gsand
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 posted on 20/11/03 at 07:05 AM |
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Mid-Bike Engines diff alternative
Well, maths is a great lesson. Especially when your are bored and finished all your work, because it seems that that is where all my creative ideas
come from. Anyway, I dont want to, and probably never will force myself to buy a diff for mid mounted bike engines for several thousands of dolllars,
so i whipped something up. It is basically exacly the same as a conventional Bike engined car. Except with out a propshaft. In short, a bike engine
mounted longitudial with a universal joint is attachet to the sprocket, then joins directly to a conventional car diff. I feel proud  . I hope you
all understand that.
4st Insanity
Maybee i should start wearing a Welding mask.....
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JP32
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 posted on 20/11/03 at 08:09 AM |
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Make a picture you are sure we all understand!
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gsand
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| posted on 20/11/03 at 08:36 AM |
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When i have more time i will do a much more detailed image
 
Rescued attachment untitled2.JPG
4st Insanity
Maybee i should start wearing a Welding mask.....
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JoelP
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| posted on 20/11/03 at 11:15 AM |
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does the engine essentially touch the diff with no propshaft, just the UJ?
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Alan B
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| posted on 20/11/03 at 12:58 PM |
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I don't want to rain on your parade, but I'm 99.999% certain it's been done already.....
However, and this is the main thing, it is still a doable and workable solution...
So I'd research a bit more then go for it...
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MikeR
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| posted on 20/11/03 at 01:05 PM |
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In fact isn't it what 99% of bike engined cars do now - except the diff is a lot longer....
on the positive it means lots of readily built bits (tiger in the uk do quite cheep prop shaft converters for bec's i believe).
The downside is that the engine has to be offset to the nearside (left when looking forward for all those not in the uk) so the prop shaft lines up
with the output from the bike's gearbox.
The idea I'm researching hopefully gets round that (although is a little more expensive). Get a Porsche 928, 944 or 968 gearbox. Its a
transaxle, feed the bec's / other engines input into that via a prop (torque tube) and away you go.
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Spyderman
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| posted on 20/11/03 at 01:09 PM |
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Another solution would be to use a Mini diferential and modify it to accept a sprocket. Then use engine in normal east-west configeration and a chain
transfering drive to diff.
It has been done many times before. Is very compact and light. Plus the axle movement is not transfered to engine. 
Terry
ps. another benefit is easy gearing changes for different circuits.
[Edited on 20/11/03 by Spyderman]
Spyderman
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Alan B
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| posted on 20/11/03 at 01:26 PM |
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Another minor point.
What is needed to couple the units is actually a compliant drive coupling (readily available) rather than a plain U/J
A U/J allows for angular misalignment and movement while holding two elements on a perfect center line.
A compliant coupling on the other hand allows for a little angular misalignment and a little eccentricity between the two elements....very common
between say a pump and a motor....
Small point, but worth mentioning....
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ned
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| posted on 20/11/03 at 01:51 PM |
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I posted this idea a while back as a cheap alternative for the MK GT1 to using the quaife torque biasing thingy. I'm sure someone else thought
of it before me!
for bike mid engined I'd drop an engine in inline with a slippy sierra axle.
Ned.
beware, I've got yellow skin
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Hugh Paterson
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| posted on 20/11/03 at 02:39 PM |
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It's been done. The Coram LMP uses it to great effect (it was thought of about 7 years ago). And I think it may be copyrighted...
Wanna photie? I'll see what can be arranged. Have a peek in tadltd's pic page in the next few days.
Shug. 
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locoboy
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| posted on 20/11/03 at 02:58 PM |
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look at http://www.spiritowners.f9.co.uk/maximus/maximus.htm
its my mates project, my idea to use the sierra diff to drive the front wheels
150bhp v4 bike engine and it is v.v.v.v light!
ATB
Locoboy
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ned
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| posted on 20/11/03 at 03:52 PM |
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Col,
there don't appear to be enough wheels! and it'll be a bitch for wheelspin!
very interesting stuff.....
Ned.
beware, I've got yellow skin
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JoelP
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| posted on 20/11/03 at 05:17 PM |
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all i can say col, is well done to your friend for getting it so far, but he really needs to come off the hallucinogenic substances! a mad and unique
idea. single seater? will weigh two thirds of bugger all...
whats he aiming for, 350kgs?
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suparuss
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 posted on 20/11/03 at 05:56 PM |
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i have an idea- stick the engine to a rotatable turret, (probably atatched to the steering wheel with shoe laces or something to control) then put a
propeller on the sprocket of the engine. come to think of it, you could use the down draft to power a cushion of air for the car to sit on and reduce
friction. you could even go on water with it!!
Russ.
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Alan B
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| posted on 20/11/03 at 06:33 PM |
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We have them here already...called airboats..
if you are interested...
http://www.airboattrader.com/boats_under_$5,000.htm
[Edited on 20/11/03 by Alan B]
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sgraber
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| posted on 20/11/03 at 06:54 PM |
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quote:
Originally posted by Spyderman
Another solution would be to use a Mini diferential and modify it to accept a sprocket. Then use engine in normal east-west configeration and a chain
transfering drive to diff.
But why not leave the bike engine facing east-west, but move it rearwards so as to place the output shaft in-line with the input shaft of the mini
differential. Then drive it directly with a "compliant drive coupling"? That way you could skip[ the chain completely and all of the
ensuing tensioner and adjuster complexity. Am I missing something here?
BTW - That front engine/front drive trike contraption is absolutely F-ing bonkers. !!! Jeez! And why is the steering wheel upside down?
Graber
Steve Graber
http://www.grabercars.com/
"Quickness through lightness"
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locoboy
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| posted on 20/11/03 at 09:01 PM |
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fuckin bonkers you aint wrong, D-day will be tuesday-wednesday, he is having the exhaust made and fitted on tuesday, he will be able to run it up
propperly. I will try to borrow a vid cam to capture the moment and post it on here, should sound orgasmic! 1200 cc of v4 with V-boost on a manual
switch!
It weighed in at about 300kg before with a 1.4 renault 5 cast iron lump in it so it should weigh in at less now, also with alloys rather than lumpy
old renault wheels.
its not the best looking thing you have seen but it will go like poo off a stick! will keep you posted.
he has bought the rights to the Hudson kit car company and will be producing these kits soon. The kit is not SVA compliant but other owners have made
them conform with a little work.
The guy who manages the website has made a 4 wheeler version and after seeing the max installation is going to go down the same route now. The kits
will be available ready to install a max engine - brake upgrades can be made with Renault 5 gt hubs and callipers or by having clio uprights and hubs
machined to fit.
Ned :wheelspin will be a problem and i think it will understeer like a bitch i bet? powering out of a corner could be interesting, especially in the
rain!
Sgraber : the steering wheel is on upside down so he can see the all important speedo when the dash is fitted.
[Edited on 20/11/03 by colmaccoll]
[Edited on 20/11/03 by colmaccoll]
ATB
Locoboy
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tadltd
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| posted on 20/11/03 at 10:51 PM |
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Just checking - is the diff installed the right way up? (i.e. shouldn't it be up-side-down to drive the front wheels - it probably is, but I
can't tell as I have no experience of Sierra diff's! )
He may also want to look at the position of his steering rack and/or the out-board track-rod ends before driving it...
Can I suggest connecting the rear wheel to a set of bicycle pedals for reverse?!
Can't wait to see it go!
Steve.
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MikeR
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| posted on 20/11/03 at 11:11 PM |
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could someone post details on how you modify the mini diff and have a guess as to how much power it can handle before it goes pop.
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gsand
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| posted on 20/11/03 at 11:34 PM |
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quote:
Originally posted by Alan B
Another minor point.
What is needed to couple the units is actually a compliant drive coupling (readily available) rather than a plain U/J
A U/J allows for angular misalignment and movement while holding two elements on a perfect center line.
A compliant coupling on the other hand allows for a little angular misalignment and a little eccentricity between the two elements....very common
between say a pump and a motor....
Small point, but worth mentioning....
Yes thats kind of what i meant to say, just didnt know the right name. Thanks.
Had a bit mrofe of a think, and came accross the idea of mouinting the diff direct to the Output shaft. This would involve a 'driveline
subframe', used in several bike engfined cars. This would mount the motor and diff very securely and with a stong design it cound have zero flex
to disrupt the aligment of motor/diff. Although this would be quite a compact install, I would much rather have a compliant coupling in between to
increse the length of the system, there for the rear of my car can me much lower. The way it should be, just like the XTR.
Regards, Glenn
4st Insanity
Maybee i should start wearing a Welding mask.....
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locoboy
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| posted on 21/11/03 at 09:35 AM |
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tadltd: the diff is the correct way up as the max engine spins the other way compared to blade/zx9 etc, hence you couldnt use a max engine in a rwd
locost mores the pitty  , plenty bhp and more torque than you can poke a stick at!
ATB
Locoboy
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gsand
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| posted on 21/11/03 at 09:40 AM |
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This is q quick thread.... 20 replies in just over a day
....(make that 21 )
4st Insanity
Maybee i should start wearing a Welding mask.....
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MikeR
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| posted on 21/11/03 at 07:55 PM |
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and still no one has answered with a "how to modify the mini diff to make it chain driven" just how many more posts are we going to
get???
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Alan B
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| posted on 21/11/03 at 08:08 PM |
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quote:
Originally posted by colmaccoll
tadltd: the diff is the correct way up as the max engine spins the other way compared to blade/zx9 etc, hence you couldnt use a max engine in a rwd
locost mores the pitty , plenty bhp and more torque than you can poke a stick at!
Ah so the diff is actually running in reverse all the time...I'll be interested to see how it holds up
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Spyderman
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| posted on 22/11/03 at 01:34 PM |
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quote:
Originally posted by MikeR
and still no one has answered with a "how to modify the mini diff to make it chain driven" just how many more posts are we going to
get???
I am still looking for the links I have about the Mini diff.
I'll post them as soon as I find them.
I don't check out the forum every day, just most!
SteveG,
I don't think you could drive the Mini diff like that as it is mounted onto the rear of the Mini gearbox and is driven by gear. The diff does
not include the input gears.
In racing applications the diff is left open and is mounted into a cradle. So basically you just have a "crown" wheel and spider gears,
but no pinion. The crwon wheel is actually just a large gear.
It is possible that the references I am thinking of are from the likes of "Race and Rally car Sourcebook".
I'm sure I've seen them elsewhere also though!
Terry
Spyderman
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