fuel economy 1990 22R Petrol RN105

[the luxorlater]

My HiLux RN 105 is only getting 21.31/100.  It has a new carburetor, new plug leads and running 31 x 10.5 x 15 Tyres.  It has extractors, sports muffler and 2.5 inch tailpipe.

It never used to use this much fuel, any suggestions would be appreciated.

 

 

[CONROD]

The tall rolling diameter of your wheel/tyre package has knocked the crap out of your gearing and its causing it to lug everywhere. eg wider opening on the throttle just to maintain speed and on the hills , Not being nasty, so don't take offence, I reckon its nearly flat to the floor or you're throwing it back through the gears revving it like mad just to maintain some momentum, on the slightest incline, Even though they are a 2.4 they only pump out 75KW and 185NM of torque. One way around it, is swap diff ratios out, but now we are talking $$$$$ for minimal gain. Think back did it start to use fuel when the wheel tyre combo went on

Edited October 19, 2023 by CONROD

[Hiro]

Is the carbie just a replacement OEM one or an aftermarket (Weber etc)?  Has it been tuned/jetted properly?  31s really wouldn't be helping either.