Snail Posted April 18, 2003 Report Share Posted April 18, 2003 Usually a full tank of tractor fuel gives me 550+ miles. At the moment im stuggling to get 475. She's just been serviced, new cam belt, new alternator belt. but still no change.... I asked for some injector cleaner to be run through her during the service....sounds like im in for some nice big bills soon! Link to comment Share on other sites More sharing options...
Gaunty Posted April 19, 2003 Report Share Posted April 19, 2003 It's only 13% Snail, how many tanks have you put through it since the service? Have you changed your driving pattern, maybe roadworks or less traffic due to kids being off school allowing you to thrash it more? I know that since I've stopped doing my regular motorway journey my mpg figure has fallen. Any difference in performance? I'd drop a few mpg to get more bhp. What about your tyre pressures? Have you checked them? Did they leave it running for a long period of time on tickover to get that jet cleaning stuff through? Do they add it to your fuel? Maybe its that that is causing it and once you've put a few tanks through it it'll go back to normal. Just a few thoughts Rich. Link to comment Share on other sites More sharing options...
Drillslinger Posted April 20, 2003 Report Share Posted April 20, 2003 Snail, have you changed wheels or tires at all? My mpg has taken a good hit since going from 205/65/15's to 225/45/17's Link to comment Share on other sites More sharing options...
peterb Posted April 20, 2003 Report Share Posted April 20, 2003 [ QUOTE ] ... going from 205/65/15's to 225/45/17's [/ QUOTE ] Err, that's reduced your gearing by over 2%! Link to comment Share on other sites More sharing options...
Snail Posted April 21, 2003 Author Report Share Posted April 21, 2003 Its happened recently, and had my 18s on for a while, so i don't think its that........my driving is always erm....."enthusiastic" so i doubt the economy change is due to that....its probably just old age in something under the bonnet (she has done 155k) I know for sure the current tank is gonna be REALLY bad, as just had a great thrash home from dropping the olds off at heathrow.....its amazing just how fast a tractor can be on the right road Link to comment Share on other sites More sharing options...
Drillslinger Posted April 21, 2003 Report Share Posted April 21, 2003 [ QUOTE ] [ QUOTE ] ... going from 205/65/15's to 225/45/17's [/ QUOTE ] Err, that's reduced your gearing by over 2%! [/ QUOTE ] Huh? If you're referring to the overall diameter of the wheels, I looked at some website calculator, and the diameter is the same as the std 195's Link to comment Share on other sites More sharing options...
peterb Posted April 21, 2003 Report Share Posted April 21, 2003 [ QUOTE ] the diameter is the same as the std 195's [/ QUOTE ] Sorry, I was comparing the 205/65/15 against 225/45/17. I don't know what 195s were standard on your car. Link to comment Share on other sites More sharing options...
Drillslinger Posted April 21, 2003 Report Share Posted April 21, 2003 No probs Dude, but that WAS your point, right? What's funny is the 205's are a factory option, but everything is still setup for the 195's The speedo, and, I'm assuming, gearing, are setup for 195/something /15's. Link to comment Share on other sites More sharing options...
Snail Posted April 22, 2003 Author Report Share Posted April 22, 2003 I must be dumb or something, but how can the width of a tyre effect the gearing, i understand the diameter etc changing it, but the width? Link to comment Share on other sites More sharing options...
peterb Posted April 22, 2003 Report Share Posted April 22, 2003 [ QUOTE ] how can the width of a tyre effect the gearing [/ QUOTE ] The height of the tyre sidewall (and, therefore, the diameter) is a proportion of the width of the tyre. This proportion is called the 'profile'. Hence, if the width of your tyre is 205mm with a 50% profile, the sidewall height is 0.5*205mm = 102.5. Double this height, and add it to the wheel diameter and you get the total diameter of wheel/tyre. Since tyre widths are quoted in mm, and rim diameters in inches, you need to convert units. Other than that, it's very simple! Link to comment Share on other sites More sharing options...
Snail Posted April 22, 2003 Author Report Share Posted April 22, 2003 Oh!!! I thought the profile was related to the size of the rim......(blonde alert!) I'll now go sit in the corner with my dunce cap on! Link to comment Share on other sites More sharing options...
Drillslinger Posted April 22, 2003 Report Share Posted April 22, 2003 Well it is, sort of. As your rim size goes up, ie from 15 to 17's, in order to maintain the same overall wheel diameter the sidewall (and profile) goes down. Also, I think I was mistaken before, IIRC the factory std for my A3 is 195/65/15, and I upgraded to 225/45/17. Link to comment Share on other sites More sharing options...
peterb Posted April 22, 2003 Report Share Posted April 22, 2003 [ QUOTE ] Also, I think I was mistaken before, IIRC the factory std for my A3 is 195/65/15, and I upgraded to 225/45/17. [/ QUOTE ] That makes more sense! A reduction of less than 0.2% Link to comment Share on other sites More sharing options...
Drillslinger Posted April 22, 2003 Report Share Posted April 22, 2003 Where'd youlook that up btw ?(or was it a "Math" thing ) I had alink to a calculator, but have since lost it Link to comment Share on other sites More sharing options...
peterb Posted April 22, 2003 Report Share Posted April 22, 2003 [ QUOTE ] Where'd you look that up btw ?(or was it a "Math" thing ) [/ QUOTE ] Simple maths! Link to comment Share on other sites More sharing options...
Drillslinger Posted April 22, 2003 Report Share Posted April 22, 2003 Ahh, in that case, nevermind Link to comment Share on other sites More sharing options...
TDI914 Posted May 3, 2003 Report Share Posted May 3, 2003 I would have them check and see if they got the pump slightly out of time. Does it have the same get up and go that it had before? Link to comment Share on other sites More sharing options...
Snail Posted May 6, 2003 Author Report Share Posted May 6, 2003 Seems to be returning to normal again.....had a couple of good drives, and its back into the 500s, so im happy again.....maybe it was just some dodgy fuel, who knows? Link to comment Share on other sites More sharing options...
fatcat Posted May 6, 2003 Report Share Posted May 6, 2003 I've just spent thw last 2 days hammering up and down 'A' roads and horror upon horrors have noticed my average mpg drop to below 45. Jeeze, the ol' gal is going in for a checkup Link to comment Share on other sites More sharing options...
peterb Posted May 6, 2003 Report Share Posted May 6, 2003 [ QUOTE ] Jeeze, the ol' gal is going in for a checkup [/ QUOTE ] I think you should get the car checked as well! Link to comment Share on other sites More sharing options...
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