Det. Mickylaren

And how it relates to the automatic transmission...
and what "direct mechanical lockup" has to do with all this...

Thanks!

Silver Stealth

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Shaun

Damn, beat me to it!

Det. Mickylaren

In an automatic transmission car with a manual shifting function (say, for example, a 325i) the reason you can floor it in 3rd gear while moving (while in manual mode) and see the engine rev a thousand or so rpm while still not getting a substantial kick in the back is because that is the torque converter "slipping." Correct?

And, then I get to the real reason for my quesiton. The CVT doesn't use a torque converter. It uses a clutch, correct? Then, if you put the car in "3rd" (manual mode) and floor it, the reason you don't get that rev is because the clutch is engaged and the engine is directly connected to the transmission, so any increase in rpms is accompanied by a proportional increase in vehicle speed.

And so, on a CVT, when you floor it from a stoplight, part of the intial lag (turbo lag aside) is from the clutch engaging, right?

Someone tell me if I'm on the right track here...does this make sense lol?

nexlvl, Dean@Evil U.

a CVT is a completely different animal. While I'm not positive about it's interface with the engine, I do know that by selecting manual mode you effectively tell the computer to lock the tranny into a predetermined ratio, so yeah any gain in rpm's would result in increasng speed.

Det. Mickylaren

The CVT sceneraio described in my previous post should be read totally ignoring the "continually variable" aspect of the CVT transmission. I am only talking about the tiptronic mode, which preselects ratios. In that sense, it is similar to a manual because it uses a clutch(es?) and no torque converter, and there is a direct connection between the engine and transmission while in motion at all times.

nexlvl, Dean@Evil U.

The "multi-plate clutch" that links the CVT to the engine only "slips" durring take-offs and even then, if it senses that the driver wants a quick launch it will slip very little and lock very quickly. But in motion and w/ the tranny in tip mode: yes, you'd be driving what is functionally a manual tranny, if not theoretically.

Det. Mickylaren

I guess the only difference is that there is no disengaging of a clutch during shifts.

nexlvl, Dean@Evil U.

Functionally yes, but there are advantages to having control over a clutch.

Det. Mickylaren

I just wanted to be able to correctly explain to my friend why his RSX revs a little while in tiptronic gear 5 and mine doesn't at all.