Fuel consumption

[davehaynes1]

Hi guys.
I've recently changed my wheels&tyres. Going from some pretty thin Road tyres to a set of 31x10.5

Since changing the tyres I've noticed my fuel consumption has gone down. I expected it to, but it seems to have drastically changed.
I can't remember exactly what I was getting before but I think around 20-25 mpg.

After doing a long highway journey today I started with a full tank. All the way up. And now it's sitting on half and I've done 150km / 90miles
I'm guessing the tank is about 50L?? That means im getting 150km/90 miles to about 25L which is a shocking 14mpg!!!
I don't think the 31s would mess with my trip meter as there are about the same over all diameter of stock tyres, unless I'm wrong?

I have recently had the rocker cover gasket changed so phoned the garage to see if any fuel lines may have been disconnected and not put back properly but he assured me the fuel lines would not have been touched.

Also the engine is a 3vze

Please any help here guys is much appreciated!!!

 

[tx_shooter]

Did you go up in tire size as well or just wider?

 

[davehaynes1]

I can't remember my old tyre size, 205/75r16 i THINK.....
When I was fitting my new ones they were pretty much the same overall diameter. Maybe an inch bigger..

 

[KidVermicious]

I can't remember my old tyre size, 235/65r16 i THINK.....
When I was fitting my new ones they were pretty much the same overall diameter. Maybe an inch bigger..

A 235/65r16 is a 28 inch tire. And you were never getting 20-25 MPG with a 3VZE, not unless Aus gallons are different than US gallons. You definitely stepped up a couple tire sizes, which not only means that your MPG has definitely gone down, but your ODO is off so you can't use it to keep accurate track of your mileage anyway.

 

[Excalseras]

I've had 31x10.5 that came stock on the 2g sr5 and it's been chugging around 17mpg. 25 in my dreams lol.

 

[kfitz77555]

I have an 87 4Runner with a 22RE. Last year I bought some 33s. The best I have ever gotten on the free way is 19.6 mpg. I avg around 15-17 in town. I drive pretty slow as well.

 

[davehaynes1]

Did another long journey today and at the end I had got 9km per litre so works out to about 21mpg
Sweet that was obviously a good day and driving like a grandad at 90/100kmh

Thanks for the replys!

 

[flyinhawaiian01]

I highly doubt you're getting 21mpg. Have you re-calibrated your speedometer for the new tires? Probably not, as it would take a new gear in the transmission to do so, as well as a junk yard that has a stack of 'em for you to count teeth and figure out which one will be closest to what you need.

I'd suggest using a gps that's relatively accurate, see what your speed is at on the speedometer and compare it to the gps. If your gearing was correct with the ~28" tires, and you went up to a 31" tire, you'll be showing about 63mph when you're actually doing 70mph!

With a 3VZE and 31" tires, on 87-89 octane fuel, automatic trans and a decently-tuned engine, you'll probably see around 17mpg with mixed driving. Expect it to go up slightly if its all flat highway driving at around 60mph.

These numbers are pretty much the same for 80% of the 4 runners out there. If one is not getting these numbers, its due to the way they drive or condition of their drivetrain.

 

[davehaynes1]

My gps doesn't show speed. But if I do say a 60km journey and reset my trip at the start the trip matches the journey distance pretty much spot on by then end of the journey. Give or take 2 km