8 & 9 speed transmissions

[Quattro Pete]

Originally Posted By: d00df00d
Originally Posted By: SubLGT
"According to those same sources, the new slushbox will be used on large displacement engines, meaning that it will most certainly come equipped on AMG models."

I find that thinking a bit dubious.

AMG engines aren't just "large", they're very torquey. Some of them are still on the old 5-speed because they would tear the 7-speed to shreds. I'd be surprised if the 9-speed would hold up.

Moreover, AMG cars are more and more about driving dynamics lately. They're not just regular Mercedes models with huge engines any more; AMG is making them much more comprehensive as performance cars now. This means the cars need to be responsive, which they won't be if they are constantly hunting for gears.

But hey, maybe I'm wrong. Hope so...

Plus, is a typical AMG customer really that concerned about fuel economy?

 

[Quattro Pete]

Originally Posted By: SubLGT
Anything more than a 9-speed is unlikely though, as engineers believe that along with certain technical obstacles, consumers don’t want that much shifting..........."


I'm sure they said the same thing about 5- and 6- speed trannies 10 years ago.

 

[stranger706]

This is getting kind of ridiculous. Here is my opinion on the matter.

The only automatic cars that need more gears, are small engines with peaky torque curves, or not enough torque at all. They need more gears so they can stay within their narrow power range. A 4 cylinder needs more gears than a V8.

As for manual transmissions, I still don't understand the hysteria with 6 speed manuals. Every 6 speed manual car I have driven, would have been much better with 5 gears intead of 6. Especially cars with forced induction. Mazdaspeed 3's are a good example of this. Everytime you shift, you loose boost and have to let it build again. This hurts performance. That car would be faster with 5 normal gears instead of 6 short gears.

Interesting side fact: The Porsche 911 Turbo with traditional automatic is faster than the same car with traditional manual. The automatic stays under boots while it shifts, giving un-interupted acceleration. The manual turbo loses boost and has to rebuild it everytime you shift. Road & Track tested this theory and wrote an article.

 

[d00df00d]

Originally Posted By: stranger706
Interesting side fact: The Porsche 911 Turbo with traditional automatic is faster than the same car with traditional manual. The automatic stays under boots while it shifts, giving un-interupted acceleration. The manual turbo loses boost and has to rebuild it everytime you shift. Road & Track tested this theory and wrote an article.

Faster... from 0-60.

And doesn't the automatic have a much shorter 1st gear ratio?

 

[Alan]

Originally Posted By: Kestas
Can you blame us? We went from rock-solid 3-spd automatics to electronically operated 4-speed automatics. The new transmissions had plenty more problems and cost plenty more to repair, probably beyond what they saved us in fuel. I fear that we may be going further in that direction.

What will you do when your vehicle hits 80K, is out of warranty, and the transmission takes a dump, with a repair bill quoted at $5000?


I used to feel the same way however I have learned to embrace the future and now enjoy the performance of 5 and 6 speed autos.

The 6spd auto in my new Camry is fantastic!

 

[edhackett]

I want one that goes to 11!

Ed

 

[xxch4osxx]

Originally Posted By: Kestas
Can you blame us? We went from rock-solid 3-spd automatics to electronically operated 4-speed automatics. The new transmissions had plenty more problems and cost plenty more to repair, probably beyond what they saved us in fuel. I fear that we may be going further in that direction.

What will you do when your vehicle hits 80K, is out of warranty, and the transmission takes a dump, with a repair bill quoted at $5000?
I totally agree here, no need for 8 and 9 speed transmissions. 4 speed automatics and 5 and 6 speed manual transmissions are more than adequate, in my opinion.

 

[FZ1]

What do I care? It's Automatic,ain't it?

 

[ffracer]

What is all the hysteria?

Automatic transmissions major flaw is that they have no eyes. Only the driver does. So, like CVTs, they react to what is presented to them, not what the driver's judgment tells the car and gearbox.

Adding more gears donesn't do much if the device is passive, except when the vehicle is driving passively. i.e. short bursts. Once it goes into hunting mode, it loses efficiency, in addition, to the coupling losses (torque converters at slow speed, CVTs at higher speeds).

Manuals with 6-speeds and clutches are generally optimal when the first 5 speeds are for go and the last is for highway cruising.

Here in automatic land (USA), you guys assume this is the only way to go and the best (invented here). the rest of the world (including US mfgs) have analyzed this to death and physics wins every time. Manuals win on efficiency when factoring in performance.

Same story again.

 

[CBR.worm]

More gears are good to a point. You don't want to be able to hit 60 mph in first and still be at 3000 rpm at 80. But at the same time many 6 speed auto's have a 1st gear that is too low, they are shifting out of first while you are still pulling out into traffic, and they don't seem to have the high overdrive that should be possible - they are geared to closely.

My dad's porsche cayanne starts out in 2nd unless you really step on it. Maybe a 9 speed will start in 2nd or 3rd and skip every other gear unless you are to the floor.

Long gone are the days of a big torquey engine with a 2,000 rpm stall speed torque converter that just slips with the engine speed sitting at exactly 2,000 rpm until you got to top gear at about 60.

I don't like CVT's, but my wifes last car had one and it drove well. I think it would be preferable to 9 forward gears.

 

[FXjohn]

Originally Posted By: Quattro Pete
Plus, is a typical AMG customer really that concerned about fuel economy?


stopping at gas stations is an inconvenience though

 

[Quattro Pete]

Originally Posted By: FXjohn
stopping at gas stations is an inconvenience though

Easily fixed by a larger fuel tank.

 

[eljefino]

I like that trans they put on the jeep grand cherokee a while back.

5 speeds, but it only upshifted through 4. The last speed was "two and a half" and where it'd kick down to for passing.

I hate an automatic where you floor the gas and it angrily mashes from 4th to 2nd, because there's lots going on, and you "nurse" the pedal 4/5 down to get one shift then floor it for the other. They say Ford RWD trannies really eat themselves up on the 4-2 downshift.

My cutlass ciera 3300 3t40 would go from 3rd to 1st at 30 mph on tight onramps. Then it always made the gap in traffic I was shooting for.

 

[Nick R]

Well, I had the 2.2L but the 3T40 was slow, but it did have great pull at the upper RPM band of 1st gear, and in 2nd around 35-50mph

 

[IndyIan]

Originally Posted By: eljefino

I hate an automatic where you floor the gas and it angrily mashes from 4th to 2nd, because there's lots going on, and you "nurse" the pedal 4/5 down to get one shift then floor it for the other. They say Ford RWD trannies really eat themselves up on the 4-2 downshift.

That reminds me of our old 91 Escort GT with the mazda 1.8L and the ford automatic, at 30 mph if you mashed it, it would go from 3rd or 4th to 1st and the engine would be near redline before it got all the shifts done...
It would spin the tires for a quite a bit on dry pavement which was cool for an auto 4 banger when I was in HS...

 

[mechtech2]

Let's see...
Who historically uses many gear in a trans?
Motorcycles and diesel semis.
Motorcycle engines are highly tuned for a lot of HP / ci. They are peaky and need revs. Many gears are quite useful.
Diesels in heavy trucks also operate a a relatively narrow power [lower] range for other reasons, and also need varied multiplication.
Why would we need 9 speeds in a gas car? Would a new engine have motorcycle like power and driveability for it's size?
300 naturally aspirated HP from 120 ci?

 

[ekpolk]

Originally Posted By: beast3300
Originally Posted By: Nick R
I personally despise CVT transmissions.


Same here. One of the most annoying auto trans I have driven lately is the 2010 Caravan. It's 6 speed and shifts through every gear to get to 40mph. On top of all the shifting the engine get's power pulled between shifts so it's even more annoying. If you ever drove a Taurus circa 00-05 you know the kind of shifts. Numb!


With all due respect, this is one of the silliest posts I've read in a long time. Sir, you contradict yourself right out of the starting gate. You agree that you "despise" CVTs, and then complain about all the gear shifting in a six-speed auto.

Newsflash: you can't have it both ways. You could have an old-fashioned 2 or 3-spd auto, with the neck-snapping BWAAAAAAAAAAAA downshifts any time you try to pass or just gain some speed, or you can live with the incessant shifting of a 5,6,7,8, or now 9 spd auto. Or on the other hand, you could have a CVT which, if well implemented, will give you just the right rpms for what you want to do, in an instant, smoothly and seamlessly. I absolutely LOVE the power delivery from the CVTs in the Prius and my Camry. I spent the first 1/3 of my USMC career flying jets, and these transmissions come very close to seamless, turbine-like power delivery, minus the spool-up time, of anything I've ever driven.

I wonder, seriously, how many of the posters who are disparaging CVTs have ever actually driven one. I find my wife's 07 Avalon, which is otherwise a comfortable and refined car, with it's 5-spd auto, to be crude in the extreme in its "stepped" power delivery.

What exactly is wrong with a transmission that's prepared to give you, almost instantly, THE perfect ratio between engine speed, wheel speed, and throttle position? The CVT may not sound like what you're used to, but what you're hearing is the sound of something that's light years ahead of ANY stepped, multi-speed auto.

OK, from this point forward, if you wish to criticize the CVT, please disclose whether you've ever driven one, and if so, what your specific problem with them is.

 

[CBR.worm]

I've driven them. Some work really well, some don't work so well. We had one in an Audi A4 (the tranny worked really well despite requiring replacement early in life) and my brother had one in a Maxima (didn't work so well and needed replacement later in life).

I appreciate them in an application like the Audi where the engine was turbo'd and had lots of torque at low RPM. It would provide good acceleration without exceeding 3,000 rpm. It was a well matched pair and made the car feel smoother and stronger than a regular auto would have. I think this would be perfect with a diesel.

In the maxima, any time you stepped on the gas more than half way, the tach would go near redline. When you let off the gas the car would accelerate faster as the ratio changed back. Additionally any time we took the car to the mountains the tranny would overheat and limit max RPM to 4,000 RPM very early in the trip. Nissan said this was normal. The maxima 3.5l V6 had a wide enough power band that it would have worked well with a 4 speed auto (we preferred our old maxima's 4 speed auto - especially in the mountains where we could just lock it into 3rd gear) It would have worked better if the CVT's programming was better matched to the engine.

I rent cars every week. I frequently get nissan CVT's (Altimas, maximas, Muranos)- they seem to be getting better. I have not driven any toyota hybrid/CVT - they may have a better solution.

I have never been a fan of automatics in general but some of the new japanese ones shift really quickly and smoothly at the same time. I do not like the BMW automatic we have now (I don't know who makes it), it takes nearly a full second to complete the first to second shift in normal drive mode - with no power being put down during that time. You actually tend to lean forward during the shift while the acceleration stops. If you have it in sport mode it bangs the shift hard enough to jerk your head back.

Our old maxima ('00) would shift at redline so smoothly and quickly that you did not feel any interruption in power and no jerk or shock. It was much easier to drive smoothly than the CVT version which changed ratios with a lurch any time you moved your foot.

I think CVT's generally feel unnatural. Too many years of gears, but they do make more sense to me than a 9 speed auto. I do not enjoy driving cars with CVT's even when they work well (but I appreciate them). I think they are great for my wife who just drives. I prefer to put the car in a gear and feel it pull through the power band to redline then shift. In my particular car I like the feel, power and sound of 4th gear from 3,500 to 7,000 rpm. I do this as often as I possibly can without going to jail. I do not like driving a car that sits at 7,000 RPM and accelerates at an ever diminishing rate.

 

[rjundi]

I don't think more speeds will effect MT's. MT's will typically always deliver better MPG in real world driving with a decent driver as they can anticipate things an automatic will never know or see irregardless of speeds.

 

[KrisZ]

I've driven in a CVT equipped... 1945 crop combine

it was much cruder than whatever is used these days, but the principle is the same.

That's why I smile when someone claims that CVT's are the latest and greatest technology and everything else is just stone age. So while the technology is new to automotive world, it's old news everywhere else.