[Overlander23]

Pretty sure it's only good for blipping the throttle to match revs for downshifts... but apparently it's very adept at getting it exactly right.

Originally Posted by samborambo

How did the Nissan shift matching control work? They must have had a brake on the crankshaft or flywheel.

Sam.

[DavidDymaxion]

2nd try on this post!

There are some other factors that will lessen the clutchless energy savings advantage, and could even make it have worse efficiency. This is even more pronounced for some of the points for a direct drive (single gear) freeway capable conversion.

• Without a clutch, you are more likely to lug the motor rather than shift, and be running it at a lower efficiency rpm.
• You lose more speed while shifting clutchess, that you'd have to reaccelerate to get back. This would be especially bad up a hill.
• With clutchless you'll be more likely to take off in 2nd gear rather than first, extending the time you are in current multiplication mode, which is not as efficient as higher rpm. Lesser motor efficiency at low rpm compounds this problem.
• You can get back a little bit of energy if you keep the motor spinning until you need to take off again
• Regen can be increased by downshifting
• A clutch can let the motor idle. There is a well respected EVDL EVer (Roland) that claims to get better range idling the motor when stopped! While I'm not sure about that myself, but it is interesting food for thought.

Most of these events would be brief and clutchless could be more efficient. At the moment the clutch lets you run in a lower gear (or downshifting isn't worth the trouble clutchless), though, then the clutched car could get better efficiency. It would depend on your driving cycle, if you have hills, if you have regen, etc.

[Overlander23]

Here's the rev matching regen thread... though there's not much info in it.

http://www.diyelectriccar.com/forums...ad.php?t=37764

Originally Posted by samborambo

Did he? Someone poke Eric please and get his input.

[martymcfly]

If you are concerned with the weight of the clutch, there are companies that manufacture light weight clutches. I had a Goldstar in a mini-stock that weighed in at 12 pounds. There are other light weight clutch options too. Some guys used a ram coupler. I have often thought about using an electric clutch, like off of a a/c compressor, or a air activated clutch like the radiator fan off of a Kenworth. Clutch weight can make a big difference in performance. Not only the weight, but the diam.

Clutch weight can make a big difference in performance.

If you are concerned about that 1/100th of a second time in a 1/4 mile run. For going to work or to get some groceries the weight of the clutch will make no difference in performance and distance.

Pete

[Dave Koller]

Originally Posted by gottdi

If you are concerned about that 1/100th of a second time in a 1/4 mile run. For going to work or to get some groceries the weight of the clutch will make no difference in performance and distance.

Pete

I second that too

[dtbaker]

Originally Posted by Dave Koller

I second that too

I'll 'third' it... having a clutch makes it a lot easier for 'untrained' drivers too. I'd much rather replace a clutch disc than a tranny chewed up from bad shifts.....

Unless you are doing lots of accelerations, where speed is critical, that weight will not be noticable.