Author Topic: Fuel Economy? (Read 9058 times)

DesktopDave · « **Reply #15 on:** July 30, 2009, 09:08:14 AM »

I've just pulled the P/S pump & I'll be seeing what that does to mileage. I know it's just a bit of power, but I'm hoping to see another mpg or two from that and the new air dam once I get that done. I'm hoping to keep in the mid-30s highway and mid-20s city.

+3 on the O2 sensor. They wear out from thermal contraction in as little as 30k miles. Even the high quality Bosch units have to be replaced every few years. I've had cars that a $100 O2 sensor paid itself off in fuel savings in less than a year. They make the biggest contribution to fuel economy in a reasonably tight engine without vac leaks. Injector cleaning will help too, as will a higher-temp thermostat or warmer intake air. A decent cold air intake or chip will sacrifice efficiency for power as well.

tjts1 · « **Reply #16 on:** July 30, 2009, 01:55:48 PM »

My car has electric fan, EV6 injectors, no PS, volvo air dam running on 87 octane. For the last month my dad has been commuting in my car while I convert his mercedes to megasquirt. His commute is 37 miles each way with some AC use, some stop and go traffic and mostly bay area feeway driving. For the last 3 tanks he has done 34.8, 35.5 an 35.9mpg. He calculates his mileage at every fill up. I wish I had the self control to take it easy like he does.

n2motorsports · « **Reply #17 on:** July 30, 2009, 02:05:19 PM »

new o2, cop conversion, and 22mpg...wth?

*edit that's with a thule roof rack, fairing and 2 bike mounts...oh with a/c running 90% of time as well.

DesktopDave · « **Reply #18 on:** July 30, 2009, 02:25:45 PM »

Those racks will take a surprising amount of fuel...I pulled the stock rack off my old minivan and saw a small but measurable improvement. It's the streamlined stock model too, not anything useful like a Thule. I lurk over at ecomodder...they do little things that add up dramatically.

A/C will suck up gas it's over/undercharged or if the compressor pump is on the way out. Mine isn't functional so it's a moot point. Alcohol in the fuel is the worst offender. If you're using a 10% ethanol mix you'll lose ~1% mileage regardless of other issues. I noted that our winter mix gas is also really bad for mileage, not just due to the longer warm-up and more time idling in traffic.