bellett.net

hi, just trying to find a automatic bellett diff..im after a 4.1 ratio diff

waldo... the story that auto bellett's (in australia anyway) had a 4.11 diff is just that.... a story.
the 3 original aussie delivered auto's i've seen had all had the normal 3.73.
as most original documentation came from japan, it says auto's had a 4.11, but not the ones we got. only explaination i can give is that our auto's were spec'ed differently when ordered?

having said this tho, i've seen 4.11 diffs around. i've only ever seen a handfull, so they are rare. as for why the cars i've seen them in actually had them ......... ??

there is a way to tell what the ratio on all bellett diffs are by looking at them. if u look at the housing, stamped into the rib that's cast into it near the oil fill plug, there's a series of numbers there.
they work like this:
early cars used a 3 digit code.
34 9 is a 3.778 ratio.
37 9 is a 4.111 ratio.
later cars used a 4 digit code.
41 11 is a 3.727 ratio.
41 10 is a 4.100 ratio.
the numbers actually relate to the number of teeth on the crown wheel and pinion. the first number (34, 37, 41) is the crown wheel, the second number (9, 10, 11) is the pinion. dividing the second number into the first number gives the ratio within.
as the later diffs had a more teeth on both the crown wheel and the pinion, they are slightly stronger than the early ones if you're pumping some decent power thru them. also, later diffs are more common than early ones too.

as a point of interest, i use a 3.73 in my race car. i've driven another car with a 4.1, and it really didn't feel that different to mine. also, we've had more success with getting gear ratio's better by using a better gearbox, but more so by playing around with tyre diameters. u'd be surprised what a difference a tyre that's 12mm smaller in diameter can do to acceleration!

hope this helps.
brett.

thanks for the info...my bellett runs a 5 speed from a gemini zz/r and it is a very tall gearbox. I remember cruising at 100km/h and it was sitting on 2500rpm, which is why i am trying to source a diff that could give me a bit better accelleration and then it will maximise the use of the 5 speed

that's a VERY tall gearbox waldo.
all of my cars that have had 5 speed box's, with 3.73 diffs, have done around the 3000 mark at 100kph.
have u checked how accurate the tacho is to make sure your figures are correct?

yeah the tacho was out by about 800rpm but we figured this out on the dyno...and the 2500rpm was the corrected rpm

Florians actually run a 4.1 diff sorry I can't help you with one.

goldy wrote:Florians actually run a 4.1 diff sorry I can't help you with one.

yes, they do too. thanks goldy!
and a wasp uses a 4.56 ratio.

ok, so the diff centre itself doesnt bolt into a bellett (the irs ones), but the crown wheel and pinion are a straight swap into a bellett housing.
maybe that would suit waldo?

lol yeah it would i only want the crown wheel and pinion but who has one of these diffs out there?

i do.....
and i may possibly be parting out the florian, as i cannot store it at this stage. i might pull the diff centre etc out just in case!

that would seriously be awesome!! please let me know if you do!