12 Tips To Save Petrol!

Discussion in 'Lounge' started by Adrian Wong, Aug 18, 2005.

  1. AAY

    AAY ARP Reviewer

    Yes :). Your engine is turning in that case not because it is producing power by burning fuel but because the car's momentum drives the engine and not the other way around.

    Yup! As long as your clutch foot doesn't get tired of course :).

    To each his own, really If you spend more time driving around KL around lunch hour or you just happen to be going through the Federal Highway at about 7pm-ish on a rainy Friday evening, I suspect you'd suddenly like automatics a lot more :p.

    Run your tyres at whatever your car manufacturer specs! The rating on the tyre is the maximum safe pressure it can handle. The car manufacturer however gives specific tyre pressures to take into account the weight and weight distribution of the car, suspension geometry and even the nature of a car (luxury vs. sport). Unfortunately, while most mechanics mean well they may not be familiar with the specifics of your car, and even then (as I'm sure we've all seen in the PC world!) many tend to follow anecdotal advice with no basis in fact. If you go racing then you might want to experiment with different tyre pressures to see how that affects your handling though :wicked: .
  2. Adrian Wong

    Adrian Wong Da Boss Staff Member

    Oh I see, but wouldn't that reduce the car's momentum then? If we disengage the engine from the drive shaft, then the car can coast longer without the engine reducing its momentum.

    Haha.. Yup! :mrgreen:

    I think it's safer to coast with the clutch engaged than with the gear in Neutral. At least you can release the clutch quicker than switching gears.

    Hahaha!! That's true! Using a manual transmission car is a real pain-in-the-ass during traffic jams! :doh:

    Hmm.. But won't setting the pressure to 30 PSI (max rating) be harmful? After all, the tyre heats up when it's running and the pressure will end up much higher than what it's rated to handle -> tyre burst?
  3. zy

    zy zynine.com Staff Member

    my car tyres are ~27 PSI i think :think:

    lower tyre pressure heats up the tyres much faster
  4. Chai

    Chai Administrator Staff Member

    Lower tyre pressure = more grip, more comfortable ride.
    Higher tyre pressure = less grip, better fuel consumption.
  5. Adrian Wong

    Adrian Wong Da Boss Staff Member

    Okay, but exactly how high can we go?

    My tyres are rated to 30 PSI... :think:

    Is that the MAXIMUM rating.. or the maximum recommended pressure?
  6. Ishtim

    Ishtim Super Moderator

    Tyres aree "load rated" i.e... MAXIMUM Load 500kg at 120kPa cold.

    This is NOT the same as what the auto makers recommended pressure is (although the MAX tyre load/pressure should include the recommended pressure from auto maker).

    The car maker should have put a recommended tyre pressure placard (sticker) on the car. Follow these recommendations. Usually it is in a door jamb, dash compartment or other hiding place. If no placard, look in owner's manual.

    As far as how soft the ride goes...that's up to you. :whistle:

    softer ride or better economy? :boohoo:
    Last edited: Aug 23, 2005
  7. AAY

    AAY ARP Reviewer

    It does do that, but it's also handy to leave the car in gear if you need to accelerate suddenly; it's all up to the driving situation I suppose.

    Err...what tyres are you using? 30psi isn't very much... Are you sure that your tyres have a max rating of that?

    Kinda sorta....but keeping tyre pressure high also reduces sidewall deflection during hard cornering :p. Of course if you drive a car with low profile tyres that's less of an issue...
  8. Adrian Wong

    Adrian Wong Da Boss Staff Member

    Just checked them. The front tyres are rated with a maximum loading of 475kg at 44 PSI (300 kPa).

    But the rear Yokohama tyres do not have any rating present. :wall:

    The question is what's the upper pressure limit, given the fact that they will heat up the air within and increase the pressure during travel? :think:
  9. Ishtim

    Ishtim Super Moderator

    If you had all 4 of the similar tyre, then
    Maximum Load is 4 X 475kg = 1900 kg @ the maximum pressure of 300kPa.

    Look on the inboard sidewall of the tyre or jot down model number and size (i.e. Yokohama Aegis LS4 All season radial P215/70R14) then look up ratings on the web at http://www.yokohamatire.com/testSearchResults.asp

    Attached is a sample...

    The recommended pressure is ALWAYS measured "cold". By cold, they mean that there is NO heat present from driving. Tyre expansion is accounted for by the manufacture process and is governed by the mathematical relation:
    Pressure X Volume/Temp.... Tyre volume is considered constant, So low pressures are BAD! :naughty:

    Let us know what you find Adrian. :think:

    Attached Files:

    Last edited: Aug 23, 2005
  10. Adrian Wong

    Adrian Wong Da Boss Staff Member

  11. Ishtim

    Ishtim Super Moderator

    That's odd... all I can find is the S306. Yours is R306? :think:
  12. Adrian Wong

    Adrian Wong Da Boss Staff Member

    Eh.. Really?? I'll go have a look in the morning. I just locked up the door and set the alarms!! :doh:
  13. Adrian Wong

    Adrian Wong Da Boss Staff Member

    It is the S306!! :doh:

    Haha... :haha:
  14. PsYkHoTiK

    PsYkHoTiK Admin nerd

    Engine braking... :mrgreen: :thumb:
  15. Dashken

    Dashken Administrator!

    So, is coasting with a gear engaged but clutch fully depressed same as neutral gear and clutch fully depressed? Coz I always do the latter, easy to change gear coz I don't coast that long time. :mrgreen:
  16. orangutan

    orangutan Newbie

    I never put on a full tank when going to the petrol station. Why waste petrol in carrying the kgs of petrol . I always pump RM45/trip.
  17. Chai

    Chai Administrator Staff Member

    I use that everytime. I never ever coast in neutral.
  18. Adrian Wong

    Adrian Wong Da Boss Staff Member

    From what AAY says, it's the same thing. :mrgreen:

    Yeah, that's what I do too. :mrgreen:
  19. Ishtim

    Ishtim Super Moderator

    I don't see the load rating available on the web... :think:

    Perhaps you will have to look at inboard sidewall... :?
  20. Adrian Wong

    Adrian Wong Da Boss Staff Member

    I will go check it in the morning and see what I can glean from it. But I remember that nothing much was printed on it. :wall:

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