rigormortis
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| posted on 23/7/07 at 08:36 PM |
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Where to start? Convert Mojo2 to bike engine...
Hi all,
I've had a Sylva Mojo2 (mid-engined cvh powered noddy-mobile) for a while now, and am planning on taking her off the road until spring '08
for a comprehensive overhaul.
Needless to say, this will obviously involve ditching the CVH in favour of a blade/r1 (or other? I'm open to suggestions) engine.
The only trouble is, I know very little about bike powered cars (other than that having sampled a sequential transmission, I have to have one), and
would like to plumb the depths of your collective knowledge.
I'll obviously contact sylva, and find out if they have any experience of what I'm planning. Am I right in thinking that essentially, you
just need to fix a sprocket to a suitable drive ratio diff and chain drive it?
I'd appreciate any advice on how best (within my modest budget, ~£3k) to go about connecting the engine to the wheels, so I can start drawing up
a plan.
Cheers,
Tom
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Minicooper
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| posted on 23/7/07 at 09:08 PM |
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They do have experience of putting bike engines in a sylvia, they do a seperate version called the R1ot, I'm fairly sure that the wheelbase has
been lengthened to accomodate the bike engines.
They used a fiesta diff allowing the use of standard driveshafts
Cheers
David
 
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rigormortis
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| posted on 23/7/07 at 09:13 PM |
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Thanks, good pic that. Looks like fitting everything in is going to be a challenge. Is that a fiesta diff in the picture then?
edit to say: looks like i've got more height and width to play with. I'd better speak to sylva and see what (if anything) can be done.
[Edited on 23/7/07 by rigormortis]
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Minicooper
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| posted on 23/7/07 at 09:19 PM |
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fwd Fiesta/Escort diff I believe
Cheers
David
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rigormortis
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| posted on 23/7/07 at 09:21 PM |
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Er, yes. Same one I'm using atm, now that you mention it 
Never let it be said that I don't have an eye for detail.
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stevebubs
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| posted on 23/7/07 at 09:41 PM |
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quote:
Originally posted by Minicooper
They do have experience of putting bike engines in a sylvia, they do a seperate version called the R1ot, I'm fairly sure that the wheelbase has
been lengthened to accomodate the bike engines.
I thought it was the other way round...but can't be 100% sure either way...
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rigormortis
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| posted on 23/7/07 at 09:47 PM |
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quote:
Originally posted by stevebubs
quote:
Originally posted by Minicooper
They do have experience of putting bike engines in a sylvia, they do a seperate version called the R1ot, I'm fairly sure that the wheelbase has
been lengthened to accomodate the bike engines.
I thought it was the other way round...but can't be 100% sure either way...
as mentioned above, the riot was developed from the mojo - while i've probably got a bigger engine bay than the riot (due to width - back wheels
are faired in), the riot is definitely more acommodating in terms of length.
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zxrlocost
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| posted on 23/7/07 at 11:00 PM |
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Hi Tom contact Sylva and see how much it would cost them to do the mounts etc and then you can source the rest and ask advice on here..?
R1 good motor
should be able to easily do it for your budget
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rigormortis
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| posted on 24/7/07 at 07:57 AM |
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Hi,
I've emailed sylva, I'll report back when I hear from them.
Tom
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bigandy
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| posted on 24/7/07 at 09:30 AM |
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Hi Tom,
I'm building a Mojo2 at the moment (3.5 years and counting!), so if you do come up with a workable solution, make sure you let me know!
I think the main problem you will come across is the lack of "length" in the engine bay on the Mojo2. A chain driven diff will take up a
fair amount of room if you want to keep the driveshafts at reasonable angles, not leaving much room to put the engine in front of it. Raising the
engine up might be an option, but it would moure than likely protrude through the engine cover area.
Offsetting the engine to one side of the engine bay, and the engine to the other, and running a shaft drive to the differential might be an option
though (although you end up with unequal length driveshafts, and a lot of custom engineering needed that hasn't really been done before as far
as I am aware.
Good luck though!
Cheers
ANdy
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rigormortis
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| posted on 24/7/07 at 10:18 AM |
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Hi. Nice to hear from another owner. Sometimes I think I've got the only Mojo in existence.
Since the fiesta diff has unequal length driveshafts, i was also thinking that offsetting the engine to the driver's side would work - albeit
provided a compact enough engine is available.
There are some sweet 600/650 engines out there, I believe a modern cbr600 makes around 110hp at the crank. That's very close to my power
goal...
I'll keep you posted.
Tom
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Minicooper
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| posted on 24/7/07 at 10:41 AM |
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I personally would go for an engine that was at least a 900cc, but if you want a high performance smaller engine, how about a GSXR750 K1 which I
happen to have for sale.
Over 140hp as standard, 13,750rev limit, all electrics, in tank fuel pump, injection, etc
£600
Cheers
David
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zxrlocost
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| posted on 24/7/07 at 10:48 AM |
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Hi Tom there would be no point whatsoever in fitting any race engine below the 899cc mark
as the smaller engines may not have as strong a gearbox parts as the bigger engines
the power/Torque CURVE will be nowhere near as good as the bigger engines
they rev even higher you do want the driveability below 8,000rpm
which the bigger engine will give no probs
youll end up spending the same
if anything why not get a ZX9r engine
cheap as chips now but you want a later engine ie 2000? as the gearboxes werent the best in the others
150bhp and got a good enough torque curve
hth
chris
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rigormortis
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| posted on 24/7/07 at 04:49 PM |
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Thanks for the engine advice everyone - However, it really boils down to what's going to fit.
Unfortunately sylva have indicated that the Riot basically exists due to the unsuitability of the mojo platform for bike engines...
Didn't really want to, but maybe it's time to start scouring ebay for a honda b18c and some ITBs.
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ChrisGamlin
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| posted on 24/7/07 at 07:43 PM |
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A 600 engine will not be significantly smaller than a modern 900/1000 engine Im afraid, so I dont think thats going to provide a solution.
The R1 is probably the "shortest" engine you'll find as it has a stacked (vertically) gearbox rather than side by side as found on
most engines, and the barrels are quite upright too which helps. Certainly when I went from the 919 blade to a 2003 R1 in my Locost, the R1 was
noticably shorter (or narrower as I look at it in my car) and when mounted sits at least 2-3" closer to the centre of the chassis than the blade
did.
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ChrisGamlin
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| posted on 24/7/07 at 07:47 PM |
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Thinking laterally, are there any canted over V Twins that would fit, ie fitted so the v angle is vertical and pointing backwards? STM used to make a
Phoenix with a Honda SP1 engine in it that had that kind of one vertical, one nearly horizontal configuration, but Im not sure if you could mount it
with the second cylinder pointing backwards in a mid engine'd car and still have a clear chain run to the diff or not.
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rigormortis
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| posted on 25/7/07 at 10:34 AM |
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The problem with that is the likely obscurity of an engine that would fit. I think I'd need to stick to one of the mainstream sportbike engines
- for the availability, support, reliability, etc.
Perhaps I could mount one transversely, dry sump it, and run a sprocket off the input flange on a front-engine/rwd style diff. Then the engine could
practically sit on top of the diff.
Would be getting quite complicated though.
How do people normally get the power to the road with a front-bike-engined car?
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ChrisGamlin
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| posted on 25/7/07 at 01:11 PM |
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With exactly that, a prop from the gearbox output shaft running to the diff. At least doing it that way the engine would be offset to the passenger
side so may be able to nab a bit of space.
Have a search for the Fisher Fury Menace, as that was mid-engined BEC and used exactly this configuration.
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rigormortis
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| posted on 26/7/07 at 09:21 AM |
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Thanks for the suggesions. I shall investigate further - i don't really see why it can't be done. Granted the engine may need to be higher
than is optimal, but when you're losing this much weight, raising the cog a bit can't hurt that much.
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TimC
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| posted on 26/7/07 at 03:34 PM |
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The R1 is very compact as Chris says. I've seen them in some pretty tight single seater installs using a very short chain.
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