Thread: How much are overdrives for Defender?

have you seen this article? I have read it a couple of times as I was going considering doing such things.

Land Rover Defender Upgrades - Equipment Tests - Overlander 4WD Magazine - Australia's leading four wheel drive magazine

Xav

I can't offer any advice at the moment but I've been asking myself the same question? if it only had a 6th gear/ overdrive and bring the revs down 500 or so this would improve economy and longevity of the donk, I've had both v8 and tdi they both rev high and 100kph, and Australia being a fairly flat country hills don't really factor into it.

i will be watching this thread with great interest.

ok at $4k for the overdrive maybe not! think i will just put up with the buzz etc

on the longevity front...it may do more harm than good- if by lowering the revs u then are increasing the load on all the components. its never good to labour an engine. i would have thought that 5th(manual) would be an overdriven gear anyway. most cars have 4th as 1:1, with 5th somewhere around .7-.85 range. is 2500rpm at 100 or 110?

also 4k. geez epensive exercise. saving a $1/100kms would mean 400,000km to recoup the costs.

False economy

Rover engine's are to small to benefit from a drop in revs at highway speed, they lack the torque and will labour

In mine 2500RPM is 100kph in 5th gear, which gives me an economy of about 12l/100km so that equals about 750k's per tank far less than most claims i've heard at 850 - 950k's that must be down a big hill with a tail wind

Originally Posted by kingyrules

In mine 2500RPM is 100kph in 5th gear, which gives me an economy of about 12l/100km so that equals about 750k's per tank far less than most claims i've heard at 850 - 950k's that must be down a big hill with a tail wind

my tdi auto sits on 2250 @ 100 and 2500 @ 110 ?

1. The overdrive is pretty expensive.

2. While the overdrive would reduce the engine rpm, I rather doubt it would make a significant change to fuel economy - somewhere you should be able to find a graph of specific fuel consumption vs rpm for the TD5 (usually published with power and torque curves), but if it is like most diesels, the change for 10% or so reduction in rpm will be insignificant (petrol engines change quite a bit more, so there is potentially a fuel saving). The power required will be the same or perhaps slightly higher for the overdrive, as there will be some power loss in the extra gears.

3. The only real advantage will be a bit less noise, and perhaps an increase in engine life, although I doubt that will be significant.

John