Honda CRX Info Needed

[paker]

Originally Posted by Christ

That's gonna be a tight fit... The D series engine is only some 16-18 inches block length, and there's only another 2-3" of clearance in front of the engine before you hit the frame rails.

You may be able to move the electric motor slightly inside the transmission bell housing, but I wouldn't count on it fitting easily.

The front track width of the car is only 57.1", and the trans comes about to the middle of the car in the front, so you've only got ~30" left, and at least 10" of that is frame and fender clearance areas.

Consider a smaller trans to swap in, or a smaller motor.

The main reason for using a larger motor is that I have 11 miles of interstste at 70 +- MPH and another 6 miles at 50 +- MPH drive to work and I don't think a smaller motor would hold up long.

[paker]

Originally Posted by Christ

You may also be able to shave some of the length off the e-motor you want to use, by pulling the end plates and milling them down. Leave enough meat for the bearings, though.

The Siemens E-Bike that OCC built, they had to remove and mill the plates several times to get it aligned and centered properly above the swingarm bracket, so it didn't bind the belt at all. Look for ways that you can shorten up the motor.

If there's a second housing bolted on the top that contains a cooling fan (not likely), you can probably remove it and use liquid cooling, which will save you some length, as well.

Or outside cooling fan like Netgain uses. I've worked as a machinist for 37 years and could possibly do it, but to me that would be an expensive experiment.

[MetroMPG]

Have you checked the EV Album for CRX examples?

crx - Google Search

[bennelson]

The other important measurement on front-wheel-drive cars is the distance from the driven shaft of the transmission to the front wheel shaft on the engine side of the car.

If you have an 11" motor, you need to make sure you have AT LEAST 5.5" (plus a little for clearance) between those two shafts.

Engines are usually blocky rectangular things, but motors are round. Nobody is happy building a custom adapter plate only to see that the wheel shaft can't fit back into the transmission!

I am using a 10" Nissan forklift motor on my Electro-Metro, it is ABSOLUTELY the biggest diameter motor that will fit the transmission. I also trimmed the end of the motor to make it meet the width available under the hood.

[Christ]

I would think (inexperienced thought here) that a 9" ADC could keep you moving with proper cooling.

I want to think that the transmission input shaft to driveshaft output is just over a foot, which will probably pose another problem for you.

While I believe you can probably get away with the diameter of an 11" motor, even if you have to trim the housing a bit, you probably won't like the length of it. I'm sure you'll have to modify the frame section on the driver's side of the car, if you can't get clearance from the motor.

If you're OK with fabrication, there is still an option for swapping in a smaller trans, as well. The OEM CRX trans can hold up to ~400HP before you start grenading it, it's a little over engineered... the axles are always the breakers.

I'm not sure what other trans you could use that would give you more clearance and not require cut axles, though.

[paker]

Originally Posted by MetroMPG

Have you checked the EV Album for CRX examples?

Yeah I believe everyone I've looked at uses an 8" motor. I believe one person in the Honda search I did reasoned a smaller motor would draw less current.

[paker]

Originally Posted by bennelson

The other important measurement on front-wheel-drive cars is the distance from the driven shaft of the transmission to the front wheel shaft on the engine side of the car.

If you have an 11" motor, you need to make sure you have AT LEAST 5.5" (plus a little for clearance) between those two shafts.

Good point. I've seen a couple of CRX that are advertised as shells with only the transmission. That would probably be a good starting point

Originally Posted by bennelson

Engines are usually blocky rectangular things, but motors are round. Nobody is happy building a custom adapter plate only to see that the wheel shaft can't fit back into the transmission!

That's what I want to avoid.

Originally Posted by bennelson

I am using a 10" Nissan forklift motor on my Electro-Metro, it is ABSOLUTELY the biggest diameter motor that will fit the transmission. I also trimmed the end of the motor to make it meet the width available under the hood.

Did you have to take out the internal fan?

[paker]

Originally Posted by Christ

I would think (inexperienced thought here) that a 9" ADC could keep you moving with proper cooling.

I want to think that the transmission input shaft to driveshaft output is just over a foot, which will probably pose another problem for you.

While I believe you can probably get away with the diameter of an 11" motor, even if you have to trim the housing a bit, you probably won't like the length of it. I'm sure you'll have to modify the frame section on the driver's side of the car, if you can't get clearance from the motor.

If you're OK with fabrication, there is still an option for swapping in a smaller trans, as well. The OEM CRX trans can hold up to ~400HP before you start grenading it, it's a little over engineered... the axles are always the breakers.

I'm not sure what other trans you could use that would give you more clearance and not require cut axles, though.

My main motivation for using an 11" motor is that it would run cooler by drawing less current due to the amount of torque it can produce.

Fabrication of a different transmission might be a nightmare task, especially if I have to redo the drive shafts.

[vpoppv]

Originally Posted by paker

My main motivation for using an 11" motor is that it would run cooler by drawing less current due to the amount of torque it can produce.

Fabrication of a different transmission might be a nightmare task, especially if I have to redo the drive shafts.

Well, I have the smallest motor I have ever seen put in a car (well, except for the guy that used a cordless drill for a motor), but I don't think it draws less current, or more current than anyone else's. Not that I can check, since I never bothered to install my ammeter. I just thought that work was a function of energy needed to be applied times weight? So, in my little mind anyway, I don't think that my motor would see a different amount of current that a 13" motor would: it takes the same amount of work to move whether an ant pulls it or an elephant. Barring efficiency, wouldn't my baby Baldor "use" as much battery amps getting me to work than a Mega Monster 250 lbs of electric fury? There's tradeoffs for sure: my tiny motor works harder, and so gets hotter, therefore more power gets converted to heat, but on the other hand, my motor is carrying 200 less pounds around than a 250 lb monster motor. I'm planning on a much bigger motor for my Toyota, because I want to hit the freeway too and a smaller motor would get fried, but a fairly light car should be able to cruise at 85 mph for a good while with an 8 or 9" motor- the holdback would be how long the batteries can provide power rather than the ability of the motor to take the beating. Here's a 9" NetGain in a BMW:

http://www.youtube.com/watch?v=W8PBE...layer_embedded

[paker]

My ideas come from my days as a reckless youth racing slot cars, and rewinding slot cars motors on commercial tracks (wow 1966 that was a while ago). The large can motors always drew less amps than higher rpm small can motors. I always had the fastest 1/24" car on the track on a long straightaways, but I always got yelled at by Kyle, the guy that ran the place, for sucking the amps out of the track.

The point being side by side, with the same current, a large motor will do more work and run cooler than a smaller motor.