I didn't place the chains and the sprocket sizes are not correct. The wheels are not correct either.
[Edited on 20/11/07 by 9000rpm]
What do you guys think of this setup.
I didn't place the chains and the sprocket sizes are not correct. The wheels are not correct either.
[Edited on 20/11/07 by 9000rpm]
someone te other day said a suzuki sj has a nice small 1:1 take off box independant to the gearbox. easier to fit that in line engine and rear axle
and a non central dif at the front with unequal lenth driveshafts. gotta be better than all those chain which will have to be lifed and changed and
adjusted regularly.
Ned.
not sure i'd be keen on all the chains either.
on a normal 4wd (say land rover) don't the 2 prop shafts from the transfer box to the axles turn in opposite directions? never checked, but just
kind of assumed they did
quote:
Originally posted by ned
someone te other day said a suzuki sj has a nice small 1:1 take off box independant to the gearbox. easier to fit that in line engine and rear axle and a non central dif at the front with unequal lenth driveshafts. gotta be better than all those chain which will have to be lifed and changed and adjusted regularly.
Ned.
It has to be said, why? 
If its going to be a hillclimb single seater then surely weight is more important than 4WD which will only be a slight benefit off the line and in
tight corners?
You need a centre diff or the transmission will lock up if you attempt to go around a bend which defeats the object as the car will drag, best one
would be a viscous type as an open diff again is a waste of time as all the power will go to the spinning wheel.
nb/ landovers props both go the same way, early suzuki has high, low and locked diff, so only good on gravel.
[Edited on 20/11/07 by mark chandler]
www.dpcars.net
I have to agree it would be fairly pointless, I've got 274Bhp in around 600kg, twin bike engines driving rear wheels only, ok I have 285's
on 10" rims at the back, but on a dry road get virtually no wheelspin. It would only have any benefit in the wet & any benefits would
probably be negated by the extra weight.
quote:
Originally posted by ChrisGamlin
It has to be said, why?
If its going to be a hillclimb single seater then surely weight is more important than 4WD which will only be a slight benefit off the line and in tight corners?
quote:
Originally posted by mark chandler
You need a centre diff or the transmission will lock up if you attempt to go around a bend which defeats the object as the car will drag, best one would be a viscous type as an open diff again is a waste of time as all the power will go to the spinning wheel.
nb/ landovers props both go the same way, early suzuki has high, low and locked diff, so only good on gravel.
[Edited on 20/11/07 by mark chandler]
quote:
Originally posted by Hammerhead
www.dpcars.net
Afraid I'm in the 'Why?' camp apart from anything else one chain driving a car in is a pain in the ar*se from a reliability point of
view let alone three!
quote:
Originally posted by D Beddows
apart from anything else one chain driving a car in is a pain in the ar*se from a reliability point of view let alone three!
Is it that bad ?
Another one for the "why" camp i'm afraid. As mentioned previously, your proposal suffers from having no centre diff so 4wd simply wont
give the traction benefits you would like and will suffer from excessive understeer.
You'd still have the big weight penalty though which on a single seater hillclimb car i'd imagine could be as much as 20 - 25%???
I've been out in the 4wd Tiger Z100WR (twin engined - each driving its own diff, front and rear, with no mechanical linkage) and that used some
very fancy Motec ECU's which acted as an electronic centre diff. The car actually had sensors to measure G Force and this was used to cut power
significantly to the front wheels to improve traction off the line and improve cornering. Before these were fitted and set up properly the car
understeered like a pig.
[Edited on 21/11/07 by Paul TigerB6]
I think you need some encouragement.
Im sure this debate comes up quite frequently on here.
Ignore everyone else and do what you find interesting. The world would be a dull place if people didnt.
Is the transmittion equiped with a centre diff? From looking at the image youve given the gearbox drives into a chain on the prop and then via two
other chains onto the diffs. Where the first chain connects to the prop seems an epicyclical gear set for a centre diff??
There are a lot of fast 4wd hillclimb cars out there. Admittedly most are car based, but things like Mike Endeans puma are immense. The acceleration
away from the line and out of corners is phenominal.
I also seem to rember a 4wd clubman car being about that was scarilly fast.
Ideally you want a powerfull engine as the transmission losses will be less of an issue. Have you though of going for a super / turbo charged engine?
and moving up to the 2ltr class?
quote:
Originally posted by jono_misfit
Ignore everyone else and do what you find interesting. The world would be a dull place if people didnt.
Its a bit of a double edged area similarity.
A lot of similarities exist in competition cars not always becase thats the best way to go, but becuse the people producing them are too scared of
their idea not working that they wont go against the norm.
This is also compounded by people who buy cars being wary of something different and untested as its their money at stake.
I am not making the decleration that 99% are incorrect to say RWD is superior, im saying that AWD is not necesseraly at a disadvantage and someone
contemplating it shouldnt be knocked for it.
Weight in hillclimbing is very important, however many of the cars have traction issues on any slow corner, the driver must back right off. A suitable
AWD system would help in this regards.
One viewpoint i hold though is if RWD is superior on tarmac why do WRC cars continue to run AWD on it? The teams would have transmission that
disengage the front drive in corner conditions if it was advantageous. In stead the bias is set to 40/60 - 30/70 or similar but maintained.
quote:
Originally posted by jono_misfit
Is the transmittion equiped with a centre diff? From looking at the image youve given the gearbox drives into a chain on the prop and then via two other chains onto the diffs. Where the first chain connects to the prop seems an epicyclical gear set for a centre diff??
quote:
Originally posted by ChrisGamlin
quote:
Originally posted by jono_misfit
Ignore everyone else and do what you find interesting. The world would be a dull place if people didnt.
I don't disagree with this but in a competition environment if 95% of the competition are doing it one way (RWD), there's usually good reason because if an alternative was quicker and not difficult to achieve, everyone would be doing it.
The only workable solution would probably come from a big quad bike, and you using a bike engine.
Whether the drive train would take the power is another thing altogether???
Cheers,
Syd.
You could try something like a DCCD centre diff from a japanese Impreza type R or current UK ones.
Im pretty certain they are an epicyclic with plate friction locking. The DCCD bit is an electrical lock up mechanism that allows you to vary it from
locked (or near locked) to fairly open. You can also buy programmable diff controllers for them.
I dont think it would be mega expensive.
quote:
Originally posted by jono_misfit
You could try something like a DCCD centre diff from a japanese Impreza type R or current UK ones.
Im pretty certain they are an epicyclic with plate friction locking. The DCCD bit is an electrical lock up mechanism that allows you to vary it from locked (or near locked) to fairly open. You can also buy programmable diff controllers for them.
I dont think it would be mega expensive.
Having done similar before, I can assure you that in any "normal" car package, those chains will melt!!
You need either EXTREMELY heavy duty 3/4" pitch drag bike chain and chage it regularly (which is what I am using on my twin bike engine grasser)
or you need morse silent chain running in oil.
Simply look up chain drive specifying guides on the net, try reynolds chain for starters.
For a car type drive, you are off the chart for nearly everything!!!!
You will be using a shorter chain than the guide will allow, with a 1:1 ish drive which necessitates a huge power capacity reduction, then you will
have high rpm and no lubrication, plus dirt.............................................
As I said, I'm using chains (2 of them) as there is no alternative for me, but I wouldn't want to do any number of miles with them!!
Reliabilty of chains !!!!
I would need to play with the ratio's too, to get a proper final drive ratio.
I would think enclosing the chain in some sort of casing would be very hard.
Chains are fine as long as you have good sprocket alignment....
Hi all,
I'd thought about a similar setup for my autocross / autograss car. But this car will only be driven on loose tracks. In autocross / autograss
4x4 is a huge benefit. Do you guys think i can run a similar setup without a central diff? Our tracks are normaly very loose heavy sand. i'm
thinking about using two ford sierra diffs connected permanent to each other with a propshaft. The rear diff will be a locked (welded) one and the
fwd diff will be open. A bike engine is then placed in the mid, with drive sprocket slightlly fwd of the right hand output shaft where i want to put a
70t sprocket on. So actually the right hand rear output shaft is driven and rear diff will distribute it to the front end.
In our class bike engines (hayabusa / zx10r / blackbird etc ) are often used with a sprocket ratio of 70/14 and rear driven on locked diffs or 4x4
with chains going all the way from backside diff to fron chain diff.
reg. Frits
My limited experience with chain driven cars put me off them for life, and that was track only use too lol.
The "why" campers surprise me. We should encourage differences, all our cars are different. Who cares if it is slower, his / her competition
won't!
The advice on chains is good to see, plenty of experienced folk here on that subject, I am not one.
I would add to look at other diffs though. MX5 may give you close enough ratios and are alot cheaper and plentiful.which is what you may need for this
development.
Did the OP ever get anywhere with his design?
I doubt he's following the thread 14 yes after the last posts.