Sanity check: Honda GL500 engine into Toyota Corolla coup - Fuel Economy, Hypermiling, EcoModding News and Forum

cyrus-the-virus · 09-12-2013, 12:17 AM

Hi, I'm new here to the forum. However I have a growing interest in minimalist economy cars and electric vehicles. In fact I recently picked up a nice little Honda GL500 Silverwing for $50 that I'm planning on converting into a electric cafe racer over the winter. Don't worry I'll be posting a build thread on here and endless spear more than likely. As I am still learning and will likely have a lot of question when the time comes.

However that left me with a question. What to do with a nice 500cc motorcycle engine with a lot of life left in it? A local junkyard has an old RWD Toyota corolla coup for around $500. I can't recall off the top of my head, but I'd like to say it's a 4th gen corolla, but don't quote me.

So I was thinking about buying it and swapping the GL500 engine in. Then strip the interior of all unnecessary equipment to reduce weight as much as possible. The bike engine is a longitudinally oriented, shaft driven, and is supposed to produce 48 horsepower stock. So the engine, hypothetically speaking, should fit with relative ease and could be as simple as making engine mounts and an adapter for the drive shaft. However I am concerned about the extra weight of the drive train. Let alone the extra 1400lbs overall. Not having a reverse gear would also suck, however I live in an area where I could get away with it.

What do you guy's think? Do you think I can improve the fuel economy with this swap over a stock toyota corolla? Or am I being a bit crazy?

Thank you for your time

Xist · 09-12-2013, 02:16 AM

While I seem to be one of the most active users here, I have not actually ever done anything, I have just read very many threads, and know how to search. From what I understand, 48HP would be more than enough. I have read many times that you only need a small amount of horsepower, actually, a fraction of the amount put out by that motorcycle engine, to move down the highway, although having more would certainly help you accelerate to that speed.

Wow, that Corolla could be as old as I am!

I am curious how it would work out. Wikipedia says the car weighs 1,880 lbs stock.

According to 1980 Toyota Corolla detailed specs and performance, you are replacing a 1.29L engine, which should make it much more efficient.

Heh. It was rated 59 HP!

I was trying to find the Cd, but did not expect to. It does say that it was rated 30 MPG.
Ah. The GT had a larger engine and had a 9.9-second 0-60 instead of a 14.3.

It sounds like a great project! If you are not committed to the appearance of a car from the junkyard, there are some great things that you could do for aerodynamics!

mechman600 · 09-12-2013, 02:49 AM

It should work. Economical? Not sure. While the GL500 engine is a fairly low-revving, torquey motor by motorcycle standards, it's a very low torque, high revving engine by car standards. Chances are you will be in the rich acclereration carb circuits most often and lean cruise carb circuits very very seldom.

I assume the car has a manual trans. I would keep the car's trans in there and couple the input shaft to the GL's trans output. Use the GL's clutch and the Toyota's trans. (The GL is shaft drive, correct? This might be difficult to do and will have lots of losses because the shaft exits the bike's transmission pointing back towards the rear wheel) This way you can leave the GL in one gear all the time, and figure out what gear works best as the proper input speed to the Toyota's transmission.

cyrus-the-virus · 09-12-2013, 12:51 PM

Quote:

Originally Posted by mechman600

I assume the car has a manual trans. I would keep the car's trans in there and couple the input shaft to the GL's trans output. Use the GL's clutch and the Toyota's trans. (The GL is shaft drive, correct? This might be difficult to do and will have lots of losses because the shaft exits the bike's transmission pointing back towards the rear wheel) This way you can leave the GL in one gear all the time, and figure out what gear works best as the proper input speed to the Toyota's transmission.

That seems like it would be over complicating things. Is there some reason why just using the GL transmission alone wouldn't work? It's an older RWD corolla, not a FWD, and unfortunately it's an automatic. Part of the reason I want to do the swap.

Xist- I plan on doing a few aero mods, it's got some body rust anyhow.

roosterk0031 · 09-12-2013, 02:14 PM

I found (check me) 3.91 final drive for the car, 2.242 primary reduction in motor, 2.733 first gear, = 25.90 turns for motor for 1 turn of axle. 155 x 13 tires about 6' circumference 5 mph = 7.33 fps, at 5 mph axle(tire) needs to spin 1.22 times per second. 1.22 x 25.90 give motor rev's per second of 31, times 60 = 1800 rpm.

It might work, hope it still has the 13" or some low profile 14", smaller diameter tires might help a lot.

Assuming 5th is 1:1, motor to axle would be 8.766, I think 7000 rpm at 55 mph. That sounds a little fast, but the bike came with 3.09 and a larger diameter tire. So it's rpm I calculate was 4900 rpm. Look that up and see if that rpm check out, if it does, the other numbers are probably reasonable.

Frank Lee · 09-12-2013, 02:27 PM

I have a GL500- it is only good for 40-50mpg as a bike and certainly doesn't suffer from excess power.

Were I to consider such a project it would be easy to "imagineer" a test where you pull a trailer with the GL loaded such that the whole mess approximates what the car conversion would be. Then you can get an idea if- with stock GL gearing anyway- there is enough power. Or you could just do a hp/lb comparison with other known vehicles.

In spite of the better aero drag coefficient of the car, the frontal area is quite a lot more, not to mention the weight.

My guess is you'd end up with a very weak car with no reverse that doesn't give much better if any better at all economy.

I would strongly consider just keeping the GL as a GL and finding a lighter chain or belt drive bike to convert to EV. The GL is a runner, right, so if it ain't broke why mess with it? There must be tons of good chain drive donor bikes that are non-runners.

user removed · 09-12-2013, 02:37 PM

Why not mount the engine to the Corolla transmission?

regards
Mech

deejaaa · 09-12-2013, 09:49 PM

i would run both trans together. years ago(at least 30), someone had an S10 (or Toyota) truck with 2 manuals hooked together. gave him lots of gears(used as a hotshot) and he said it was good on gas. he would leave looked funny to me at the time, second trans shifter was almost in the back seat area and he would leave it in the higher gear until he needed to either pull or lower rpm. real foggy mixed with the cobwebs in the brain bucket but i can still picture it.

Frank Lee · 09-12-2013, 10:21 PM

Bad idea. There is precious little power to begin with and transmissions don't transmit 100% of the power.

Ryland · 09-13-2013, 01:19 AM

I agree that it's going to end up being a gutless car without reverse that is going to get lousy mileage, I could maybe see this working if you had plans to make it a hybrid as well, but at that point it would weigh a bit much and cost even more to build, but a hybrid would be awesome.
If you want to build the electric motorcycle tho, I might be able to sell you some parts to allow you to bolt a golf cart motor up to your frame, I still need to get a bid to know what the parts I have already are worth but it's going to be in the $300 to $500 range and allow everything to bolt together.