5.0 V8 - Automatic vs Manual

[burntire]

Nah, I think that's a big-time generalization and is very dependent on power level, driver skill and traction, among other factors. For instance, I guarantee you there is NO WAY a stock GT with an auto would beat a good manual driver by .5 seconds, all else being equal. A half a second (or more) is a HUGE difference in ET (multiple car lengths). Now maybe when you get up into the crazy power numbers what you're saying becomes more plausible.

Regardless, I do agree that the necessity for an automatic increases with power level, if competition is the top priority.

A stock gt auto with a converter and tune will beat a stock gt stick with a good clutch and tune all day long with traction being equal. The auto with dyno less RWHP and be ahead at the finish line due to torque multiplication. A good auto setup will always beat a stick with engine HP and traction being equal. These auto cars have converter lockup so its an even bigger bonus on the top end.

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[smitty]

This is a debate that cannot be 'won' because it really boils down to the priorities of the individual. Some value the simplicity of an automatic over the attachment to the car, extra challenge and more 'pure' driving experience provided by a manual. Others have really crappy commutes and spend a ton of time in stop and go traffic and a manual is basically more pain than joy to drive. Others have physical limitations that necessitate an automatic. It's all been said. It's all valid.

The only argument I take exception to is when someone favors an automatic simply because it's the only thing they've ever driven. THAT is being closed minded. If you have not TRIED a manual, you should. Don't get an automatic simply because it's all you know. You never know what you might be missing! ;)

I agree with this and mirrors to some extent what I said earlier. Having driven mostly manuals in my life, I'm certain I'll make more effective use of the paddle shifters available with the new auto than someone who has never driven a manual because I have trained myself to pay attention to the car in ways that someone who has never driven a manual didn't need to learn. I take exception to the assertion that if I chose an auto at this point, that I'm somehow less "involved" with my car. I'm still paying attention to what's going on with the car as if I were driving a manual. I think it's a good idea to expand your abilities and challenge yourself whenever you can in life. Learning to drive a manual will make you better driver period. ;)

 

[KGrGunMan]

I think a good flappy paddle could very well be the best compromise to please most and keep one more involved with the car.

There is still penalty regarding involvement and joy for an enthusiast however, there is nothing in the driving world that can put a bigger smile on my face than; getting on the brakes hard coming off a straight, blipping the throttle while on the brake dropping down 3 gears at once, turning in, clipping the apex and powering out hard.

Yea, you can move your left hand 3 times, and maybe I'm too abnormal, but if I lost the ability to heel-toe, my love of driving would severely diminish.

 

[scottpe]

A stock gt auto with a converter and tune will beat a stock gt stick with a good clutch and tune all day long with traction being equal. The auto with dyno less RWHP and be ahead at the finish line due to torque multiplication. A good auto setup will always beat a stick with engine HP and traction being equal. These auto cars have converter lockup so its an even bigger bonus on the top end.

I'm not disagreeing with you that a well sorted auto will typically be faster... but at normal power levels, and all else being equal, it will not be anywhere near the .5 seconds you previously touted. Anyone that gets beat that bad in a race between two near stock cars is not launching and shifting the manual right.

Now, as I mentioned before, once you get into power adders and the crazy power numbers that result, the margin of victory for the autos typically widens.

I do have to say I'm not sure I follow your 'torque multiplication' comment. The 6MT has a higher gear ratio in 2nd thru 5th gears than the auto does, which would seem to give the manual the overall 'advantage' in respect to torque multiplication. Maybe you can enlighten me as to what I'm missing in that regard...

 

[burntire]

I'm not disagreeing with you that a well sorted auto will typically be faster... but at normal power levels, and all else being equal, it will not be anywhere near the .5 seconds you previously touted. Anyone that gets beat that bad in a race between two near stock cars is not launching and shifting the manual right.

Now, as I mentioned before, once you get into power adders and the crazy power numbers that result, the margin of victory for the autos typically widens.

I do have to say I'm not sure I follow your 'torque multiplication' comment. The 6MT has a higher gear ratio in 2nd thru 5th gears than the auto does, which would seem to give the manual the overall 'advantage' in respect to torque multiplication. Maybe you can enlighten me as to what I'm missing in that regard...

I can see you have limited experience drag racing or following how much the 6r80 S197 mustangs have been destroying the manual cars at the track with less power since the 5.0 came back into the scene.

http://www.ultimateconverter.com/article.html

[ame]

A torque converter multiplies torque during acceleration. There is not such thing as torque multiplication on a manual transmission. Torque is what gets you down the drag strip not peak HP. A good torque converter will create a broader torque range compared to a manual car. More torque in the auto is is what causes the manual car with the same HP to lose. A lockup converter can be set to lock at a certain point eliminating the the loss of efficiency of a non lockup converter at the top end of the track. So now you have a car that makes more torque accelerating and manual transmission efficiency at the top end. This is why the manual car falls car lengths and tenths behind.

An auto with 60ft and ET better every time. A stick will do a good job at breaking parts when sticky tires come into play. Trust me I know. :eyebulge:

 

[scottpe]

I can see you have limited experience drag racing

Actually I have a good amount of experience with drag racing and cars in general, thanks.

A torque converter multiplies torque during acceleration. There is not such thing as torque multiplication on a manual transmission.

What??? Anything that has gears can multiply torque. A manual transmission absolutely has torque multiplication! That physics is what makes it much easier to launch a car in 1st than in 4th. Also, a higher (numerical) gear ratio multiplies torque more than a lower gear ratio.

Since we're posting links to 'enlighten' each other, you might want to read this one: http://en.wikipedia.org/wiki/Gear_ratio

Torque is what gets you down the drag strip not peak HP.

Agreed. And WHERE in the power band the motor makes that torque makes a big difference too.

A good torque converter will create a broader torque range compared to a manual car.

Sorry, but you lost me there. In my experience a good torque converter will minimize drivetrain losses within the natural power range of the motor (that's what the lockup feature is for). It doesn't 'create' anything outside of the forces transferred from ratio of each of its internal gears... just like a manual. A good torque converter could potentially improve the torque that exits the tranny compared to an inferior torque converter, simply by virtue of the fact that it's more efficient at transferring the available power and less is lost, especially if the converter has the lockup feature. But a torque converter does not magically cause an auto to make more torque than a manual.

More torque in the auto is is what causes the manual car with the same HP to lose.

I disagree. In my experience, what makes autos generally faster is that they allow faster and more consistent launches by nature of their more smooth power delivery, and they usually shift faster than most humans can.

An auto with 60ft better every time.

This, as I said above, I do agree with (though I don't like using absolutes like 'always' and 'never' when it comes to such topics). Autos are simply easier to launch consistently. Plus, the auto in the S197 has a higher 1st gear ratio (there's that torque multiplication thing again), BUT, as previously mentioned, the manual has higher ratios in 2nd thru 5th, and an overall higher final ratio, which theoretically means higher overall torque multiplication.

Again, to me this all still comes down to power levels. As I said before, when you get into really high horsepower setups (slicks and forced induction), the autos tend to widen the gap. But again, I go back to your comment implying that a race between two stock-ish GTs (auto and manual) would result in a .5 second (or more) whipping. That is simply not realistic unless the manual driver is just not very good.

I do agree that the autos are generally more durable, and simply a better overall way to go for drag racing than a manual. But the performance gap between them is not a constant. It starts out relatively narrow and widens as you get into the higher tier power levels. That was my whole point from the beginning, and one I still stand by.

 

[burntire]

You have two mustang GT's

One Auto , One Manual

They both create the same HP / TQ at the Flywheel / Flex Plate

For the purpose of education they both have the same internal tranny ratios and rear end ratios.

The auto gets a good converter and a tune.
The manual gets a good performance clutch and a tune.

The manual makes x amount of torque at the flywheel which is transferred thru the clutch to the input shaft of the tranny. The clutch does not multiply the torque. :frusty:

The auto makes x amount of torque at the flex plate then a good converter will multiply the torque by a good margin. Usually 2.0 -2.5 to 1. The torque applied to the internal ratios of the auto transmission is higher.

From ProTrans a good summary.

"A typical torque converter will have a torque multiplication ratio in the area of 2.5:1. The main point to remember is that all properly functioning torque converters do indeed multiply torque during initial acceleration. The more drastic the change in fluid path caused by the stator from its "natural" return path, the higher the torque multiplication ratio, a given converter will have. Torque multiplication does not occur with a manual transmission, clutch and pressure plate; hence the need for heavy flywheels, very high numerical gear ratios, and high launch rpm. A more detailed discussion of torque multiplication can be very confusing to the layman as high multiplication ratios can be easily considered the best choice when in fact more variables must be included in the decision. Remember, the ratio is still a factor of the engine torque in the relevant range of the torque converter stall speed, i.e.: a converter with a multiplication ratio of 2.5:1 that stalls 3000 rpm with produce 500 ft/lbs of torque in the instance of full throttle acceleration if its coupled to an engine producing 200 ft/lbs of torque at 3000 rpm. However, if this same engine produces 300 ft/lbs of torque at 4000 rpm, we would be better off with a converter that stalled 4000 rpm with only a 2.0:1 torque multiplication ratio, i.e.: 300 x 2.0 = 600 ft/lbs at initial acceleration. Of course it would be better yet to have a 2.5:1 ratio with the 4000 rpm in this example (provided this combination still allows the suspension to work and the tyres don't spin). This is just a brief overview as the actual scenarios are endless."

The auto car will have a broader torque across the RPM range. Torque is what moves you down the track.

If you would dyno both cars your will see the HP and torque comes on faster and spans across the rpm range greater than the manual. The manual may have a higher peak number but it is minimal if the converter is locked on the top end.

For example my 10.6x cobra manual put out at 626 RWHP
When I went to an auto it put down 575 RWHP but went 10.1x ?????
Rear end an final drive ratio thru the traps was the same. 3:55 and 1:1
I power shifted the crap out of the manual so we can eliminate the bad driver argument.

Notice how the HP comes is faster but doesn't peak as high. I can't find an auto torque dyno log but it is the same result. The torque comes in faster and is more usable across the RPM range. This was with a non locking converter. With lockup I bet I would have gone 10.0 or 9.9 due to no converter slip on the top end.

Autos and torque converters have come a long way. They days of the stick being quicker are history.

 

[Zshazz]

First off, burntire, you keep glossing over the part that scottpe has a problem with which is the comment that a *stock* Mustang auto will get .5 seconds over a manual. He has said many times that he expects a modded Mustang to be that much faster as an auto, but not a *STOCK* Mustang. Supporting your argument that an auto Mustang will be faster by giving experiences with modded Mustangs is irrelevant to his point.

As far as the "torque multiplication" point: I think what scottpe is looking for is more of an explanation of what you're talking about when you say "torque multiplication". Indeed a manual transmission has "torque multiplication" via gearing, as any thing to do with levers/pullies/gears can do. However, the "torque multiplication" the automatic transmissions give you via the torque converter is different.

Consider the following diagram:

When you press the brake and accelerator at the same time in an auto, the RPMs will climb until a certain point (which varies based on the power of the engine and the torque converter used). The engine is still producing full power (in the case of the diagram, 200 ft-lbs), but the thing you don't initially notice is the fact that there is a sort of "rubber band" type effect with the torque converter. It *really* wants the wheels to reach engine RPM. Hence, in this diagram, despite the engine only producing 200 ft-lbs, the wheels are receiving 400 ft-lbs (hence, 2x torque multiplication). Once you let go of the brake, the wheels will want to (ideally) meet up with the engine RPM.

There's also the fact that higher RPMs tend to have more torque than really low RPMs. So at 1k RPM you might produce 100 ft-lbs and 4k RPM you might produce 200 ft-lbs and a torque converter would give you 200 ft-lbs extra on top of that (using the same effect described above), so there's a LOT more torque when compared to the engine directly connected to the wheels.

Thus, initially, there is a LOT more torque being transferred to the wheels. This should result (in a case where you aren't traction limited) in several mph of extra initial boost over a manual. That extra speed over the entire quarter mile makes a huge difference.

 

[burntire]

I never said a bone stock 5.0 auto will beat it by .5

But here is one getting beat by .2

[ame]

I said an auto 5.0 with a good converter and tune will beat a manual 5.0 with a good clutch and tune all day long. IMO I bet with the converter and tune it would be by .5

The stock converter is not a good street/strip unit just like there are limits to the stock clutch with high rpm launches on sticky tires.

400+ horsepower can take advantage of a good converter and will beat the manual car every time.

Someone who wants to concentrate more on drag racing would be better off with the auto. Road Course / auto x drivers may prefer the manual. Someone who just wants to drive around can pick whichever tranny suits their needs best. As we can see by the video the auto/manual cars are very close in performance. The autos have come a long way over the years.

 

[scottpe]

First off, burntire, you keep glossing over the part that scottpe has a problem with which is the comment that a *stock* Mustang auto will get .5 seconds over a manual. He has said many times that he expects a modded Mustang to be that much faster as an auto, but not a *STOCK* Mustang. Supporting your argument that an auto Mustang will be faster by giving experiences with modded Mustangs is irrelevant to his point.

Thank you. Yes, he basically kept trying to convince me of things that I already knew, but what he didn't do was present any facts that truly addressed my original point.

As far as the "torque multiplication" point: I think what scottpe is looking for is more of an explanation of what you're talking about when you say "torque multiplication". Indeed a manual transmission has "torque multiplication" via gearing, as any thing to do with levers/pullies/gears can do. However, the "torque multiplication" the automatic transmissions give you via the torque converter is different.

Yes, this is what I really wanted. I think he and I were definitely viewing that terminology from different perspectives. To state that manuals do not use torque multiplication, from a physics standpoint, is a fundamentally flawed statement. They absolutely do, just not in exactly the same way that an auto does. I think he may have been taking something he read and treating it as gospel, without actually thinking about the implications of the statement.

When you press the brake and accelerator at the same time in an auto, the RPMs will climb until a certain point (which varies based on the power of the engine and the torque converter used). The engine is still producing full power (in the case of the diagram, 200 ft-lbs), but the thing you don't initially notice is the fact that there is a sort of "rubber band" type effect with the torque converter. It *really* wants the wheels to reach engine RPM. Hence, in this diagram, despite the engine only producing 200 ft-lbs, the wheels are receiving 400 ft-lbs (hence, 2x torque multiplication). Once you let go of the brake, the wheels will want to (ideally) meet up with the engine RPM.

...

Thus, initially, there is a LOT more torque being transferred to the wheels. This should result (in a case where you aren't traction limited) in several mph of extra initial boost over a manual. That extra speed over the entire quarter mile makes a huge difference.

This is a great explanation, and further supports why autos launch better on slicks (something I definitely had no doubts about).

I never tried to imply that a manual is faster in any way -- as you correctly ascertained earlier, my whole point was that one cannot make blanket statements that, all else being equal, an automatic will always trounce a manual by a huge margin (.5 seconds is a HUGE margin in a race between two stock cars). That's it, and I still stand by that assertion.

Peace.

 

[scottpe]

Someone who wants to concentrate more on drag racing would be better off with the auto. Road Course / auto x drivers may prefer the manual. Someone who just wants to drive around can pick whichever tranny suits their needs best.

I think this is the bottom line, and I agree completely...

 

[burntire]

Yes, this is what I really wanted. I think he and I were definitely viewing that terminology from different perspectives. To state that manuals do not use torque multiplication, from a physics standpoint, is a fundamentally flawed statement. They absolutely do, just not in exactly the same way that an auto does. I think he may have been taking something he read and treating it as gospel, without actually thinking about the implications of the statement.

A torque converter supplies additional torque that is not available to a manual car with the same engine power.

A manual car can manipulate the torque with the mechanical advantage gained thru gear ratio changes.

An auto has the benefit of additional torque multiplication created by the fluid coupling "Converter".

When talking about trannys the term torque multiplication is usually associated with the converter.

I have never heard anyone say hey the torque multiplication is awesome since changing manual tranny ratios.

So we can debate terms and definitions all day long and if it makes your happy I will revise my statement to say Autos provide additional torque multiplication not available to a manual.

The end result is the same the 5.0 autos have been eating the manuals lunch and dinner since 2011.:amen:

 

[Voodoo1796]

I've never seen this on less expensive cars, but on very expensive automatics (the old BMW M5 use to have this) you can change how fast or slow you want the automatic to shift, i believe it was on a scale of 1-7 from smoother slower shifts to faster more aggressive shifts. this makes a lot of sense; sometimes you want to be smooth and easy, saving on gas and maybe giving your lady a nice ride to dinner while other times you don't care about fuel economy and want to smoke the person next to you and rip to triple digits as fast and hard as you can....does anyone on this fourm own a transmission that does this?

I had the SMGII gearbox on my M3. It has its ups and downs, but I very much enjoyed it. I could leave it in auto mode, turn down the shift speed, and cruise without thinking about it. With a quick tap on the shift lever or paddle shift, I could change it into DIY mode, crank up the shift speed, an a no lift WOT shift was like getting kicked in the back of the head. It was a good option: my wife doesn't drive a stick, so if we took the M out and I had a few to many, it was easier for her to drive, and I still got a good bit of performance and control over the car.

The SMG unit, though, isn't a dual clutch box, but an actual six speed gear box that was the same as the one in the six speed DIY cogwapper M3s. It just didn't have a clutch pedal as the shifting was automated. So you did get a really cool looking shift knob thing that confused the hell outa people who have never driven one. Some people try to sell the idea of paddle shifters short, but I think the benefits way outweigh the "boringess" of them, and there is a reason why even the traditional performance only brands are all moving to them.

Given equal drivers on a road course, I'm a firm believer that a proper performance dual clutch box or SMG style box is going to win every time. You remove the variable of missed shifts, shifting early, shifting late, etc. It also allows you to focus more on proper breaking, turning, and acceleration out of corners.

That all being said...unless the 'Stang comes with a proper, performance oriented dual clutch box similar to what you get in a GTR, Lambo, Porsche, or the 335is/M3, its gonna be a manual trans for me. I live in big flat open Texas, and don't really get all that much into the track stuff, so rowing my own is fun and my commute is all of ten miles each way with four lights and little traffic.

 

[Vickstang]

That all being said...unless the 'Stang comes with a proper, performance oriented dual clutch box similar to what you get in a GTR, Lambo, Porsche, or the 335is/M3, its gonna be a manual trans for me. I live in big flat open Texas, and don't really get all that much into the track stuff, so rowing my own is fun and my commute is all of ten miles each way with four lights and little traffic.

Dual clutch would be awesome, but not gonna be available for the 2015 Mustang (maybe not until later on in its life?).

The best automatics available these days are pretty amazing though and really shocked me how good they are. For example the ZF 8 speed transmission felt almost as fast to me as a good dual clutch tranny, in both flap paddle and auto modes.

 

[Voodoo1796]

The best automatics available these days are pretty amazing though and really shocked me how good they are. For example the ZF 8 speed transmission felt almost as fast to me as a good dual clutch tranny, in both flap paddle and auto modes.

Wont disagree with you there...when I got out of college, I worked at a BMW dealership until I figured out what I was going to do with my life. It was right as the 335i was coming out. The ZF 6 speed in that was nice, very smooth and fast shifting.

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