Tires and Airtabs oh my!

[kitcar]

27 mpg here I come! My current mileage on the highway is 25.6. I'm paying for all three of these experiments with my handy dandy government $600 rebate check because for once in my sorry life I did something right and overpaid my taxes on purpose which qualified me for the 600 bucks.

My new tires are here (Hankook Dynapro AT) that Consumer Reports rates above average on the rolling resistance. The current tires are Kelly tires that have a lower than average rolling resistance, according to CR. I'm having them installed tomorrow. I got them from savontires.com for $64 a piece, free shipping. Installation is $30 per tire. Shipping cost: $0. Cost of modification: $0

At the same time, a set of Airtabs got here. I've been talking with Ron Davidson there and will be reviewing them for This Old Shack. For those that don't know, their facility was destroyed by a tornado this past spring. This should be the easiest review I've ever done. Well, maybe not. Ron told me that the way they test the position of them is to use aluminum duct tape, attach the tabs to the aluminum side of the tape and use the tape to attach them to the vehicle. For the first test, I'm going to put them on the roof of the truck 3 inches from the back and on the door posts. For the second test, in front of the rear wheel wells. The goal is to get the bed cover (which billows behind the cab and presses down at the tail gate) to billow the entire length of the bed. Cost of modification $0.

Once I see if that works, I'm going to actually pay for some for the hood and other parts of the truck to get closer to the elusive 30 mpg point. My thinking is that we can use the Airtabs to create an artificial teardrop aerodynamic shape.

If that wasn't enough, I'm experimenting with a device that in my opinion everyone should use after using it for a couple of weeks. That is a vacuum gauge. I raised my city mileage 1.8 mpg by using it to gauge my throttle pressure. Cost of modification: $0.

[ZugyNA]

What works better than a vac gauge?

A spring that you put on your throttle pivot. Need just enough extra tension so that your lead foot can feel it.

I set this at right around the throttle needed for cruise at 55 mph.

No need to watch a gauge...the DETENT is always there reminding and training you to go easier on the gas.

Can be overidden when the cops are after you.

Need to install it right so there is no issue with a sticking throttle....

[theholycow]

Another way to watch throttle position would be a simple multimeter tapped to the throttle position sensor. A cheap $3 meter from Harbor Freight would do it and isn't too big to mount to the dash. In fact, it might be easy to relocate its LCD so that you can mount it in any position.

[kitcar]

That's all well and good. I've got several of the HF cheapo multimeters that we use at the shack for measuring the outputs of the solar panels and the battery bank besides using the hydrometer.

But my point is to provide people that don't have the technical expertise to tap into the TPS a route that they can use more easily by mounting the gauge in their vehicle with some Velcro and a tube. In the end while we here have the expertise to tap into the electrical network of the vehicle, I want to teach people that don't have the knowledge a way to measure their gas mileage in real time using a very easy method that doesn't require any mods other than finding a vacuum tap on the intake.

It's a bouncing an idea thing off of you guys to make it as simple as possible for the below average driver to learn about hypermilage techniques. I mean, what could be simpler (other than using the OBD port) than a simple gauge? Plus it's cheap as hell too.

[theholycow]

Ah, I see what you mean. It wouldn't occur to me because for me it's far easier and less intimidating to just tap the TPS than to try to figure out how to install a vacuum gauge. I guess I'd have to find a vacuum line and tee off of it?

I'm great with wires, terrible with hoses.

[kitcar]

I think that for the average joe, messing with the electrical system of a vehicle is probably not a good idea.

Here's the beauty part. They're just sitting there all fat dumb and happy just waiting for someone to pull the cap off the port. I showed one of the ports on Stinkerbutt in the first part of the episode, which is rapidly devolving into a 3 part maelstrom of details. So what I'll do is show the ports on the kid's jeep, the wife's soccer mom van as well as my truck.

However, you have just tickled an idea. When I had my last Stinkerbutt, a yellow Dakota with a 3.9 liter V6 (LA block based), I had tapped into the IAT (Intake Air Temp.) sensor with a rheostat and several resistors to trick the computer into thinking that it was like -700000 F which caused it to richen up and add 4 degrees of timing. This deal also allowed me to do the opposite and lean out the engine and retard the timing. If I had the thing too far one way the engine would just stumble and die.