Need suggestions for Chain-driven diffs

[DigitalPho3nix]

Hey!

I am helping design and build a new hillclimb car at uni, and we are in need of a diff.

We are using a Yamaha R1 Motorcycle engine, so needless to say the drive output is via a chain.

We thought of using a Quaife diff first, but does anyone know of any viable alternatives off the top of your heads?

Cheers,

Chris

[roadsailing]

RMIT boys uses an MX5 KAAZ i believe, as its the smallest one they made (looked damn small too)

you will of course need to make up a sprocket that bolts where the crown wheel would normally want to go.

look into using a solid axle, has its downsides but will be very light and simple, and if there are any drift courses you will win!

[DigitalPho3nix]

RMIT boys uses an MX5 KAAZ i believe, as its the smallest one they made (looked damn small too)

you will of course need to make up a sprocket that bolts where the crown wheel would normally want to go.

look into using a solid axle, has its downsides but will be very light and simple, and if there are any drift courses you will win!

Mmmm, not keen on that. I am looking for bolt-in solutions, and we are not hard pressed for space.

The diff also needs to be new out of the box. No used car type stuff.

[roadsailing]

used car type stuff? dunno what you mean. solid axle just means no diff, KAAZ LSDs are available new

[DigitalPho3nix]

used car type stuff? dunno what you mean. solid axle just means no diff, KAAZ LSDs are available new

Ah sorry, misunderstood you!

Not looking at a solid axle at this stage as it will be too hard to service should something go wrong. We can't just slap another chain on there in a few minutes otherwise.

The KAAZ website looks like it only makes diffs for road car applications, and we do not want to venture into modified diffs although, having an easily removable sprocket may be interesting...

[roadsailing]

last one for the night:

a diff from a 1100kg car will handle all the punishment you can dish out from an R1 motor (probably)

look into using a split sprocket, so you can change your final drive ratio easily, without having to remove axles or anything.

with a live axle you can still slip another chain on very easily, you just can't use a linkless chain.

[DigitalPho3nix]

last one for the night:
a diff from a 1100kg car will handle all the punishment you can dish out from an R1 motor (probably)

True. The car itself will probably only weigh around 300-400 kg with the driver.

look into using a split sprocket, so you can change your final drive ratio easily, without having to remove axles or anything.

That may work... I'll look into that for sure.

with a live axle you can still slip another chain on very easily, you just can't use a linkless chain.

The plan is to use a linkless drag racing chain. It is a little more maintenance, but well worth the peace of mind when a chain is whizzing around behind you and so close to the fuel tank which will be under the driver's seat and next to the firewall.

[mrshin]

Could you use a solid axle, with a flanged removable piece in the centre to allow chain removal? It wouldn't be that difficult to machine up suitable flanges etc.

[crowncustom]

Best thing for you to do is have a talk to someone that races the Speedway scene and races Formula 500's as they run motorbike engines and use a chain drive rear.
Cheers Brett.

[DigitalPho3nix]

Could you use a solid axle, with a flanged removable piece in the centre to allow chain removal? It wouldn't be that difficult to machine up suitable flanges etc.

The solid axle will be a bad idea I think. Given that this is a hillclimbing car, there is certainly going to be tight and technical corners to negotiate. Having a solid axle in this case would be serious disadvantage. Sure, there are going to be some fast sections but nowhere near as many as the tight corners.

[DigitalPho3nix]

Best thing for you to do is have a talk to someone that races the Speedway scene and races Formula 500's as they run motorbike engines and use a chain drive rear.
Cheers Brett.

We are having a looksee at a proven-to-win hillclimb car today, so we shall see what setup they use.

[Ben Wilson]

The solid axle will be a bad idea I think. Given that this is a hillclimbing car, there is certainly going to be tight and technical corners to negotiate. Having a solid axle in this case would be serious disadvantage. Sure, there are going to be some fast sections but nowhere near as many as the tight corners.

You can set up your geometry to compensate for the lack of a diff, have you ever seen a supercart on a hillclimb track?

[Screamn_Sleeka]

UTS used a rav-4 front lsd diff last year, but only because it was free (sponcered), and they are imported.

I dont think it matters if its a live axle because of racing limitations, but the point of building this is to achieve a well constructed and planned car. IRS defiantly gets you more points. (if this is for what i think this is?)

[DigitalPho3nix]

You can set up your geometry to compensate for the lack of a diff, have you ever seen a supercart on a hillclimb track?

No, but that would be pretty cool!

While a good idea, we already have the suspension and so we can't change it (too much). As this is an experimental car, and the objective is to get it racing ASAP, we have taken the suspension from a Formula Ford as it is a given quantity.

[rick q]

The English Clubman community get into this a fair bit. It would be worth doing a search on
http://www.locostbuilders.co.uk/index.php.

I found a couple of links there :-
http://www.westgarage.co.uk/services...aindrives.html
http://purplesagetradingpost.com/sum...%20page-4.html

There are plenty more

[Hiro]

UTS used a rav-4 front lsd diff last year, but only because it was free (sponcered), and they are imported.

I dont think it matters if its a live axle because of racing limitations, but the point of building this is to achieve a well constructed and planned car. IRS defiantly gets you more points. (if this is for what i think this is?)

Uni of Newcastle SAE team used a Rav4 Torsen LSD for the last few years, I think it was the rear diff though not the front. Made up our own sprocket and housing, and it was all good. Easily handled the punishment that the CBR600F4i put out, although the axles didn't (thats a whole story of it's own, by the way)

[Ben Wilson]

As this is an experimental car, and the objective is to get it racing ASAP, we have taken the suspension from a Formula Ford as it is a given quantity.

Then go for a spool, simple, light, reliable and consistant. With LSDs you get preload adjustment, heat variation, wear and added weight.

[julzy_quads]

Just weld a cog or gear onto the flange of the diff and have a chain from that to the engine. I have done this on my 450cc trike and works a treat. Need to be very precise when you weld the cog on though.

[Hiro]

Just weld a cog or gear onto the flange of the diff and have a chain from that to the engine. I have done this on my 450cc trike and works a treat. Need to be very precise when you weld the cog on though.

Our sprocket was CNC cut and bolted on, thus was removable which is very desirable in case you lunch a tooth into the chain and need to replace the sprocket (this DID happen to us, although only on the much much smaller crank sprocket)

[julzy_quads]

yeah probably a much better way to do it. especially if your going to be changing the sprockets around for different tracks and the such