Any experienced Man to Auto people here?

u beat me to it thats what i was going to say

a hell of a lot of work to change from manual to auto

When you stick the slipper in, the motor revs up a little and the torque converter starts to work - this produces more torque to the tail shaft - just like changing back a gear. Many erroneously think that when a motor revs higher it is just "the torque converter slipping." This is just the same as saying "when I change down a gear the gear box slips."

PeterD

The torque converter really has the wrong name, it should be called a torque multiplier, but in all reality its main function is to convert power into torque and this multiplies torque in the process.
The reason manuals are generally given more engine torque from the factory is that they have the disadvantage of being driven through a clutch, thus relying on reduction gearing for any increase in torque and low engine torque is detrimental to clutch life.

I thought a torque converters (stall converters) was just a fluid clutch, virtually just two fans with fluid inbetween. When the rev's got high enough on the flywheel side the fluid had enough force to move the fan on the gearbox side. Thats how the street car boys changed the converters to to 3500rpm etc, by just changing the anglke of the fan blades.

I have always been told that the auto's where only better at applying power more smoothly than the manual, (which makes the cars power more usable in most 4wd applications) but the lack of direct coupling between the auto box and the engine resulted in power loss (and engine braking).
Later model over came the lack of dierct transmission coupling by using a electronic lockup. But these could only come in when the gearbox was up to speed.

Also a auto will always use more fuel than a manual if driven in the same way and the same conditions as a manual. So logically a auto must require more power to perform the same amount of work than a manual.

Hi Chucky,
Without getting too technical, you are basically right.
Although commonly refered to as a fluid clutch, a fluid coupling would be a more accurate definition. It consists of three elements, an impeller, a stator and a turbine. Technically it multiplies engine torque by changing fluid velocity into power. Practically, this means it provides an infinite number of gear ratios.
The drag racing boys build high stall converters because their engines don’t make torque in the lower rev ranges so they need the converter to flair until they get into the torque band. This comes at the cost of inefficiency at higher speeds, but a lockup system overcomes this. Generally higher stall converters are physically smaller in size and changing the angle of the fins can help, but make it less efficient at higher rpm.
Auto’s do use more power than a manual to drive, partly because of their rotating mass, but once the converter is locked, there isn’t much difference in efficiency. In the case of the 3.0Di Patrol, an auto is thirstier around the city, but possibly more economical on the highway at speeds over 90km/h because the converter should be locked and they have a much higher overdrive ratio than a manual.
With a manual you have the option of fitting a better or heavier duty clutch to help overcome some difficulties, but with an auto, there are many modifications that can improve the drivability and off road performance of your car. I can lock my converter at any speed and in any gear at any time, even reverse. The gearbox changes quickly and crisply every time and being able to shift up or down on a 45 degree slope is a luxury that a manual driver can’t afford.
I’m not saying that autos are better than manuals, but in this case, I can understand why Voxson wants to change over considering the low rpm torque characteristics of the 3.0Di Nissan. I have a Dtronic, 3” straight through exhaust and no EGR system and my car will pull hard from under 1500rpm, but in some off road situations that may not be good enough if it was manual.
Chaz

Fluid clutches are a product of the 30s. Since then torque converters have ruled the roost. The stator changes the direction of the fluid such that more torque is transmitted to the turbine - as the turbine reaches the speed of the impeller the stator ceases to be stationary and the three elements rotate at the same speed producing a nearly direct drive. The converter lockup available on the later autos is just a normal type clutch - it can be built lighter because it does not have to suffer clutch slippage during start off.

"Also a auto will always use more fuel than a manual" You can make a manual use more fuel - just change down a gear every time you accelerate. Higher engine speeds mean more power developed (under heavy throttle application) and more power means more fuel consumed. I reckon that if you changed down every time that an auto would produce more torque you would be producing higher engine speeds in a manual and you would use more fuel in a manual than an auto - it is only the young and stupid that drive manuals that way and they are renown to produce higher fuel consumption figures than we the older generations.

PeterD

Truckster, is that auto to go behind your 4.2 TD? May have to have a chat to you if it is? John

Yup, thats the one. its a straight bolt up.. All TD42's have the same bolt pattern from 88.....

He had a dtronic and pulled it off and sold it! Can't for the life work out why. But I'd do the above as well. I have been thinking the exhaust for a while and recently decided to try blocking the egr valve. I think this is my next mod, not because I need the torque/pwr more for the curiosity.

Leroy

drive on sand and you will know how much the auto comes into it's own!

An auto will out perform a manual in all off road situations except engine braking, but that can easily be improved with a manual lockup converter and lower transfer gears.
Also, in the patrol a manual is doing 2600rpm@100km/h and an auto is just over 2000rpm at the same speed. In the 3.0Di autos work much better at lower speeds because the converter puts you straight into the engines maximum torque band.

Well there ya go, learn somethin new everyday... Still prefer a manual tho :P

Chaz, Mark's adaptors do not have an adaptor to go from a Nissan engine to a Chev/Holden transmission only an adaptor to go from a Chev/Holden engine to Nissan transmission.
Regards Andrew.

Hi Andrew,
I'm sorry, I thought they did.
I thought they had one to bolt a TH700 up to an RB30, although I'm not sure if that will fit a ZD30. Do you know if ZD30 and TB/TD42's use the same bell housing patern? It shouldn't be too hard to make one if they don't, but I assumed they would because the TB42's did come out with the same auto trans as ZD30's.
I just remembered that RD28/RB30 used different manual transmissions, but similar Jatco RE4R01A auto transmissions.
I'll stand corrected.

Andrew,
The Castlemaine Rod Shop (http://www.rodshop.com.au/transmissions.htm) has an adaptor to suit GM Turbo & P/G Trans to Nissan 3 Litre P/N: AP 65, but I would assume that’s for the RB30.

Thanks voxson for the info.....i actually didn't know the real difference in them other than the stated figures.

BTW, stupid question, would the 4.2 auto be even better still given your statements......or am i missing something obvious :-)

Have a good one,

Andrew

Yes... "if" the 4.2 came in an auto it would be the best weapon built yet by Nissan... thats where Toyota has it over Nissan... an auto behind a high torque motor is great...