EeryEleven

One question that keeps coming to mind is.... Why do the automatics need such different gears? I figure there must be a technical reason for this... but, I keep asking myself why they couldn't have used the same gearing but just made it automatic...

Just a thought... sorry if it has been answered before.

chrisalberts

Historically it's because automatics lag behind standards in terms of technology. They're more complex to engineer and therefore more expensive to develop, and so tend to be used longer (to amortize the development costs). Some of the automatics used in domestic cars have their roots in decades old designs.

As a result, while many (most?) "sporty" cars now come with a 6 speed manual, automatics are still 5 speed. There are very few 6 speed true automatics (Audi/MB/BMW). Same with 5 speed sticks and 4 speed autos in cheaper cars.

With a different number of gear ratios, the ratios themselves have to end up being different. (That sounds like the Phoenix from the movie "Mystery Men".)

Also there are different goals with sticks versus automatics and these might change the ratios the engineers think are best.

Well that's my non-technical answer anyway.

C.

moda_way

Simply put, Honda wanted the 5AT to be more fuel efficient and retain some, though minimal, sport. The 6MT is completely geared for us more dominant Type A personalities. Everyone buys a MT for 1 reason over an AT... CONTROL. With that we get better performance within our own capability. Eventhough sport shift Autos are like Manuals, only 1 company in my knowledge uses a tranny in their ATs that is in the MT... BMWs (in the general consumer market; this excludes Ferrari for instance). When you get the M3 with sport shift, IT IS the MT controlled by a computer. It is painfully notchy downshifting on the AT config, but you are getting a computer controlled Auto.

Simply answer on the TSX... fuel economy.

EeryEleven

so.. with this said.. it sounds like it would be possible to get a new transmission with better gearing for the automatic?

I have always loved manual transmissions... BUT, with my 1.5 - 2+ hour comute in bumper to bumper traffic I chose the 5AT for my TSX... but I miss the gearing on the manual...

moda_way

It would be completely custom and I don't know about you, but custom gearing for an AT is pretty expensive. Remember, the "gears" in a AT are actually fans with a torque converter. MT have real gears, so it isn't like you can swap.

Am I overstating the obvious?

EeryEleven

obvious to some people maybe.. but not to me... I don't really know anything about this...

Thanks again for the info.

ClutchPerformer

No, autos have "real" gears, too. They're just sun/planet/ring gears instead of "regular" gears like in a manual. You could swap them in theory, but I think the cost to do so is prohibitive.

fdl

Right. Most AT drivers want the best fuel efficiency and a smooth ride, over sport or performance. You could however put very agreesive gearing in an AT.

EeryEleven

that is exactly what I was wanting to do sometime... that is.. put very agresive gearing in my AT.... but I bet it may cost quite a bit... doh!

chrisalberts

You would not replace an AT on a car to improve sportiness. ATs are not plug and play.

However, most modern ATs are computer controlled - which means that it should/may be possible to modify the settings to make it feel more sporty.

Example: I'm a manual transmission guy. When we bought an Audi S4 Avant (sadly deceased) for my wife she wanted an AT. I didn't particularly enjoy driving the car because it just seemed like the AT was never in the gear I wanted it to be, and I didn't like the delay if I used tiptronic. A friend with a VAG-COM tool (Audi/VW only) was able to put in a few codes, and make the transmission shift pattern much sportier. Earlier kickdown, hold gears longer while accelerating, quicker shifts, no real downside. It transformed the car for me so that basically it was always in the gear I wanted it to be in.

So is this available for the TSX? Good question. If there isn't any similar function, it would require a tuning company to come out with a revised transmission program that could be uploaded to the car. Unfortunately, unless there's tons of people who want this, a company won't do it. It's worth asking around but you may be stuck without a stick.

C.

Nachoman

Can the dealer reprogram the computer like this or only someone with an aftermarket VAG-COM tool (I have no idea what this tool is).

TinkySD

I wonder if you oculd swap the 4.44 final drive on the auto for the 4.76 final drive on the mt....not sure if those two are interchangeable.

EeryEleven

I am not sure that I understand or agree that you can't change a transmission in AT.... So, there is no way they can make an AT for this car with better gear ratios?

majormojo

I'm not sure that's entirely fair. Yes, some current auto trans designs haven't changed much in the past few decades, but neither have manuals. Adding more ratios isn't much of an advancement really. But the changes we've seen in autos like computer control and monitoring, the implementation of "manumatic" modes, etc, make a modern auto trans much more advanced than its predecessors.

At any rate, I'd say that the biggest reason for different ratios in auto vs manual transmissions comes down to the use of the torque converter and the need to make best use of the power/torque the engine is producing. Autos can typically get away with lower gear ratios in the lower gears (and I think lower final drive ratios) than their manual counterparts because of the torque-multiplication effect of the TC. The use of the TC allows the engine to have more 'effective torque' when at low speeds and it means the relationship between flywheel speed and driveshaft speed in any given gear isn't constant as it is in the manual.

That generally means that autos are less fuel efficient than manuals, but in the case of the TSX that's not true. I think that has more to do with the selection of the ratios for 5 & 6 in the manual than any magic being performed in the 5AT. 6th in particular on the MT seems like it should be a fair bit lower. The torque curve is flat enough that there would still be a decent engine response at highway speeds if the engine were turning over a few hundred RPM slower than it is, and that would improve fuel economy.

That's my take on it, fwiw.

chrisalberts

The dealer could easily if they wanted to, but whether they would want to is another matter. It took 5 minutes.

C.

sponge

I have to disagree with one thing...

Buying a manual means you are a more dominant Type A personality? Give me a break!:pee:

Brad

I know very little about ATs, but some AT cars have two automatic modes, such as "Economy" and "Sport" (or some similar nomenclature). Some AT Accords have had this as well as some Mitserbitchies (Colt, I think).

Are these modes actually different gear ratios or do they merely affect (effect?) the car to shift sooner or later, depending on the mode?

Nachoman

VW Jettas have those two different modes. The computer calculates the weight, incline, how far you push the gas peddle, etc. and then decides which mode to be in. I think it mainly differs in how high the revs get before changing gears and how soon it downshifts. I don't know if it actually affects the ratios or not.

schalliol

I'm not going to turn this into "manual tranny... a dying art????," but MB has a 7-speed auto and Bugatti has a 7-speed SMG. The Aston Martin DB9 has a 6-speed conventional manual and 6-speed SMG (the SMG is 0.2 seconds faster to 60 than the standard stick.....if you want to reply to something related to this, click the link here, but watch out for the slippery slope that is that thread )

So, all I'm saying here is that you can get whatever transmission you want (really nice 6-speed conventional manual - haven't seen a 7 in a car), a 7-speed SMG, and a 7-speed auto), and a car can have equal number of gears.

moda_way

Ever heard of sarcasm.