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Re: rev counter fitted.. now to bring the revs down..

Posted: Fri Jul 26, 2013 11:04 am
by ScottieJ
I think you missed my point Twiss

My old 31x11.50ss that i ran with the 970cc weighed pretty much the same as my 33x12.50s that I now run with the 1590cc, there is hardly any difference in size, I said "I have ONLY swapped from 31s to 33s" as in it's not a big change so should not have much of an effect on the fuel economy comparison between the two set ups I have run on MY sj

The twin transferboxes on mine makes a difference though with the extra transmission drag and weight. my 970cc was about the same on fuel with the 31s than my 100% standard 1.6 vitara was.

The best way to improve fuel consumption in an Sj is to run a more modern fuel injected engine, our 2.5 v6 is more economical than my Sj :lol: look at the f10d for example it probably uses half as much fuel as the f10a does on carbs.

Re: rev counter fitted.. now to bring the revs down..

Posted: Fri Jul 26, 2013 12:53 pm
by twiss
My point was that a truck with 33s will be heavier than one with 215s... and that you have added lots of extra weight.. vit box obviously heavier than the SJ one, then you've got stuff like the t-case bucket, axle trussing, blah blah blah

I wasn't trying to say that 2" of tyre increase will make that much of a difference but it will be noticeable. In my tyre pattern 31s weight 45lbs and 33s weigh 57lbs.

Carrying around 5 of those tyres even though they are only 2" bigger still adds almost 60lbs of extra weight. Thats like carrying 8ish gallons of water around with you.

If I went from 29s up to 33s I'd be adding 90lbs of weight, which is roughly 11 gallons of water...

Anyway in comparison with other 1000cc cars, 410s are terrible on fuel consumption, as are vitaras, especially autos... and especially 3 speed autos... my mates old v8 range rover used less fuel than a 3 speed vit!!!

Anyway my point was just that adding weight (such as tyres) will reduce your fuel economy.
Another weight saving tip... leave your spare wheel at home, just take an AA card with you... costs less money in fuel!!! ;)

Re: rev counter fitted.. now to bring the revs down..

Posted: Fri Jul 26, 2013 1:09 pm
by ScottieJ
I know what you was trying to say but you didn't read what i wrote, I'm not comparing my set up to an sj with smaller tyres I was comparing the two set ups I have personally ran with both engines, there really wasn't much weight difference between my 31s and 33s certainly not 8kg a tyre :shock:

You said to me "big tyres weigh a lot" and I replied that I was running big tyres anyway so that can't really be used as an argument comparing my two set ups.

Re: rev counter fitted.. now to bring the revs down..

Posted: Fri Jul 26, 2013 1:36 pm
by twiss
Yeah, I didn't mean so much about the weight difference between your two set of tyres...
more just that bigger tyres, while the larger tyre size will increase your gearing, that they will weigh considerably more and negate the effect of the gearing raise fuel economy increase to some degree...

Slightly misleading post there...

Re: rev counter fitted.. now to bring the revs down..

Posted: Fri Jul 26, 2013 2:21 pm
by ScottieJ
Anyway all tyre size debates done and dusted :thefinger: SJs are crap on fuel compared to modern cars no matter what engine, gearing or tyres they run :lol: If you get 28-30mpg you are doing well :lol:

Re: rev counter fitted.. now to bring the revs down..

Posted: Fri Jul 26, 2013 2:24 pm
by twiss
hahah yeah its just something we will have to live with!!!
We've been driving SJs about for years and years now so they can't be that bad on fuel haha

Re: rev counter fitted.. now to bring the revs down..

Posted: Fri Jul 26, 2013 4:10 pm
by dan_2k_uk
I burn most of my fuel post engine to make bangs and fire :D

On a serious note. With my current gearing, tyre size, engine size, etc. my fuel consumption is by far the best its ever been.

When we go somewhere Scottie has to go fill up and I normally still have half a tank!

Re: rev counter fitted.. now to bring the revs down..

Posted: Fri Jul 26, 2013 4:11 pm
by twiss
dan_2k_uk wrote:I burn most of my fuel post engine to make bangs and fire :D
hahah i know that feeling!

how much extra weight do you think youve added to yours dan?

Re: rev counter fitted.. now to bring the revs down..

Posted: Fri Jul 26, 2013 4:25 pm
by ScottieJ
dan_2k_uk wrote: When we go somewhere Scottie has to go fill up and I normally still have half a tank!
I've done pretty well recently and it's not been quite as bad as it was, gonna rebuild the SU though as I think it's not quite right, plus the mixture screw keeps adjusting itself :pissed:

Re: rev counter fitted.. now to bring the revs down..

Posted: Fri Jul 26, 2013 4:29 pm
by twiss
ScottieJ wrote: I've done pretty well recently and it's not been quite as bad as it was, gonna rebuild the SU though as I think it's not quite right, plus the mixture screw keeps adjusting itself :pissed:
At least it hasn't fallen apart yet!!! My dashpot is holding up pretty well with its new washers!