R30 diff

[machg]

Guys,

Doing a lot of K's in my HR30 now. It would be nice to have a taller diff. What is the tallest diff I can get for my car? It currently runs the L20ET auto diff with L24E manual box (120km/h = 4000rpm) so how much difference would the "tall" diff make assuming I could find one. Not worried about getting off the line as 1st gear is ridiculously short anyway!

cheers,

machg

[V8skylineMAN]

i *think* the earlier skylines...(c110) had a 3.7 in the auto cars?

[B0oStEr]

What ratio is the auto diff? I think the tallest R180 ratio available is 3.54:1 but I don't know where you would find one.

If you ever have the L24 gearbox open drop in a set of overdrive gears from an L20 box. It gives you a very tall overdrive ratio and doesn't make the car sluggish in the lower gears like a taller diff does.

I had this gearset in my old L28 powered R30 and it drove very well.

I can't remember the exact revs at 100 kph but I think it was about 2600rpm with a 3.9:1 diff.

[V8skylineMAN]

What ratio is the auto diff?

Look up ^^

[SteveL]

3.5 R180 was used in 4-speed manual 240K's sold in Australia - pre-1975 or 1976. Hard to find these days. Diff would bolt in, but don't know about the driveshafts.

[rsx84]

my old 82" r30 auto hatch would sit at about 3500rpm at 100km/h so that sounds about the same as the diff you have.

[stagefumer11]

mine sits at 2900 at 100k. Thats reading off a Autometer Tac. Factory gauge says 3000rpm.

Factory 3.9 diff

[BensDR30]

I bought a new 3.54:1 R&P a few years ago & fitted it to my MR30, was a few hundred $. With the 4-speed auto it was a bit tall, but I expect it would be good in a manual or 3-speed auto. It's about to be fitted to a friends turbo MR30, as he runs out of revs with the 3.9:1 (yes, even in 5th...)

[machg]

BOoStEr

I like the sound of putting overdrive gears in my box. When you say L20 box, do you mean as in OZ Nissan Bluebird 5-speed?

BensDr30

R&P; do you mean crownwheel and pinion?

machg

[BensDR30]

Yes, a 3.54:1 Crownwheel & Pinion.