6 Speed Auto

[Grass]

And as for running a tighter torque converter ? Is there such a thing ?

The 4Speeds have a lockup torque converter, so you aren't going to get any better economy out of an Auto that you are now...

Remember, it still takes a lot of valuable engine horsepower to run the pumps and push that oil.....

The current box only locks up with constant speed and constant throttle position – I.e. cruise control set. I assume by “tighter torque converter” that his will happen more often across a broader rev range in the new box.

Trent.

This box can do that too, it can unlock the torque converter just long enough to change gear and then lock the convert back through...(I have been in the car while it does it) just gives you a bit of whiplash as it does it.....

Ford have just asked for these things to be programmed a certain way for "public acceptance" not for all out shifting speed...

[Grass]

I wait for proof in the pudding.

I know my physics, I know pretty much how gearbox and Diff design work (I qon't admit that I'm partially responsible for the 4speeds you guys have, cause I don't want to get flamed) , but  it doesn't matter how far the revs drop as long as you stay within the Torque curve, which we have from 2500-4000, so the only advantage will be the quicker shifting and hopefully the removal of the torque tagging....

And Auto's don't need to drop the revs to pick up the next gear, that's that the torque converter is for..

And as for running a tighter torque converter ? Is there such a thing ?

The 4Speeds have a lockup torque converter, so you aren't going to get any better economy out of an Auto that you are now...

Remember, it still takes a lot of valuable engine horsepower to run the pumps and push that oil.....

No offence, and I'm sure you know what you are on about, but it's just that everyone else seems to disagree with you...

Most motoring magazines, who have plenty of engineering nouse behind them, seem to think that economy will improve as well as performance. And yes, it does matter if the revs drop less between each shift...

Think about it, gears are a ratio. Gear ratios multiply the torque. If you can have a higher torque value at the rear wheels for the duration of the quarter mile, then you are going to have more force pushing you forward. This also equals a higher average horsepower applied over the quarter mile because the revs are always higher.

Which brings me to my next point, when it comes to outright quarter mile times, its horsepower that does the trick... Horsepower is how much torque can be applied over time. Its the work done. So the the higher the average horsepower you can apply to the rear wheels over the entire quarter mile, the lower your ET will be... MPH will improve sightly as well, but your ET will most certainly improve...

Its a concept I've only just got my head around, average horsepower applied... But it makes a whooooole lota sense when you see just what the difference that it makes is... What gave me the revelation of this was Pro Stock cars. The don't put out thousands of horsepower like door slammers, but they run similar ETs at less MPH. They have less outright power, but they have 5 or 6 speed's in them, very VERY fast shifting 5-6 speeds (auto's I think, the clutch is only for laucnh.. Not sure, will have to get back on that), and the average applied horsepower (not torque, torque is not as close) over the quarter mile is similar... If just a little less.

Meh, I think its a fascinating concept, then again, I love anything that makes power and loud noise.... But you get that

Hmm, some interesting points, but ... no

You have torque. The torque curve is flat. As long as your gear ratios keep you within the flat torque curve it don't matter if you have 1 or 5 gears.

Just look at top fuelers......they run 2 or 3 gears at most..... if there was an advantage, as you are suggesting, then they would run 7,8,9 or 10 speed boxes.

Sorry for the "slap stick" but Wannabe Mechanical engineer might be right...

I have the bit of paper and the design time with gearboxes and diffs......

Sorry.

[turbocorty]

I will add my view on this topic...No experience in this field!!

I believe that the 6 speed will be noticeably quicker down the quarter for the following reason.

First gear could have a higher ratio thus quicker takeoff (less time out of boost also)

Second gear in the ZF will have a higher ratio than second gear in the current 4 speed so it will also have slightly faster acceleration.

3 gear in the ZF could be the same as 2 gear ratio in the current box...and so it continues.

Because the revs don’t have to drop as much between gear changes, the internal clutches/bands can be smaller and lighter than the current box.

A question to GRASS regarding the Torque theory.

Q. If two XR6 turbo Manuals where to race and one of the drivers shifted 1st, 2nd, 3rd, 4th...and the other 1st, 3rd, 5th..assume they shift at the rev limit. who do you think will win the race? I think it will be the guy using all the gears. The driver shifting from 1st to 3rd will still be in the peak of the engine torque, but will not keep up because of the lower ratio which = less torque to the rear wheels.

Anyone may step in and correct me as I have no mechanical engineering background... this just what I believe to be the case.

Go easy on me if I have totally confused myself.

Cheers

[Turbo6man]

turbocorty> you are right with your summation in that analogy (even though your reasoning is not quite there, see below).

Sorry Grass, don't care how much experience you have had, the fact is that power = torque by revs - so higher revs at the same torque level is greater power. Power is work over time so the guy using all five gears will have a lower time to do the same work. It's no more than high school physics really - just a pity I missed so many classes

[FPV GTHO]

Hmm, some interesting points, but ... no

You have torque. The torque curve is flat. As long as your gear ratios keep you within the flat torque curve it don't matter if you have 1 or 5 gears.

Just look at top fuelers......they run 2 or 3 gears at most..... if there was an advantage, as you are suggesting, then they would run 7,8,9 or 10 speed boxes.

Sorry for the "slap stick" but Wannabe Mechanical engineer might be right...

I have the bit of paper and the design time with gearboxes and diffs......

Sorry.

<{POST_SNAPBACK}>

I always thought top fuel run direct drive, as they cant affordably make multi speed transmissions that are both strong, smooth and fast enough to get a car down the quarter. In any case, they usually run half the strip still on clutch slip anyway, and are literally hitting max revs right off the start line.

[aiboart]

Thought experiment:

Two flat torque motors, one direct drive and one driving through a variable ratio drive.

At any given road speed or engine speed both motors put out the same torque.

At any given road speed the direct drive motor's revs are proportionate to the road speed, the motor driving through the variable ratio drive however stays at max revs. (and hence max power as it a flat torque curve motor)

At any given road speed the variable ratio drive converts the excess engine speed of the motor to additional torque at the wheels.

Real world complications:

We do not have variable ratio drives, we have automatic or manual boxes.

Torque converters act somewhat as variable ration drives but their efficiency is variable.

Power on (and hence torque on) time lost in manual shifting.

Our engines do not have flat torque curves.

Boost.

Regards

aa

[Grass]

turbocorty> you are right with your summation in that analogy (even though your reasoning is not quite there, see below).

Sorry Grass, don't care how much experience you have had, the fact is that power = torque by revs - so higher revs at the same torque level is greater power. Power is work over time so the guy using all five gears will have a lower time to do the same work. It's no more than high school physics really - just a pity I missed so many classes

Ok, if that's the concept and consensus so be it....

Power = Torque by Revs... If I have a lower gear I get more torque, but not as many revs so power would be pretty constant through all gears, so why does having more or less matter, as long as every gear stays in Torque range... That is the problem with the Skip every second gear theory.. I wouldn't be sitting in the torque curve all the way....

I'll wait and see how much faster they really are and seeing I've already seen an ION 5 Speed auto in a T.. I pretty much know what the answer will be....

[aiboart]

turbocorty> you are right with your summation in that analogy (even though your reasoning is not quite there, see below).

Sorry Grass, don't care how much experience you have had, the fact is that power = torque by revs - so higher revs at the same torque level is greater power. Power is work over time so the guy using all five gears will have a lower time to do the same work. It's no more than high school physics really - just a pity I missed so many classes :blink:

<{POST_SNAPBACK}>

Ok, if that's the concept and consensus so be it....

Power = Torque by Revs... If I have a lower gear I get more torque, but not as many revs so power would be pretty constant through all gears, so why does having more or less matter, as long as every gear stays in Torque range... That is the problem with the Skip every second gear theory.. I wouldn't be sitting in the torque curve all the way....

I'll wait and see how much faster they really are and seeing I've already seen an ION 5 Speed auto in a T.. I pretty much know what the answer will be....

<{POST_SNAPBACK}>

Your on the right track.... because you stay in the torque range the torque at the motor is the same whatever the revs are, no problem there... torque at the motor is the same! You are correct!

Now, it's different story for the torque at the wheels. With more gears the rev drop on upshifts is slightly lower so the engine is spinning slightly faster. Remember the torque at the motor is the same what ever the revs are, but, in this example the motor is spinning slightly faster.

So while the torque at the motor is the same! the gears take the extra revs from the motor and turn those revs into extra torque at the wheels! More torque at the wheels means more acceleration!

So in this simple model you should go faster with more gears... But, and it is a big but.. there are a lot of other things going on too and it is not that simple in the real world.

In conventional manuals you loose torque (you disconnect your engine) time every time you shift. It depends on how long it takes you to shift and what the rev drops are and what the shape of the torque curve is and what the gear rations are and how many shifts you make, as to whether you are winning or loosing by having more or less gear changes.

In an auto there is the additional complication of the action of the torque converter to consider. This thing acts as gearbox with lots and lots (an infinite number) of gears, which is very cool. Unfortunately it wastes a lot of energy when doing its clever infinite ratio trick and it is nowhere near as efficient as hard step type gears in doing the revs to torque conversion. So when the torque converter is converting you gain by getting the infinite ratio effect but you loose because it wastes energy.

Conclusion. You could build a super complex model that will predict reasonably well what actually happens. You could fit a G-Tech and see what is happening.

Or you could go out and simply enjoy some great inspired design and engineering in all its glorious flavours.

Regards,

aa

[marc86au]

I think the new 6-speed auto will be just what the typhoon needs to become the car most people thought it would be to start with. I think it will make the car considerably faster than the manual version.

also I don't know if this has changed or not but near the start of the year I got told by someone who works for ford that they were pulling the 6-speed auto directly from the jags. hopefully it will also shift gears a lot faster than the current auto.

and apparently it can skip gears when under normal acceleration so you don't need to go through all 6 gears during everyday driving but when accelerating hard it will use all 6 gears

[Phido]

ZF isn't making them. Ford is (ZF design though), they are going to make 200,000+ a year.

The ZF 6 speed is pretty much the ultimate automatic gearbox. All the ratios you will ever need (in a car), light, compact, efficent, low parts count, high torque capacity, etc.. 4wd or RWD..

Which is why these days they are sticking them into almost everything, from top of the line BMW's, bentleys, jags etc to entry level 4 cylinder BMW's, to Falcons to Ford pickups and SUV's, to off road Military vechicals and landrovers etc..

Mercedes doesn't use it because it has its own 5 and 7 speed autos, and GM doesn't use it because it has its own range of gearboxes. But really none of them are better than the ZF all round.

AFAIK most ZF cars take off in 2nd gear under light throttle opening because its still short enough to do this, requires less shifts (smoother) etc..

The only thing that would be technically better it is something like BMW's M5 7 speed box with its electromechanical clutch instead of a torque converter (good because auto gearboxes don't like 8500 rpm!!)..