Max Acceleration from Honda's 7-speed CVT

[Eyke]

extracted from TOVA's Honda City review (asia.vtec.net/article/2003City2/index.html:

 

 

For the driving enthusiasts, the 7-speed mode is the key to overcoming whatever shortcomings the operating characteristic of the CVT program has. Again, I find that best results are obtained via a combination of S-mode and 7-speed mode. For acceleration from a stand-still for e.g., I found that the best technique is to get into 7-speed mode (from S-mode). Then press the downshift button once. This moves the 7-speed mode from an auto to a manual shift option. And at standstill, the CVT will be in 1st gear. Now floor the throttle and the CVT behaves exactly like a regular gearbox with a very high geared 1st gear. The car accelerates at a good pace - maximum drive is available at the front wheels since the gear ratio is fixed. We need to observe the tacho carefully now because we want to get the CVT out of 7 speed mode just immediately before the CVT shifts into 2nd gear. This will be around 5500-5800rpm. So once engine revs hits 5500rpm, press the 7-speed button to switch back into S-mode. We need to press when the tacho needle reaches 5500rpm because of possible delay in reflexes. If we try to switch at 5800rpm, it may be too late and the CVT would probably have switched to 2nd gear. But if we time it just nicely, the engine revs stays at around 5800rpm for as long as we keep the throttle at WOT. This immediately places the CVT at the highest possible gear ratio for the speed the car is now travelling at and thus ensures maximum acceleration. So, from standstill, getting into 1st gear allows us to get to max engine revs as fast as we can without going through the stage where we are accelerating but the CVT is slipping the gears at the same time. And once at max revs, we will have max acceleration for as long as we want. This is the key to the City's max acceleration from standstill. When I use this method, I find I was easily able to pull ahead of the general traffic at the toll-gates and traffic lights.

 

The same technique can be used to good effect for extracting maximum acceleration from a 'rolling start'. For example, when I later needed to overtake another car in the same trunk road as above, what I did was I switched to S-mode and then into 7-speed mode. Next I downshift to the lowest possible gear ratio. The 'idiot-proof' designed into the CVT 7-speed mode is very useful here as I just have to keep pressing the downshift button until the CVT won't downshift anymore because any further downshifting will over-rev the engine. Thus when this is done, the CVT gearbox would be running at the lowest possible gear for the car's speed and thus the highest possible fixed gear ratio. Now I cut out to overtake the car and floored the throttle. Maximum drive is transmitted to the front wheels since the gear ratio is fixed. There is no interference from slipping gear ratios. Engine revs climbs to 5500rpm and I switch back to S-mode again (this means we have to keep an eye on the tacho and the road as well so do this with extra care !). With engine revs at max (~5800rpm), we now have maximum acceleration. With this technique, overtaking was done much more effectively and without any drama. Certainly I did not over-commit at any of the overtaking manuevres I did when using this technique.

[Mondeost220]

[Mondeost220]

does this applies to the CVT of the earlier batch of ES series civic?

[Eyke]

ES Civic CVT don't have 7-speed manual mode, so it's not applicable

[Mondeost220]

icic..i reckon ur a honda fan?

[Eyke]

Yeah, love the Fit/Jazz, Integra Type R