Thread: Improving fuel efficiency v8i

Originally Posted by blitz

Quote
"However this theory has absolutely nothing to do with and is completely incompatible with what they are trying to apply it to. If you "spin" air or water down a pipe or tube etc, you INCREASE the amount of contact area it has with the pipework, taking longer to get down the pipe and significantly increasing the frictional loss through the pipework resulting in less flow. .... ..... ...

Blythe

I think where a lot of people get sucked in with the Hiclone is that they have seen the demonstration where an inverted soft drink bottle of water empties faster if you spin it to create a vortex.

It's true. The water does drain out significantly faster. But surely that is because the vortex allows air to flow back into the bottle continuously so that the flow isn't interrupted.

Hopefully there is nothing trying to get back up the inlet tract as the air enters the engine.

Originally Posted by vnx205

I think where a lot of people get sucked in with the Hiclone is that they have seen the demonstration where an inverted soft drink bottle of water empties faster if you spin it to create a vortex.

It's true. The water does drain out significantly faster. But surely that is because the vortex allows air to flow back into the bottle continuously so that the flow isn't interrupted.

Hopefully there is nothing trying to get back up the inlet tract as the air enters the engine.

http://www.aulro.com/afvb/864104-post3.html
read my post in its entirety. Its basically all explained. I did 11 years in control valves with a manufacturer and advised supposed all knowing design consultants prior to coming back to the automotive industry.
I do miss it, but in WA, the WaterCorp is still 20 years behind the times and the water industry in general has been price driven into the ground by cheap rubbish product. But thats another story.....

How to get better economy out of the V8?

Get rid of all the extra weight - bullbar, winch, rock sliders, rear Kaymar bumper, driving lights, roof racks, etc.

Make sure paper air filter is clean, MAF is working, and if fitted with O2 sensors, that they are working properly too. Pump up tyres, stick with 29" diameter tyres (stock size) and use it for highway work only and don't drive it past 100 km/hr.

But life wouldn't be fun then....

Just fit LPG and let Mustang Sally drive it!

Can't help you if you want to do long distances with a V8 though....

Originally Posted by Dougal

Of your overall commute, how long is this hill? 1%, 3%?
Do you have a fuel computer or other method of measuring fuel usage other than calcs at fillup?
What rpm range are we talking about?

Like I said, I am NOT going to get into a techo argument over these issues.
My observations are "anecdotal" based on regular driving pattern and how much fuel I put in at the servo. I keep accurate records of Klm's v Litres.

My regular driving around town used to be 19 - 20 lt per 100 Klm.
With improvements to air filter I went down to 18 - 19 lt per 100 Klm.
Since changing driving style (using lower gears where I use to use higher gears) I am now 17 - 18 lt per 100.

If this is NOT scientifically sound then so be it, I'll just keep it to myself

I agree that removing some weight may also help but I am quite happy to keep lugging around my steel bull bar/driving lights etc.

It's nice to get good fuel economy but not the be all and end all.
As I keep telling everyone the fuel is one of the cheapest elements of 4 x 4 ing.
Fuel is such a small portion of overall running cost for most people I don't see what all the fuss is about.

Thommo
D1V8ESman

Originally Posted by Dougal

Just to keep rovercare amused a little longer.

The more vacuum you've got in your intake, the less air and fuel you've got going in with each stroke.
Full throttle = minimum vacuum (maximum intake pressure) and maximum flow.
Idle = maximum vacuum (minimum intake pressure) and minimum flow.

I've fitted a vacuum gauge to my V8. It has an economy scale which correlates with vacuum in the range 10-15" Hg. To achieve this at cruise, a very light throttle opening is required. Any further opening of the throttle and the gauge drops below 10 - further into the red 'uneconomical' zone. As someone previously said, driving with a vacuum gauge is a great way to cure 'lead foot' syndrome.

Hence, I'm struggling to reconcile your theory that maximum flow = maximum economy with the way the gauge is designed and what it tells me during real world driving. My experience is that maximum vacuum on the gauge = maximum economy.

Originally Posted by mark2

I've fitted a vacuum gauge to my V8. It has an economy scale which correlates with vacuum in the range 10-15" Hg. To achieve this at cruise, a very light throttle opening is required. Any further opening of the throttle and the gauge drops below 10 - further into the red 'uneconomical' zone. As someone previously said, driving with a vacuum gauge is a great way to cure 'lead foot' syndrome.

Hence, I'm struggling to reconcile your theory that maximum flow = maximum economy with the way the gauge is designed and what it tells me during real world driving. My experience is that maximum vacuum on the gauge = maximum economy.

Compare 100km/h in top gear with 100km/h in the next gear down and you'll see what I mean.
The higher gear produces less vacuum but is far more economical.

["...It's nice to get good fuel economy but not the be all and end all.
As I keep telling everyone the fuel is one of the cheapest elements of 4 x 4 ing.
Fuel is such a small portion of overall running cost for most people I don't see what all the fuss is about."

Thommo
D1V8ESman[/QUOTE]

Thommo
Very well put - I did a detailed cost comparison between a V8 and a diesel (300TDi or 4BD1T Isuzu) in a 93 Range Rover classic manual transmission. There was only 3.5 cents a kilometre difference in total running costs - 39.1 cents/km V8 and 35.6 cents/km Diesel (conversion costs were factored into a different calculation but have left out in the costs above - the difference increased very slightly) Fuel costs were 18cents/km 300TDi and 19cents/km V8 petrol. As they say in Latin: quod erat demonstrandum - that which has been demonstrated. Why did I do the costings I am hoping to buy and sort the Rangie in the new year DV and had been thinking seriously of fitting an Isuzu or 300 TDi - I now intend to enjoy the V8. (Note the running costs do not take into account deptreciation or finance costs).

CHT

Originally Posted by C H T

Thommo
Very well put - I did a detailed cost comparison between a V8 and a diesel (300TDi or 4BD1T Isuzu) in a 93 Range Rover classic manual transmission. There was only 3.5 cents a kilometre difference in total running costs - 39.1 cents/km V8 and 35.6 cents/km Diesel (conversion costs were factored into a different calculation but have left out in the costs above - the difference increased very slightly) Fuel costs were 18cents/km 300TDi and 19cents/km V8 petrol. As they say in Latin: quod erat demonstrandum - that which has been demonstrated. Why did I do the costings I am hoping to buy and sort the Rangie in the new year DV and had been thinking seriously of fitting an Isuzu or 300 TDi - I now intend to enjoy the V8. (Note the running costs do not take into account deptreciation or finance costs).

CHT

What fuel consumption figures were you using to get your $/km estimates?
My 4BD1T powered rangie averages 10km/l. 300tdi's can do even better if you drive them slower.