part with only a 4.5 at max 220 hp...

mark kibort

again, its not the 220hp, its the downshifts, especially on all the short course work you have done. That's a LOT of torque placed on the clutch discs, and short shafts.
ive used the same short shaft for the last 25 years! that's well over 150 race days too, and countless DE days (originally from my 1984 S) If you treat it well, it will treat you well and handle well past 400rwt in racing conditions.

OBehave

I think the biggest point of this story,is that Greg has produced a replacement part that if it is still available from Porsche it is unrealistically expensive, will eventually be NLA in the future and reasonably priced in comparison to a good used one if you can find it. Seems like a huge win with a side benefit of handling large amounts of power if you so decide to need it. Thanks Greg!

Imo000

At $600 from Porsche and now a cheaper alternative available at a much lower cost. Those Porsche parts will be available for a long time.

69gaugeman

To be clear, we have no idea what power it will handle. We have a best guess, and some anecdotal evidence from other similar (but not the same) applications, but we have no proof that it is stronger than the factory one.

69gaugeman

Whaaaat? lol. Finance guys.... sheesh

James Bailey

Mark you should look at which side of the shaft splines has the wear.... You also seem to not realize that a proper downshift where you match engine RPM to the speed in the lower gear is ZERO load on the clutch !! Even allows you to downshift in a CORNER without upsetting the car. The car has three pedals and it is quite easy to manipulate them with just two feet.

And frankly I find it insulting that you state that " If you treat it well, it will treat you well .." I can only hope that someday I might be nearly as good a driver as you think yourself to be....

mark kibort

Yep, I agree and have been saying this all along.. Ive made it a point to learn from others (both their mistakes and sucesses) and find things out myself to make the car faster and last longer. If you or others cant take advice or look at information that leads to better performance or durability, then you are in the wong place.

We know the clutch wear is reduced when engine rpm matching is used. (both up shifts and down) what Im saying is if you DONT match the RPM , as Brian showed in his video, you run the risk of breaking the driveline at some point, because the forces will likely exceed the engine torque you produce!

Your post is confusing, because i DO realize that about matching RPM during shifting. Its the entire point of my posts. YOU said you "wore out" the splines. that could be due to not matching RPM on downshifts. it was 10 years ago, right? maybe you are better now as a driver. we will never know. never seen you drive.
I see no wear on my splines. As far as clutch wear, you see my racing for the last 17 years or so... Im using the same clutch discs and short shafts. the only thing that has worn out or been replaced is the throwout bearing (i was in denial of its failure) and the improved pressure plate. Ive even reused the orginal INT plate from 1987. (the pinning exersize). (you have seen the pictures of my clutch discs.... you can still see the ink for the serial numbers on the contact patch )
I race, the car lasts, its fast...... all because of things ive learned.

dont be a hater Jim.... Its unbecoming.

as far as the new shafts..... as long as they are strong enough and are cheaper, and dont move a failure point to something more expensive, im all for it.

Here is the brian video at thunderhill
go to 4:40 on the video. I instruct lots of people that still do this. not uncommon, and i think it is a force that can do damage. so, i advise against it. thats it.
Its not a matter of who is faster. its just an observation of what might cause issues. Brian might be faster than me now at T-hill. thats not the point. its about an effort to improve our skills and keep our stuff from breaking.
http://www.youtube.com/watch?v=_IGtwCNQWoU#t=296

Here is one of my segments at the same point on the track See 2:20 on the video below

James Bailey

Mark look again at the wear in post 17 notice it is ALL on one side of each spline the side driven under power....let off the gas and it loads the OTHER side downshift without matching rpms and it loads the OTHER side yet all the wear is on the normally driven side !! Think of the splines as gears and the loading becomes more clear. So would you agree that the wear is primarily on the driven side ?? And therefore could NOT be caused by downshifting.

Rob Edwards

Wait-

#1. You're on a racetrack. Being faster than the other guy is the only point.

#2. Brian's faster than you? Sure you don't want my sharktuner?


We keed, we keed, only because we love......

BC

(Edit)

I'll say it again - great stuff Greg.

hacker-pschorr

Can I remind everyone this is a product announcement thread. Not yet another bench racing thread?

I don't want to start deleting all the "noise" in this thread but I will if it continues.

Mark, we get it - your car never breaks and you are a track God. The rest of us mere mortals have to improve the car to survive our inferior skills. Please allow us to do so in relative peace and quite. Ok?