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      02-21-2012, 05:02 PM   #111
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Quote:
Originally Posted by Roffle Waffle View Post
They tested a home made one. Thats the problem
That would probably be it haha. Supposedly there is a compromise with carbon fiber between harmonics and torsional load. The steeper you lay the fiber the better the harmonics but the flatter you lay it the better the torsional load. I am not an engineer so I am just the messenger.
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      02-22-2012, 12:12 AM   #112
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Villa if you're serious post in the southeast forum so we get a guinea pig.
somebody else can post it. Im done trying to give away free R&D.
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      02-22-2012, 01:09 AM   #113
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Originally Posted by Radar vs Sonar View Post
somebody else can post it. Im done trying to give away free R&D.
Fine I posted for you, but you better not flake out if someone offers
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      12-04-2012, 09:54 AM   #114
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Question

What happened to this?
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      12-04-2012, 10:11 AM   #115
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nobody got excited so the project evaporated
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      12-04-2012, 10:25 AM   #116
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Too bad, found this btw, anyone tried it?
http://global.rakuten.com/en/store/o...item/acpt-z4m/
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      12-04-2012, 01:51 PM   #117
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Two things:

1. We never got a florida car to guinea pig, see my post above.

2. We don't have a donor drive shaft to send, and buying one just for this purpose is expensive.

I still really want to do this mod if we can work out the kinks.
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      12-04-2012, 01:52 PM   #118
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Quote:
Originally Posted by SmartBastard View Post
Too bad, found this btw, anyone tried it?
http://global.rakuten.com/en/store/o...item/acpt-z4m/
Woah nice find. If that's the case then ACPT doesn't need a donor and already did the work to fit it. I sent them an email.
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      12-04-2012, 02:32 PM   #119
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Originally Posted by beta View Post
Woah nice find. If that's the case then ACPT doesn't need a donor and already did the work to fit it. I sent them an email.
Cool, not in market for one right now, but still interested if they have one available for the Z4M, keep us posted please.
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      12-08-2012, 07:45 PM   #120
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damn....nice indeed
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      12-09-2012, 01:44 PM   #121
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Still no response from ACPT. If someone else wants to drop them an email or give them a call, that would be great.
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      12-10-2012, 12:44 PM   #122
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$3600 is waaaay to much for a driveshaft.

Where is the florida shop located? I moved to south florida a few months ago
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      12-10-2012, 01:27 PM   #123
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Well 3600 is the 'round the world price (to japan and back it looks like, with all taxes and fees that this entails, plus a heavy markup I'm sure). I was imagining we'd get it for way less than that by talking to acpt directly.

ACPT is in CA, but the first shop we talked about in FL was PST. Here's their address zstig.
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      12-10-2012, 02:02 PM   #124
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id love one of these!!!!!
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      12-10-2012, 07:04 PM   #125
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I'm still very suspicious that people have shattered these. Not sure if they were from this manufacturer or not..
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      12-10-2012, 07:29 PM   #126
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Very interesting info about possibly saving our stock axels from breaking during hard launches with wheelhop:

Quote:
Directly from ACPT
"All driveshafts twist to some degree when torque is applied. The resistance to this twist is measured as torsional spring rate. Standard carbon driveshafts have a torsional spring rate a little less than aluminum and about half that of steel. The advantage of a lower spring rate is less driveline shock and a reduction of stress on other drivetrain components, as well as increased traction."

If you are having issues breaking your rear axles, or ring and pinion this might be a good way to prolong the life of those parts. Reason is that the carbon drive shaft will be like a rubber band, when launched hard it will twist slightly to absorb some of the shock and then spring back to its normal shape. The twist would be minimal (only a few degrees 5-10) on VERY hard launches, however that twist is absorption of energy. Thing that breaks many parts such as gears is shock to the part from abrupt and high application of power. F=M*A, so if you slightly reduce the acceleration of the power application you prolong life of components. *simple way of thinking this, you can put a 10lb hammer on your finger slowly with no damage, however if you slam the hammer you will do allot of damage. Similar concept with the carbon shaft twisting slightly, as it slows down the application of the energy on the component.


4) When the CF shaft fails, the fibers will come apart and un-wind. When a Aluminum shaft fails...well you have a 14lb sledge hammer spinning at over 1000RPM going to town under the side of your car and you just hope it does not penetrate.

The big concern many people have with the CF units is the CF shaft separating from the metal yokes. The adhesive that actually holds the 2 together, how its assembled, and how its cured is a trade secret of these manufactures as this will separate many of the manufactures and really make or break a manufacture.

That was a big concern for us as well when getting into the CF drive shaft market, however after many conversations with PST about they have yet to have a failure of the carbon or the adhesive itself. They state that the failure point is....the metal yokes actually. Not something that they have seen on import applications much in the past, but more or less on 1/4 mile domestic applications. And at that point they have a option to custom make a billet yoke if your car really needs it
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      12-11-2012, 04:22 AM   #127
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Interesting stuff.
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      12-11-2012, 06:45 AM   #128
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Quote:
Originally Posted by ZStig View Post
Very interesting info about possibly saving our stock axels from breaking during hard launches with wheelhop:
Isn't that why we have a guibo flex disc?
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      12-11-2012, 07:06 AM   #129
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^ +1

I don't think you need more flex in the driveshaft.
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      12-11-2012, 11:50 AM   #130
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:dunno:
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      12-11-2012, 02:13 PM   #131
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i still want one.... sadly i have no money right now. :-( as usual .
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      12-11-2012, 03:02 PM   #132
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Quote:
Originally Posted by inTgr8r View Post
Isn't that why we have a guibo flex disc?
True, however the Guibo disc is to make a street car's shift energy transfer FEEL smoother and less abrupt.

It will fatique and fail quickly with horsepower above its spec'd limits. Or at least cut its life in half.

We are essentially looking at the weakest link in the drive-train....which is joints and metal to metal contact point via gears.

Something gotta' give and eventually its traction....but in the meantime shit is getting torqued to death.
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