mods that affect fuel consumption

[sem]

Hey Guys I'm just wondering if you have noticed any mods that really affect your fuel usage? I have a 2.5 D22 and since new have got just over 700km a tank. About 2 months ago I put on a tray back with ladder rack and quickly after that I did a suspension lift and a new set of MT STZs. My per tank went down to about 600km so I was quite upset. I'm guessing that the difference is the wind drag being a bit higher and have a wider tray and a ladder rack where I had a soft cover on the back previously.
I have now done the EGR mod and the fule went back up to almost 700km. But now I'm wondering is the increase due to better fuel usage or that the power increase to push the extra wind? I really don't think that had I done the EGR before the tray my usage would have gone to 800km a tank.
Any thoughts?

Also I have noticed that Wollies vortex diesel will give me at least 50km more a tank than other diesels other than BP ultimate but it is always about $0.06 p/l more around my place.

 

[Old.Tony]

Anything that squeezes more power out - turbocharger, intercooler, removal of dampening devices like the EGR - will increase the power. A chip will increase the power as well, but will sacrifice fuel economy to do so. That's not always a bad thing.

You can use the extra power to go faster, haul more - or to go like you did before but using LESS fuel. This means that putting a chip in your vehicle isn't necessarily going to make the car use more fuel to go faster (the usual result) - it could make your car use less fuel to make it go like you normally drive it.

Driving style does greatly affect consumption. Using your diesel's torque curve to advantage will improve economy considerably - but generally that's a highway thing.

I've noticed that larger tyres do cause an increase in fuel consumption, even with a conservative driving style. The reason would be in the forces required - the distance between the centre of your rear axle and the road surface forms a lever which you are twisting (turning the rear axle) through sets of gears and the longer that lever, the harder it is to turn it - so the more power is required to make it go.

Also consider this - if you can save 1 litre per hundred kilometres (LPHK) and you drive 20,000km in a year, you're saving 200 litres of fuel - $300 - over the entire year. In your calculations of what to spend money on to improve your economy, ask yourself if a $1400 chip, or a $2000 LP Gas installation etc will provide enough benefit to offset the $300. Usually the answer is 'no' - but weigh that up with the extra power, flexibility and the face that the mod will be there for years and you may consider it worthwhile.

Depends on how much money you want to spend.

The cheapest mod of all is to leave a little earlier and drive a little slower. You get there at the same time, and use less fuel doing it.

 

[RustyNav09]

Hey sem, this is a good topic and gives lots of mixed answers. I have an 09 d22 with the 2.5l motor which is in yours. I was getting the 700km per tank before the egr block the after was getting anywhere between 750-800kms after so the egr block does work. Just to add I have only ever used Vortex Diesel in my navara and on the few occasions I have used normal diesel I have put an additive in to clean the fuel. Old Tony has got it all down pat with his fuel consumption stuff. A chip depending on how it is tuned ie, if its just increased injection pressure or its remapped the ecu can and cannot increase economy. I also found that oil thickness can change it aswell. I used to use 5w-40 Enviro oil cause that was when noone knew the difference in motors. Now using 10w-40 oil which makes ur car work harder on cold starts. I'm gonna try the thinner oil again to see if it does make a difference.

Goodluck
Rusty

 

[WoodyD40]

really top answer there OldTony ... could not have put it better myself.

 

[sem]

Well that is more detailed than i was expecting thanks.
so just to expand a bit what about things that aren't so dramatic or that until the other day I wouldn't have thought of.
A bull bar and winch will add weight and increase wind drag
A snorkel will increase wind drag but will the ram effect of the cooler cleaner air offset that

 

[Old.Tony]

Forget the wind drag of things like the bull bar and the snorkel. They'd only make a difference if you were racing the thing in LeMans and trying to reach speeds of 300km/h or more. In our sub-140km/h world, they don't make a difference to the wind resistance - the brick shape of the vehicle is more than enough drag on its own.

The bullbar really just offers protection to your vehicle if you are traveling in places where you're likely to strike an animal. It is very heavy, it will cause your front springs to sag a little, but when a roo pokes its stupid head out in front of you, you'll be happy it was there. The winch will tack on another 40kg or thereabouts and finds a nice home on a steel bar - alloy bars require some additional engineering to get the winch in.

The "ram effect" in your snorkel is also a bit of a joke. The intake isn't big enough to make a difference. Look at the intakes on a formula 1 car - they're not large, they're not scoops - they're simply openings up high to take the air from as far above the hot road surface as they can manage. If anyone knows about performance, those guys will.

It's not about ramming air in - it's all about cooler air and minimising particulates. Heavy dirt, sand and dust particles thrown up by the car in front of you will fall to the ground faster as they aren't buoyed by the passage of air, so when your air intake arrives, there's less heavy stuff - your air filter will thank you for it. It's also a lot cooler up there than it is in your engine bay, and the cooler the air going in, the better your engine likes it - that's the entire reasoning behind an intercooler, which has the additional task of catching bits of broken turbocharger which can happen if you don't let your engine cool while idling after a hard haul.

 

[joe2006]

After fitting my bullbar & canopy, I managed to squeeze 9.9lt 100k's out of mine. (down from just above 10)

I am certainly not saying that they helped reduce consumption but I don't think they had a detrimental effect.

 

[Dave]

Mine has changed in fuel consumption since going to the Cooper ST's and adding the bullbar.

90% of my driving is on the highway at 100km/h, so I always get around 10.3-10.5L per 100km's.

I will say though, that the ZD30 doesn't use much extra fuel towing.

Loaded car trailers will only make mine use an extra 2-4L/100km's.

A few months back I towed a car trailer to Balmain and then had a 1200kg car on the back on the way back.

That tank I got 10.7L/100km's.

That was doing 100km/h on the F3 to. A mate was in the car and can back that up.