AT officially 1 sec slower than MT at Tsukuba
 

hopefully this isnt a repost. and even if it is. it deserves its own thread imo. there was some talk in the past about how the AT might actually be faster around a road course due to its very quick shifting. but the latest reports suggest that the gearing of the MT gives it an advantage over the AT. we now have hard numbers to confirm these reports.

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and some other cars from same test

[ame="http://www.youtube.com/watch?v=DE-Lzl3kI94"]CARトップ　ç*‘波サーã‚*ットテスト2012æ ˜¥ (後編) - YouTube[/ame]


Edit: fixed. looks like this site now has auto embed?

^ FYI - the embedded vids not showing up

The thing I don't understand is why charge $1100 more for the auto and get terrible gearing to the manual in comparison? The auto should've been geared the same or slightly better like how Hyundai did with 6 spd manual vs the 6 spd ZF auto.

im sure there will be shorter final drives available that can negate the effects of the overly tall AT gearing. clutch type LSD with shorter FD would be nice.

From what we can tell, the A/T seems to be the same basic unit as the A960 in the IS250, with identical ratios. The valve body is updated however. So the ratios are the same as the IS to save money it seems.

arghx7 or someone who knows about this subject, is it more expensive for the manufacturer to change AT ratios? I understand they use some sort of planetary gear setup but never really looked into that.

I have a few thoughts on this.

1) Like most things in manufacturing, production volume is a big element in determining costs. The FT-86 platform is intended to be a low-volume vehicle and relatively inexpensive vehicle. I don't think either Subaru or Toyota are expecting to make a lot of money off it, except maybe the fully loaded models.

2) "more expensive" relative to what? Well, is it more expensive to change a design or not change a design? A design change needs testing and validation. It needs a new supplier and/or new tooling for manufacturing the part if it's not an off-the-shelf piece. If the FT-86 is using the main gearsets and transmission architecture right from the IS250 (same ratios and everything), well that saves a ton of money on a low volume, inexpensive vehicle. The manufacturer has to ask, would the customer be willing to pay more money for different gears ratios? The normal customer doesn't see/understand gear ratios. They notice fuel economy, noise/vibration, driving characteristics, and of course price.

3)Is it more expensive to change gear ratios in a step A/T versus a manual? I imagine that's application dependent. Remember that gear ratio = # output teeth / # of input teeth . That's easier to understand on a simpler manual transmission because it doesn't rely on brakes and holding elements. On an automatic transmission this gear ratio calculation isn't always so straightforward because it depends on how the elements of gearset are being operated. You'd have to look through power flows in the transmission to see how everything is working.

I know that's a vague answer but in many ways automatic transmissions are so different from "regular car stuff." You can know a ton of stuff about engines and suspension but very little of that translates to an automatic transmission. Learning about an A/T requires you to start all over again in essence, at least for a lot of people.

Go to autoshop101 technical section http://www.autoshop101.com/autoshop15.html and it has old training documents for Toyota 3 and 4 speeds. You can also read about the powerflow of the A960 6 speed (in the IS250) from this document, http://avtopedia.ru/akpp/a960eaut.pdf , which was linked to in another thread.

Thanks arghx7!

Then what do you think of the manual transmission? Someone posted some article or something describing how the origin of the transmission is not clear because they changed "80%" of the parts. However, it keeps the exact same gear ratios as the late S15.

My question is, since the S15 is quite old, is it still a direct part share of some sort?

I really haven't seen enough about the manual transmission to have formulated many thoughts on it. I'm sure there are parts being shared for it to some extent--Aisin isn't going to design a new transmission family for a low volume car, especially since manuals are becoming less and less popular.

IMO, usually AT encourage to have more drivetrain loss and being heavier so it should be a bit slower than MT. Unless there are something like DCT (like SMG-II or GR6) equipped with the car so I don't see that a regular car with AT could be any quicker.

I love how it sounds when a japanese person says hachiroku lol. All funny business aside i liked how the toyobarus were quicker than more powerful cars!! Tsukuba is a very technical track so this is where the toyobarus will shine!!

It's an off the shelf part from another car that Toyota stocks. Easier to just use that. I'd guess that they expected the MT cars to outsell the AT cars by a large margin (and worldwide that definately seems true so far) making sinking even more money into the AT an even worse idea.

It really has less to do with the weight and drivetrain losses through the torque converter and more about the ratios.

The OP mentioned that the AT would be quicker because of the fast shifts but that's nonsense when you look over the numbers.

Sure, an auto may be a 1/10 of a second faster than the manual in making the shift but for the 3-4 seconds you are in gear the auto is transmitting to the ground 10% to 30% less power.

Wow, that is just total b-shiite. Did you just time-warp in from the 60s? Go read a few of the other threads on the auto and learn something. Gears 2 to 6 - totally locked, virtually no loss relative to manual at same rpm. Any differences virtually entirely due to taller gearing in the AT.