ignatiuslee

MT is faster than AT because it has 6 gears in compare to AT's 5?
If they both have the same number of gears, would the performance be closer?

ForceSHO

no, its the torque converter ? on at it eats up 10-15%

crap i dont remember what else.. someone here more technical knows

Dan Martin

Gear ratios are one thing, the other would be the standard inefficiencies of an automatic transmission such as the use of a torque converter instead of clutch.

An AT is typically 7-10% less efficient than a MT.

McGriddle

Torque converter.

matelot

a trout slap from dzuy

iamhomin

Not to mention some weight difference.

TSX Cman

its that lazy robot in your car shifting under your seat.

jlukja

When you say "faster" do you mean 0-60mph? I believe the top speed is the same. The engine output is the same but the AT, because of the torque converter, is less efficient and thus delivers less of the engine output to the tires. The AT is also a little heavier. So, fewer horses pulling a slightly heavier car will result in a slower accelerating vehicle.

ignatiuslee

Yea, I foucus on the 0-60

dom

IB

CGTSX2004

iTrader: (1)

Actually, the gear ratios of the AT mean that it has a theoretical top speed significantly higher than the MT.

But if he's talking about quickness, what the other have mentioned pretty much covers it.

sauceman

CVT > Sequential > MT > AT.

Whiskers

The driver.

ClutchPerformer

You're right, it would be *closer* but still not the same. Even with the same number of gears and the same gear ratios, an MT would still be more efficient (faster if you like) because they're simpler mechanically.

TinkyWinky

Wouldn't better efficiency (torque conversion) result in better mpg?

ClutchPerformer

Yes. And the MT has the better efficiency and better MPG.

TinkyWinky

Was there a glitch in the Matrix? The last I remember, the 5AT had better highway mpg.

Seems like Acura updated their specs for the TSX.

o_nate

The 5AT has better highway MPG because of gearing - it has a steeper top gear - so it requires lower RPMs to go the same speed at highway cruising speeds.

dzuy

:troutslap

gearing.

ClutchPerformer

Yes, actually there was.

Seriously, though. Gearing wasn't changed, and the stated MPG numbers have. The only explanation we had at the time it happened was that it was always this way and the previous numbers were preliminary (and wrong).

So basically, the MT's efficiency is able to overcome the AT's (pretty big) gearing advantage.

One more victory for the MT...

Dan Martin

Don't even look at the MPG figures that are posted on the car, they're pretty well meaningless. They just put a car on a dyno and calculate fuel consumption (it's not even directly measured). The calculations don't include aerodynamic resistance so if you put a Civic engine in a H2 they'd end up with the same MPG.

TinkyWinky

But I do believe that the 5AT runs at 2500 rpm @ 70mph, while the 6MT runs at almost 3000 rpm. Would this not suggest that the 5AT has higher highway mpg?

AcuraGT-3

sauceman

Naaaah!

They just decided to revise their numbers when I whipped out a 38.5mpg last year!

Seriously though, has any AT equalled that number yet?

jonesy

Ok, let's clear a few things up: the driver makes the difference in a 0-60 time run like you're talking about. A "good" shifter should theoretically be able to get a manual transmission car up to 60 faster than the same car with an automatic transmission. This has to do with the different gears (usually taller on an automatic), less efficiency (more mechanical stuff going on with an automatic), and better clutch starts off the line compared to what an automatic's torque converter can handle.

Second: your top speed is not determined solely by your gearing, if it was then yes, the automatic would have a higher top speed. However, it just so happens that that is not the case. The TSX is drag limited, which means it just doesn't have enough horse power to overcome the drag forces generated by going 136 MPH. I don't know which car has a higher top speed mind you, but it's based on what engine speed you're at when you reach top speed, and where that falls in the power curve.

Third: the gas mileage is also based on several things: driving style, air temperature, gasoline quality, and slew of other variables. According to Acura, for the 2005 model year, the AT does get better gas mileage. By my best guess this is because the automatic is not geared as aggressively as the MT. 500 RPM's on the freeway can affect gas mileage and Acura's automatics have become fairly efficient compared to their MT counterparts.

sauceman

with jonesy about the gas mileage.

The top speed of the 6MT is actually higher than 136mph. I've personally been up to 143, Kurt Bradley's been up to 144, and I know a few other members have been at least that high too.

I suspect that since gearing is a lot taller on the AT, due to the powerband of the engine, the ATs won't make enough power to sustain 140+ mph speeds.

jonesy

when your top speed is drag limited, your top speed will be highly dependent on the wind direction and velocity. If a car can't push through wind faster than 136 MPH but you have a tail wind of 20 MPH, then when your car is going 136, you're still only pushing through wind at 116. The rest of the math is up to you.

ClutchPerformer

Everything else I agree with, though. Good post.

jlukja

dom

21? I don't think I've ever done as bad as 21. I avg 24 easily. 23 when its really cold

Dan Martin

Those are good ol' EPA numbers. Totally meaningless in reality.

jonesy

I apologize for the post, but I have the sticker in front of me and it says 21/30 (yes i have the 6 speed). I also specifically remember the salesperson telling me the automatic got slightly better gas mileage (and the stickers on the automatics did say 22/31). So apparently acura has some confusion with the web page or the sticker printing process.

ClutchPerformer

I'll take a look at my sticker when I get home (yes I still have it )...

jonesy

I'm curious what other stickers say, is my car special?



Hey, shutup you

jlukja

lol, who knew jonesy was schizophrenic?


The mileage numbers changed from 04 to 05. I recall the 04 numbers showed the AT to get better mileage. Maybe they just had some 04 stickers left over?

TinkySD

A couple random comments:

The auto tsx 4th gear is a similar ratio to the mt 6th. Cruising on the freeway an auto will be turning significantly lower rpms. The 100lb weight increase is negligible when just cruising. Also, when cruising the at will have it's torque converter "locked up" which eliminates most of the ineffiiency it has compared to a manual. This also lowers power output.

SO i'm not sure why or if acura really did change the mpg claims but I can't see how the auto is less efficient than the manual, at least on the highway.