Submitted: Saturday, Jul 19, 2003 at 17:22
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Just completed 4000 odd km trip up the Odnadatta Track and across the Simpson and down the Birdsville Track, really great trip but I was fairly disapointed with the fuel economy. My machine is a 3lt Hilux dual cab and we were averaging 18mpg fairly disgusted I was after having a 2.8lt before this one that ran on the smell of an oily rag. I was wondering if anyone had any comments on fuel economy for the same vehicle, I am running 9.5R tyres,I did have a roof rack over the canopy that did pull me up on the hwy with a head wind (back to 75km flat out). It has done 65,000km does it still need to loosen up a bit? other sugestions are that a turbo will improve fuel economy. Any way we had a great trip and if thats how much it uses so be it. I just got spoilt by the 2.8.
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Reply By: Member - Oskar(Bris) - Saturday, Jul 19, 2003 at 18:04

Saturday, Jul 19, 2003 at 18:04
I just did 4000K's out to Birdsville and beyond into the Simpson in my 2.7 Turbo Diesel Terrano. Normally loaded up WITHOUT a roof rack I would get about 28MPG or 10 L/100K's or 10 k's/L. (Makes it easy to calculate at 10 each way). That's on the blacktop stuff. With the roofrack, this time my fuel consumption started at 13.2 L/100K and gradually got worse to 15.2 L/100K. At this point I decided something was not quite right and I decided to change the air cleaner element. The consumption dropped immediately to 12.1 L/100K. The air cleaner was full of dust from all the dirt roads.
I suspect, like you, that the roof rack has made a considerable difference to the fuel economy, adding between 2 & 3 L/100K on the downside of my normal hiway figure of 10 L/100K.
I reckon the idea of a snorkel up above the dirt and dust has to be the way to go.

By the way, we were on the Birdsville track about 3 weeks ago and it was "porridge" following some late rain. We spent 3 nights camped on the side of the road waiting for it to dry. It's a good thing we did camp it as when we got to Birdsvile we found out from Paul, the local Cop, that in SA there is a $1000 a wheel fine for driving on a closed road. eg. Birdsville track after the rain.
AnswerID: 25360

Follow Up By: Ray M (Vic) - Saturday, Jul 19, 2003 at 19:40

Saturday, Jul 19, 2003 at 19:40
That's gonna be one high snorkel to get ya above the dirt and dust. Ya may need a red flashing light on top....check with civil aviation dept :)))Hooroo
FollowupID: 17190

Follow Up By: Bobby - Saturday, Jul 19, 2003 at 21:13

Saturday, Jul 19, 2003 at 21:13
OSkar If you had continued your tripyou wouldn't have been fined - only if you go onto a road that has been closed, that is go past the closed signs and onto the road. They will let you complete a trip!!
FollowupID: 17193

Follow Up By: SAm - Saturday, Jul 19, 2003 at 21:17

Saturday, Jul 19, 2003 at 21:17
BArnsy - something not right there!! I get 18mpg towing a 16ft van with a 3.4l Prado petrol.
FollowupID: 17194

Reply By: barnsy - Saturday, Jul 19, 2003 at 18:26

Saturday, Jul 19, 2003 at 18:26
Thanks for the reply
We had to wait at Delhousie until the track reopened, heard that someone decided to go down the Birdsville track before it reopened $20,000 dollars later he made it to his destination........

I had a new airclaener in and regularly cleaned it, didn't seem make any difference though.

Still we had a great time.
AnswerID: 25361

Follow Up By: Member - Oskar(Bris) - Saturday, Jul 19, 2003 at 18:43

Saturday, Jul 19, 2003 at 18:43
When we were at Poeppels we met some bikers who said there were quite a lot of you guys waiting over there. We were planning cross the desert travelling in the other direction but our stay beside the Birdsville track stuffed our plans and we were only able to go into the corner and then back again (160K each way). But the whole experience was fantastic and we just need to get back there ASAP.
The wild flowers were only just starting to bloom on our way back to B'ville so I guess you got the best of them. Did you see the big herd of camels near the corner?
The guy who got booked (reportedly) out on the B'ville track got a hefty fine (the cop said about $5000 but who knows really), and rightly so. He passed us while we were camped beside the road and we bumped over his wheel ruts all across the road (and off on each side of the road) all the way to B'ville when the road dried out. The locals really hate that sort of thing.
Makes a good trip yarn though.

Anyway glad you had a great trip
FollowupID: 17187

Follow Up By: barnsy - Saturday, Jul 19, 2003 at 18:53

Saturday, Jul 19, 2003 at 18:53
We saw one group of wild camels and a bloke from Echuca walking 2 across to Purni bore and back to Birdsville. as for the ..... who drove on the close road, we heard as well as the fine he had to pay for the works on the road as well amounting to between 20,000-25,000 all up expensive little drive for being impatient. Flowers were just starting to come out lots of different types.
FollowupID: 17189

Reply By: xr500 - Sunday, Jul 20, 2003 at 15:50

Sunday, Jul 20, 2003 at 15:50
were you in low range for some of the dunes ?
a turbo will give better economy at cruising speeds but under load if the engine is producing more horsepower then it will use more fuel
I have a 2,6 petrol bravo loaded @ 110 kph is 14.4 L/100km
if it a 4wd then pay the fuel cost !!
AnswerID: 25404

Reply By: howesy - Sunday, Jul 20, 2003 at 16:45

Sunday, Jul 20, 2003 at 16:45
Try getting the pump timed with a dial guage. It cant hurt, gives peace of mind and only costs around $80. Reguards the air cleaner, i got a washable foam type filter (and a spare one) and purchased a cyclonic filter head for the top of the snorkel to replace the snake head. I smear all the inside with baby oil and have it pooled about 5mm deep in the bottom. You would not believe the amount of crap this head stops before it makes it's way to the filter. (p.s I noted no difference in performance from the snake head)
AnswerID: 25406

Reply By: Darren - Sunday, Jul 20, 2003 at 17:35

Sunday, Jul 20, 2003 at 17:35
I have the same model hilux with a 3.0L D engine. Last year i did a trip out past Camerons Corner and down into the Flinders, up the Odnadatta and across the Simpson for the Birdsville Races and then back home to the Hunter Valley. For memory I averaged somewhere between 9-10 L per 100 KM. I dont have a roof rack fitted but I do have a snorkel and I do make sure the air cleaner is clean. I have also done trips up into the Kimberley, down the West Coast, through the center, and Cape York since I have had the Hilux and have pretty much avearged the same fuel economy 9-10L per 100 km for all of these trips. This figure includes both the highway and the low range crawling around. I also don't travel any faster than 100kph and have notice the fuel economy is best at around the 2400 rpm mark where the max touque is. I did notice an inproved fuel economy after the 40000km mark and it has been getting better. I also have notice when I do have a strong headwind the fuel economy gets much worse but have never been slowed down to 75kph. Hope this helps, Darren.
AnswerID: 25410

Follow Up By: barnsy - Sunday, Jul 20, 2003 at 17:59

Sunday, Jul 20, 2003 at 17:59
Thanks for the info
Your fuel economy is what i was getting out of my 2.8 that is why i am wondering what is going on. As for the speed the roof rack sticks up a fair way and acted like a sail so i am not real suprised about that, but the economy did not get any better at slower speeds. The only time i noticed any difference was when i had a howling tail wind, my sail worked well then. Just trying to get some suggestions from anyone that has experienced the same. Have heard that this model does use a significant amount of more fuel than the 2.8 so your figures do suprise me.
FollowupID: 17225

Follow Up By: Darren - Monday, Jul 21, 2003 at 09:44

Monday, Jul 21, 2003 at 09:44
barnsey I actual had a look at my travel diaries last night and i got it the wrong way round. On all of the trips I have gotten 9.2-9.8 km per litre. This equates to 10.86-10.2 litres per 100kms or 26-27.7 miles per gallon. Sorry for my confusion.
FollowupID: 17250

Follow Up By: BOB - Monday, Jul 21, 2003 at 19:58

Monday, Jul 21, 2003 at 19:58
i have a 2002 turbo diesel dual cab no load on the black top around town i get 22mpg and on a trip not much better i am very disapointed with these figures. have a friend with a navara gets 31mpg
FollowupID: 17293

Reply By: Truckster (Vic) - Monday, Jul 21, 2003 at 10:47

Monday, Jul 21, 2003 at 10:47
Roofracks = parachutes... if you were doing 75 flat out on a highway, theres your problem!! You should be able to cruise 110 pi$$ easy.
AnswerID: 25468

Follow Up By: barnsy - Monday, Jul 21, 2003 at 17:32

Monday, Jul 21, 2003 at 17:32
Sure was a parichute, I do not have the speed problem without it on the hwy cruises at 110 no probs. But cant seem to improve the economy though.
FollowupID: 17277

Follow Up By: Truckster (Vic) - Monday, Jul 21, 2003 at 20:19

Monday, Jul 21, 2003 at 20:19
There was a post by AWILL4x4 on air foils for roofracks(he knows his shiat he makes Roofys!), and said they arent really worth the effort.

Do you NEED the roofrack? Is your fuel econ ok without the rack?

Are you saying with or without the rack its the same?
FollowupID: 17298

Follow Up By: barnsy - Monday, Jul 21, 2003 at 21:07

Monday, Jul 21, 2003 at 21:07
No Truckster it seems to make no difference with or without the rack on the fuel economy side, if i have a head wind sure it uses morebut in general the fuel economy is sh..

The only difference is the speed without the rack I am fine.
I need the rack for extended trips as there are 2 Adults and 3 Kids trying to fit everything in is impossible.
Would be great to not have it.
FollowupID: 17305

Reply By: Wayne - Monday, Jul 21, 2003 at 12:19

Monday, Jul 21, 2003 at 12:19
Hi Barnsy,
I have a 1999 3litre diesel single cab tray back. No snorkel. Done 130,000k. Around town (empty) I get about 10 ks to the litre, or 10 litres per 100 ks.
We did a 4,500 ks trip with a canopy on that sat up above the roofline about 100-150mm. Also 2 surfskis on top. This trip was mainly bitumen with dirt roads whenever we could and a bit of 4wd along beaches etc near Esperance. We were down to 90 odd kph on the way south from Wave Rock (Hyden) to the beach from headwinds. Used a LOT of fuel (nearly double?) on this leg. We kept records from trip and it averaged out at 8.9 litres per 100ks overall. So all in all I'm pretty happy with fuel consumption. Of course these figures are for roads that a car could be driven down, apart from a few side trips. We checked the air cleaner before,during and after the trip and it's still in there. This is the factory filter with the air box fitted before the cleaner. Mates '99 dualcab doesn't have this box, but he gets around the same figures.
Hope this is of some help to you.
AnswerID: 25474

Follow Up By: barnsy - Monday, Jul 21, 2003 at 17:30

Monday, Jul 21, 2003 at 17:30
Thanks for the info, mine had the same box before the air cleaner but i had to remove it to put my second battery. I don't think that this would have contributed to the problem though as i would have expected the increse air flow to have the opposite effect, will get it checked out when it is serviced, due now after our trip. Thanks for the info
FollowupID: 17276

Follow Up By: Wayne - Monday, Jul 21, 2003 at 20:27

Monday, Jul 21, 2003 at 20:27
Hi Again, Did you notice any difference in noise levels when you removed the airbox? I vaguely remember reading that the box was only put on to reduce the induction roar. Of course that may or may not be true. (depends on who you talk to/read.) I was thinking of removing mine for the same reason (extra battery) and also to fit a snorkel.
FollowupID: 17299

Follow Up By: barnsy - Monday, Jul 21, 2003 at 21:26

Monday, Jul 21, 2003 at 21:26
I was in 2 minds whether to remove the box or not as I had heard the same about the induction noise, but you can always put it back. It does make a difference to the noise levels but not enough inside the cabin to make me give up the second battery.

You can certainly hear the difference outside though I can hear my wife coming home one block away no sneaking around. It only took me an hour approx to pull it out as there are 2 parts to it as it actually goes inside the guard as well , the intake ends up just behind the front of the front door not behind the headlight as in previous models.I have removed the box from the moulded piping that it is attched to and closed up the hole so i can fit the piping back as I think it is needed to attach a snorkel.

I had an experience with my first hilux (2.8) with the snorkel, I had an airtec one fitted NEVER AGAIN. From day one it vibrated and the induction noise was horendous, Put a sock in it marginal improvement. It also has a rigid pipe through the body work, I cut that off and replaced it with flexible hose 100% improvement I then went through and put rubber inbetween all parts near the body, got rid of 90% vibrations was happy then. Other suggestion is that if vehicle turboed it would also get rid of the Problem. I will be fitting a Safari one to this vehicle when i get around to it, they come with flexible hoses as standard.
I think if you did a search on this forum there are a few unhappy hilux owners with noisy snorkels and apparently it is a bit of hit and miss Some are noisy and some are not.
FollowupID: 17311

Reply By: Member - Russell - Thursday, Jul 24, 2003 at 16:59

Thursday, Jul 24, 2003 at 16:59
I haven't read all of these posts, but will throw my one cents worth about drag. Remember that drag is all about drag coefficient, area and velocity - particularly velocity. The first two are obvious - 4wds have terrible Cd s, and are made that much worse by roof racks. They also have a big frontal area even without a roof rack. However, these things are a constant, and the real killer is how fast you go, since drag is proportional to the square of your velocity. If you want to do the numbers, the formula is D = Cd x 0.5 x air density x velocity squared x surface area. Clearly if you can cut down the Cd and frontal surface area, you'll improve it. However, all these things (other than speed) being constant, consider the change from 80 to 90 to 100 to 110 km/h. 80 km/h = 22.22 m/sec, sqared = 493.8. 90 km/h = 25 m/sec, squared = 625 (27% increase). 100 km/h = 27.8 m/sec, squared = 771.6 (56% increase over 80, 23% more than 90). 110 km/h = 30.5 m/sec, squared = 933.6 (89%, 49% and 21% increase respectively). And so on. Enough already - the point is that drag increases exponentially, not linearly. In this example, speed went up by 37%, but drag by 89%. Doesn't help you if your truck is worse than other 3 lt Hiluxes though..... Hope you can sort it out.
AnswerID: 25803

Follow Up By: Member - Russell - Thursday, Jul 24, 2003 at 17:02

Thursday, Jul 24, 2003 at 17:02
Sorry, should also have stated the bleedin' obvious - that drag is all about air speed, not ground speed (hence head winds and tail winds make a big difference), and I've ignored all the other factors like tyres etc.Russell S
Prado RV6
FollowupID: 17523

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