Transmission i shift information - Page 3

allan40alt · 23rd January 2007, 17:16

Quote:

Originally Posted by Maldax

Their boxes come out a little more expensive than a Civic!

Yes, and the're lucky if they last much longer than a few hours usage!

TTDegs · 24th January 2007, 00:34

having driven my last 2 cars as automatics, and as 1 of them was the superb Audi DSG box, I have a couple of comments, if that's ok...

My wife's 206 Auto was, I thought, pretty good - certainly compared to the much older auto cars which was all I had to compare it to.
Generally always in the right gear (not struggling, not revving it's guts out).

The DSG in my TT was, in a few words, a marvel of modern engineering

BUT - it was still possible to catch them both out.

Ultimately, these boxes (inc I-Shift) are automatic in as much as they have pre-programmed stratgies for working out what gear they should be in at any one time.
They are based on any number of inputs, but 2 of the most important relate to revs and throttle position.

For example, in the TT, from standstill, if you just pressed lightly on the gas, it would have changed up to 6th gear by the time you got to 30mph (and you wouldn't have noticed the gear changes)

However, if you floored it from stopped, it would still be in first at 30 and you would be busy hanging on and

ing LOL But the change to 2nd was then more noticable.

With I-Shift jerking from 1st to 2nd - think about what it is trying to
do.
Reasonably high revs, it 'dips' the clutch, and engages 2nd as soon as possible.
At which point, the wheel rotation tries to slow the engine down to match the road speed.
So it jerks.

Lifting off slightly means that the engine revs are already dropping slightly as the clutch dips, and probably at slightly lower road speed.
So the jerk as the clutch re-engages and sorts out road speed vs engine speed is less.

hope that makes sense!

IWANTACIVIC · 24th January 2007, 02:41

love to have a go in a i shift , ill have to go and sweet talk the dealer or my friend to let me try his jazz , but am i right the i shifts not on the 2,2 ?
is there to much torque for the i shift ? love the idea of paddles 7 speeds Sime's a bit much ? or is it about right ?

allan40alt · 24th January 2007, 08:55

Quote:

Originally Posted by IWANTACIVIC

love to have a go in a i shift , ill have to go and sweet talk the dealer or my friend to let me try his jazz , but am i right the i shifts not on the 2,2 ?
is there to much torque for the i shift ? love the idea of paddles 7 speeds Sime's a bit much ? or is it about right ?

I don't think the Jazz has the same system. They have CVT which is very different.

I-Shift is for the 1.8 VTEC.

Charles_Harding · 24th January 2007, 14:13

Quote:

Originally Posted by Maldax

Their boxes come out a little more expensive than a Civic!

You took the words right out of my mouth!

"There's nothing wrong with me that re-incarnation won't cure!"

Charles H.

MC Hammer · 24th January 2007, 19:37

As TT so correctly points out the i-shift is a manual box with an automatic change system.
The jerky gearchange will of course happen in a manual if you keep the throttle at a constant level and change gear. I imagine it would take a little bit of getting used to, but possible to drive smoothly.
Not having driven one, I'm not sure if this is possible on today's roads.

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This thread is about: i shift information, it's in Engines and Transmission at the Honda Civic forum Civinfo; Originally Posted by Maldax Their boxes come out a little more expensive than a Civic! Yes, and the're lucky if they last much longer than ...

24th January 2007, 00:34	#42 (permalink)
TTDegs Super Moderator Civinfo master Join Date: 4th August 2006 Location: Cardiff Posts: 5,638 Thanks: 0 Thanked 1 Time in 1 Post iTrader: (0)	having driven my last 2 cars as automatics, and as 1 of them was the superb Audi DSG box, I have a couple of comments, if that's ok... My wife's 206 Auto was, I thought, pretty good - certainly compared to the much older auto cars which was all I had to compare it to. Generally always in the right gear (not struggling, not revving it's guts out). The DSG in my TT was, in a few words, a marvel of modern engineering BUT - it was still possible to catch them both out. Ultimately, these boxes (inc I-Shift) are automatic in as much as they have pre-programmed stratgies for working out what gear they should be in at any one time. They are based on any number of inputs, but 2 of the most important relate to revs and throttle position. For example, in the TT, from standstill, if you just pressed lightly on the gas, it would have changed up to 6th gear by the time you got to 30mph (and you wouldn't have noticed the gear changes) However, if you floored it from stopped, it would still be in first at 30 and you would be busy hanging on and ing LOL But the change to 2nd was then more noticable. With I-Shift jerking from 1st to 2nd - think about what it is trying to do. Reasonably high revs, it 'dips' the clutch, and engages 2nd as soon as possible. At which point, the wheel rotation tries to slow the engine down to match the road speed. So it jerks. Lifting off slightly means that the engine revs are already dropping slightly as the clutch dips, and probably at slightly lower road speed. So the jerk as the clutch re-engages and sorts out road speed vs engine speed is less. hope that makes sense!

24th January 2007, 02:41	#43 (permalink)
IWANTACIVIC Supporter Magic Rear Seat Join Date: 16th September 2006 Location: LINCS UK Posts: 658 Thanks: 0 Thanked 0 Times in 0 Posts iTrader: (0)	love to have a go in a i shift , ill have to go and sweet talk the dealer or my friend to let me try his jazz , but am i right the i shifts not on the 2,2 ? is there to much torque for the i shift ? love the idea of paddles 7 speeds Sime's a bit much ? or is it about right ?

24th January 2007, 19:37	#46 (permalink)
MC Hammer Kids use a lot of space Magic Rear Seat Join Date: 16th June 2006 Location: UK Posts: 608 Thanks: 0 Thanked 1 Time in 1 Post iTrader: (0)	As TT so correctly points out the i-shift is a manual box with an automatic change system. The jerky gearchange will of course happen in a manual if you keep the throttle at a constant level and change gear. I imagine it would take a little bit of getting used to, but possible to drive smoothly. Not having driven one, I'm not sure if this is possible on today's roads.