gear ratios, and other questions, putting xs1100 engine in a fiat

[jakeb]

I am doing a bit of research and thinking about putting a xs1100 engine in a 1960 fiat 500. The power output is right where I would like and I like the idea of a bike engine to keep things light.

I am working a deal on a 1100 engine with 12k and rebuilt carbs for $375, will come with everything connected to the engine, wiring, etc etc and an instrument cluster from a 750.

My plan is to mount the engine behind the rear axle with the shaft drive going into a diff from the front of a AWD car/truck.

I am looking for some information about the engine before I go for it....

First if anyone has any pictures of an engine outside of the bike from all different directions that would help.
Does anyone know the dimensions of the engine?
What about the weight of the engine and trans?

From searching around I found the final drive is a 3.31:1 unit. Is that correct?
What are the ratio of each gear?
Where in the RPM range does the engine like to be? I would like to pick a final drive ratio so it keeps the engine in the power as long as possible.


What is the direction of rotation of the shaft? I want to make sure the car goes forward and not backwards.

Here is something sorta odd.... I would like the car to have reverse. I have a couple of options but the coolest if at all possible would be this. I would like to add a reverse gear from a yamaha raptor or one of the other yamaha quads to the xs1100 trans. Do you think it would be possible? I would be willing to get rid of one of the forward gears. This idea would be the best but also would be the hardest. The other idea for reverse is a electric start motor turning a gear on the driveshaft.

Here is a pic of what it will be going in.

[CatatonicBug]

Interesting idea, and cute little car!

I can answer very few of your questions, other than the RPM ranges. Generally, at 70mph, the engine will run at 5k RPM in 5th gear. The main jets in the carbs don't kick in until 2500-3k RPM, so anywhere between 3k-5500 would probably be good.

I have a couple of concerns though:

1. The engine is air-cooled. How will you provide the proper air flow to the engine when it is cooped up in a car shell? I know with the old VW bugs, the engine directly ran a fan that sucked air up from underneath, through a cowling, and through rather important air ducts around the engine.

2. The alternator in the XS1100 engine is rather dinky. It puts out somewhere around 22amps. Generally, that is just enough to run the signals, one headlight, one tail light and the few dash lights on the bike. How will you compensate for the need for 2 head/tail lights along with whatever method you are planning for cooling the engine?

3. There is no fuel pump in the XS. The carbs are fed by gravity. Where is the fuel tank in this little car, and how will you manage fuel delivery?

[cywelchjr]

I can answer one of your questions and give you a possible solution to one of bugs questions. The engine and transmission weigh about 120 pounds.

As for the cooling and charging system, you will probably need to remove the alternator and plug the oil gallery under that cover and come up with a pully for that end of the crank to run an alternator, depending on the alternator you may have to size your pulleys right to keep the alternator from grenading, and with enough charging power you can run an electric fan for cooling, or run one off the pulley, but I'd recommend electric.

I don't think you can put some other transmission in place of it, so for reverse you would likely need to come up with some type of assembly to allow reversing the output between the engine and the differential, but how cool would that be to have not only 5 forward gears, but 5 reverse gears as well!

It does sound like a cool project, I'm just not sure how doeable it's gonna be.

[Incubus]

Alternator should not be too big an issue. I have seen pictures of Goldwings equipped with a GM automotive alternators in place of the stock alternators (pulley in its place running to the alternator mounted aft of the engine).

If a Wing can do it, an XS can certainly do it.

Patrick

[bikerphil]

XS1100 gear ratios...

http://www.xs1100.co.uk/geartech.htm

[jakeb]

thanks for all the info so far guys...

I didn't think about the alternator. But I should be able to make something work there I would think.

As for cooling the engine that came in the car was air cooled. A 17hp 2 cylinder. I was thinking of adding some ducting to blow air towards the engine while moving as well as add a bunch of louvers to the back cover. The idea of an electric fan is there as well to cool the car while it is sitting.

As for headlights...the car will have them but I doubt it will see much night time driving. This car will be built for the $2011 Grass Roots Motor sports challange. Where you have to build a car for $2011 or less and compete in a autocross, drag race, and concourse.

I think a small low pressure fuel pump should solve the fuel issue...or a little tank above the engine so it is gravity fed and a pump to fill the small tank.
hmmm

[Guy_b_g]

Shaft rotation is clockwise (looking at the shaft from the rear of the bike).

[crazy steve]

I'd look at something water-cooled...

Some sort of big-bore V-4 would be a better fit, and with a cheap small-car radiator, electric pump and fan, your cooling problems are solved.

[jetmechmarty]

The XS1100 engine likes lots of RPM. The car weighs more than a bike, so you'll need it even more. Off hand, I'd say you need around 5K RPM to make the torque you'll need to make that little car go.

[WMarshy]

The XS1100 engine likes lots of RPM. The car weighs more than a bike, so you'll need it even more. Off hand, I'd say you need around 5K RPM to make the torque you'll need to make that little car go.

I agree, 5k is the sweet spot, the beginning of the power band. Make sure you consider the clutch ability to get that amount of weight moving. HD springs will be a must, you might want to consider the ALTO friction mod... offers more clutch surface (search for ALTO mod).

[FJ111200]

Have you looked at these cars? They use FJ1200 engines and it might give you a few pointers in the right direction.

http://www.legendsracinguk.com/carspec.html

[motoman]

Nice try on the XS's weight........try closer to 280lbs.

[tadtl1]

weight 280 concur

Hi,
While I cant be specific about the weight, I have moved an xs 750 engine setup around the garage and believe it would be very close to two hundred, so the eleven has to be well above that. I also concur with the water cooled v4 idea, that engine will almost certainly overheat without serious fans cooling it, it seems much easier to do with a water cooled engine to begin with.