Driveshafts - steel, aluminum, Metal Matrix or Carbon Fiber

[V10_P70]

With all of the discussion about the issues with the driveshaft on the Marauder.

The current driveshaft with the current gears seems to be limited to 117 mph. Change to a P71 Metal Matrix shaft and you can go 130 mph.

Change the gear to 4.10 and the current shaft and the P71 shaft will not work for 130 mph. The current fix is to replace the shaft with a Dynotech shaft.

Use a Carbon Fiber Driveshaft and you not see a problem with vibration and as a side benefit you will see 5% more horsepower to the rear wheels. Sort of like a mini chip being put in the car.

The thought is to get as much benefit for each part installed on the car. Aluminum and Metal Matrix shafts do not deliver the 5% to the wheels. This is just one benefit to using Carbon Fiber. Ford Motor Company has used production Carbon Driveshafts during the 80's. Just a thought.

[RF Overlord]

I'm confused as to the mechanism by which a carbon fibre driveshaft will increase RWH...being stiffer should improve the response time from input of torque to output, and being lighter should allow the shaft to spin up faster, but neither should change the power delivered through the shaft... :confused: ...or am I being too literal...?

Dennis? Logan? Marauder Team?

[V10_P70]

This is not a endorsement of ACPT. Out here in California, they are the convient.

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

[cyclone03]

On a rear wheel dyno a reduction in receipicating wieght may show an increase in RWHP because the dyno measures the rate of exceleration of a fixed mass(the drum the wheels drive) of 800lbs on a Dyno Jet.
A change in gear ratio can do the same thing with lower HP vehicles.

[SergntMac]

Originally posted by V10_P70
The thought is to get as much benefit for each part installed on the car.

This is very true, and should not get lost in any discussion about mods, or, problem solving. Get what you need to fix a problem, or add the mods of choice based on best performance for the dollar. Just don't run out and buy stuff on someone's opinion.

What started my involvement in this drive shaft issue is exactly that, opinion offered here that I have to replace my driveshaft once I geared up to 4:10. This is simply not true.

I have driven over 120 mph, and I have not detected any drive line vibration with my factory shaft. I like to drive fast when it's safe to do so, and I may do a little racing every now and then. The factory shaft appears adequate for these applications, at the present time, IMHO.

[tetsu]

I wouldn't run an aluminum shaft near 6k rpm for any length of time...

At 130mph with 4.10s you are way up in the cams.

Personally, I find it hard to believe that there isn't noticeable vibration. Could it be that you may just not be picking up on it? I've driven a few MMs and they all vibrated noticeably at high rpms.

I sure hope you at least have a driveshaft loop so that you dont get killed if anything fails near the tailshaft.

[Pantherman]

Typical industry practice is to design drive shafts with about a 25% speed margin of saftety. What that should mean is that Ford thinks its shafts are perfectly safe at their limited max RPM's. What that also means is that typical shafts will be OK at 25% higher revs. Some shafts will go even higher. At some speed (+50%?), all shafts with the same basic design will come flying out of the car.

[SergntMac]

Just got back from the dyno, I'll start a new thread on that experience shortly. Meanwhile, some news regarding this thread.

"No drive line vibrations to speak of through 120 MPH" the pro said, "smooth as glass." I was pleased to hear this, there could have something amiss that I wasn't detecting with my "seat-of-the-pants" instrumentation. On sound advice here, a second and professional opinion was in order and that was comforting to hear. Next, a peek underneath.

My MM has a brush finish silver colored shaft with polished ends. There are three painted rings in the center, one light purple and two lime green. The flange at each end has similar colored dots in place. I ask the "pro" what's up with this, and he says " looks like matched parts from the factory, they're doing something right here." I ask for more, he says "they measure the parts for balance, and match equally unbalanced parts to make them balance themselves, like sticking a penny on each part and screwing them together with the pennies opposite of each other, and that cancels each imbalance, and balances the shaft." Oh...

I told him about some of the thoughts exchanged here and he said "well, if you're gonna pull something apart, you should put it back together in the order it came apart." Okay...

The pro couldn't guess at the material of the shaft, but his magnet wouldn't stick to it. Seems to me, that someone in LM design is paying attention afterall. Guess if you're gonna steal motors from Mustangs, why not steal other goodies too.

Part number on my shaft is 3W3Z-4602-AA, Marauder specific in the LM parts book. Same book says a GM "with 350:1 sport package" shaft is number 3W7Z-4602-DA.

Anyone care to peek underneath their MM?

[tetsu]

That's interesting. My earlier MM does not have markings on the shaft. Perhaps they wised up and balanced them at the factory.

That could explain your smoothly rotating mass at high rpms.

If you can go 120 smoothly with 4.10s youre probably in good shape as long as you dont add too much torque.

I cant wait to hear your dyno results. :)

Johnny

[SergntMac]

OASIS says my build date was 5/27/02, if that helps any.

Lack of paint may mean a "natural" match in parts, which I'm sure must occur every once in a while.

What do you think it's made of? What does it look like to you?

[Marauderman]

All this sounds very interesting--but On Christmas Day ( see my thread Police drive my MM) I had my MM up to 125 and 120 with no problem and with what appeared alot more energy to go more before having to slow down for traffic----so I'm thinking this is what I should except but reading alot of views here it appears that the MM should not be able to be doing that--I ask --Why not? Yet everyone seems it's necessary to change/add mods here and there and whatever..but whats wrong with it if it is doing what mine is doing..or maybe your stock isn't or wasn't..I just doin't get it--is my current stock exceptional to all this ...?

[Pantherman]

Marauderman, read my feeble explanation above. MOST stock shafts can handle some extra revs. Shaft revs, not mph are what is important. That is why going from 3.55 to 4.10 gears will lower any given shaft's critical speed about 15% in terms of mph. As I said MOST stock shafts will survive higher speeds, just as most engines will survive exceeding the red line. It's just that higher speeds put us into an area the manufactuer has not certified, and we get to play test pilot. There's nothing wrong with that as long as we are willing to accept the risks and possible consequences. The only real concern is that if enough of us try this, someone will eventually get hurt. By the way, the stock shaft is aluminum.

[V10_P70]

Let's talk horsepower and modifications. The true test of rear-wheel horsepower is a eddy-current dyno. This dyno can be used to run the car for several hours to see how the modified parts work on the unit. Spark timing can be offset by heat. Also, try a steel, aluminum, MM and Carbon Shaft to see the difference in rear-wheel horsepower.

Here is a link for Eddy-Current Dynos:

http://www.mustangdyne.com/ChassisDyno/50mustang/50-article6.htm
:cool: