Thread: Adelaide Q: TD5 power vs TDi 300 power

Originally Posted by rick130

but the manufacturers keep making the whole car heavier with each successive model

And FWIW, the high range is different 'tween a 'fender and Disco, with the Defender using a 1.410:1 high range, and, IIRC a Disco around 1.22:1, so the overal final drive ratio is slightly lower in a 'fender, but actual gearing possibly works out the same when tyre diamater is taken into account.

My DII auto Disco ran approx 2250 rpm at 100 k/hr. The 03 Fender runs 2500 rpm at 100 k/hr. (both diesels).
The difference in towing ability is quite marked because of this. Particuarly up the range. The auto played tunes all the way up, and the manual just plugs away. Chipped, it eats the mountain. Can tow the the caravan up the range (tare 1100kgs), at 80 k/hr in 3rd gear. Embarrasses the hell out of the big Tojo,s.
Trev.

Originally Posted by 4bee

I realise we ain't talking sound barrier stuff here, but I seem to recall reading somewhere, that a vertical flat **** end creates turbulence & therefore drag.

Is why the back end should be tapered off to a point.

A 130 with a pointy tail thing? I'd like to see that.

You'd breeze up the Freeway, (or should I say the M1) then spudb.

but turbulance and drag = aerodynamic stability, whereas an aero rear end promotes lift and is quite unstable, so a Defender ar$e end is preferable for the drivers underwear when doing those uber high speed runs around Mallala or Eastern Creek.

Originally Posted by disconut

My DII auto Disco ran approx 2250 rpm at 100 k/hr. The 03 Fender runs 2500 rpm at 100 k/hr. (both diesels).
The difference in towing ability is quite marked because of this. Particuarly up the range. The auto played tunes all the way up, and the manual just plugs away. Chipped, it eats the mountain. Can tow the the caravan up the range (tare 1100kgs), at 80 k/hr in 3rd gear. Embarrasses the hell out of the big Tojo,s.
Trev.

and I stuffed mine up with the 33" tyres.
That's where a 3" exhaust and pump tweaking help. Much nicer to drive. (other than the noise and drumming sans muffler...)

whereas an aero rear end promotes lift

Shirley that can only be a good thing, Rick?
While it may be unstable, just think of the uber low fuel consumption. In fact, would it be presumptious of me to think one could leave home with empty tanks & arrive back with them overflowing?


Or should I go back to the drawing board?

Originally Posted by rick130

but turbulance and drag = aerodynamic stability, whereas an aero rear end promotes lift and is quite unstable, so a Defender ar$e end is preferable for the drivers underwear when doing those uber high speed runs around Mallala or Eastern Creek.

Don't know about lift, but you can stuff more into a square box, and back up closer to things to gain more manouverability.

Trev.

Originally Posted by 4bee

Shirley that can only be a good thing, Rick?
While it may be unstable, just think of the uber low fuel consumption. In fact, would it be presumptious of me to think one could leave home with empty tanks & arrive back with them overflowing?


Or should I go back to the drawing board?

NO, and stop calling me Shirley !

1. A streamlined shape does not necessarily produce lift, but if, like most (but not all) cars it is streamlined only in the vertical plane, this coupled with turbulent flow under the car, as with almost all cars will certainly produce lift. It is possible to streamline the car only in the horizontal plane, but this would invite problems with crosswinds, as sideways lift would be generated whenever the airflow was not along the axis of the car.

2. The problems of a rectangular box such as a Defender are, in fact, much more easily solved. A series of small vortex generators could be installed on the sides and top just in front of the back to break the airflow away from the body. This small scale turbulence allows the vehicle to pull a cone of air behind it and give less drag than the large scale turbulence you get otherwise. Somewhere recently I have seen an article about someone (in Sydney I think) planning to sell just such a device for large trucks. This type of vortex generator consists of a strip of thin metal about 2cm wide and 5cm long with the last cm bent up (90 deg) at each end, the two bent up bits being about 30 deg to each other . The centre section is attached to the panel normal to the airflow. These vortex generators have been used for many years on some aircraft, usually as an add on to solve airflow problems that only appeared in flight testing when it was too late to make major design changes, but occasionally as part of the original design.
John

What he said.