4 Cyl. engines and front wheel drive cars

[IndyIan]

Originally Posted By: supton
How would a proper manual control on a CVT work? For manual control on gear ratio that is. A simple slide/lever?

I think the only practical solution is just pre-set ratios that you choose with some flappy paddles. Controlling the throttle and gear ratio at the same time would be a hypermilers dream, but general use, it would be too confusing for people to learn how to do it well. Even a simple hydrostatic CVT in a tractor takes some thinking to realize you are changing the gear ratio(and torque to wheels) with the foot pedal, not the engine rpm or torque output. So when the rpms start to drop going up a hill, you have to let off the pedal a little to select a higher ratio to increase torque to the wheels. Your instinct is to press the pedal more which only makes things worse.

Also, no auto manufacturer is making an engine optimized for a CVT anyways. VVT, turbos and tuning are still being used to make a torque plateau, which shouldn't be needed for a CVT.

 

[Mykl]

I don't know how CVTs actually work, so please be patient with the following question...

Is there increased wear on the transmission if it's constantly slipping ratios to hold a single RPM while the vehicle speed changes? Would there be less wear if it locked a ratio and "shifted" between them?

 

[badtlc]

CVTs won't be as efficient as an MTX anytime soon. Until they do, give me the MTX every time.

 

[Mykl]

Originally Posted By: badtlc
CVTs won't be as efficient as an MTX anytime soon. Until they do, give me the MTX every time.


I think that ship has already sailed. ATX efficiency numbers are starting to exceed MTX numbers.

 

[IndyIan]

Originally Posted By: Mykl
Originally Posted By: badtlc
CVTs won't be as efficient as an MTX anytime soon. Until they do, give me the MTX every time.


I think that ship has already sailed. ATX efficiency numbers are starting to exceed MTX numbers.

In terms of just putting a maximum percentage of engine HP to the road, a MTX is still the leader. If they just made the MTX's with the same upper gear ratios as the ATX's, the MTX would win everytime, but they don't, so the gearing advantages of a ATX can overcome their other inefficiencies, of the hydraulic pump, TC slippage, or belt friction in a CVT.

 

[supton]

Gearing can overcome some issues. Right or wrong the EPA test procedure (if I recall the descriptions I've stumbled across) do not allow downshifting, or the OEM frowns upon downshifting; as a result top gear seems to wind up short on a number of econoboxes. Thus the automatic can spin slower in top gear, and a good driver can use that to their advantage.

Seems to me that despite the lockup convertor the drag from the clutches and brakes will always hold back the traditional slushbox. The newer CVT's I'd think would still have more drag than a good manual. The automated manuals ought to be beat by non-automated by a good driver; being able to anticipate what is coming up (hill, coasting to a stop, etc).

That said, I saw a blurb elsewhere that BMW was going to pipe the GPS to the trans and use that info (hill grade, turns, maybe upcoming stops?) for the purpose of another variable for shift logic.

 

[Mykl]

Originally Posted By: IndyIan
In terms of just putting a maximum percentage of engine HP to the road, a MTX is still the leader. If they just made the MTX's with the same upper gear ratios as the ATX's, the MTX would win everytime, but they don't, so the gearing advantages of a ATX can overcome their other inefficiencies, of the hydraulic pump, TC slippage, or belt friction in a CVT.


You're splitting hairs. The difference is, at best, typically no more than a tenth of a second or a single MPG. What I'm saying is that more often now than ever the advantage ends up going to the ATX, as it does in the GTI.

 

[badtlc]

Originally Posted By: Mykl
Originally Posted By: badtlc
CVTs won't be as efficient as an MTX anytime soon. Until they do, give me the MTX every time.


I think that ship has already sailed. ATX efficiency numbers are starting to exceed MTX numbers.


No. MTX is 96%+. DCT should be close but I'm not sure how much might be lost with the 2nd clutch required.

ATXs max out around 86% and CVTs don't do much better.

 

[badtlc]

Originally Posted By: IndyIan
Originally Posted By: Mykl
Originally Posted By: badtlc
CVTs won't be as efficient as an MTX anytime soon. Until they do, give me the MTX every time.


I think that ship has already sailed. ATX efficiency numbers are starting to exceed MTX numbers.

In terms of just putting a maximum percentage of engine HP to the road, a MTX is still the leader. If they just made the MTX's with the same upper gear ratios as the ATX's, the MTX would win everytime, but they don't, so the gearing advantages of a ATX can overcome their other inefficiencies, of the hydraulic pump, TC slippage, or belt friction in a CVT.


Some cars do it right. CX-5, Fiesta EB are two examples where the MTX version significantly outperforms that automated versions in MPGs.

I think most cars are just engineered to push people to pay more $ for the automated transmissions to increase profits.

 

[Mykl]

Originally Posted By: badtlc
No. MTX is 96%+. DCT should be close but I'm not sure how much might be lost with the 2nd clutch required.

ATXs max out around 86% and CVTs don't do much better.


Okay, so you're telling me that there are NO cars with ATXs that are faster and/or more fuel efficient than their MTX counterparts?

So it's absolutely impossible for an ATX equipped car to be faster?

 

[IndyIan]

Originally Posted By: Mykl
Originally Posted By: IndyIan
In terms of just putting a maximum percentage of engine HP to the road, a MTX is still the leader. If they just made the MTX's with the same upper gear ratios as the ATX's, the MTX would win everytime, but they don't, so the gearing advantages of a ATX can overcome their other inefficiencies, of the hydraulic pump, TC slippage, or belt friction in a CVT.


You're splitting hairs. The difference is, at best, typically no more than a tenth of a second or a single MPG. What I'm saying is that more often now than ever the advantage ends up going to the ATX, as it does in the GTI.

I just saying if the gearing was equal, a MTX would give better real world mileage with a driver that knows what to do. Maybe a few percent? Many ATX's can now out accelerate a MTX with faster shifts though, but I suppose a sequential mtx, like in rally cars, would be near equal.

 

[Mykl]

Originally Posted By: IndyIan
I just saying if the gearing was equal, a MTX would give better real world mileage with a driver that knows what to do. Maybe a few percent? Many ATX's can now out accelerate a MTX with faster shifts though, but I suppose a sequential mtx, like in rally cars, would be near equal.


I don't disagree with that, but we have what we have. I'm not so well researched on the subject that I can rattle off a list of cars with good ATXs that can hang with the MTXs, but I do know that the ATX in the GTI is both more fuel efficient and faster than the MTX. The difference is marginal, but the point is that technology is developed to the point where a good ATX can hang.

I understand that for every GTI there are probably 100 turdbox econo-cars with slushboxes running low tech ATXs that could be from 20 years ago that are slow, inefficient, and miserable to operate. But in the good cars, ATXs are starting to hit the marks.

 

[badtlc]

Originally Posted By: Mykl
Originally Posted By: badtlc
No. MTX is 96%+. DCT should be close but I'm not sure how much might be lost with the 2nd clutch required.

ATXs max out around 86% and CVTs don't do much better.


Okay, so you're telling me that there are NO cars with ATXs that are faster and/or more fuel efficient than their MTX counterparts?

So it's absolutely impossible for an ATX equipped car to be faster?


You are asking a different question and irrelevant to what I stated. I am talking efficiency. Maybe that has confused you?

 

[badtlc]

Originally Posted By: Mykl
Originally Posted By: IndyIan
I just saying if the gearing was equal, a MTX would give better real world mileage with a driver that knows what to do. Maybe a few percent? Many ATX's can now out accelerate a MTX with faster shifts though, but I suppose a sequential mtx, like in rally cars, would be near equal.


I don't disagree with that, but we have what we have. I'm not so well researched on the subject that I can rattle off a list of cars with good ATXs that can hang with the MTXs, but I do know that the ATX in the GTI is both more fuel efficient and faster than the MTX. The difference is marginal, but the point is that technology is developed to the point where a good ATX can hang.

I understand that for every GTI there are probably 100 turdbox econo-cars with slushboxes running low tech ATXs that could be from 20 years ago that are slow, inefficient, and miserable to operate. But in the good cars, ATXs are starting to hit the marks.


Your GTI example isn't true in the real world. Many real world people are getting better MPGs out of the MTX.

Also the CX-5 and Fiesta EB have better EPA numbers than automated counterparts.

 

[JHZR2]

Originally Posted By: badtlc
Originally Posted By: Mykl
Originally Posted By: badtlc
No. MTX is 96%+. DCT should be close but I'm not sure how much might be lost with the 2nd clutch required.

ATXs max out around 86% and CVTs don't do much better.


Okay, so you're telling me that there are NO cars with ATXs that are faster and/or more fuel efficient than their MTX counterparts?

So it's absolutely impossible for an ATX equipped car to be faster?


You are asking a different question and irrelevant to what I stated.


+1.

MT is superior in every way - mass, complexity, build cost, efficiency.

ATs offer perceived benefits because they can be run on maps where the computer controls torque in a smarter way than a human.

On top of that, the MTs are often geared stupidly and completely differently than the AT.

For the same number of ratios, same final drive and gear ratios, and same engine, the MT car will be lighter and have fewer driveline losses. A DCT would have a performance edge because of speed of gear changes versus an AT or manually operated MT, with driveline losses likely equivalent to the MT, so the only parasitc is when the shifting actually occurs. But the AT would be the worst of the crowd (assuming a skilled driver), heaviest, and second most costly to acquire and maintain (DCT being the most expensive).

Since they are able to cram more gears and different drive ratios into most ATs vs MTs, what you see practically is the ATs starting to do better with economy. Plus most drivers are lazy as can be and cant figure how to drive in traffic with an MT.

Having just visited Istanbul Turkey, it was interesting to ride around in the little Fiat cabs which all had MTs and small diesels, and were pushing 600-700k km on a number of the ones I rode in.

 

[jgm038]

I think it depends on a lot of things. I drove up and down the east cost in a 2009 Malibu with the 2.4l and 4 speed auto. Probably the worst driving experience ever, lol. The thing would refuse to downshift in the name of economy and passing on single lanes was pretty much impossible most of the time

Last summer I bought a new 2013 Malibu with the 2.5l and 6 speed. I was looking to get better fuel economy than in my car with a 5.3l v8. On the test drive I was impressed, it was nothing like the Malibu. While smaller displacement engine from Honda, or turbod motors from other makes put out more power, the 198 hp from an N/A 2.5 i-4 is still pretty dang good. I average a combined 25.5-26 mpg which is mostly city driving.

I would have no problem buying another 4 banger...after a test drive to see how it feels however.

 

[Mykl]

Originally Posted By: badtlc
Your GTI example isn't true in the real world.


If you're going to base your opinion on unpublished, anecdotal evidence we can't really have a discussion. Because if I can pull hearsay out of my tail-pipe and present it as fact we're not going to get anywhere.

You're also not reading what I'm writing. I didn't say that all ATXs were better. I said that technology is getting to the point that a good ATX can equal or exceed an MTX in performance and efficiency. I provided one very well documented example and I'm sure I could find more if I really tried.

 

[Mykl]

Originally Posted By: JHZR2
MT is superior in every way - mass, complexity, build cost, efficiency.


Except in one critical way that's important to a lot of people...

Ease of use.

Not everyone has the same values as you. Some people simply couldn't care less about their car being equipped with an automatic gearbox.

 

[KrisZ]

Originally Posted By: Mykl
Originally Posted By: JHZR2
MT is superior in every way - mass, complexity, build cost, efficiency.


Except in one critical way that's important to a lot of people...

Ease of use.

Not everyone has the same values as you. Some people simply couldn't care less about their car being equipped with an automatic gearbox.


People don't care about a lot of things. Most couldn't care less about the engine and tranny dipstick, real coolant temp. and other gauges. Most just want a big dummy light, actually most would probably want an extra LSD screen instead of all those pesky lights.
Going after the lowest common denominator is hardly a proof of a superior design. In practice, it proves to achieve the opposite. That is, unneeded system complexity, additional cost for initial purchase cost of operation and servicing afterwards, just so that people can be even dumber behind the steering wheel.

 

[Mykl]

Originally Posted By: KrisZ
People don't care about a lot of things. Most couldn't care less about the engine and tranny dipstick, real coolant temp. and other gauges. Most just want a big dummy light, actually most would probably want an extra LSD screen instead of all those pesky lights.
Going after the lowest common denominator is hardly a proof of a superior design. In practice, it proves to achieve the opposite. That is, unneeded system complexity, additional cost for initial purchase cost of operation and servicing afterwards, just so that people can be even dumber behind the steering wheel.


Then feel free to buy the cheapest, lowest tech vehicle you can find and enjoy it to the maximum extent possible. I'm sure you can find a '60's Mustang somewhere in decent enough shape made entirely of components that can all easily be rebuilt in your garage. If you want something more modern a Geo Metro is pretty simple, although it does have fuel injection and air conditioning.

Objectively, a gearbox that can swap gears faster than you can move your arm packaged with more gears allowing for greater fuel economy is a superior design. That you prefer more involvement behind the wheel doesn't change the numbers.