I’ve been following a few conversions and it seems that there is a conflict about retaining a functional clutch. My question is: Do the popular DC motors, intended for EVs, have a thrust bearing to handle the front to back loading that a clutch would place on it.
That’s a great question. One I don’t have an answer for. But I do know that over the years lots of people have built setups that retain their flywheel and clutch and have not experienced any issues from that.
Unlike an ICE setup, you only would use the clutch to assist in gear changes, which minimizes the duty cycle that such a bearing (or lack thereof) would have to be subjected to.
I’m more concerned with the additional rotational mass of the flywheel/clutch/pressure plate than I am the loading that would be present on the motor’s bearings when the clutch is disengaged. Maybe it’s just me, maybe I am concerned for no good reason, but it does take a little more oomph to turn that large diameter weight on the shaft than it would without it. What I wonder really is would it be easier to ‘float shift’ the transmission with or without that flywheel being on there…
[QUOTE=TX_Dj;3018]
Unlike an ICE setup, you only would use the clutch to assist in gear changes, which minimizes the duty cycle that such a bearing (or lack thereof) would have to be subjected to.[/QUOTE]
I just bought a manual car today to convert, and I’m not used to driving manuals anymore. Is it true then that an electric car won’t stall? Or would putting it into gear and then driving kill your transmission? (Not letting up on the clutch while pushing the accelerator like with an ICE, but pushing the clutch, shifting into first with the right foot on the brake, letting out the clutch completely, and then using the accelerator.)
I would just get a motor that had enough rpm range and power to just lock the tranny into one gear. Some of the kits I have seen come with a one speed tranny so it isn’t uncommon. As far as using the clutch to shift. You don’t really need it to shift. You will just wear your blocker rings depending on how well you match your rpms.
Isn’t it more efficient to use all of the gears? Or would I be able to do everything in 5th gear?
If I don’t use the clutch, wouldn’t I grind down the gears? I’ll be honest and say I don’t know a whole lot about manual transmissions, but I would think that it wouldn’t work without a clutch.
For one thing you wouldn’t use 5th gear. You may at the most use 3rd gear. Electric motors are most efficient at the upper end of their speed rating. If you run an electric motor at the same speed as you do your gas engine its hp and efficiency are going to suck as well as pull a lot of amps. The guys I have seen lock their transmissions down usually do it in 3rd gear. Most of the single speed trannys for electric cars I have seen have a 10 to 1 ratio. The main thing you would have to watch on using a clutch with an electric motor is make sure the clutch can handle the rpm. Your motor might be able to handle a whole lot of rpms but your clutch might turn to cotton candy before then
As far as grinding gears thats why I said you would have to match rpms and it will wear on your transmission more. I could drive my car all day only using a clutch to take off but it would be hard on the transmission.
[quote=Caps18;3084]Isn’t it more efficient to use all of the gears? Or would I be able to do everything in 5th gear?
If I don’t use the clutch, wouldn’t I grind down the gears? I’ll be honest and say I don’t know a whole lot about manual transmissions, but I would think that it wouldn’t work without a clutch.[/quote]
This is a great video on the subject:
[ame=“http://www.youtube.com/watch?v=mCwXfqua84k”]http://www.youtube.com/watch?v=mCwXfqua84k[/ame]
It concerns clutchless shifting in an electric Delorean.
-enganear
That looks like how I imagined it to be, and is exactly the way I wanted it to be. I’m not very good at driving stick and have a difficult garage to get into with a manual. But I still don’t quite understand the mechanics of the transmission and how he clutch works (and why it doesn’t grind the gears when shifting in EV mode)
You can easily pull many manual transmissions out of gear without using a clutch when there is little pressure (acceleration or engine braking) being put on the transmission by the motor.
The design of the transmission also is a factor. On many motorcycles, especially sportbikes, the transmission can be tapped between gears without using the clutch.
I shift the electric Porsche up and down with no problem; the clutch went in the trash.
tommyt
What about wearing out your syncros faster? I’ve heard that could be a problem but I’m not sure how many miles people with clutch designs have gone to prove or disprove all the pros and cons of each setup.
[QUOTE=bblocher;4759]What about wearing out your syncros faster? I’ve heard that could be a problem but I’m not sure how many miles people with clutch designs have gone to prove or disprove all the pros and cons of each setup.[/QUOTE]
I plan on shifting a lot less. Since you dont need to got to first to start, thats one shift you do at every stop that is eliminated. Second you can wear the syncros with bad shifting habits anyway, (with ICE and clutch). The additional wear may shorten life by 5-10%, (most transmissions are expected to last 100,000 - 200,000 miles), or more. With carefull shifting, and good lubrication they can last >1,000,000miles. Originally I planned on retaining the clutch, again the added load may shorten life of motor bearings, but by what percent? Is it significant? After reading more about it I decided it wasn’t worth it to do the extra machining to retain the clutch. The only added functionality is to have an additional disconnect to the drive shaft, (but you may fry your motor if you use it under load!). An EPO button serves the same purpose and drops all power, (safer). I have shifted clutchless with the ice, it just takes timing, and a slight lifting of the accellerator to drop into the next gear. One advantage is the electric motor doesn’t stall if the RPMS drop too low, and it free spins when not under power, a little patience should allow movement between any gear.
From what I understand, there in no conflict in retaining a clutch in your conversion. I’ve driven in a couple of cars that use clutches and they operate fine. What it comes down to is your particular application and needs as well as your philosophy.
Everytime the clutch question comes, you see the different camps come out to argue their opinion about what is best. But I believe that what is best is what works for your design and needs and wants.
There are successful conversion that have used clutches, that are clutchless, that have pinned the transmission in a fixed gear, that have taken out the transmission and used an aftermarket one or two speed gearbox, that have direct drive…so there are many possibilities.
I will say there is a good argument for keeping a shiftable multi-speed transmission for efficiency reasons, but then again, maybe if you only do street driving this will not affect your situation as much.
With more particulars about your conversion, people might be able to offer more specific advice. there are many variables.
Good luck.
[QUOTE=enganear;3246]This is a great video on the subject:
http://www.youtube.com/watch?v=mCwXfqua84k
It concerns clutchless shifting in an electric Delorean.
-enganear[/QUOTE]
Hey, that’s my video! I just joined the group. There are reasons to keep the clutch and reasons not to. In a gas engine car you need the clutch to start off because the engine is always turning. In an electric car you don’t have that problem. As I see it you’d only want a clutch if you absolutely had to shift as fast as possible, ie. you are drag racing or you have some special fear that your controller may fail full on. Other than that I say, go clutchless!
Dave Delman
eLectricDeLorean.com
evalbum.com/1482
Can someone recommend good hub motors to buy? That way i wouldnt need gears or a clutch or even a diff.
Update I have been driving my “clutchless” conversion for several weeks. The clutch went in the trash, I dont even miss it. The only problem is when I park in 1st it takes a few seconds of wiggling to get it to drop into reverse. That is the only time I remember you need a clutch to shift.
I have put over 2500 miles on my Saturn and no problem without a clutch. I just let off the go pedal and shift the sincromeshers take care of the rest and voila I am in the next gear, I don’t rev it up while in neutral like Engineer Bill does either it just goes in. I let other people drive my car also and rarely they miss a gear. Downshifting is the same, also I start out in 2nd gear and it is good to 45 mph.
I’m keeping the clutch & 5 speed
it’s more work , it’s more weight
I’ve polled many and decided to keep the clutch. I feel it will be an advantage when racing the worlds fastest electric delorean
I’d vote for no clutch, to save weight. Since you can go either way. It would save on money to get the clutch to work correctly.:rolleyes: