6spd manual transmission differences

Now YOU have made me laugh! That is a good one.

 

Your fact has nothing to back it up. Googling something does not make it fact, it makes you an idiot. You can spew your BS and lies with each response, but nobody is going to take you serious, because you have no experience with said situations to back up your claims. I can provide links on pigs flying, that still doesn't make it fact. Sorry, but you fail.


Bill is an ASE Master Tech. I've seen all his degrees myself. I've also had a fair amount of work done by him. The man knows what he is doing. He's Very experienced and knoledgable. For me, I would believe a man who has experience in the field, and has worked on these things first hand rather then the interwebz. Why argue with a man who obviously right? Are you just butthurt because you're wrong? Quit with the childish banter and you might learn something.

 

1) he claimed that torque converters are 100% efficient. See post 24.
2) he doesn't have a complete grasp of how a speed differential equates to torque alteration/multiplication. See post 34, the second response to me contains a quote that contradicts his first response to me.
3) where his supporting evidence doesn't contradict his position, his supporting argument is "I say so and I'm ASE certified". See post 28, 34, 37, 39, 41.

Now my claim is extremely simple: a torque converter is not 100% efficient at transferring energy from the engine to the transmission.

My supporting evidence is very simple:
1) the torque converter generates a great deal of heat (hence the use of transmission coolers for heavy loads). This heat IS the energy that the torque converter fails to transfer.
2) the presence of a lockup clutch within a torque converter is the solution to the low transfer efficiency of the torque converter, by essentially eliminating the torque converter.
3) if a torque converter was 100% efficient, no heat would be generated and no lockup clutch would be required.

I have a strong suspicion that the disagreement may be partially a result of reading comprehension. I am beginning to suspect that he is of the opinion that I am arguing that the output torque is lower than the input torque, in fact, I am not arguing this point. The point I am arguing is that based on the speed differential between the input and output of the torque converter, a gear reduction of the same ratio would yield a higher output torque for the same input torque, effectively, it would be more efficient at torque multiplication. Where a gear reduction will yield a transfer/conversion efficiency of well over 95%, a typical torque converter would be lucky to hit 85%.

 

???
Yo momma so fat, when she walked by a construction site they used her as a wrecking ball.

 

As we've discussed before, I'm just trying to relate to you at your own level

 

I think you are arguing something completely different than his intended point.

 

lifesaflaw123: thank you for redirecting this back to an intelligent topic.

The specific quote that started this is this one: "As for torque stealing, that information is incorrect."

Now simply put, in order for this claim to be true, it follows that it must be 100% efficient, or at least some reasonable approximation of this. Since a typical automotive torque converter is nowhere near this, as shown by the heat output, this claim is quite severely flawed.

You are nearly there regarding the relationship between speed and output energy. In fact, it is speed and POWER that do not impact each other. Speed is how power and torque are related. The power is constant at any point in the drive train, if you ignore various losses relating to things like friction. The alteration of the speed, through changing gear ratios, torque converters, etc., allow us to manipulate the torque. As an example, take a typical electric winch, power wise it is very low, say 1-2 horsePOWER, and yet through gearing it very slow, it has sufficient torque to drag a truck out of a mud hole.

Now what the major consideration is, is this: the energy transfer efficiency of a torque converter is much lower than the energy transfer efficiency of a gear. We generally think of gears as being perfectly efficient, obviously they too have a loss, just a loss so much smaller that we generally dont worry much about it.

What ravenlord stated that resulted in the questioned quote, related to the power loss of an automatic. He quoted 25%. If an automatic with an unlocked torque converter is 25% loss, a manual will be about 15% since it isnt subject to the torque converter loss.

Now the theory of a torque converter is that the added power output by the engine when the torque converter unlocks, will make up for the efficiency lost as a result of enabling the torque converter. At least as far as performance goes. On a manual, downshifting one ratio has the same increase in engine output without the energy loss of a torque converter.

Well, in the case of the low ratio 6th gear on the 6MT, 6th is about the same ratio as the 5AT in an unlocked state. The extra engine speed is the reason why the 6MT burns more fuel than the 5AT. In addition, the torque converter generally remains locked while cruising, so the overall effects of torque converter energy loss is relatively low.

 

l should say, the 6MT has the same torque multiplicative advantage as the 5AT when the torque converter is unlocked, but without the energy loss.

 

This is what I was stating. The numbers taken directly from Toyota show that the Automatic gets equal or better MPG than the manuals, especially when you compare a manual 4X2 that gets 21 hwy, against a 4X4 that gets the SAME. Seems to me that their efficiency is better. As for efficiency percentage, I never claimed they were 100% efficient. Just that they are more efficient than they were in the past, and that was due to the improvements in the torque converters. Seems someone else's "comprehension" needs some work as well.

 

well fellas his screen name is "KNUCKLEHEAD"

 

The majority of that post is perfectly fine and correct. No arguments. The ONLY part I take exception to is your claim regarding the efficiency of a torque converter. "As for torque stealing, that information is incorrect."

I AGREE that the AT's get better mileage, and as you point out, that is related to the gear ratio. AT=0.716:1, MT=0.849:1.

If the MT had a better gear ratio, it would be slightly more efficient than the AT.

And yes, torque converters ARE a lot more efficient than they were in the past, but they are still less efficient locked than what is effectively a straight shaft on an MT, and they still have a very significant energy loss when unlocked/loaded.

 

You must have taken some basic engineering courses and now you think you can design a transmission... you are rambling on about pointless shit. It has been proven over and over in the case of the tacoma that the automatic gets better mileage. Fact.

You also keep talking about the converter unlocked... well You must not realize how quickly they lock up nowadays.

In summary: we all know nothing is 100% efficient, but the Tacoma 5 speed is obviously slightly more efficient than the manual.

 

Mind if I ask where you get this from? A locked TC has zero slip. i.e. the input shaft turns at the exact same speed as the engine does. This is the same when a manual transmission's clutch is engaged. If both input shafts turn at the same speed of the engine, how could one be less efficient than the other?

 

Yes, the gear ratio is different between the two transmissions. However the MT would NOT benefit from a better ratio, because a manual transmission IS locked to the engine, and you need the engine RPM at it's most efficient range. I am pretty sure that the engineers that work for Toyota would put the most efficient gear ratio they could. Mileage is a HUGE selling point, why would they REDUCE the efficiency of something, allowing a different manufacturer to best them in the fuel economy battle?

 

When locked, although the impeller and turbine are perfectly synchronized, this combined unit is obviously still turning within a fluid bath. The loss of transfer efficiency is simply the fluid resistance. It is very close to perfect efficiency in this manner, but a straight shaft only has the air around it to reduce its efficiency.

 

You are again, incorrect. When the TC goes into lockup, the converter housing which is bolted to the engine flex plate is internally locked to the input shaft of the transmission via the stator and turbine. Hence there is NO loss of RPM.

http://www.youtube.com/watch?v=q2fRCITXn4o

 

We can't get anywhere trying to argue their reasoning, and I do see where you are coming from. Some people have suggested that their motivations may have been related to upselling the AT. There are a few examples of weird and/or questionable decisions on these.

What the argument comes down to though, is that having AT or MT does not affect the engine's "most efficient" operating speed. Locked up in 5th should be the same ratio as 6th MT.

A more plausible argument for this point, is that the MT gear ratios were selected to give the engine a little more headway over potential torque needs. For example, one might expect the cruise control to be able to maintain speed up a moderate slope without having to downshift. The AT, being automatic, can vary its gear ratio without disengaging the cruise control.

Regarding torque converter being attached to flex plate: that point where the fluid enters the torque converter is a source of friction.

 

I think what you're trying to say is that the "fluid bath" is spinning with the entire unit? So in lockup, for all practical purposes, there are no converter parts being slowed down by fluid friction, since they spin together? If the fluid does spin with the unit, that would get pretty darn close to 100% efficeincy. I would also suspect that the converter is cooler while traveling down the road for extended periods due to less friction while locked, and hotter while sitting at a stoplight in gear, idling.