Bike power!

[Caractacus]

Hi guys,

Just two quick questions for you on bike engines in kit cars.

Why do they all seem to be four cylinder engines?

Has anyone used a V Twin, a la' Suzuki a la' Suzuki TLR/TL 1000?

An old mate of mine has a TLR and it goes rather well. I also love the V Twin sound and additional torque.

Cheers,

C.

[Sam_68]

I've got an Aprilia V twin sitting in my shed waiting to go into a car, and yes, it's been done before (notably in a version of the Sylva Phoenix and by SDR in the V-storm).

[slomax]

most 3 wheel kit cars are v-twin utilising the Moto-guzzi or honda CX engines. I have seen a few V4 engines used in the likes of pheonix's too. Never seen a triple used. Some trikes also use the BMW R80/R100 engines too.

O/T
There is a 2cv floating around somewhere with a BMW GS1200 engine and it goes like stink.

[Yazza54]

4s make the power. Twins are less willing to rev and are more difficult to fit under a bonnet without hacking away at bodywork.

Until you have driven a bike engined car, don't underestimate the torque. My R1 fisher fury pulls fine and is happy at 30mph 4th gear about 3500rpm.

[Smart roadster]

To use something like a Ducati inline twin would be very difficult to package. Once you have turned the engine side ways to get the drive in the correct direction(front engine rear wheel drive) then the forward cylinder will be poking out of one side of the car.
For a rear mid setup the car would be very long as the front cylinder would want to be where your bum should be.
Across the frame twins like Guzzis and BMWs are easier as would be a Harley as the gearbox is a seperate item (but why would you want to use a Harley?) The S+S engine used in the new Morgans is the same layout as a Harley so would be a good bet.

[jason61c]

A Harley would be an crap choice, heavy slow and American engineering.... enough said. BMW's are low power too.

A honda sp1/ducati/morini/tl engines are all V twins so would fit very well in a car. They'd sound better than anything too.

It'd be great to have a car with an engine that said HRC on the crankcase!

[Yazza54]

The only cars a vtwin is really suited to is the v twin 3 wheelers like slomax says.

I've seen a pan euro v4 in a phoenix and it looked a right lump and the carbs come right up in the middle of the v fouling the bonnet.

Besides that they don't make the power the inline 4s do and aren't as well supported/well known.

[Smart roadster]

Jason

How do you get over the front cylinder poking out of the side of the car on an inline 90 deg V twin?

Aprilias and morinis are slightly better as they are 60 deg but you get a very tall engine which you might struggle to see over.

[jason61c]

the sp1 is a 90 degree V-twin along with the ducati's(infact they're called a L-twin).

I can't see how a 90 deg twin will stick out of the sides of a car, they're not that wide even side on. It would sit perfectly in the middle of the car, output shaft straight down the tunnel.

[Mr2Mike]

jason61c said:

the sp1 is a 90 degree V-twin along with the ducati's(infact they're called a L-twin).

I can't see how a 90 deg twin will stick out of the sides of a car, they're not that wide even side on. It would sit perfectly in the middle of the car, output shaft straight down the tunnel.

The output shaft from a bike engine is typically well back from the crank, so the propshaft wouldn't be going straight down the tunnel if the engine was mounted so the cylinders were central.

[jason61c]

its not far off though, I guess it depends on the gearbox arrangement.

[Sam_68]

Yazza54 said:

The only cars a vtwin is really suited to is the v twin 3 wheelers.

Or a lightweight mid-engined installation...

They don't make as much power as the 4 cylinder bike engines (hence are better suited to the very lightest cars only), but they're significantly lighter, have better torque delivery and because they fire half as many times as a 4-pot at the equivalent revs (and tend to deliver their torque and power at lower revs anyway) they won't feel as ridiculously short-geared as most BECs.

[dave de roxby]

slomax said:

There is a 2cv floating around somewhere with a BMW GS1200 engine and it goes like stink.

Hi Slomax, In connection with our deliberations elsewhere on trike designs, do you know what gearbox this 2CV uses? Is it the original Citroen or something more special. I've been having thoughts about using a BMW flat twin in a fwd format but am stuck for a suitable transaxle unless I design something myself. Have considered the old Alfasud/145 but they are not that prolific and audi seems a tad heavy.

Edited by dave de roxby on Saturday 2nd April 10:16

[slomax]

dave de roxby said:

Hi Slomax, In connection with our deliberations elsewhere on trike designs, do you know what gearbox this 2CV uses? Is it the original Citroen or something more special. I've been having thoughts about using a BMW flat twin in a fwd format but am stuck for a suitable transaxle unless I design something myself. Have considered the old Alfasud/145 but they are not that prolific and audi seems a tad heavy.

Edited by dave de roxby on Saturday 2nd April 10:16

dave,
if you are planning on using the r60, r80 or r100 then the original 2cv box is strong enough. I can direct you in the way of a few conversions if you want. I believe that the gs1200 engined car was running with a beefed up GS box, although I still can't imagine it lasting too long and finding one might be difficult. The engine of choice amongst pembleton owners and other Citroën special owners, apart from the guzzi is the r100rt, but they are getting scarce now.

HTH

[Stubby Pete]

The best aprt of having a BEC is the high reving engine. The V-twin has more car-like characteristics (not exactly like a car mind!) than the 4 pots.

I've been on track at the same time as an Apprlia V-Twin which was much slower than mine, albeit still being "shaken down".

If you're looking at V-Twins, two of them has to be the way forward!!

[Caractacus]

Thanks for the replies

So it seems a Seven type car with a TL1000 lump (or TLR) is out of the question (without butchering the bonnet).

I know it's horses for courses and all that, but I just love V Twins!

Cheers - have a cracking weekend.

C.

PS - my reason for bringing this subject up is I may well be in the market for another summer fun mobile so am considering BEC's. Cheers.

[66Quinny66]

Hmmmm. I've got an Aries Locoblade with an Aprilia v twin in it. Yes, it's a little tall with the tb's in the v but, even with the fairly lowline Aries bodywork, I just have a scoop covering them. It's also dry sumped so it can be mounted fairly low. I think you'd struggle with a 90 deg v twin because of the "width".

[slomax]

66Quinny66 said:

Hmmmm. I've got an Aries Locoblade with an Aprilia v twin in it. Yes, it's a little tall with the tb's in the v but, even with the fairly lowline Aries bodywork, I just have a scoop covering them. It's also dry sumped so it can be mounted fairly low. I think you'd struggle with a 90 deg v twin because of the "width".

can we have some pictures? I'm all intrigued now....

[jason61c]

Just to add a modern v-twin(ducati 1198) makes 165bhp at the wheel and more torque than a 1000CC IL4.

[Yazza54]

jason61c said:

Just to add a modern v-twin(ducati 1198) makes 165bhp at the wheel and more torque than a 1000CC IL4.

200cc bigger for a start. Besides it'd cost a fortune to find a modern 1198 duke and fit it in a car.