# Why the flywheel?



## Woodsmith (Jun 5, 2008)

Not having done either yet I can only explain why I decided I will keep the flywheel.

My intention is to lighten the flywheel and mate it to the motor and also use the clutch. My reasoning is that the syncromesh is only designed to syncronise the speed of the gears and the clutch friction plate. The friction plate is relatively light and so the syncro rings can cope.

The motor, if it is a direct connection, will allow clutchless changes but there is the extra mass of the spinning armature for the syncro rings to have to cope with. That means that it will take longer to syncronise the speed and effect the gear change. That will lead to extra wear on the syncro rings.

From the videos I have seen of clutchless changes on an EV the change is very slow and sometimes needs several goes to get the gear to select. I have seen this lead to a frustrated 'slamming' of the gear stick in at least one video and that is really hard on the gear box.

Ultimately, for the slight weight gain for keeping the flywheel and clutch I think you save the gearbox from a lot of unnecessary wear. From experience I would rather change the clutch then rebuild a gearbox. Also it means that the transmission components are only doing the jobs they were designed for.

I know that there are people who say that a clutchless change is possible with an ICE car. I know it is and my driving instructor back in the 80's taught me how to do that. However, I think it is easier to listen for the correct speed of a noisy ICE then the silence of an electric motor. Also I wouldn't like to be blipping the throttle on an unloaded motor as it could over speed very easily hence some converters will fit a neutral lock out to prevent that happening inadvertantly.

Anyway, that is my reasoning. I'm sure others will have their thoughts too.


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## O'Zeeke (Mar 9, 2008)

I recently removed the clutch/flywheel setup from my 0.0 mustang and went direct for several reasons, not the least of which eliminating 65 pounds of rotating mass (78 lbs with t.o.b., fork) which has made a noticeable difference in acceleration (no stats yet) and I expect some increase in range as well. Not concerned about synchro wear as it will drop right in with a little practice and a lot of the time i just leave it in 3rd anyway. Also someone here has a thread on thrust/lateral load exerted on the rear motor bearing while depressing the clutch and that got me thinking. Just my 0.02$


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## Woodsmith (Jun 5, 2008)

O'Zeeke said:


> Also someone here has a thread on thrust/lateral load exerted on the rear motor bearing while depressing the clutch and that got me thinking. Just my 0.02$


Interesting point.

I wonder if it would be worth placing a phospher bronze thrust bearing behind the adaptor to transfer the axial thrust to the motor case for the brief moment of declutching?

Maybe replacing the bearings at both ends of the motor with taper rollers?


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## Jimdear2 (Oct 12, 2008)

Woodsmith said:


> Interesting point.
> 
> I wonder if it would be worth placing a phospher bronze thrust bearing behind the adaptor to transfer the axial thrust to the motor case for the brief moment of declutching?
> 
> Maybe replacing the bearings at both ends of the motor with taper rollers?


Woodsmith,

The concensus after a bit of research on bearing numbers and contact with motor Mfg.s was that the type bearing and the end cover designs used in these purpose built motors have sufficient lateral thrust capibilities to handle de-clutching loads. 

Even those using Hi Lo motors have not reportrd failures due to de-clutching loads. It appears that modern bearing deaigns can handle these loads.

Hope this helps,
Jim


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## fugdabug (Jul 14, 2008)

geoffscott1 said:


> Why do nearly all conversions keep the flywheel (sometimes lightening it). Doesn't it just add unnecessary mass right where it hurts the most? Why not just couple straight to the tranny?


Due to the fact that most have a clutch... maybe?... P.S. the weight of a flywheel is negligible, unless you are using only a direct drive system, which for practicality is not used in most on-road vehicles. 
The real weight concern comes in battery packs and unnecessary equipment left on the car... gas tank, exhaust, extra seating... ~8)...


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## DavidDymaxion (Dec 1, 2008)

I wanted to keep the clutch, and the clutch hangs on the flywheel. I have steep hills to climb, and want to shift quickly for racing. You can also get more regen by downshifting. I did get a lighter flywheel and pressure plate to reduce rotating mass.

A Camaro conversion I rode in shifts very slowly without the clutch -- but you don't need to shift very often. My Porsche does not like shifting without the clutch, it is hard to get it to shift without grinding.


geoffscott1 said:


> Why do nearly all conversions keep the flywheel (sometimes lightening it). Doesn't it just add unnecessary mass right where it hurts the most? Why not just couple straight to the tranny?


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## Stunt Driver (May 14, 2009)

My Fiero had clutch problem when I got it, so for a while I drove it on ICE without clutch. Well, even with my 10 years on stickshift experience - I was very frustrated sometimes. Especially going from 2nd to 3rd. and downshifting. 
So for my convertion with limited voltage and so torgue - decided to keep clutch. Seems that compared to all the rotating parts weight of clutch assembly with flywheel is misarable. Tires for example have bigger weight AND bigger radius - so much bigger momentum. 
Since my EV is not built for racing - most probably I won't notice the extra .001 sec accelerating, but will value comfort.

Plus, talked to some local fooks who've done convertions a while ago with out clutch - both advised to keep it


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## Forklift Guy (Apr 20, 2009)

I originaly started to make a clutchless adapter, at the same time, was looking for an aftermarket tach with a shift light, to be used with a RPM limit circuit. The only tach setup i found was a tachometer adapter kit for diesel engines that used a magnetic pickup on the flywheel, the converts it to a tach output for any aftrmarket tach. I had to install the flywheel to run the tach, so i went with the clutch/flywheel setup with my motor adapter..


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## ga2500ev (Apr 20, 2008)

Stunt Driver said:


> My Fiero had clutch problem when I got it, so for a while I drove it on ICE without clutch. Well, even with my 10 years on stickshift experience - I was very frustrated sometimes. Especially going from 2nd to 3rd. and downshifting.


I did do some clutchless practice on my Corolla. It's doable but a bit frustrating because you had to match speeds before
the gear would drop in.



> So for my convertion with limited voltage and so torgue - decided to keep clutch. Seems that compared to all the rotating parts weight of clutch assembly with flywheel is misarable. Tires for example have bigger weight AND bigger radius - so much bigger momentum.
> Since my EV is not built for racing - most probably I won't notice the extra .001 sec accelerating, but will value comfort.
> 
> Plus, talked to some local fooks who've done convertions a while ago with out clutch - both advised to keep it


I'm curious to why that's the case. I had always planned to go clutchless, but now I see I may have to rethink the decision if there is actually a real issue.

From the 2 years of living on this forum I gathered 4 main pieces of information about clutchless operation:

1. The necessity of the clutch is lessened because until an ICE which stalls at 0 RPM, electric motors have no such issue.

2. The extra rotating mass issue already discussed here.

3. That because electric motors have such a wide power range and that torque is maximixed at 0 RPM that shifting isn't as critical as a ICE vehicle. If you're willing to live with slower acceleration, that functioning strictly in 3rd is easily done.

4. That because of the solid coupling design, that a clutchless conversion is easier to do.

The only two downsides are that shifting is a much slower operation that clutching, upwards of 10 seconds to get the syncros to mesh and that as a non standard shifting method, drivers new to the EV may have an issue. But both are mitigated by point 3 above. If you don't have to shift much, then there's no problem if the shift time is slower.

Now that's what I've learned so far. Is anyone willing to refute these points? Am I missing something big?

ga2500ev


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## Lordwacky (Jan 28, 2009)

I think really it comes down to just a handful of factors the big one being the quality of the transmission/sykros you will be using.

I used to drive an old ford escort (1987) and a 1980 toyota pickup I was able to shift gears once I was going relatively easily with out using a clutch. BOth of which would probably work fine clutchless as long as you weren't revin' too high.

I currently drive a 1999 Volkswagen A4 jetta and I have tried many times to shift clutch less no luck, its even hard with the clutch some times. I would never dream of doing a Clutchless conversion with that POS transmission.

My opinion, if you are going to be laid back driving around town at 35 -45 MPH with limited hills get a good transmission and go clutch less. If you are going to be doing freeway driving or racing where you need to get up to high speeds quickly go for the clutch. Or if your transmission isn't very good, go for the clutch.


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## DavidDymaxion (Dec 1, 2008)

There are other factors.

Your electric motor has poor efficiency at very slow rpm. If you need to stop-and-go up a steep hill, but then get up to 2nd gear speeds you'll be tempted to just leave it in 2nd gear, heating the motor more than necessary. This is especially bad if you only have the internal fan to cool, low rpm = less cooling.

If your controller is jerky, a clutch can smooth the takeoff.

These are courtesy of Bill Dube:

Having a clutch is safer. A tranny is designed to lock into gear under torque. Suppose you had the controller go full on up a hill, and your electric disconnect didn't work. With the torque of hill climbing you might not be able to pull the car out of gear. A clutch acts as a "mechanical fuse."

A clutch can slip before the torque gets so high it damages other components.

The springs in the clutch provide some vibration isolation, like when you hit a pothole less of that shock will get transmitted to the tranny and motor.



ga2500ev said:


> I did do some clutchless practice on my Corolla. It's doable but a bit frustrating because you had to match speeds before
> the gear would drop in.
> 
> I'm curious to why that's the case. I had always planned to go clutchless, but now I see I may have to rethink the decision if there is actually a real issue.
> ...


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## tj4fa (May 25, 2008)

ga2500ev said:


> ...
> The only two downsides are that shifting is a much slower operation that clutching, upwards of 10 seconds to get the syncros to mesh and that as a non standard shifting method, drivers new to the EV may have an issue. But both are mitigated by point 3 above. If you don't have to shift much, then there's no problem if the shift time is slower.
> 
> Now that's what I've learned so far. Is anyone willing to refute these points? Am I missing something big?
> ...


The only point I would refute is the Upwards of 10 seconds thing.

Holy crap, if it took that long to shift between gears without a clutch, I would have put a clutch in LONG ago.

There is a lag but from normal shifting by a second or three (normal shifting is not power-shifting). I can get the motor/transmission to synchro just a bit quicker by giving the motor a couple hundred revolutions before dropping it into gear.

If I had to do it again, I would keep a clutch but only if I could lighten it CONSIDERABLY.


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## BradQuick (May 10, 2008)

I've been driving my clutchless Del Sol for about a week now. At this point, I'm perfectly happy not having a clutch. It does take two to three seconds to shift, but I don't have to shift often. I start in second and can go to 60 mph in third. Third is also fine for turning corners, so I only need to go back to second when I stop.

I kept the springs from the clutch, so I get the load isolation.

- Brad


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## Guest (Sep 8, 2009)

Clutch = Smooth shifting, Tranny saving, clutch disengage safety, Easy, Extra few pounds is nothing on a street driven vehicle for what you get. 

Clutchless = Harder on tranny and syncro's, no safety disengage, must think about each and every shift, extra few pounds removed make no real difference in a street driven vehicle. 

Even in a race EV I will retain my clutch/flywheel assembly.
Go with the clutch. Sure you can do it without and some are easier but over all you will be a very happy camper if you keep the clutch. 

Pete


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## fugdabug (Jul 14, 2008)

with about a year of experimentation and a lot of down-time due to this and that...
The flywheel is something I personally would like to keep for the mass in the application it is made for. I removed the gear-toothed ring from the outer rim. And I did machine about 3/8" inch from the 'counterweight cast into the back and into the back of the plate flush with the surface. (I have a transaxle out of a 92 Toyota with 5 spd transmission with a ES31B for a motor) with this configuration and its hydraulic clutch for me it is perfect for where I live:
That is the key in this discussion. Where you live. How many miles daily do you commute or drive on a regular basis? In my case I drive long distances to anything, and when I get there there is a lot of stop and go, construction, pedestrian traffic... so I need to be versatile. 2nd or 1st around town on average, 3rd or 4th for stretches of highway and freewheeling... A direct drive would be really good for high density areas I would think or racing... but for someone like me more rural (and we really need the tech out here) an ability to shift gears makes a world of difference. And the flywheel (which this thread is all about) is very important in making sure the shifting is SMOOTH... no flywheel is like having absolutely no synchronizers... tuff going.... and we who worked on 50's models three-speed FORD's have some knowledge of the importance of sychronizers... uuu goooddddd!


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## MJ Monterey (Aug 20, 2009)

In most racing applications a smaller diameter clutch is used. One to consider for an EV would be this one. A bit of $$ but light weight.

http://www.speedwaymotors.com/5-1-2-Inch-2-Disc-Racing-Clutch-for-2300-2000-Pinto,5872.html


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## lou-ace (Jul 21, 2009)

great O'zeek, we need to talk, I'm having a hard time designing a splined to 7/8" motor to trans. connector shaft please drop me a line in the e-mail area so we can chat.... thanks


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## RE Farmer (Aug 8, 2009)

Has anyone tried a hard anodized aluminum flywheel? This would save weight, and since EVs don't have to slip the clutch to get going, wear shouldn't be an issue.


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## DavidDymaxion (Dec 1, 2008)

I have one. http://www.fidanza.com/aluminum-flywheels.aspx . The flywheel has a steel wear surface where the clutch rubs it.

The Fidanza flywheel saved 2.8 lbs. The Kennedy engineering pressure plate saved 7.4 lbs. On my car more of the mass was in the pressure plate than the flywheel. Losing the ring gear saved 0.3 lbs (the ring gear just unbolts on my car). That's about 1/2 the weight of before.


RE Farmer said:


> Has anyone tried a hard anodized aluminum flywheel? This would save weight, and since EVs don't have to slip the clutch to get going, wear shouldn't be an issue.


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## Woodsmith (Jun 5, 2008)

RE Farmer said:


> Has anyone tried a hard anodized aluminum flywheel? This would save weight, and since EVs don't have to slip the clutch to get going, wear shouldn't be an issue.


I have cut up a 19mm thich aluminium disc to make my adaptor plate. The ebay seller has two more and I was thinking of getting one to machine into a flywheel on the same premise that I could get away without a steel wear surface.

I need to price up the cost of getting someone to machine the weight away from my steel flywheel compared to making an aluminium one from scratch.


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## DavidDymaxion (Dec 1, 2008)

I'd be really nervous doing that. I don't recall ever hearing about an aluminum friction surface -- maybe the properties of Al are bad for it. There are "no slip" clutches, you have to do a burnout to get going (I think they use copper). Even expensive exotic cars use steel for the brakes and clutch surface.

My Fidanza flywheel was $300 and was engineered for the job. Are you skilled enough to do all the engineering from scratch for a 6000 rpm part? How do you know that grade of aluminum won't fly apart? The shrapnel from an exploding flywheel can be lethal.


Woodsmith said:


> I have cut up a 19mm thich aluminium disc to make my adaptor plate. The ebay seller has two more and I was thinking of getting one to machine into a flywheel on the same premise that I could get away without a steel wear surface.
> 
> I need to price up the cost of getting someone to machine the weight away from my steel flywheel compared to making an aluminium one from scratch.


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## Woodsmith (Jun 5, 2008)

DavidDymaxion said:


> I'd be really nervous doing that. I don't recall ever hearing about an aluminum friction surface -- maybe the properties of Al are bad for it. There are "no slip" clutches, you have to do a burnout to get going (I think they use copper). Even expensive exotic cars use steel for the brakes and clutch surface.
> 
> My Fidanza flywheel was $300 and was engineered for the job. Are you skilled enough to do all the engineering from scratch for a 6000 rpm part? How do you know that grade of aluminum won't fly apart? The shrapnel from an exploding flywheel can be lethal.


Well, those are the things I would need to think about, however, it is all slightly hypothetical based on the assumption that the clutch doesn't need to slip much.

I wouldn't do it myself as I don't have a big enough lathe and I would rather an engineering company did it and balanced it all at the same time. I wouldn't just dive in with whatever I had but I would check the grade of the cheap off cut would be suitable first.
I could buy an aluminium flywheel for the MR2 but it cost a bit. Maybe making one will cost as much anyway.

Either way I need to get some machining done on a flywheel.


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## RE Farmer (Aug 8, 2009)

For my MG the Fidanza Al flywheel is 7# & $500-600. Stock is 16# and can be machined down to 8# (at least for ICE). Since EV doesn't need pulse absorption feature of flywheels, perhaps they could be machined lighter. 

Anodizing hardens the Al surface for increased wear resistance, and as I stated earlier EVs don't need to slip their clutches so the wear will be minimized.

As for as material goes, the Fidanzas use 6061T6, a std. aircraft grade Al alloy. Now I just need to check with my local machinist to see what his rates are to compare costs.


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## kixGas (May 2, 2008)

I have never really understood this. If the only advantage of going without a flywheel and going clutchless is it reduces rotating mass does it really make any significant difference? With everything else that is turning including the wheels and tires whose job it is to propel the 3000 lb vehicle how is shaving off 20 lbs going make a difference? Seems like there are a lot of negatives just to get a very small positive.


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## MJ Monterey (Aug 20, 2009)

Kixgas has brought up the opposites as practiced today, Full flywheel and clutch verses direct drive. Both work in an EV.

What is being discussed is what an optimum clutch/flywheel assembly would look like for EV applications that require one and how best to achieve it. 

Having crewed the same G-production ICE Spitfire with both a stock flywheel and clutch and then with the aluminum flywheel (steel insert) and small diameter clutch I can tell you the difference in acceleration/laptimes was amazing!

Back to EVs... An electric motor tends to drop RPMs slower than an ICE because it has no compression to slow the spinning mass. Slowing the spinning mass is necessary for smooth up shifts. 

If you look at down shifts, matching motor to driveline speed is even more problematic. Blipping the throttle is not the best solution because you may over speed the motor and blow the windings. A small amount of cluth slippage will bring the motor to speed quickly. Much more smoothly and more quickly if you have less rotational mass/momentum. Therefore our goal is the smallest lightest clutch that can get the job done.

Nothing wrong with the stock flywheel/clutch setup we are just chasing the ideal....


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## Stunt Driver (May 14, 2009)

I thought of lightening the flywheel - just wasn't sure it won't blow up after that. Even kept the pinion ring for the same reason. In Fiero flywheel is only 20 inch away from driver's back. And putting protective steel plates would be reduculus. 

My car is not top-end racing application - I don't think the whole flywheel assembly takes more than 5% of juice on very worst case. And it is always possible to remove later - no dimentions restrictions exist for clutchless coupler. I need to drive it for a bit to understand - do I really need to shift that often?


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## Guest (Sep 10, 2009)

You can lighten the stock flywheel. I will post photos of the turned vw flywheel

Pete


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## MJ Monterey (Aug 20, 2009)

It may not be a question of how often but how quickly you need to shift.

I would hate to be road pizza because I could not accelerate for a couple of seconds while shifting and get run over by a big rig. 

Maybe it's just a phobia I developed having a big rig "pushing" me on the on ramp and another rig just rolling along in the right lane who was not going to yield to the Honda 600 car....


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## Guest (Sep 11, 2009)

gottdi said:


> You can lighten the stock flywheel. I will post photos of the turned vw flywheel
> 
> Pete


Here is a stock VW flywheel cut and lightened for the electric motor. Works perfect. 










Pete 

The one on my motor is just about the same. Not quite as light.


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## Travdude (May 11, 2009)

That looks like a good idea Pete. So you took the stock flywheel to a machinist and asked them to turn the teeth off of it and lighten it? How much did it cost?


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## Guest (Sep 11, 2009)

Travdude said:


> That looks like a good idea Pete. So you took the stock flywheel to a machinist and asked them to turn the teeth off of it and lighten it? How much did it cost?


The one in the photo was done long ago but I did buy two that were already done. Not quite as much as these. The VW gear ring is removable. Remove the ring and then it is easy to trim down the flywheel. Take it down as far as you can go and still attach the pressure plate then take off some weight on the engine side. Leave the clutch face alone. The two flywheels I have are very light. One 6 lbs and one 9 lbs. The stock one I believe is like 24 lbs. I do not know how much it would cost. All shops are different. 

Pete


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## Travdude (May 11, 2009)

Ah, I did not know the tooth ring comes off. Good info! Thanks.


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## DavidDymaxion (Dec 1, 2008)

If you are just driving slowly, steady speed, it's just 20 more pounds. You'll give up 20/3000 = 0.7% of your range. At steady highway speed, where half your energy fights wind resistance, it's only 0.35%.

Now suppose you just do lots of first gear acceleration -- your life is stop and go traffic. Now that flywheel is geared weight. It's like the flywheel toy cars that are hard to push but then keep going for a while. First gear is around 12:1 or 10:1 for many cars. So the flywheel turns at about 10x the speed of the wheels, but it's diameter is about 1/2 that of a wheel. Then each pound on the flywheel acts like 12 pounds on the car! In second gear it's about 8 lbs, and in third gear it's about 5 lbs. However, stop and go means you stop as much as you accelerate, so it's only hurting your range 1/2 the time (assuming no regen), so on average it's like 6 pounds in 1st, and 4 lbs in 2nd. If you do just first gear stop and go, it could cost you (6*20)/3000 = 4% of your range (and about 3% in 2nd, and about 2% in 3rd). These would be worst case numbers.

In reality very little driving is constantly accelerating and stopping, so realistically your loss for keeping the 20 lbs of flywheel and pressure plate is only of the order of 1%.

For drag racers, however, it's a different story. They accelerate the whole time, and shaving a tenth or 2 off the time could be worth $500 for the lighter flywheel.



kixGas said:


> I have never really understood this. If the only advantage of going without a flywheel and going clutchless is it reduces rotating mass does it really make any significant difference? With everything else that is turning including the wheels and tires whose job it is to propel the 3000 lb vehicle how is shaving off 20 lbs going make a difference? Seems like there are a lot of negatives just to get a very small positive.


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## Woodsmith (Jun 5, 2008)

Possibly the issue for an EV is not so much wanting to keep the flywheel but wanting to keep the clutch.
Unfortunately, keeping the standard clutch also means keeping the standard flywheel in most cases. 

Although it can be made lighter most of the effect of the mass of a flywheel is due to the mass at its edge and it woild be difficult to reduce diameter due to the fixings for the pressure plate.
The overall weight would be much less of an issue if it was concentrated in a small diameter.

This is why some of us have been thinking of other methods of keeping a clutch but without the flywheel. Electric clutches as found on AC pumps would be nice if they could handle the torque and power. Cone clutches would be good but there doesn't seem to be off the shelf items that would do the job.
I've thought of breaking an overdrive unit to get at the cone clutch but it would mean a lot of re engineering to fit a long item in the bell housing and then having it hydraulic operated somehow with either its own pump or an external one.


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## kixGas (May 2, 2008)

thanks for the responses guys. I understand the reasoning for wanting to lighten the flywheel in racing applications and the goal of retaining a clutch in an EV. I just didn't understand why some people thought the benefit of not having a standard flywheel and clutch assembly was worth all the cons of direct coupling. However with the discussion intended for finding the ideal then there definitely a lot of possibilities out there. The Al plates with steel faces on them and the 5" clutch packs certainly would fit the bill if someone was willing to pay for it.
When lightening the flywheel- other than removing the gear do you also turn some material off the OD and the face?


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## Guest (Sep 11, 2009)

You can turn material off the out side edge and the back side. DO NOT TAKE OFF THE FACE if you intend to use the stock pressure plate and clutch disk. If you make a custom pressure plate and disk then you will need to remove material to match. If you machine off the face to clean it up then you must also take off the same amount to the pressure plate mounting face to keep the pressure plate measurements proper to stock. 

Pete


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## Guest (Sep 11, 2009)

> I've thought of breaking an overdrive unit to get at the cone clutch but it would mean a lot of re engineering to fit a long item in the bell housing and then having it hydraulic operated somehow with either its own pump or an external one.


And therein lies the rub. Why spend all that to re-engineer when it was already done in the first place. I agree to use a smaller lighter flywheel and pressure plate assembly and think that such could be built and used but built like stock but only smaller in diameter but not strength or durability or ability to hold when needed. It still has to hold all that torque that the electric motor can produce. 

Until someone builds a usable clutch/flywheel setup that can be retrofitted to almost all the EV's then I will keep my lightened stock setup. 

Pete


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## MJ Monterey (Aug 20, 2009)

Woodsmith said:


> I've thought of breaking an overdrive unit to get at the cone clutch but it would mean a lot of re engineering to fit a long item in the bell housing and then having it hydraulic operated somehow with either its own pump or an external one.


Which takes us in the direction of direct drive automatics. My most likely course. I have considered either the old Laycock or old Borg Warner tail shaft over drives directly bolted to the motor however the overdrive is only 20% and what I would like is 50% reduction and straight through. Hence the Powerglide trans with direct drive and an auxiliary pump.


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## Guest (Sep 11, 2009)

Ever consider the old Velvet Drives used in boating? Those may make a perfect alternative and an off the shelf item too. I see good used ones all the time. Never till now did I ever think of using one of those. Mmmmmmmmm. 

Pete


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## MJ Monterey (Aug 20, 2009)

Pete,
I have virtually no knowledge of boats, fill me in on the velvet drive.

Can they be shifted from under drive to 1:1 on the fly?
Or are they a forward/neutral/reverse with reduction?

Jack


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## Guest (Sep 11, 2009)

Was thinking of them because they are single forward drive. Kind of like a single speed automatic transmission but they are not automatic. Many are 1:1 but some have different ratios. I don't know the full in's and out's of these but thought maybe they could be used to work. Like using the GM Powerglide without the torque converter.  Without the hassle of the modifications of the Powerglide. 

Just thinking here.


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## MJ Monterey (Aug 20, 2009)

It sounds like he velvet drive would work as an underdrive and reverse shifter for a motor direct to driveshaft conversion.

However the Powerglide will give you a low and high so that you can more easily stay in the power/efficiency range of a motor.

And you can purchase proven parts to convert the Powerglide through most any dirt track racer supply. 

Yes you can actually purchase Powerglides made from all new parts.


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## JRP3 (Mar 7, 2008)

Funny I've been kicking around the boat transmission idea for a while. You can get Velvet drives in 1:1 or 1.52 ratios and it gives you a nice way to reverse an advanced motor, but they do weigh 160lbs or so, I think Powerglides are a lot lighter.


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## MJ Monterey (Aug 20, 2009)

Looks like Powerglides are under 100lbs. As an added bonus you get a parking pawl.


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## Guest (Sep 11, 2009)

Velvet drives are 95 lbs. If you couple it with a v-drive the the weight goes way up. But I do like the idea of a parking pawl. Problem I have is that I can not use a powerglide or any other type of transmission except VW. I did think of the auto stick but those are big and bulky. No way to modify here at home. Oh well. 

Pete


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## Guest (Sep 11, 2009)

Problem is that I just remembered is that they have a cast iron case. Drats.


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## Woodsmith (Jun 5, 2008)

MJ Monterey said:


> Which takes us in the direction of direct drive automatics. My most likely course. I have considered either the old Laycock or old Borg Warner tail shaft over drives directly bolted to the motor however the overdrive is only 20% and what I would like is 50% reduction and straight through. Hence the Powerglide trans with direct drive and an auxiliary pump.


Yes, my thought on this was to turn the overdrive unit back to front and then remove external clutch band so that it is either no drive or direct drive. 

I was figuring that when stopped the drive would be locked on due to no hydraulic pressure, nothing is spinning, so moving off would be as normal with an ev.
Once moving the gearbox primary shaft would be driving the hydraulic pump allowing the cone clutch to be disconnected for a gearchange.
The downside is that the moment you shift to neutral in the gearbox the primary shaft could stop spinning and the hydraulic pressure would dissipate and the cone clutch would come back on.
If that happened slowly then it would be ideal for getting the gear change. If it happened quickly then it would be like letting the clutch up in neutral making the change more difficult but a pressure reserviour could be used just to cover that moment.
There would be a lot of machining needed to get the overdrive unit to mate up to the motor and the primary shaft and still be short enough to fit in the bell housing for the conversion.


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## JRP3 (Mar 7, 2008)

gottdi said:


> Velvet drives are 95 lbs.


This place seems to think they are 160 lbs. http://bpi.ebasicpower.com/mm5/merc...duct_Code=BOR1017-000-004&Category_Code=ALL3D

Edit: Apparently the base direct drive unit is 95lbs, the gear reduction is an external unit that adds the extra weight. http://www.simplicity-marine.com/velv71.htm


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## MJ Monterey (Aug 20, 2009)

The overdrives were not a common option in the states. So I would be not inclined to rip one apart and modify it extensively.

I can get a Powerglide and rebuild it (how I would need it) for just a little more money than buying an used unknown condition overdrive from the local Brit specialty wrecking yard (and I would then have many hours in machining before it's ready). 

I also know the Powerglide will hold up and I can get parts.


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## O'Zeeke (Mar 9, 2008)

O'Zeeke said:


> I recently removed the clutch/flywheel setup from my 0.0 mustang and went direct for several reasons, not the least of which eliminating 65 pounds of rotating mass (78 lbs with t.o.b., fork) which has made a noticeable difference in acceleration (no stats yet) and I expect some increase in range as well. Not concerned about synchro wear as it will drop right in with a little practice and a lot of the time i just leave it in 3rd anyway. Also someone here has a thread on thrust/lateral load exerted on the rear motor bearing while depressing the clutch and that got me thinking. Just my 0.02$


I'm no mathematician but I did some calculations of the rotational energy used to get the 33kg, .35m dia. flywheel/clutch assembly spinning to 4000 rpm. Formulas from Wikipedia http://en.wikipedia.org/wiki/Rotational_energy

K(rotational) = 1/2 x (k) x mass(kg) x radius2 x angular velocity(rad/sec)

K = 46274 Joules 

My 20 mile commute involves an average of 22 stop lights requiring 22 x 46274 = 1,018,028 Joules or 0.283 KWh. 

Charging uses 10.5 KWh (525Wh/mile) so about 2.7 percent of the total charge was used just to get the mass of the flywheel/clutch spinning so for my Mustang this translates into about 0.6 miles for a 20 mile trip (maybe a little more because of the 78 less pounds to haul around). Not a huge increase but in a heavy car I'll take all I can get and its free.

Also interesting is doubling the speed increases the energy requirement by a factor of 4. No guarantee on the math, just my $0.02


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## MARTINSR (Mar 10, 2008)

O'Zeeke said:


> my 0.0 mustang


LOLOL, I am a lurker who comes by once in a while. Your "0.0" Mustang name is hilarous and you have my intrest once again in an electric. I'll keep learning and maybe jump into it. 

Thanks!

Brian


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## rfengineers (Jun 2, 2008)

Interesting thread! Here's my $0.02:

I am a strong proponent of direct drive. I've put about 2000 miles on my EV over the past 9 months. 95% of the time I am in 3rd gear, 1% of the time I am in reverse, 1% of the time I am in 1st gear so I can smoke the tires to impress someone, 2% of the time I am in 2nd gear because the speed limit on the University campus is 20mph and 1% of the time I shift up to 4th or 5th because I am doing 60 or 70mph. In other words, I do almost all of my driving in 3rd gear and almost never shift. If I do shift it takes no more than 1 or 2 seconds to do so.

Being in neutral makes me nervous, since that means there is no load on the motor. I consider a clutch a dangerous liability, since the "knee-jerk" reaction in an emergency would be to disengage the motor.

Case-in-point: I was driving in one of our common Florida "frog-drowning" rain storms. There was quite a bit of standing water on the road and I went through a puddle at a much higher speed than I should have. Water got up inside my throttle pot (a condition that can no longer happen, by the way). The wet pot told my controller that we wanted to GO! I got off the road and shut the car off without any trouble. If I had a clutch in the car I am quite sure that my 9" motor would now be junk and I would have holes in my hood and fenders where bits of the old motor exited at high velocity!

You can keep you clutch, thank you very much!

Joe


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## Stunt Driver (May 14, 2009)

*rfengineers *- i don't understand why no flywheel was better for you? Were you able to stop? What if you had no other way to stop, and no clutch? I see you scary story as - use clutch.


*O'Zeeke* - thanks for math. 
I am convinced that clutch is needed, and so built my coupler that way BUT - my slave clutch cylinder broke, and so 2 days I drive w/o clutch. I am only able to rev my 48v motor up to 2k rpm somewhere, so there should be less energy waste, but still - some present.
AND - going from 2nd to 3rd, or 3rd to 4th is not a problem at all. Takes around 2 seconds until stick slides right in the gear. No grinding AT ALL, not a single time.
But going 1st to 2nd takes around 4 seconds. And that happens exactly when i need to accelerate fast, like on busy intersection. I would use clutch there. Not sure i'd be able to accelerate much faster without flywheel to be happy.

My second thought however - energy of rotating armature can't be much more than that of rotating flywheel-press plate (arm is smaller in diameter). So no-clutch shifting should be even easier than what I have now, and now it's not too bad. 
I think i'll build direct coupler (luckly I have another splined part and clutch disk to use) and keep it till next chance/reason to take motor out.
Also going to replace clutch cylinder today/tomorrow, so may get different perspective then.

And ofcourse - no clutch shifting is VERY different from how it's been with ICE (i had cylinder broken back then already)


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## rfengineers (Jun 2, 2008)

Stunt Driver said:


> *rfengineers *- i don't understand why no flywheel was better for you? Were you able to stop? What if you had no other way to stop, and no clutch? I see you scary story as - use clutch.


If I had unloaded the motor it would have very quickly over-reved. The result of that is almost always complete destruction of the motor and surrounding stuff.


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## Stunt Driver (May 14, 2009)

Yes, but why would you need to disengage the clutch, knowing that moter will overrev?


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## rfengineers (Jun 2, 2008)

Stunt Driver said:


> Yes, but why would you need to disengage the clutch, knowing that moter will overrev?


What!?

My point is, a clutch is purposeless in an electric car. If the motor stops spinning it does not 'stall'. An electric motor has full torque from zero rpm, so there is no need to "slip the clutch" to get the car moving. Further, since people are used to using a clutch in an ICEV to disengage the engine if something goes wrong, then they are also likely to push in the clutch in an EV if one is installed. My position is, this will usually get you in more trouble in an EV.

In my experience (2000 EV miles over the past 9 months) there is no reason to have a clutch.

This is really a "religious" question, Mac vs. PC, if you will. The "cluchees" will never agree with the "cluchless" and vice-versa.

Joe


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## Guest (Sep 17, 2009)

It is true but if you have your foot off the throttle then if you push in your clutch it will only be spinning the speed at which it was disengaged. If it over revs then the motor was already in an over rev situation. Some transmissions don't shift well with out the help of the clutch, like the old VW transaxle. If I had a very high rpm motor I would have gone clutch-less and just used second gear. But alas I have a low voltage and normal rpm motor and at freeway speeds I am nearing the max rpm and I do need the gears to get to speed safely and being able to shift from gear to gear quickly. I am a proponent of the clutch but there are some situations where it is just fine to not have one. 

Pete


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## Stunt Driver (May 14, 2009)

*rfengineers* - don't forget to mention cost of your conversion, and specs. Mine is 10 times cheaper, and also less powerfull, I need to shift alot, just like driving ICE (except starting from complete stop doesn't need clutch). Also, some transmissions don't shift well w/o clutch. So it all depends on details.

I wanted to keep economical sence in my conversion, which I did. Otherwise, I could continue to drive my truck (2000 dakota bought for $2500) and remaining $7500 would be enough for 318000 miles of gas even with my poor milege.


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## O'Zeeke (Mar 9, 2008)

rfengineers said:


> What!?
> 
> people are used to using a clutch in an ICEV to disengage the engine if something goes wrong, then they are also likely to push in the clutch in an EV if one is installed. My position is, this will usually get you in more trouble in an EV.
> 
> ...


Joe, I agree completely since my clutch pedal now activates my main breaker disconnect I have accidentally "disconnected" a few times due to "left foot retained memory syndrome", but as you said thats what people do out of habit. Absolutely no clutchless problems so far


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## Guest (Sep 18, 2009)

Where you get into trouble with the clutch is if you forget and downshift like an ICE. Then you risk over speeding the motor and destroying it. I'd like to see some super high rpm DC motors so if you happen to do that you won't blow the motor if you happen to declutch the motor. Yes it is easier to do no clutch but the big issue is many transmissions just don't play well without one. Many if not most conversions are not using high rpm motors and many are also low voltage and do require the constant use of the transmission and clutchless would not fare well if you needed to shift fast. 

Driving with a clutch and no problems so far. 

Pete


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## paker (Jun 20, 2008)

If you down shift with an ICE you risk blowing syncros in the transmission, so one should learn not to down shift a manual transmission for any reason.


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## Guest (Sep 18, 2009)

paker said:


> If you down shift with an ICE you risk blowing syncros in the transmission, so one should learn not to down shift a manual transmission for any reason.


Say What? I have been doing it since I have been driving and I drive hard and I have never had a manual transmission failure. Ever. Even the manual says to downshift to help slow you down. 

Pete


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## Woodsmith (Jun 5, 2008)

gottdi said:


> Say What? I have been doing it since I have been driving and I drive hard and I have never had a manual transmission failure. Ever. Even the manual says to downshift to help slow you down.
> 
> Pete


Same here. I've down shifted with the clutch, without the clutch and double declutching in everything I have driven, and driven hard, and not had a transmission fail.

A friend even down shifted too far by mistake, found second instead of forth at speed in a truck, and the engine braking momentarily locked up the wheels when he let the clutch back up. The transmission was fine but the engine blew up!


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## O'Zeeke (Mar 9, 2008)

Anyway It seems pointless to downshift with an ev as there is no real drag from the motor (unless you have regen) and even with my ice I dont downshift as brakes are much cheaper to fix than trans/engine repairs


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## BHall (Aug 1, 2007)

Someone may have already mentioned this but I have always heard that there is a 4:1 ratio for rotational weight vs. static weight. Basically, removing 20# of rotational weight is like removing 80# of static weight. If this is true, then that's pretty much the weight of one battery. Before the ICE crapped out on me I practiced shifting without the clutch and it was not bad at all. I realize the ICE behind the tranny vs. an electric motor behind the tranny acts differently but I have also heard on this forum that an electric motor is even easier to shift clutchless than an ICE. All of this has my Fiero conversion being clutchless. Some of us have to learn on our own. 

Brian


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## Guest (Sep 19, 2009)

O'Zeeke said:


> Anyway It seems pointless to downshift with an ev as there is no real drag from the motor (unless you have regen) and even with my ice I dont downshift as brakes are much cheaper to fix than trans/engine repairs


The only problem with the clutched EV is that after years of driving an ICE you will have a habit of downshifting and if you happen to forget and downshift you can blow the electric motor. Of course it is pointless to down shift but lapses in memory are not uncommon. Auto Pilot Syndrome. I down shift all the time with my ICE. Helps stop my car and saves wear and tear on my brake system and my engine and transmission have not had any problems. I have been driving since 73. Pretty good luck then I guess. 

Check out the clip from a manual. If you do use a clutch and do follow simple rules you will not overspeed your motor. 


Pete


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## Guest (Sep 19, 2009)

The key word is excessive speed when down shifting. Should be no problem. I don't have a problem with my EV. Works fine. I actually do downshift just before I make a turn and need to be in a lower gear. That way when I come out of the turn I am in the correct gear for my speed. 

Pete


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## Guest (Sep 19, 2009)

You can shift some transmissions pretty well without the clutch BUT you won't do it quickly and some of us actually need to shift quicker than you can without the clutch. Do what ever you want but weigh the pros and cons carefully before you decide. I just don't endorse clutchless. I have tried with other vehicles too and I still feel the clutch is the best way to go. 

Pete


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## shadow (Sep 19, 2009)

I have three Bradley GTEs so I can test different ideas they are all stock Bradley -GE parts and I can tell you that with the stock VW flywheel clutch and even the starter ring gear I can leave the car in gear and coast farther than the Bradley with the lighten flywheel setup and the heaver flywheel seems to make so little difference on take that I can"t measure it. I prefer the heavy flywheel more coasting longer range.


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## JRP3 (Mar 7, 2008)

Since the mass of the flywheel can only store energy your longer coasting has to come at the cost of more energy used in accelerating.


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## Woodsmith (Jun 5, 2008)

Coming back to the debate on clutch or no clutch, I was thinking....

The situation with no clutch is that generally up changes are slow but not unacceptable in the most part.
Down changes are difficult and sometimes impossible with speeding the motor a bit and then there is the risk of speeding it too much when in neutral and damaging the motor.

So, how about a freewheel clutch between the motor and gearbox. It would allow drive as normal and be 'invisible' to the transmission when an up change is made and the syncro rings slow the motor armature.

But when a down change is made only the primary shaft is accelerated by the syncro rings and the transmission would act as if the motor was disconnected.
The motor will 'catch up' with the transmission as the throttle is depressed and then drive in the lower gear. It would remove the need to power the motor in neutral and remove the risk of over speeding the motor if too low a change is made.

Now all that is needed is a freewheel clutch that can go in the otherwise solid coupler.


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