Why the 8-speed auto had to be a Worlds First
#1
Speaks French in Russian
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Why the 8-speed auto had to be a Worlds First
Not sure if this is a repost or not...
Chief engineer wanted eight-speed to be world's first
Mark Rechtin | | Automotive News / August 21, 2006 - 6:00 am
Chief engineer wanted eight-speed to be world's first
Mark Rechtin | | Automotive News / August 21, 2006 - 6:00 am
Satoru Maruyamano has spent 17 of his 28 years with Toyota Motor Corp. developing transmissions. So it made sense that he would be the chief engineer for the 2007 Lexus LS 460, which has the world's first eight-speed automatic transmission. Maruymano spoke with Staff Reporter Mark Rechtin at the vehicle's press introduction in Salzburg, Austria.
How did you decide it was necessary to have an eight-speed transmission?
We decided right from the start. When we launched the LS 430, BMW already had a six-speed, which beat us in the "world first" category. At that time we started studying eight speeds. We met with Aisin at a World Cup game (in Japan) about four years ago about the transmission's development. The Mercedes S class has seven speeds, but sixth and seventh are so close that we think it's just a six-speed.
OK, so you're first. But why do it?
For power, performance and fuel economy. First-gear ratio is very low, and top gear is much higher than that of a six-speed. So in top gear we get low engine rpms and good control logic for good fuel economy. But we also developed the 4.6-liter engine with big torque, as passing power is very important. We use the 4-5-6-7 gears as the sweet spot of the transmission.
Early in development, we were worried it would be too busy-feeling, too frequent-shifting. So we have several control logics. The computer recognizes a freeway or a winding road for the suitable gear ratio. The previous six-speed also had some transmission noise. So in designing the eight-speed, we needed to look at the various shaft sizes and dimensions at their most basic level of engineering.
Did you begin developing the base model first?
We started the base model first. But r&d on both was almost done together. We had been planning a long-wheelbase version all along, where it would be more luxurious. For example, the tires on the long-wheelbase model would be more plush. The base model had just coil springs, but the long-wheelbase version has coil springs and an air suspension. And within that air suspension, we have a European-tuned suspension and a choice of 18-inch or 19-inch wheels.
It appears you are copying the BMW's "Bangle butt" trunk-lid design …
The current LS was a boxy four-door. This time we wanted a change. We wanted a lower, more stable feeling. Not that we ignored packaging, but we wanted to pay attention to design. We had to keep interior packaging, and we also had to consider our passive safety crush zones. So we increased the wheelbase and used bigger tires. But if you put big tires on the current LS, the turning radius is too big. So we had to deal with that in the design by increasing the width of the car, which also looks like a stable design.
Why only have a V-8 and a hybrid?
It would have been easy to do a V-12 for Lexus. But it's very expensive, when you look at the prices BMW, Mercedes and Audi charge. Besides, if we developed a V-12 for the LS, we would be following others, not leading. So we stayed with a hybrid focus instead. The hybrid focus is on fuel economy, but with a hybrid you get all-wheel drive. The competition's V-12s have great straight-ahead speed. But at some point a turn comes, and you have to brake. Our hybrid will beat their V-12 power.
How did you decide it was necessary to have an eight-speed transmission?
We decided right from the start. When we launched the LS 430, BMW already had a six-speed, which beat us in the "world first" category. At that time we started studying eight speeds. We met with Aisin at a World Cup game (in Japan) about four years ago about the transmission's development. The Mercedes S class has seven speeds, but sixth and seventh are so close that we think it's just a six-speed.
OK, so you're first. But why do it?
For power, performance and fuel economy. First-gear ratio is very low, and top gear is much higher than that of a six-speed. So in top gear we get low engine rpms and good control logic for good fuel economy. But we also developed the 4.6-liter engine with big torque, as passing power is very important. We use the 4-5-6-7 gears as the sweet spot of the transmission.
Early in development, we were worried it would be too busy-feeling, too frequent-shifting. So we have several control logics. The computer recognizes a freeway or a winding road for the suitable gear ratio. The previous six-speed also had some transmission noise. So in designing the eight-speed, we needed to look at the various shaft sizes and dimensions at their most basic level of engineering.
Did you begin developing the base model first?
We started the base model first. But r&d on both was almost done together. We had been planning a long-wheelbase version all along, where it would be more luxurious. For example, the tires on the long-wheelbase model would be more plush. The base model had just coil springs, but the long-wheelbase version has coil springs and an air suspension. And within that air suspension, we have a European-tuned suspension and a choice of 18-inch or 19-inch wheels.
It appears you are copying the BMW's "Bangle butt" trunk-lid design …
The current LS was a boxy four-door. This time we wanted a change. We wanted a lower, more stable feeling. Not that we ignored packaging, but we wanted to pay attention to design. We had to keep interior packaging, and we also had to consider our passive safety crush zones. So we increased the wheelbase and used bigger tires. But if you put big tires on the current LS, the turning radius is too big. So we had to deal with that in the design by increasing the width of the car, which also looks like a stable design.
Why only have a V-8 and a hybrid?
It would have been easy to do a V-12 for Lexus. But it's very expensive, when you look at the prices BMW, Mercedes and Audi charge. Besides, if we developed a V-12 for the LS, we would be following others, not leading. So we stayed with a hybrid focus instead. The hybrid focus is on fuel economy, but with a hybrid you get all-wheel drive. The competition's V-12s have great straight-ahead speed. But at some point a turn comes, and you have to brake. Our hybrid will beat their V-12 power.
#3
Cycle Savant
iTrader: (5)
Why only have a V-8 and a hybrid?
It would have been easy to do a V-12 for Lexus. But it's very expensive, when you look at the prices BMW, Mercedes and Audi charge. Besides, if we developed a V-12 for the LS, we would be following others, not leading. So we stayed with a hybrid focus instead. The hybrid focus is on fuel economy, but with a hybrid you get all-wheel drive. The competition's V-12s have great straight-ahead speed. But at some point a turn comes, and you have to brake. Our hybrid will beat their V-12 power.
It would have been easy to do a V-12 for Lexus. But it's very expensive, when you look at the prices BMW, Mercedes and Audi charge. Besides, if we developed a V-12 for the LS, we would be following others, not leading. So we stayed with a hybrid focus instead. The hybrid focus is on fuel economy, but with a hybrid you get all-wheel drive. The competition's V-12s have great straight-ahead speed. But at some point a turn comes, and you have to brake. Our hybrid will beat their V-12 power.
I'm glad to see that even though there are negatives to having a hybrid system instead of a bigger displacement, they have hit a spot in the automobile world.
Huge halo for Toyota and "being green." Take that Kermit the Frog!
By the way, I am quite interested in hearing more news on the 8-speed tranny. There is word the IS500 will have it...
#5
exclusive matchup
iTrader: (4)
very nice and intensive review. and i think another great reason for 8 speed (besides the reasons he stated) is the quietness. the engine is mostly low rev so it makes it easier to keep the noise level of the car low. that's what lexus have been trying to do for long time
#6
Great interview, I do think he sidestepped the Bangle butt question by not answering it. But I forgive him for that, since the LS looks so much nicer than the 7-series disaster!
#7
Lexus Champion
A 6-speed manual maybe, but that wasn't THAT rare at the time, nor was it nearly the technical challenge to develop that an automatic would be.
You'll never see something like an 8-speed traditional manual transmission (with clutch, manually shifted) because there's just no way to gain any real benefit from that number of gears considering how slowly the average driver shifts. Even the best drivers wouldn't really benefit from an 8-speed.
I think I saw some exotic with a 7-speed manual, but even that is probably too much. Most 6-speed cars only use 4 of the gears for acceleration anyway and the last two are cruising gears.
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#8
Guest
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I'm pretty sure it didn't have a 6-speed automatic.
A 6-speed manual maybe, but that wasn't THAT rare at the time, nor was it nearly the technical challenge to develop that an automatic would be.
You'll never see something like an 8-speed traditional manual transmission (with clutch, manually shifted) because there's just no way to gain any real benefit from that number of gears considering how slowly the average driver shifts. Even the best drivers wouldn't really benefit from an 8-speed.
I think I saw some exotic with a 7-speed manual, but even that is probably too much. Most 6-speed cars only use 4 of the gears for acceleration anyway and the last two are cruising gears.
A 6-speed manual maybe, but that wasn't THAT rare at the time, nor was it nearly the technical challenge to develop that an automatic would be.
You'll never see something like an 8-speed traditional manual transmission (with clutch, manually shifted) because there's just no way to gain any real benefit from that number of gears considering how slowly the average driver shifts. Even the best drivers wouldn't really benefit from an 8-speed.
I think I saw some exotic with a 7-speed manual, but even that is probably too much. Most 6-speed cars only use 4 of the gears for acceleration anyway and the last two are cruising gears.
Lexus has always been close to the most gears..
The 1996 GS 300/SC 300/400 switched to a 5 speed....
#9
Lexus Champion
Interesting factoid - the "SR5" designation on Toyota trucks historically (when it was originally used) was used to advertise the fact that the truck came with a 5-speed manual transmission (back in the days when 4-speed manuals were more standard fare).
Now days they're still using SR5 to mean more or less the standard model level, even if it has a 4-speed auto or whatnot.
OK I assumed you were talking about a 6-speed auto since that's, well, pretty much what the discussion was all about before that point.
Now days they're still using SR5 to mean more or less the standard model level, even if it has a 4-speed auto or whatnot.
OK I assumed you were talking about a 6-speed auto since that's, well, pretty much what the discussion was all about before that point.
#11
Lexus marketed quite a bit on the latest LS 430's 'added 6th gear,' which the SC 430 now has...you can bet they'll push the 8-speed a lot. Have to drive it to find out...although at Taste of Lexus the course is rather limited. Still, no fussy salesperson in the way! Or traffic!
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