View Dunkv's first 2010 Jazz I-shift trip in a larger map
So, what was it like then? CVT to I-SHIFT? The short answer is slightly scary. The CVT required so little throttle and rewarded you with a gentle and consistant acceleration or deceleration through engine braking. IShifty doesn't have an infinite number of gears between the lowest and the highest - only six. So there are going to be some very noticable differences for CVT drivers. Ex-manual, automated manual and non-CVT drivers will not really appreciate this difference.
Here is how I would typically accelerate to 60MPH on the level in my previous CVT in light traffic from rest. Select Drive, gently accelerate engine speed from idle to 2200 rpm over a period of 20 seconds. Initally the engine speed would move to 1200 and remain there until the maximum road speed in the highest ratio was achieved (approx 35MPH) then I would (intuitively) increase the engine speed gaining a matching increase in road speed until 2200 rpm was reached and 60 mph achieved. This is possible by the gearbox changing the pulley sizes to give increasingly higher ratios by going through many steps (although probably not than 30 - a guess - or more but certainly not perceptable as "gears").
In the I-SHIFT there is an immediate lack of gears. Only six. Therefore there is a need to return to the less refined sawtooth engine speed relative to a linearly increasing roadspeed model. So like non-CVT automatics, automated manuals (like I-SHIFT) or manuals, you have to accelerate the engine in repeated bursts to gain speed. So the 0 to 60MPH goes 1st gear idle to 2000RPM, 2nd gear 1000RPM to 2000RPM and so forth.
This isn't all straightforward because the I-VTEC can do clever things with the engine intake valve opening times to increase torque allowing more higher gears to be selected earlier than would have been the case in the previous i-DSI engine used in the CVT Jazz I had. Although the i-DSI did have a clever mechanism of firing its twin spark plugs per cylinder either at the same moment or staggered to gain torque too.
So in short you have to give the I-SHIFT a lot more throttle and assert more revs in regular bursts to gain speed even. This is really only an issue for Jazz CVT and other CVT experienced drivers.
Today's conclusion: I-SHIFT does seem a giant step backwards from CVT but I believe issues with:
- gearbox service life (it needed high quality lubricants, careful servicing staff)
- apparent emission targets
- almost universal motoring journal dislike.
So, I am going through the process of relearning the sawtooth approach to gaining speed. I miss the silky smooth, low reving CVT but don't get me wrong, there is lots right about the 2010 Jazz and note the I-SHIFT isn't totally awful. It's just that ex-CVT folks will have to remember life before their CVT days :)
My own experience of CVT life expectency: My last Jazz CVT had travelled 115 000 and although there was a slight sluggishness with the engagement of the start-clutch when moving off from 110 000. It drove perfectly. Of course I never stressed it, regularly had the CVT oil changed with the Honda CVT-F oil - the only transmission oil that should ever go into your Jazz CVT transmission.
