Thread: Diesel Auto v.s Manual

Originally Posted by vnx205

What is a Tasmanian's idea of a long distance drive.

An overnight stay is more than 100km.

Originally Posted by rowland0

Hey guys this is my first post on here and I'm on the hunt for a diesel D1. Now I have had a fair look around on here but couldn't seem to locate any thing comparing Autos and manual. My main concerns are the differences in fuel economy between the two and the how laggy the Auto are, I have never owned an auto but having done a fair bit of long distance driving laterly in an auto I may be getting turned

So any info on this would be awesome and if there is already a thread on this could you share the link.

Thanks Rowdando

The factory fuel consumption figures at steady ~55mph is the only place an auto will use less fuel. This is mainly an artifact of the auto being slightly higher geared than the manual. The automatics in these can only lock up the torque converter and acheive solid drive above about 80km/h in top gear. The rest of the time they are unlocked, burning more fuel to stir oil and make heat. They have a loose torque converter which creates a lot of loss from stirring oil when unlocked.

I have a 300tdi auto RRC, it's not road legal so I don't have any fuel consumption figures, but driving it offroad so far is enough to know I'll be looking for a manual gearbox conversion once the other issues are sorted. The parts that annoy me are the looseness of the torque converter and only having four gears.

I have another 3.9 V8 RRC with the same gearbox, the torque converters are of course different and this changes the driving behavior hugely. The 3.9 V8 will start moving off at idle and transfers more torque with fewer rpm. The 300tdi auto requires a lot of throttle and rpm before it'll even move off the spot. I also have a 4BD1T RRC with 5sp manual for the other extreme.
Putting the larger V8 torque converter in the 300tdi (or TD5, same fitment) auto requires a lot of machining and also requires engine modifications for a lot more low end torque (VNT turbo or compound turbochargers to provide more boost down low).
If you try to fit a tighter torque converter without the engine modifications it'll just bog the engine and not give it enough rpm to build boost. With a manual of course you can choose a higher gear locked up for cruising or a lower gear for more rpm when required. Fuel consumption is always better.

My wife has an auto and i manual. I wish it was an auto the next one will be.