33inch Tyres for GU

[GavandNat]

Got myself a set 33inch tyres 2 weeks ago and have been brilliant on the beach. But fuel economy has gone to the dogs. Anybody know what to expect when changing to larger tyres? I was getting arround 15l/100km with the 3.0Diesel, it is now more like 25litres. Seems like to much of a jump and I am wounderring if I have a problem with Oxygen sensor or something.

[oncedisturbed]

Can't honestly answer that as I get 21L/100k in the 4.8 running 285/70/17 AT's on mine.

What gear on the GU etc have you got? There are members better experienced than me to answer.

Have you cleaned / checked the MAF and MAP sensors? No noticable leaks etc?

[Steve4wdin]

You are not measuring fuel econ from beach driving I hope???? You will use a ship load beach driving compared to road or even general off road. I am getting around 11-12 on standard tyres on the road. Don`t even think about it off road, It gussles

[happygu]

GavandNat,

If that is your economy on the road - you need to look into it quick, as this is not normal.

I run 33's and have never had anything close to that in any terrain.

Is it a Di or CRD? Does it blow heaps of smoke, or does it seem to have lost power?

If so, my best guess would be the MAF, but do some checks first.

[GavandNat]

Thanks guys, I will have a look at the suggested suspects (MAF and MAP). I headed straight for the beach after getting the tyres and so was not looking at fuel consumption as it is never great. But filled up last week and used 45l in 150km on the tarmac.
Got the new tyres for a Simpson Trip in a couple of weeks. Getting a Kaymar rear bar this week for the spares and really looking forward to getting out there.

[Clunk]

You may get a slight increase in fuel consumption when you go to a larger tyre but no where near tht much, that's astronomical......... don't forget your odo reading will be out as well so you need to take that into account

[GavandNat]

Patrol is a 2011 TI. Working on all the goodies, essentials to date are a long range fuel tank, dual batteries and 2 inch lift.

[threedogs]

Dual batteries, rear bar its all weight, I run 305/70/16 MTZ muddies and tow my camper to the Murray fully loaded with 3 blokes and get around 17/100Ks.
I'm happy with that

[happygu]

GavandNat, I have exactly the same car as you and my economy with 33's on the road is normally around the 13.3 L per 100K's. It can vary a little depending on what I am doing, but even in the hard stuff, i'm not getting 25.

Do you run a K&N filter, because these can cause the MAF's to fail. I would be surprised if yours has failed so quickly if it has the normal filter. From all reports, the later style MAF's are fairly robust, and don't give much trouble.

If the car isn't low on power and blowing heaps of smoke I would try filling both tanks to the brim with a quality diesel such as BP, and do a run around for a few days, then refill to the same mark to verify your economy.

You may have just had a really bad batch of fuel, or you might not have filled all the way up the last time.

It is a little worrying that with the standard you were getting 15l/100 anyway, as this is fairly high. There have been reports of some of the earlier CRD's using extra fuel ( usually Auto's ), and maybe yours is one of them, but the complaints are not coming through like they were early on.

Mic

[Steve4wdin]

This may seem silly but have you thought of getting a dyno tune done. I had similar probs with my 2011 and it was the factory set up. I ended up with a lot more power and used a lot less fuel.