choices

[kai]

Hi all, need some advice, been thinking of upgrading my drive-train, these are my options , convert to 3:54 ratio diffs or high ratio transfer case, i have already got an overdrive and although it does help it is not enough. My reason for this is this, i am running a chev 4.1 which is pushing out about 143kw, 298n/t but cannot rev above 3500 for a prolonged period of time. I love this motor but if i cant get the fuel consumption down ive got a 2L TD waiting to be put in, i'm just worried about the reduction in power/torque. What should i do? By the way my landy is a south african r6 which means it has the santana gear box which is very robust.Any other ideas?

[acornhoek]

The high ratio transfer case affects only the high range gears by raising them by 31.8% and leaves the low range as is.

The 3:54 diffs raises both high & low range by 32.8% as well as throwing off your speedo.

IMHO, keep you low range low and go for the Ascroft High Ratio Transfer Case.....can't use the overdrive anymore, but you won't need it. BTW, Series overdrives give you approximately a 28% difference from stock.

-B

[kai]

Would love to fit the Ashcroft High Ratio Transfer case conversion in but a bit difficult since i'm in south africa. Been looking around for someone local who can do it, no luck so far. I think i'm going to put the 2l td motor in, it is quite a high revving motor for a diesel, sits at 4000rpm quite happily. Hopefully this as well as the overdrive will help my landy keep up with traffic.

[acornhoek]

a bit difficult since i'm in south africa

Not sure why it's more difficult. If you don't have a local dealer you can order directly from Ashcroft.......I got a new R380 for my '96 Disco from them and had it shipped to me in Colorado (really great to deal with). As far as installing it....the transfer case isn't rocket science by any stretch and is a lot easier than taking apart the tranny. You or any competent local shop could do it. Easier than an engine swap IMHO.

I kind’a figured you're in SA from your handle........you could probably figure out where I originate from by mine.

Good luck with the 2l td though.

[onslow]

Originally Posted by kai

Hi all, need some advice, been thinking of upgrading my drive-train, these are my options , convert to 3:54 ratio diffs or high ratio transfer case, i have already got an overdrive and although it does help it is not enough. My reason for this is this, i am running a chev 4.1 which is pushing out about 143kw, 298n/t but cannot rev above 3500 for a prolonged period of time. I love this motor but if i cant get the fuel consumption down ive got a 2L TD waiting to be put in, i'm just worried about the reduction in power/torque. What should i do? By the way my landy is a south african r6 which means it has the santana gear box which is very robust.Any other ideas?

I would go with the 3.54s simply because your engine will have the torque to deal with the higher gearing in low box and unlike high ratio transfer boxes they are relatively cheap and plentifull and easy to replace if they bust and they also tend to be a lot tougher than the 4.7

[Kevin]

Kai I've sent you an e-mail direct because lately I've struggled to log-in on the site. In brief I've got the lwb s/w fitted with the Chev 4.1l and fitted with 3.54:1 ratios into a Salisbury rear axle and standard front axle. These ratios are the answer. 60mph equals 2000rpm on the rev counter. My buddy has a 2.8l Petrol Skyline motor and no overdrive and standard ratios. At 60mph (my speedo his is 70mph) he is a full revs and putting huge strain on his motor (even melting the rubber exhaust hangers!)

Let me know if you get my e-mail.

Cheers.

[pickuprover]

Kevin. I assume that since you have 3.54 in the back and the standard in the front that you do not use 4 wheel much. That must put a lot of strain on the tranny/tc/driveshafts/axles/tires. Your front wheels and rear wheels would be turning at different speeds in 4 wheel. Any problems yet.

[TerryS]

I suspect what Kevin was saying is that he has the standard Front AXLE, i.e. Land Rover, as opposed to Salisbury or EVO. I rather doubt he would have 2 different ratios, and if he knew he did, I also rather doubt he'd admit to it.

[pickuprover]

That was what was confusing me.... would think that two different diffs running different ratios would not last to long. Something would have to give unless all of his driving was done on something with zero friction like ice. Would be so much worse than driving a fully locked front end on dry pavement in a sharp corner. Guess that I just read it wrong.

[captcory]

I am running the MerCruiser engine ( chevy 3.0liter 140 bhp ) I just swaped my 4.7 to RR 3.54 and will tell you this is the answer for the $. I would love to have the ashcroft but the RR 3.54's are fine in hi as well as low. I cruise 55mph at 2300rpm, yes the spedo is off...I used my GPS. As long as you are not running the stock 2.25 or the 2.5 then you are fine. Larger engines with more torque as you and I have need the taller gearing, higher ratio diffs are just cheaper.

[Kevin]

Sorry I wasn't clear about that. The front axle is standard EXCEPT for the diff that was also changed to the 3.54. I mentioned the change to the Salisbury axle because the original was either the EVO or the Rover (probably the latter).

I haven't driven a conversion with an overdrive so I can't compare there but definitely the ratio change is the way to go against standard diffs. Off road the standard diff with this engine would probably make the landy go where no man has been before but if you use your vehicle for on road use as well then he conversion can't be beaten.