Date: Mon, 28 Jul 2003 22:38:50 -0400 From: ma_twain <ma_twainnopsamo.com> Subject: Re: Gas economy
Why the difference between summer and winter gas? Depending on where you live, the winter gas contains more oxidizer, so the gas will burn cleaner at lower temperatures - the goal is to reduce pollution. More oxidizer and less petroleum by-products could account for the lower gas mileage. Andy Hookins wrote: > "'nuther Bob" <yetanotherphonyaddressnopsamacereally.com> wrote in message > news:9a7aivs9j3ndjv97gl90k0gn59qusjmj6inopsamcom... > >>On Mon, 28 Jul 2003 09:13:05 +0100, "Andy Hookins" >><andrew.hookinsnopsamamnopsamodata.co.uk> wrote: >> >> >>>"Chris O'Malley" <comalley2nopsamrr.comnopsamrr.com> wrote in message >>>news:VPHUa.53995$852.12482nopsamter.nyc.rr.com... >>> >>>>Why is there a difference between summer and winter? >>>> >>>> >>>I don't know exactly, but I can see it very clearly as i plot >>>MPG through the year. >>> >>I think it's almost entirely the warm up time. I see mileage as >>low as 14mpg when the temps get down there. It comes back up >>once warm. I think the difference is all that gobbling of gas >>while the engine is cold. >> > > That's only part of it, warm up only accounts for a few minutes > of my 45-60 minute commute. There's got to be more to it. BTW > the owner manual has a nice graph depicting relative engine > efficiancy against engine deperature. > > >>If you have a turbo, the compensation is the added boost you >>get from a nice cool winter charge. >> > > Oh yeah :-) the Trionic-5 system works to a fixed boost > pressure - although intake temperature is measured it is only > used for fuel metering purposes. Cooler - denser air at the > same pressure > greater air mass > more fuel to get the right > mixture > more power :-) > > Later T-7, I suppose T-8 on the 9-3 sport sedan too, aim to > deliver a fixed engine torque, so boost pressure is slightly lower > in cold weather :-(. I don't know if the 'hot-wire' AMM used in > the APC system behaves like the older T-5 or the newer T-7/8. > > AndyH > '94 9000 CDE > > >>Bob >> > >
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