I know there was some interest in these on the board, and we have a thread about it in one of the forums right now. So, if anyone is interested.

I just hung up with ACPT. If we can GP 5+ of these, they will be $200 off of the regular $795 and $40 freight (48 states of the US only). Meaning, $595 each (plus shipping).

The tech info is this:

Aluminum yokes.
800 ft lbs torque rating
3 1/4" OD
12,500 RPM critical speed

For an additional $100 you can have (and I know you guys will love this one).....

3 3/4 OD
2000 ft lbs torque rating
14,500 RPM critical speed


Anyone interested?

What are the benefits of a cf driveshaft over an aluminum one? Lighter, stronger?

Jason

They are light (should be lighter than aluminum, I forgot to get the weight) and if they fail, they "broom" into a bunch of carbon fiber "shredded cloth" instead of punching holes in your floor, "pole vaulting the car" (if possible) or trying to remove the rear end from the car by catching on something. So, essentially, it's light, generates considerably less noise, vibration and such (NVH) and has a far safer mode of failure than a metallic shaft.

Here's more info.

http://www.acpt.com/driveshaft/driveshafts.html

I'm in.

Where do I send the money?

As soon as we get 5 buyers, you'll send it to me and I'll place the orders (like the wheel GP). Hang onto your cash for the moment, and I'll gather it up when/if we make the number (5).

Thanks Andy, 4 to go.

Well, as luck would have it I just brought my driveshaft in yesterday to get a stronger replacement made, so I'm not in the market, but I'm curious.

Is the 800 lb*ft TQ rating for the base driveshaft the TQ it can take at the driveshaft? If so, if we make 400 lb*ft TQ at the flywheel and 1st gear is about 3:1, I'm thinking the shaft goes poof into a cloud of dust.

Dang it! Dang it! Dang it! I'm tapped out ....

I got the impression it was flywheel torque, but I can verify that information. Also, since we don't see these things exploding on the various high HP cars they are under, that sorta verifies that feeling.

I agree, but I don't know how they can rate them for flywheel TQ, since the driveshaft shouldn't care at all about that. What if someone runs a different gear ratio in their transmission?

I suppose they sell these shafts in stock length with stock yokes so that makes it unlikely someone will do that.

On the other hand, 800 flywheel ft lbs is STOUT. I don't care how you slice it, it's going to put a large quantity of torque to the rear axle. Meaning, it should/would be more than enough for anything most of our mere "mortal" cars are making for hp and torque. But, I understand and agree with your point.

And, most F-body transmissions become a fuse at the 800 ft lb torque level.

I am guessing these are not ESP legal. If they are legal I am in.

I don't know, and my rulebook has expired (and I've not been ESP legal since week 3 of owning my car anyway).

Anyone know for sure?

If allowed, I may be that "5th buyer" in case there is one more needed. I could always use a 3.25" driveshft for my daily driver car.

The current 3.45" on my track freak was one that I had opted for just so I could tinker with their consultants (a la me being the guinea pig while offering my recorded information just for their keepsake. This is the same deal that I did through Koni for me to convert my ASN's into rebound-only adjustibles. )

Any driveshaft covered by update/backdate is legal in ESP, but nothing else is. No, it's not legal.



Do we know which one is being used under those high hp cars? Hopefully they can clarify the rating.

I'll call today.

I have pitiful timing... I bought wheels from someone on here about one month before the wheel GP... and my ACPT driveshaft just arrived one week ago....


If I wasn't broke from this (re)build-up, I'd get a spare.

You know, I though of doing this sooner, but decided that the thread didn't look like there were that many buyers. Jon A said his is in the brown truck right now and is headed to his house, you just got one, etc. I should have gone for it ASAP I guess.

As I said, you guys know I'll try to do these things for you, just ask.

I would love to get in on this, but I do not think the small one is strong enough and the big one would not likely fit.



I had another pull that spiked the torque to 775.

And the space under my car is limited with a 4" collector on my Y pipe.



I was planning on one this winter too.



I'm sure that the 3 3/4 would never fit, the custom DOM steel one is relatively tight.


Is there a good technical contact there that might be able to help me find a solution?



Rampant

I'd just give them a call.

And, what do you have in that thing to make that kind of power? (I'll probably be splitting this portion off later).

Hey where was this GP a couple months ago when I paid full price for one of these?

FWIW, I fit my 4 inch CF drive shaft next to my 4 inch collector by cuting the floor pan and welding in a new piece of sheet metal. This allowed me to move the exhaust an aditional 1.25" towards the passenger side.

412 ci LS2 M6 that makes 506 rwhp NA and then for the strip I'm using a bit of spray. About 150 shot worth.

The car is a lot of fun, not really good at any one thing, but pretty good at most.


Suspension has been set up for autocross, motor and drivetrain (except having a real differential instead of a spool) for drag racing. the interior still has all the factory options(Ac, power everything and a CM roll bar)

The car is starting to get heavy so I'm going to try to lighten it up a bit to help it perform a little better at everything. This year I want to do a K member, possibly the drive shaft, and light weight carpet. I also may have access to a light weight WS6 hood to replace the WS6 hood. I think all of these would help me shed up to 75-90 lbs.

My diff does not seem to like the torque combined with the weight about 3800lbs with me in it. Broke the spiders at an autocross and 5 weeks later took 8 teeth of the year old ring and pinion at a drag event.

I also thought the CF shaft might soften the M6 hit on the launch.

Thats the Coles notes on it.

They are in CA, so I figured I'd call them about 6pm EST. The gentleman I need is gone for the day, so I left him a voicemail. I'll post the info as soon as I get it.

The ACPT CF driveshaft may soften the shock, but it won't save weight. Mine was about a pound heavier than the stock aluminum LS1 driveshaft. The big advantage is a much higher critical speed and the much safer "brooming" action if it breaks.

It should save a few off the weight of my current DOM tubing DS. It is close to 25 lbs with 1350 yokes.

I like the idea of the safer brooming too, but would hope it would never happen.


Rampant

AS big as your specific DS is Cal, you probably can give your vehicle another nickname:

Freightliner Columbia

If my motor didnt go, id be all over this.

You blew it up? What happened?

I just hung up with the tech guys at ACPT. The info you seek is this.

The 3" version (3 1/4") broke the yoke ears off at 2500 ft lbs of actual applied torque (in a test fixture), they've never been able to break the actual shaft, the U-joint or yokes break before the carbon tube. It weights about 11 lbs

The 3 3/4 inch version handled 6000 ft lbs applied to the actual driveshaft and something (besides the shaft) broke in that case also. It weights about 13-14 lbs.

He said they set the limits based on the limits of the U-joints that fit these shafts. It's not so much a function of the actual shaft, but the attaching hardware. Meaning, if you're u-joints fit it, and you haven't broken them, you won't break it.

All better?

Do these include U-joints and the slip yoke for a T56, or just the bare driveshaft?

mine came with everything needed.

I'm going to get Sean grounded......

We'll have several waves of houseguests next month - sleeping in the garage doesn't sound all that bad ....

I was packing up my car leaving my parents house to come back to school and time I got in, before I touched anything the oil pump died and it started knocking. I was dissapointed to say the least but thankful that it happened there because to tow it back to my parents house wouldnt have been cheap. Ill PM you to discuss the rest. don't wana clutter this thread up too much, lol.

I've got a friend interested. He has to verify that the 9" he's looking at will fit with a stock length (I think it should).

We have one "in" (Andy J), one possible (foxxtron) and Sean's thinking... and my friend.

Anyone?

I am totally in. How much is the cost with more than 5 people?

With 5 or more, it's $595 (which is $200 off). After that, we'd need about 15 buyers and then it's only about $10 more off....

I can resist anything but temptation. It's too good a price to pass up, but I just bought a car for my wife and the season is over, so, uh, take your time. February would be fine

Yeah, I'm in

Quick, somebody buy my wheels

If it runs a bit longer, I'll probably grab one too. We just bought a car for my wife too.

That's:

IN

AndyJ
9ssc1man
Sgarnett

Possibly in

Foxxtron
Zane (local to me)
Me (if it runs long enough)

I need a balance driveshaft, and it'd be wicked cool to get CF - it's not that much more than a 1LE at that price (OK, I'm trying to rationalize, give me a break).

I'm in. The smaller one.

D

That's:

IN

AndyJ
9ssc1man
Sgarnett
Dan

Possibly in

Foxxtron
Zane (local to me)
Me (if it runs long enough)

Based on this, I have a question: The main benefit here seems to be the safety involved in a catastrophic failure, but the testing indicates that the u-joints or yoke ears will fail long before the shaft. So in a real world failure, you will not broom the shaft, but break a u-joint or yoke ear and drop the driveline just like with a metal unit. Assuming a driveshaft loop, it seems to me a cf tube rattling around in the tunnel will wreak as much havoc as an aluminum one. Assuming no loop, and a broken front joint, wouldn't you now have a better and stronger lever hitting the asphalt and lifting the car? One with a lot more flex and rebound potential so it is less likely to bend or break and therefore more likely to lift the car?

I'm not a materials science guy , so don't know if the linear force from an impact will effect the cf differently than the torsional force it is (well) designed to resist, but it seems any safety benefits would be non-existent over aluminum or steel.

So how far off base am I?

As I understand it, CF doesn't take impacts well. Meaning, once it starts banging around, it should come apart instead of just beating things up (like a metallic shaft). It's very strong when loaded in the direction of its intended load, but not in other directions. You can build a part with strength only where you need it.

That should be the difference.

Kevin is right - the CF would not survive the first sideways hit on the loop without coming apart. Makes it very important to keep it clear of exhaust clamps, TQ arm, etc.

Make it strong in the right direction, but come apart in the wrong direction. Sounds too good to be true. One of these days I'll grow out of my 80's drag race mentality ... maybe.

If I can recover (financially) from this weekend's trip to Alan's shop quickly enough, I may be in. Sgarnett's February date sounds good to me!!

An earlier post indicated it would come complete with u-joints and trans yoke? Posible to get one with a TKO600 yoke instead of T56?

John - Double check the length you need for the TKO600 vs T56 - can't just run down to the ds shop and have these things shortened for $20 like a metal one.

Alright, is anyone ready for this GP?

I just blew my second DS in ~12 months and I'm ready to quit messing around with stock ones. Blew the ears off... front and rear!

I'm in, need it ASAP


Kevin, can we still get the hookup on this?

I can call and verify prices (it is a new year) and see what the scoop is.

I am still in

I currently own two different ACPT CF driveshafts on two different vehicles of mine- They are both daily drivers and the lightweight driveshafts made a remarkable difference in high speed smoothness AND (not a huge difference- but) a noticible difference in acceleration, and mostly a big noticcible difference in RPM's attained. It upped my shift rpms by about 300-500 rpms in each lower gear because of increased spinup speed and lack of vibration (on both vehicles).

As for any question of durability? One of these is in my daily personal work truck (lowered and built 89 Chev c1500 longbed) which happens to be 6 feet long X 4" dia with 1350 joints (the shaft with the yoke weights 7.8 lbs- the steel one was 28 lbs). This truck puts down a modest 340 hp and has a severely built 700r4 (5 planteries, the works- thump your head on the rear window every time it shifts, as well as a Currie 9" rearend with a Detriot Locker. I have the frame completely weled up on this truck and it can haul 4000lbs in the bed and weekly has an average 3000lb load in it for a delivery(last week was 3670). IPoint of this info is I beat the living crap out of this truck daily. This truck also does 140 mph and has been rumored to touch that weekly also although that can just be construde for legal purposes as an internet boast.

These CF driveshafts are strong and light- and will hold up
(ps- the 6 foot 1350 truck shaft cost me $1200 to have custom made (no shipping- I am local to them) Well worth it though considering I was breaking tailshaft yokes with the old steel unit every 6 months due to bad vibrations at critical speeds -had it rebalanced 3 diffenrent times by different shops and everyone said nothing else they could do- it was just too long and too heavy and was suffereing from critical speed vibration.

Camaro acpt shaft- 4.7 lbs: http://www.cardomain.com/member_pages/show...752_16_full.jpg

Truck ACPT shaft- 7.8 lbs: http://www.cardomain.com/member_pages/show...52_101_full.jpg

One of my broken tailshaft collection from the truck with the "prior custom made 1350 STEEL shaft": http://www.cardomain.com/member_pages/show...52_102_full.jpg

Wow, under 5lbs!!!Damn thats light.