42.6 mpg city

[lovemysan]

Finally made it to the 40s in town. I've been cod-fishing a quite a bit. But I'm still driving normal in town speeds and the same routes. I had one trip to the country in there for about 70 miles that kinda skewed the numbers. But overall I'm very pleased to finally make my 42mpg city. I've also been carrying a lot of junk(tools,etc) + my wife, child, bags, and car seat the whole time. Its a lot of excess weight thats for sure. I had 20 miles with 4 people on board. This is not commuting miles either. Its short trips all over town. I would also mention that my wife drove 70 miles and you know what that does to mileage.

This was after I had to pull my IAT resistor because of the crummy gas.

[Matt Timion]

I've personally always been a fan of not screwing with sensors. Sensors work for a reason. I would rather actually increase the heat temperature than fool the sensors. Less potential engine damage that way.

Anyway, congrats on the awesome tank. I've been reading more about Saturn lately, and the EPA estimates on their cars are VERY impressive. It's a shame they didn't stay an independant company instead of being reabsorbed into GM.

Now that you broke 42mpg, what's your next goal?

[Compaq888]

I have to agree with Matt. I don't mess with sensors unless I replace broken ones.

[lovemysan]

My next goal is to maintain this level of economy through the winter. I'm going to redesign my HAI inlet to get more consistant hotter air. I'm also going to read the plugs and regap them. I might index and radius the tips also. I'd like to do a 55mpg tank on the highway also. Maybe next summer I can get a scangauge.

[onegammyleg]

The Sensors on a modern EFI car realy cover most of the operating conditions an engine can experience.
The software in the computer are also usually well written , and its hard to beat.
If someone is claiming a huge FE improvement after manipulating the output of a sensor , ide be thinking that they have an undiagnosed problem elsewhere and this has covered it up.

For example , perhaps your EFI car has an altitude sensor fitted and its slighty on the fritz.
Not bad enough to turn on the check engine light , but enough for the computer to richen up the mixtures greatly , ruining FE.
Now comes along ¨add-on resistor guy¨ and he alters the water temperature sensor.
The computer will still caluclate the inputs and deliver the amount of fuel to suit what information it has recieved.

The newly modifed water signal may actually compensate for the faulty altitude sensor bringing the mixtures back to a more normal level , and giving a better FE result.

Likely tho because this doesnt exactly match what all of the other sensors are seeing the car may present with flat spots on accelerating or missing or surging across the rev range.