Carrier bearing or 1-piece driveshaft?

[tsupranami]

Have you seen them fail at their other automotive shows? Like having no idea what fuel trim is, then calculating which truck has better milage after driving in traffic. And thinking the Knight Rider stunt wouldn't work? They are special effects riggers. They don't know anything about anything. Well, the one guy is an engineer. I think. On the second team.

Too many variables to accurately predict outcomes. That is what usually shows up during thier experiments.

My buddies '68 Chevelle lifted about two feet off the ground at~65mph as the driveshaft buckled under the car. His front ujoint jet go, not the DS itself. When the shaft buckled under the rear axle, it couldn't rotate anymore and locked up his rear end. We were following (racing?) in another buddies '71 Plymouth Satellite and actually rammed into the back of our friends Chevelle, as the Satellite didn't have much in the way of brakes and the Chevelle was uncontrollably skidding to a stop while dragging a sparking anchor.

As I mentioned earlier, I have seen and experienced many driveline failures, from slip yokes snapping while trying to free stuck logging equipment, to the regular ujoint failures while driving on a shaft I knew needed repairs but I didn't have the money or time to fix. I've seen 'em twist like pretzels during my early years playing with 4x4's (one ding with a rock, and you're playing a whole different game...). Fatigue failure at the welds is a common area for failure as well in my experience (usually corrosion,and/or damage has been a factor in these types of failures).

But in almost every instance there was ample warning to prevent catastrophe. Every time I can think of, there was vibration, noise, and/or harshness (NVH, anyone?), or obvious signs of damage immediately prior to the failure, sometime for months prior...

And while it is almost impossible for me to to imagine the perfect set of circumstances where a DS could fully support a moving vehicle without buckling, race sanctioning organizations still feel it is important enough to warrant a hoop on all driveshafts, regardless of the style or material.

So if the car is going to be raced (or driven like a race car), then a hoop should be considered...1pc or 2pc....

 

[IJ.]

My life>cost

 

[tsupranami]

My life>cost

Then get a truck. Or a Prius.

Supras go fast. Fast is dangerous.

 

[IJ.]

Then get a truck. Or a Prius.

Supras go fast. Fast is dangerous.

Guessing you don't know much of my history.....

seriously stupid post.

 

[CyFi6]

I think the bottom line here is that every application has its own suitable type of shaft... not much more to it. There are many applications that a one piece is fine and others that it is not. If you are building a high horsepower car, you use parts that are going to be suitable for the application, but a lightly modified street car does not need high end performance build parts (quality and high performance built parts are two different things, the shaftmasters alum drive shaft seems to be very high quality from everything I hear, though it may not be suitable for continuous high speed and high horsepower cars).

 

[Nick M]

My buddies '68 Chevelle lifted about two feet off the ground at~65mph as the driveshaft buckled under the car. His front ujoint jet go, not the DS itself. When the shaft buckled under the rear axle, it couldn't rotate anymore and locked up his rear end. We were following (racing?) in another buddies '71 Plymouth Satellite and actually rammed into the back of our friends Chevelle, as the Satellite didn't have much in the way of brakes and the Chevelle was uncontrollably skidding to a stop while dragging a sparking anchor.

Hence the strict NHRA rulebook. I have a helmet and flame jacket, and I am not even a serious racer. But they have rules for a reason.

---------- Post added at 12:30 AM ---------- Previous post was at 12:28 AM ----------

I think the bottom line here is that every application has its own suitable type of shaft... not much more to it.

Speaking of Ford, now that the Mustang is larger in size and comparable to an MA70, it too has a two piece driveshaft in place of the one piece for the long running Fox platorm.

 

[CyFi6]

Fact of the matter is that there are several Supras that won't put the aluminum shaft out of its safe range, so there is no problem with running one.

 

[tsupranami]

Guessing you don't know much of my history.....

seriously stupid post.

Seriously Stupid is going 140+mph on public roads. And yet...

And of course I don't know your history, we've never met, let alone gotten to know each other. But I understand that you have a concern about 1pc driveshafts in mk3's.

I'm just trying to understand the basis of your concern.

 

[IJ.]

Seriously Stupid is going 140+mph on public roads. And yet...

And of course I don't know your history, we've never met, let alone gotten to know each other. But I understand that you have a concern about 1pc driveshafts in mk3's.

I'm just trying to understand the basis of your concern.

Post 588 should help you understand, I have a much better idea just how dangerous fast cars can be than most here....

 

[redhot91gt]

So then you don't know the size of a fairmont platform. I didn't realize it. The Fox Body weighs in less than 3200 lbs with a cast iron block and heads. It is a small car with a short wheel base.

There were plenty of ~3700+lb 03-04 cobras running around with one piece driveshafts. Id be interested in knowing the difference in length of the driveshaft though.

 

[tsupranami]

Post 588 should help you understand, I have a much better idea just how dangerous fast cars can be than most here....

I'm confused. That wasn't the result of a driveshaft failure, was it?

I thought I recognized it from my own experiences to be the result of a brilliant application of sheer stupidity.

Believe me, I'm no stranger to stupid. I'm currently recovering from surgery necessitated by my latest application of sheer stupidity. My scars also bear testimant to my routine application of it.

But unless I'm completely off, I don't see how either my snowboarding accident, or your car accident, relate to a 1pc. driveshaft.

 

[IJ.]

Just that I'm aware of how dangerous fast cars can be and that I don't need someone telling me to buy a Truck or a Prius......

I've been playing fast cars for well over 30 years and have been a Fabricator on one of the top Group A race teams here in Australia so I don't take chances on safety related issues which a well designed driveshaft is one, as I posted earlier I crunced the numbers for my car on a one piece shaft and it would have been idiotic to have gone ahead.

I'm not bagging on one piece shafts in general just that people should be smart enough to do a little research on the subject and find out if they have a good enough safety margin instead of listening to a bunch of guys on a forum that may or may not have a fucking clue what they're talking about.

 

[Poodles]

Just that I'm aware of how dangerous fast cars can be and that I don't need someone telling me to buy a Truck or a Prius......

I've been playing fast cars for well over 30 years and have been a Fabricator on one of the top Group A race teams here in Australia so I don't take chances on safety related issues which a well designed driveshaft is one, as I posted earlier I crunced the numbers for my car on a one piece shaft and it would have been idiotic to have gone ahead.

I'm not bagging on one piece shafts in general just that people should be smart enough to do a little research on the subject and find out if they have a good enough safety margin instead of listening to a bunch of guys on a forum that may or may not have a fucking clue what they're talking about.

Exactly, it boils down to this in the end:

If your life is worth a cheap driveshaft, go right ahead. Rebuilt 2-piece is a couple hundred more from shaftmasters than their 1-piece (includes a new support bearing). Or you could go the IJ route and have one made locally and source one of the other cheaper support bearings. The cost difference really isn't that much.

http://www.supramania.com/forums/showthread.php?58272-Driveshaft-Critical-Speed-A-Calculator/page2

Use the wrong materials or the wrong diameter or thickness, and a 2 piece can be far worse...

Yes, and you'd have to be really fing stupid and make the driveshaft SMALLER than stock to do that. Idiotic comment.

Is anyone suggesting that the DS shops are knowingly selling parts that are designed and/or built improperly? If anyone has evidence of this, they should come forward as this would be a serious legal and safety issue that should be addressed ASAP.

As the driveshafts are not of the stock design, all bets are off. There is no legal issue as it's basicly sold as some "racing" part for off road use.

And the thread on the 140mph Cressida/Chaser? 80mph critical speed? Seriously?

They would have had to been using playdoh...there is no mathematically possible way otherwise? Look at the photos again. And follow the thread. No updates, no word.

There are far too many variables in this equation to base an entire opinion on one isolated incident in a completely different type of vehicle.

You'd also know that the Cressida and Chaser share their drivetrain with the MKII and MKIII Supra. So it's the same car so far as the driveshaft is concerned.

Besides, I own a Supra, not a Cressida, nor a semi. My car was actually factory designed to go 150+mph. None of the other vehicles you've compared here are. That's why I keep comparing to vehicles designed to do that or more.

Same car so far as the drive shaft is concerned. Also, I've told you time and time again that you're comparing to vehicles that have nothing to do with a Supra. They either have shorter driveshafts, torque tubes, or different gearing (or all of the above). Inversely, yes the Supra was designed to go that fast, and they used a 2 piece driveshaft. Even better, the MKIV was designed to go faster, and they used a 2 piece driveshaft. The MKIV was even designed to be lighter (even going so far as to use hollow carpet fibers), but yet they kept the 2-piece, I wonder why... :icon_roll

 

[3p141592654]

From an engineering perspective, the only reason to go one-piece is cost. All other factors favor the two-piece.

 

[Enraged]

nice and sunny today, perfect day to swap my center support bearing, and keep my 2 piece.

 

[IJ.]

nice and sunny today, perfect day to swap my center support bearing, and keep my 2 piece.

<golf clap> well done!

 

[tsupranami]

From an engineering perspective, the only reason to go one-piece is cost. All other factors favor the two-piece.

Again, if 2pc driveshafts were as efficient as 1pcrs, they would use them in racing. But they are not and do not.

From an engineering standpoint, they are not equal. The greater mass, more moving parts, and increased drag reduce efficiency of the 2pc. The greater complexity means increased costs.

All other things being equal, the 1 piece transmits more power to the ground.

From an engineering standpoint, each has their own drawbacks and weaknesses, strengths and advantages. It is up to the intended purpose each individual has for the car to determine the most efficient solution ($ and time included).

 

[tsupranami]

Exactly, it boils down to this in the end:

If your life is worth a cheap driveshaft, go right ahead. Rebuilt 2-piece is a couple hundred more from shaftmasters than their 1-piece (includes a new support bearing). Or you could go the IJ route and have one made locally and source one of the other cheaper support bearings. The cost difference really isn't that much.

If it's the same company making it, how is cheap related to quality? Wouldn't it be cheaper because it uses less parts, less fabrication, and less time to produce, not because it was built to a lesser standard? It would appear that you have confused inexpensive with lesser quality.

Yes, and you'd have to be really fing stupid and make the driveshaft SMALLER than stock to do that. Idiotic comment.

And you believe that someone sold the Cressida guy a shaft with an 80mph critical speed? If you believe it was truly built with an 80mph critical speed, then you agree that someone WAS really fing stupid and DID build one "smaller" than stock (thinner walled tube, wrong material with incorrect modulus of elasticity???)

I liked the direct insult as well, too. That supported your position with substantial evidence while simultaneously demonstrating your superior intellect.

As the driveshafts are not of the stock design, all bets are off. There is no legal issue as it's basicly sold as some "racing" part for off road use.

Agreed.
Go 140+mph on a public road and all bets are off as well. At posted speeds on public roads, a 1pc is as safe as a 2pc anyday. 140+mph is for "off road" use only. Even if the factory 2pcr lets go at 140 on public roads and causes you to crash, you are still legally f*cked. Agreed?

You'd also know that the Cressida and Chaser share their drivetrain with the MKII and MKIII Supra. So it's the same car so far as the driveshaft is concerned.

When they were brand new and unmolested, perhaps. But that is not what we have here, agreed?.

Same car so far as the drive shaft is concerned. Also, I've told you time and time again that you're comparing to vehicles that have nothing to do with a Supra. They either have shorter driveshafts, torque tubes, or different gearing (or all of the above). Inversely, yes the Supra was designed to go that fast, and they used a 2 piece driveshaft. Even better, the MKIV was designed to go faster, and they used a 2 piece driveshaft. The MKIV was even designed to be lighter (even going so far as to use hollow carpet fibers), but yet they kept the 2-piece, I wonder why... :icon_roll

And again, talk to an automotive design engineer. My father started our engineering consulting business back in 1986. I have been an engineering project manager at the company since graduating from WSU 1994. I am in constant contact with hundred of engineers across the US in all types of disciplines. The 2pc driveshaft is primarily used to reduce NVH in more expensive luxury passenger cars. Not because it is better or stronger or safer at high speeds or any speed for that matter. Every engineer knows that a properly designed and built 1pc shaft can perfom just as well as any 2pcr, except when it comes to reducing NVH transmitted through the drivetrain.

Put this through the 1pc witchhunt: Millions of cars over millions of miles, since the dawn of the automobile, have used 1pc driveshafts, some much longer than that a Supra, many with much more torque and HP carrying far heavier loads.

Yet there is no, nor was there ever, an epidemic of catastrophic driveline failures that keeps being harped on about. Not in a Supra; Not in any car.

If someone here wants to back up all the insults and name calling with some real forensic evidence supporting the MK3 1pc catastrophic failure argument, well, this would be an excellent place to do it.

And can we let rest forever the airbagged Cresida that bent his driveshaft when he dropped his car on a rock in his driveway (?) just prior to running 140 on the street. Or did his airbags drop him onto his driveshaft while he was going 140? Airbags, 140mph, public roads, 30+ yr old Toyota SW. And people are surprised? If anyone can't see what is wrong with that story, well, they probably should get a truck or a Prius...

There is no safety issue with a 1pc. The choice of 1pc, 2pc, or 1pc w/hoop depends on personal preference (or level of paranoia), intended usage, and budget.

OK I'm done.

The baseless paranoid 1pc bashing can continue now. Or, start calling me names...whichever makes you feel smarter.


P.S.
No one here knows me either. No one has any idea what engineering background I come from, nor my racing (crashing) or vehicle history. I have refrained from calling people stupid or referring to their comments as stupid or idiotic, because I believe everyone here has a valid point when taken in the correct context. Comments aren't stupid or idiotic. They are comments. You might not agree, or you might have evidence to the contrary, and you should say so if so. But insults and demeaning labels are the tools of the weak, insecure, and incompetent, and should be avoided if your comment is to have merit.

---------- Post added at 07:39 AM ---------- Previous post was at 07:32 AM ----------

nice and sunny today, perfect day to swap my center support bearing, and keep my 2 piece.

Good for you. Proper inspection and mantenance is the key, regardless of which part you use. Neglect it or abuse it and it will fail, no matter what is is made of.

 

[Poodles]

If it's the same company making it, how is cheap related to quality? Wouldn't it be cheaper because it uses less parts, less fabrication, and less time to produce, not because it was built to a lesser standard? It would appear that you have confused inexpensive with lesser quality.

You're forgetting the simple fact that the stock driveshaft can be rebuilt for cheaper than building a 1-piece (outside of the support bearing). The point is, the 1-piece has to be of higher quality because of it's inharent design.

And you believe that someone sold the Cressida guy a shaft with an 80mph critical speed? If you believe it was truly built with an 80mph critical speed, then you agree that someone WAS really fing stupid and DID build one "smaller" than stock (thinner walled tube, wrong material with incorrect modulus of elasticity???)

I liked the direct insult as well, too. That supported your position with substantial evidence while simultaneously demonstrating your superior intellect.

You missed the point. You said the 2-piece could be more dangerous. I said you would have to make your stock driveshaft smaller to do that, which is REALLY DAMN STUPID. Hence me calling the comment idiotic.

Agreed.
Go 140+mph on a public road and all bets are off as well. At posted speeds on public roads, a 1pc is as safe as a 2pc anyday. 140+mph is for "off road" use only. Even if the factory 2pcr lets go at 140 on public roads and causes you to crash, you are still legally f*cked. Agreed?

Agreed. But as a lot of people build these cars up, it's assumed that people are going to use that power every once in a while. Hell, it doesn't have to be on public roads either, I know of several road courses a few hours from here where you can hit some crazy speeds on the straights. Safety is always an issue in the advice I give for that exact reason.

When they were brand new and unmolested, perhaps. But that is not what we have here, agreed?.

Then we wouldn't be here. You wouldn't be replaceing the driveshaft unless there was something wrong with it in the first place.

And again, talk to an automotive design engineer. My father started our engineering consulting business back in 1986. I have been an engineering project manager at the company since graduating from WSU 1994. I am in constant contact with hundred of engineers across the US in all types of disciplines. The 2pc driveshaft is primarily used to reduce NVH in more expensive luxury passenger cars. Not because it is better or stronger or safer at high speeds or any speed for that matter. Every engineer knows that a properly designed and built 1pc shaft can perfom just as well as any 2pcr, except when it comes to reducing NVH transmitted through the drivetrain.

You also left out the simple fact that 2 driveshafts made of the same materials, but one being a 2-piece and one being a 1-piece, the 1-piece will have the lower critical speed. It's all about overkill and headroom. Want a part to last? Overbuild it.

Put this through the 1pc witchhunt: Millions of cars over millions of miles, since the dawn of the automobile, have used 1pc driveshafts, some much longer than that a Supra, many with much more torque and HP carrying far heavier loads.

Again, we're talking about a car with high RPM, high gearing, and the chassis to support sustained high speeds. Power is not the issue here, it's the speeds. This isn't a good comparison since most cars aren't able to attain the speeds we're talking about.

Yet there is no, nor was there ever, an epidemic of catastrophic driveline failures that keeps being harped on about. Not in a Supra; Not in any car.

Absence of evidence is not evidence of absence.

If someone here wants to back up all the insults and name calling with some real forensic evidence supporting the MK3 1pc catastrophic failure argument, well, this would be an excellent place to do it.

Insults? I called your comment idiotic.

And can we let rest forever the airbagged Cresida that bent his driveshaft when he dropped his car on a rock in his driveway (?) just prior to running 140 on the street. Or did his airbags drop him onto his driveshaft while he was going 140? Airbags, 140mph, public roads, 30+ yr old Toyota SW. And people are surprised? If anyone can't see what is wrong with that story, well, they probably should get a truck or a Prius...

Read the thread, he said how it happened. Since when are airbags bad? Sorry, a truck or prius doesn't suit my needs.

There is no safety issue with a 1pc. The choice of 1pc, 2pc, or 1pc w/hoop depends on personal preference (or level of paranoia), intended usage, and budget.

Just cause you say there isn't one, there is. Driveshaft should be engineered to withstand redline in 5th gear.

OK I'm done.

The baseless paranoid 1pc bashing can continue now. Or, start calling me names...whichever makes you feel smarter.


P.S.
No one here knows me either. No one has any idea what engineering background I come from, nor my racing (crashing) or vehicle history. I have refrained from calling people stupid or referring to their comments as stupid or idiotic, because I believe everyone here has a valid point when taken in the correct context. Comments aren't stupid or idiotic. They are comments. You might not agree, or you might have evidence to the contrary, and you should say so if so. But insults and demeaning labels are the tools of the weak, insecure, and incompetent, and should be avoided if your comment is to have merit.

You're ranting about insults when there were none.

Good for you. Proper inspection and mantenance is the key, regardless of which part you use. Neglect it or abuse it and it will fail, no matter what is is made of.

Correct. It's also about MTBF which is why I tend to stick with factory parts that lasted over 100K miles and 20+ years...

 

[Nick M]

Sorry, a truck or prius doesn't suit my needs.

..

Eh, you would like the Yukon. My fill up this week dropped $7 with the 30 cent drop in prices. It only ran me $79.00.