Ferrari and others: why auto is slower?

Can anyone tell me why, with the same number of gears, an auto is always slower? I know this is the case, but a friend of mine insists that in "sport" mode, his BMW M3 (E36) is just as quick as a 5spd model...PLEASE someone, help me explain why autos are NEVER as fast!

 

Because a torque convertor sucks power.

 

Weight also tends to be an issue. Of course it still depends alot on the driver, if he/she sucks at shifting gears then it doesnt really matter.

 

with an manual, going fast happens like this:

1. Decide you want to go fast
2. downshift and floor it


with an automatic it happens like this:

1. Decide you want to go fast
2. Floor it
3. Wait for the computer to figure out that your flooring it means you want to go fast. Wait for the computer to put two and two together, finally downshifting for you

 

Then when you start going through the twisties, its a matter of how good of a job the computer programmers did in telling the transmission to behave when your approaching red-line while the rear-end is just about loose traction while guiding your car around a hairpin. If the computer decides to shift in such a situation... well your not exactly going to be going faster than a manual now will you?

 

frank hit the nail on the head... the very nature of the torque converter causes you to lose power.

 

Torque converter is the main reason and then there are also clutches between the gears to make it shift smooth so there is always a lag between shift and go.

 

Whats the deal with the new Mercedes/McLaren SLR and its automatic transmission???

 

Its a Mercedes, and Mercedes is a luxury first, sport second kinda brand. Therefor they do not have manuals. Except maybe on the cheapest C class?

 

I was kind of looking at it on more of a technical scale, because im sure there is some kind of manual-like system, Im just not an expert on that type of stuff.

 

From what I understand the Mercedes SLR has a good old torque convertor hands off seven speed automatic. It may have a tip-tronic style "fake manual" but I really don't think so... I don't recall something like that being mentioned in any of the drivers/reviews of the car.

 

As others have already mentioned, the torque converter in an automatic eats more of the power. More important than how much power an engine makes is how much the vehicle puts to the ground. Take two identical cars with identical motors ... one with an auto and one with a manual ... the manual will physically put more power through the drive wheels. This is why when generalising wheel-horsepower for most automobiles, you lose 20% of flywheel power when put through an automatic transmission and only 15% through a manual.

It should be noted that most manu-automatics, while allowing you to select the gear you'd like to use, still run through a torque converter. Sequential manual transmissions do use torque converters, they use hydraulically actuated clutches and put as much power to the ground as a regular manual.

Bill in Brooklyn

 

Almost forgot .. your friend with the glue sniffing problem needs to live up to the fact that his car will never be as quick as a similarly engined stick.

Bill in Brooklyn

 

Autos thend to have less gears also. Not as much anymore, but you can still find 4 spd autos around. Less gears means wider ratios for those gears and less performance 'feel.'

 

Friend of mine with his Audi TT 3.2 with the DSG (Paddleshifters) thinks that his paddleshifter car would beat the same exact car with a 6-spd everytime.

Think this is true?

 

I think your friend with the glue sniffing problem needs to meet up with bostonmini's friend with the glue sniffing problem and the two of them need to go to rehab together.

A) The stick physically accelerates harder in a given gear at a given RPM because more power is getting to the drive wheels.

B) Your friend is limited on his launch by the pathetically low stall speed his OE torque converter dictates while the stick can launch at any RPM it wants.

C) Your friend's slush box shifts considerably slower than someone who knows how to shift a manual can.

Yes, there are some purpose automatics that work well in drag cars with lots and lots of horsepower, but at that level, there are different rules governing what's going on and those automatics can help create consistant launches. When I say "that level" ... I'm talking cars in the 9 second range and lower.

Bill in Brooklyn

Bill in Brooklyn

 

This is why I've always say:

"Never ride less than a Ducati & Never drive LESS than a manual 6-speed!"

 

That should have read: "Sequential manual transmissions do NOT use torque converters ..."

Bill in Brooklyn

 

Isn't your 540 an auto Jimmy?

Bill in Brooklyn

 

Actually, the DSG is not a normal automatic transmission. It doesn't use a torque converter, it is more an automated manual tranny equipped with two clutches (one for gear 1, 3 & 5 and one for 2, 4 & 6) working together so you never have to wait more than a split second before the nex gear is engaged.

Here you can see a technical drawing of the DSG:
http://www.audi.se/mediadb/_files/user_uaudi/dsg_3951.jpg

And here you can learn more about the DSG.
http://www.audi.com/com/en/new_cars/driveline_suspension/directshiftgearbox/directshiftgearbox.jsp

 

Cancel what I wrote then, I wasn't aware that Audi had a true SMG equivalent. It might be faster than someone with a stick, it truly depends on how fast the guy with the stick can shift and how well thir DSG system can launch the car.

Bill in Brooklyn

 

I did drive the TT, and I thought the launch was very weak...No way to rev the RPM's up before slipping the clutch like in a manual. I still prefer the gated 5/6 speed manual to the paddles. It's so boring, it feels like your flashing your high beams or something. The paddleshifting just didn't do it for me.

 

Yes, that's why it's doing a 6-speed tranformation as we speak.

 

Yeehaw Shawinggggggggggggg!

Bill in Brooklyn

 

I drive both daily. 6 speed in the 360, and electro hydraulic in the maser. I believe I and can match and sometimes exceed the upshift times of the maser, but honestly cant touch the downshift times(sport mode). Burnouts with the trc cntrl off are still fun in the maser.