- Funny you post this, last night I was stunned by my trucks behavior. We had a big air temperature drop yesterday, like 30 degrees. Last night my Burb felt like it had 20 percent more power and was begging for me to cruise her around. That cold air made a huge difference in the power of this truck. However, doesn't cooler air mean more fuel?
- If my oxygen sensor was bad wouldn't the engine light say so?
*Not necessarily. A failing o2 sensor will not trigger a light, unless it starts operating outside of the programmed boundaries for its normal operation.
- Does a spacer really improve mileage? Does it affect factory sensors or computer?
*It depends on the spacer design. With a smooth Dual bore spacer, you should be fine with stock components. You will benifit from the added manifold volume, which has been dyno proven, but the gains are very small, almost un noticed, exept for maybe better throttle response. The CFM-Tech spacer, that is of the "Open to both sides design" (trans dapt makes a similar piece) requires at least an Adjustable fuel regulator IMO, because there is a bit of a lean "tip in" on accelleration. It boosts power just a tiny bit in the mid to upper rpm ranges.
- They make "economy" tuned chips? I might want one.
*Let me know when you are ready to do this, I can get you a drop in chip that has been fine tuned for a stock 4wd Squareburban, stock exhaust, that has a wide open throttle air fuel ratio of 12.5, and yeilds around 19.5 MPG, due to the use of Highway cruise mode, which is disabled from the factory.
- Doesn't changing intake and exhaust flows burn more fuel?
*Not the way you drive, which is similar to my driving style...laid back and chill, unless in the company F-150.
Better flow=less work for the engine to do, intake and on exhaust.
- I want to go back to factory size tires. 235/75-15's.
*I aim to do this as well. just make sure you keep 35 psi in them, and you should be ok. They are a few inches shorter than 31's, and that will translate into less work for the engine as well, just like installing a bigger set of gears. Shouldnt be a big mpg factor on the highway.
- Do sudden stops really hurt gas mileage?
*Only if there is a hole in the front of your fuel tank. Its the required starts after a stop(of any kind) that is detrimental to fuel economy, because you have to go through the gears again, to get the engine back to a steady cruising rpm, which is where it is most efficient.
- I have heard p/u trucks get the best mileage with an open bed. It creates a rolling ball of wind in the back and cut's down on the drag on the back of the cab. Anybody else hear that?
*Yes- its kinda like us with burbs, installing a large cone on the back(like on the space shuttle, when its piggyback on its 747) or, the panels I have seen on the back of Van trailers.
That swirling ball of air behind the cab prevents a vacuum from being formed, smoothly passing the air over the bed area, and the result is only a small vacuum area behind the tailgate. With the tailgate down, there is no opportunity for the bubble to form, resulting in an area of vacuum, just as bad as on our Burbs.
Anther example...which is easier to row? a Boat with a Flat tail, or a Kayak that is sleek on both ends?
