Saloon diff ratios

[Robyn Slater]

Just looking for informed opinions on final drive ratio for my historic anglia saloon.I,ve got to assemble the lsd and at the moment have got a choice between 4.4 and 4.9.
btw its 1300cc pre x-flow. 2000e cr box.

Cheers,
Robyn

[morninggents]

Robyn
If you are running the Dunlop CR65 in 4-50 M x 13 size you will need the 4.9 ratio.
Peter

[GORDON STREETER]

If you go for the 4.9. You will run out of revs on the circuits with long straights unless your engine will pull 9500 - 10 000 in top. Idealy go for a 4.7 that will suit most circuits. It will pay you to build them both up then you can swap them over at the track and see. I used to run 5 different ratios but have narrowed it down to 4. In the grand scheme of things buying another LSD isn't that expensive and you will wish you had if you have a diff problem at a meeting .

[zefarelly]

agreeed Gordon, I carry a 4.4 spare and use a 4.7, a 4.7 seems to work best for me with a 1500 and 5.25 tyres and the current engine

most LC's run 4.4 or 4.7 depending on engine, Dan Cox ran a 4.9 and sometimes a 5.1 on his old Anglia, although he said he was bouncing off the limiter at 10k with a 5.1!

[morninggents]

Originally Posted by zefarelly

agreeed Gordon, I carry a 4.4 spare and use a 4.7, a 4.7 seems to work best for me with a 1500 and 5.25 tyres and the current engine

most LC's run 4.4 or 4.7 depending on engine, Dan Cox ran a 4.9 and sometimes a 5.1 on his old Anglia, although he said he was bouncing off the limiter at 10k with a 5.1!

Agreed the 4.7 is the best ratio. I use a 4.7 with spare 4.4 and 4.125 in the Cortina with 5-25Ms.

However, for the 1300 engine I think the 4.4 is too high. What sort of max revs will you be using Robyn?

Peter

[Robyn Slater]

Thanks guys.Its good to get this kind of advice from people in the know.

I,m hoping to get this engine to rev to 9500+,but its going to need some development first.
The whole project is a mass of parts at present,having spent months repairing the shell and collecting bits.

Tyres wise i assume the 4-50m is the right tyre for the anglia (5.5j wheel),
do i have a choice on tyre size?

Looks like i need to find a 4.7 diff as well.

Robyn

[morninggents]

Robyn
If you are racing with HRSR you must use the Dunlop Racing CR65 tyre.
Tyre size is optional but most Anglias use 4-50 M x 13 all round. Some have tried the 5-25 M on the rear but they should be used with 6 inch rim widths and may prove to be too wide for the wheel arches. Most Anglia drivers agree that the cars are far better balanced with 4-50s front and rear.
Peter

[zefarelly]

I think 5.25's require chopping on Anglias which is forbidden by pretty much everyone isn't it ?

anglias and cortinas are both homologated with 5 1/2" rims, and a 4.50 seems to fit very well

Cortinas seem to run ok with 5.25's on the rear with 5 1/2" j's although I'd agree 6" is probably better to reduce wall movement, I've seen them on 7" rims on sports racers, which also reduces the profile a bit

[GORDON STREETER]

I have tried various tyre sizes over the years only to revert to 185/60x13 profiles. Bigger tyres always have the clearance problem and the car doesnt seem to have that "chuckability" factor into corners. Also they never improved my lap times, even on slicks its only about one and a half secs a lap faster at Brands.

[zefarelly]

therefore crossplys rule, stick yer slicks in the dark!

I've never tried 4.50's on the back, although I beat the only other GT I've ever raced with and that was on 4.50s with a linked rear end and discs all round . . . . . sits bag with smug feeling

[Robyn Slater]

So CR65,s are crossplys, that must make it interesting then.

Tyres are just one of the many things on the shopping list.

[zefarelly]

yes they are . . . don't waste your time trying to shop around either, go straight to HP Tyres

£100 a corner

[Gerry Taylor]

I ran just two 5.3 and 5.5 this did me for long tracks such as Snetterton and Silverstone and also Mallory and smaller circuits.
That was using my m.a.e. unit reving to 12,000 max (well...ahem......)
Hope that is of help.

[GORDON STREETER]

Gerry That might well have been OK then, but don't forget we are now running a lot lower profile tyres. Not the lorry diameter R7s we used to use !
I remember buying an original racing Anglia shell in the early 70s and it looked ridiculous when we put the "then new" 20in diameter slicks on with the massive cut away wheel arches .