8 speed

[mclarendriver]

Why in the world is there an 8 speed tranny In the lexus isf rm? That's a bit overkill isn't it?

 

[TenEightyOne]

That question's better directed at Lexus, isn't it? Or Plexus...

They obviously think it's faster, but they don't give a specific reason for 8 gears that I can see. There's a nice demo of the box on their site though...

This IS F's Sport Direct-Shift transmission uses a special lock-up clutch for improved responsiveness, plus a control system that enables virtually instant manual upshifts (as quick as 0.1 seconds) and blips the throttle on downshifts, while giving the driver full control over gear selection.

[Lexus Transmission Demo]

This should probably be in Auto discussion...

 

[saleenf5]

my guess is for better fuel economy, or because the car is so amazing it needs an 8th gear to handle it.

 

[Famine]

Why in the world is there an 8 speed tranny In the plexus isf rm? That's a bit overkill isn't it?

There's one in the stock Plexus IS F too. And one in the Pnissan Skyline 350 GT-8 - which was in GT4 with the same 8 ratio gearbox.

At least the Plexus one is useful - you won't reach a speed the Pnissan can accelerate in 8th at unless you drop it out the back of a Phercules.

 

[mclarendriver]

Haha. Yeah. Sorry. My phone did that. But. Its odd. Because its so hard to get 8th gear on most tracks that I've raced it on. I've tuned the top speed down to 193. And still only get to seventh on a .17 mile straight accelerating from about 40. So I guess ill take it down even more.

 

[VTiRoj]

It's good for fuel economy if you set 8th gear quite tall. Imagine only being at 1,000rpm when you're doing 100mph, you'd just be sipping fuel instead of chugging it down. For racing, you can make better use of the gears for each corner if you set the gears quite close, or obtain a higher top speed with longer ones.

 

[mclarendriver]

It's good for fuel economy if you set 8th gear quite tall. Imagine only being at 1,000rpm when you're doing 100mph, you'd just be sipping fuel. For racing, you can make better use of the gears for each corner if you set the gears quite close.

I guess that makes sense. I'm just used to six or seven speed gear boxes. Its hard to use all 8 gears effectively.

 

[Baggy Spandex]

It's embarrassing that I googled "Plexus" before I read to the end of the thread.

 

[OK8]

I read somewhere the IS F's engine is quite peaky so maybe 8 gears is a good thing.

 

[Moot]

8 speed pah! old tech.
Mercedes has a 9 speed auto.

It's a trend in modern autos, it provides comfortable seamless transitions to get to a final gear that is long.

 

[JER_CREST]

One of the Nissan Skyline sedans has an 8 Speed Transmission.

 

[Snake55wildcat]

while its only 7 not 8, the Suzuki Cervo SR has 7 gears with full transmission upgrade, and thats for a kei car, which is pretty insane in itself

 

[LilMcGinley]

Why doesn't your tranny have an 8 speed is the better question.

 

[toymdngn]

while its only 7 not 8, the Suzuki Cervo SR has 7 gears with full transmission upgrade, and thats for a kei car, which is pretty insane in itself

it's to make good use of the first 5 gears for getting up to speed (since the car is low powered) and 6th and 7th gears are really tall, since at 65+mph it only takes a couple HP to keep that speed.

 

[mclarendriver]

It's embarrassing that I googled "Plexus" before I read to the end of the thread.

Facepalm! Course if my phone wasn't stupid that wouldn't have happened.

 

[The Stalker]

8 speed pah! old tech.
Mercedes has a 9 speed auto.

It's a trend in modern autos, it provides comfortable seamless transitions to get to a final gear that is long.

My Mercedes has 12 gears and two reverse gears. Oh, and 8 wheels ;-)

 

[mclarendriver]

My Mercedes has 12 gears and two reverse gears. Oh, and 8 wheels ;-)

Wouldn't that make it rather heavy?

 

[Raven_WET01]

It's good for fuel economy if you set 8th gear quite tall. Imagine only being at 1,000rpm when you're doing 100mph, you'd just be sipping fuel instead of chugging it down. For racing, you can make better use of the gears for each corner if you set the gears quite close, or obtain a higher top speed with longer ones.

Please learn how cars work.

Thanks.

 

[mclarendriver]

Please learn how cars work.

Thanks.

you couldn't do it at 1000rpms. But maybe 2000 or 2500. I used to have a thunderbird in real life that did 70 at 1800. with an automatic 8 speed I'm sure it could do that. But it wasn't an ordinary thunderbird. It was a 94 lx with the 4.6l V-8. And a t3000? Torque converter. It was there OBD2 test car.

 

[The Stalker]

Wouldn't that make it rather heavy?

Yep! 8500kgs of heavy. Sadly it'll only do 56mph.

 

[sumbrownkid]

Pfft who wants 8 gears when you can have an infinite amount of ratios from a CVT tranny?

 

[mclarendriver]

Id rather have a paddle shifted 8 speed. Its more fun to drive than something I can't shift.

 

[PureLogic]

and the 2J could do the same speed at 3rd gear lol

 

[apex28del]

The world needs 8 speed gearboxes like how it also needs 8 string guitars.

They're both technological wonders that I can't figure out for the life of me.

 

[Bushby_23]

IRL its a fuel saving and nvh measure. In racing, I really dont think 8 gears have much use...

 

[mclarendriver]

8 gears could be useful in a race if they were really close together to give you better acceleration out of a corner. While still maintaining a some what good top speed.

 

[counter345]

I reckon it's something to do with hitting the torque peak more often.

 

[sumbrownkid]

Eight gears in a racing transmission wouldn't make much sense in the reliability department.

One of the last things a team wants is a complex transmission that's broken.