More info about limited slip differential

[Memmeddu]

Hi everyone .
We (my friend and I) are wondering about making a little funny rally car.
But something enough unique.
FIAT 126 ,4WD, 150 to 200HP(R1,CBR,GSX,NINJA engine) on roughly 600Kg of weight.
But since we are practically broken and we'll put all the money on the seats,roll cage, stiffening parts, suspensions and brakes.
Anyway back on topic.
I was wondering if I can use some sort of spring to create resistance between the free spinning spur gears (not the ones connect to the axles) so they will have reduced spinning speed and should give little bit more torque on the inside wheel

Ps from what I've understood the LSD it's not a good idea on the front axle

 

[hotponyshoes]

It's definitely not a good idea on a front axle as you need the wheels to be able to rotate at different speeds for the steering to work

 

[hotponyshoes]

If your budget does not stretch to a drop-in replacement there must be something cheap in a scrapyard that you could make fit?

 

[bricol]

It's definitely not a good idea on a front axle as you need the wheels to be able to rotate at different speeds for the steering to work

Depends. Certainly get LSDs in front wheel drive that otherwise would simply spin one wheel and go nowhere - does make the steering pull a touch a though

Can get LSDs to fit the front of most performance 4WDs.

 

[bricol]

Hi everyone .
We (my friend and I) are wondering about making a little funny rally car.
But something enough unique.
FIAT 126 ,4WD, 150 to 200HP(R1,CBR,GSX,NINJA engine) on roughly 600Kg of weight.
But since we are practically broken and we'll put all the money on the seats,roll cage, stiffening parts, suspensions and brakes.
Anyway back on topic.
I was wondering if I can use some sort of spring to create resistance between the free spinning spur gears (not the ones connect to the axles) so they will have reduced spinning speed and should give little bit more torque on the inside wheel

Ps from what I've understood the LSD it's not a good idea on the front axle

What are you going to use for the front diff? Or rear? Or to get the drive to either end?

 

[dobbslc]

Get the transmission from an Alfa 159 Q4
Torsen diffs in one of those ...

 

[whm_fab]

It's definitely not a good idea on a front axle as you need the wheels to be able to rotate at different speeds for the steering to work

well, sorry but thats simply not true.
practically all FWD race/rally cars that are allowed by the rules (and some not )will absolutely have an LSD fitted, and with an LSD the wheels will still be able to rotate at different speeds.
a FWD rally car without an LSD would be useless.

Ufortunately theres no cheap way out of this for the OP, those miracle cures you see advertised with springs don't work, and you have really no option but to fork out for an LSD unit if you want one sadly

 

[Brad93]

Quaife used to be the go to for small front wheel drive cars

 

[hotponyshoes]

I know you can get them, I have got one in my 4wd track car (not that it's much use on tarmac).
I was referring to the op's post about the spring loaded ones not being reccomend for the front.

To the op, providing you don't need to comply with any regulations or have all the parts in date then, if I was building a budget rally car for fun, I would source whatever parts I needed, build a tubular chassis to join all my bits togeather, then wrap the body around it.

Used motorsport parts are cheap enough, or buy a need-for-speed Japanese motor that some boy racer has spent half a million on bolt-on bits but only ever used to cruise around mcD's carpark as a donor.

 

[Munkul]

if its 4wd then just weld the back diff up, you don't need a diff on the back. It'll make a huge difference to the way you can corner. Leave the front diff alone.

Seriously, I drove my 200sx with a welded diff every day for a year... was great. Much more predictable than an open diff. The scuffling in carparks got a bit annoying though.

 

[bricol]

In over 25 years of tuned Lancia integrale ownership, and a couple hundred thousand miles on the road, I can only recall a handful of times I got momentary front wheelspin.

Quite a few of wonderful smooth four wheel drifts though (closed road, private test track, professional driver etc )

 

[atomant48]

Used motorsport parts are cheap enough, or buy a need-for-speed Japanese motor that some boy racer has spent half a million on bolt-on bits but only ever used to cruise around mcD's carpark as a donor.

anything JDM seems to command quite a premium at the moment (which is great - my stash is going up in value!)

ive always wondered if the earlier bmw minis would make a fun rally car or even a Ford ka. Something with the wheels pretty much at the 4 corners.

 

[fizzy]

The Focus RS - or one of them - was fitted with a Quaife torque biasing diff - similar to the torsen but better.
I had a pair of them fitted to my Defender 110 V8 - awesome in the snow and gravel - great fun on muddy fields as well.

 

[hotponyshoes]

anything JDM seems to command quite a premium at the moment (which is great - my stash is going up in value!)

ive always wondered if the earlier bmw minis would make a fun rally car or even a Ford ka. Something with the wheels pretty much at the 4 corners.

Might be time to clear my container out!

 

[Rannsachair]

I have front and rear lsd's on my Defender, fitted as upgrades to damaged/worn diffs, certainly the traction control comes on less with them.

 

[atomant48]

Might be time to clear my container out!

What have you got ?

 

[hotponyshoes]

What have you got ?

Allsorts.
Tell me what you want and I will go digging for it.

 

[Memmeddu]

What are you going to use for the front diff? Or rear? Or to get the drive to either end?

I still have to make researches about what I could use , because we're talking about a really small car ,it born 1.34meters wide ,1.4 tall ,3 long

if its 4wd then just weld the back diff up, you don't need a diff on the back. It'll make a huge difference to the way you can corner. Leave the front diff alone.

Seriously, I drove my 200sx with a welded diff every day for a year... was great. Much more predictable than an open diff. The scuffling in carparks got a bit annoying though.

It's going to be 4WD mid mounted engine (as a Lancia Delta S4 with the same intakes too ) but it born RWD rear mounted engine as a Porsche 911
I'd like to have most of the power on the rear .
I'm not so inclined to weld the rear differential because I'd like to keep as small as possible the minimum steering diameter (8 meter stock I think)
Little bit wider (100+100 mm)

 

[Memmeddu]

well, sorry but thats simply not true.
practically all FWD race/rally cars that are allowed by the rules (and some not )will absolutely have an LSD fitted, and with an LSD the wheels will still be able to rotate at different speeds.
a FWD rally car without an LSD would be useless.

Ufortunately theres no cheap way out of this for the OP, those miracle cures you see advertised with springs don't work, and you have really no option but to fork out for an LSD unit if you want one sadly

I was wondering about ,by seeing those kits used on BMW's but I've instantaneously thought that would be a gear grinder because of all the pressure on the gears .
I've seen how a real LSD it's made and it's practically a tube with friction disks on the gears

I know you can get them, I have got one in my 4wd track car (not that it's much use on tarmac).
I was referring to the op's post about the spring loaded ones not being reccomend for the front.

To the op, providing you don't need to comply with any regulations or have all the parts in date then, if I was building a budget rally car for fun, I would source whatever parts I needed, build a tubular chassis to join all my bits togeather, then wrap the body around it.

Used motorsport parts are cheap enough, or buy a need-for-speed Japanese motor that some boy racer has spent half a million on bolt-on bits but only ever used to cruise around mcD's carpark as a donor.

All safety regulations have to be followed .
And that's why all the money it going on the roll cage etc
It Will be not on the 2 cylinders category
And not on the proto one because we'll have to make it street "legal" because otherwise it will only see slalom on asphalt .
Other money
It will be a group N .

FIAT 126s are already pretty funny with their 2 cylinders and 26HP
But we found one for 200 euros and no engine

 

[ronan]

Superfast matt, he does some great builds. He is doing a huge old jag atthe mo, converting it to tesla power.