18 replies to this topic

[Ice]

Highway driving and 3.55 dont go together that well your engine will be revving its arse off at 100 kph
3.08 would be better for highway driving imho

[S pack]

3 and 4 speed both have 1:1 ratio in top gear so no difference. I'd go the 3.55 also.

^^^ Agree, however if you are going to do a fair bit of highway driving then I wouldn't go below a 3.36.

Years ago I changed up from a 3.36 to a 3.08 and was much happier with the revs at 100kmh.

[Ice]

More legs with the 3.08 and 4 speed

[EunUCh]

Wheel/tire size plays a fairly important role in what ratio to run as well,usually most engines were run at peak torque

or just above at 60mph.

This calculator might help a bit.http://www.advanced-...Size/index.html

[BIG KEV]

It all depends on what kind of driving you intend to do .....3.08 is a good all rounder ....but if you want more go down low go 3.36 or 3.55 but no good for highway driving......read above post sounds like most guys here have been down this road before ......good luck

[76lxhatch]

Wheel/tire size plays a fairly important role in what ratio

 

Exactly, I don't see any mention of this...?

 

Factory 13s (assuming we're even talking about a Torana) will be quite a bit different to say a set of 17s or 18s with bigger rubber

[caterham2]

G'day all,

 

I'm rebuilding my banjo rear end and I'm having a dilemma over what centre ratio to put in as I can't really be f****d changing it if its not what I expected.

I'm running a 202 with an M20 aussie 4 speed but I haven't actually had a car with a munchie 4 speed before so I don't have any idea how it effects the setup but I've got a 3.08, 3.55 or even a 3.9 if needed, so was after peoples experiences with that setup/diff ratio combos.

In my experience I've had the following but both were 3 speeds so I'm trying to work out how a 4 speed would effect things:

- 202 with trimatic and 3.08 diff- Not bad off the line but responsiveness at highway speeds (100kmh +) was average and I always felt the engine seemed to be a bit overworked due to 3rd gear topping out.

- 186/192 with crashbox and 3.9 diff- Killed it off the line but was terrible at highway speeds (well obviously) and it struggled to maintain 60mph

 

I'm leaning towards the 3.55 as I would like to have some punch down low, but how difference does a 4 speed make at highway speeds? and would it make a huge difference with a 3.08 opposed to the 3.55?

- I'm not concerned about economy as it wont be a daily driver

- I would like to do a fair bit of highway driving so be easy to maintain 100k plus without having to push it along too much, but still be fun to drive around the city.

 

Any insights anyone?

 

cheers

Callen, I have tried ALL the ratios available in my car............  LJ XU1, engine hp 250, Bathurst ratios  in box ( dare I say it, a verified Bathurst build former group C  car) used for all sorts of things including hillclimb events. With this gearbox and very tall first gear a 3.08 is near unuseable on any sort of incline when starting off due to cam characteristics, 3.9 buzzes like mad at highway speeds but its lots of fun, 3.36 and 3.55 tried and found to be good all round  on the road, I will put the 3.36 back into mine when I get round to it, I think it was the best combo bearing in mind Victorias 100kph limit, but maybe with your lower first gear 3.08 would be a chance.

[N/A-PWR]

Stick a 2.78 LSD in it with a M22 Box and Skinny tyres. Dave I

 

p.s. The M22 (6cyl One Tonners only) has a 1st gear ratio of 3.74

Edited by TORYPOWER, 07 August 2013 - 07:59 PM.

[N/A-PWR]

Hi Callen,

As said in Post #13 - You will start off like a M20 ( 3.05 1st ) with a 3.55 diff and the rest is History. Dave I

 

p.s. Fully Worked Motor can handle the gear ratio spaces of a M22 and 2.78:1 LSD Banjo Diff

 

p.p.s. tried and proven in which is my new build

Edited by TORYPOWER, 07 August 2013 - 08:24 PM.