Tires, my secret sauce formula.

[Compaq888]

Originally Posted by thisisntjared

the receipt does lie, you can over or under fill a tank up to one gallon. that leaves a lot of margin for error.

the only way you can weed out this error is to consume a lot more gas to make the difference insigificant.

i guess the radiology guys dont have to take statistics...

I don't drive 30-70 miles and fill up. I drove more than 300 miles and fill up. I don't do any tricks at the pump, I get the once click and that's it. My 29.08mpg would of been a 30mpg if I didn't lower my tire pressure at the end and remove some aero mods.

This isn't one tank. My last 3 tanks have been 50+psi. My 29.92mpg tank has been 55 psi the whole tank, the other 2 were 50psi or were 55 and were drodded off.

The 29.92 is the fuel receit for 55psi only. I'm going to start labeling my fuel receits.

[Compaq888]

go look at my gas log, I updated the tire pressures. Then make your remarks.

[psyshack]

In this same vein. My wife called me yesterday. And stated she got 41 mpg in our Accord. She just filled it up, did the math and was soooo happy. I told her good. Then droped the BOMB on her. Asked her if she filled it all the way up to the very top of the filler neck,, like Ive been doing for the last several months. She didnt. So her mpg is wack. I loved busting her bubble.

[Sludgy]

What a loving husband........ do you tell her she's fat, too?

[thisisntjared]

hahahaha sludgy thats mean. but seriously so is bursting her fuel economy bubble.

Originally Posted by Compaq888

I don't drive 30-70 miles and fill up. I drove more than 300 miles and fill up. I don't do any tricks at the pump, I get the once click and that's it. My 29.08mpg would of been a 30mpg if I didn't lower my tire pressure at the end and remove some aero mods.

This isn't one tank. My last 3 tanks have been 50+psi. My 29.92mpg tank has been 55 psi the whole tank, the other 2 were 50psi or were 55 and were drodded off.

The 29.92 is the fuel receit for 55psi only. I'm going to start labeling my fuel receits.

o man, you dont think i swear!

look the first click is not in the same place every single time. the angle of the car has a HUGE impact on the amount of gasoline pumped in.

also i see NOTHING in your gaslog that supports your thesis. the only way to truely prove the % in savings with tire pressure is to do 3 full tanks of one psi range then 3 full tanks of another. one tank of each or one half tank of each is not enough. i cant believe you are taking everything at face value.

look if you want to find your standard deviation then take the info you have now on the last tank and calculate the mpg for there being a gallon more or a gallon less. that will give you the approximate range your working with. then you will see how your readings truely are marginal.

also remember that ambient temperatures have gone up significantly in the past 45 days.

i cant believe you are getting defensive. its obvious that you dont know anything about statistics. dont refuse knowledge, accept it and become more knowledgable. im trying to help you, not make you sound like an idiot. your not an idiot so stop acting like one

remarks made!

[zpiloto]

I agree the only way to do it would be with consistant condition. The gas log showed highway driving and a coolant temp change. I think that you would have to do some kind of test on the same day since temp and driving condition change so much from day to day.

[Compaq888]

I have been driving on 30psi for more than a year and kept getting 24mpg.

As you can see in my gas log the more I increased fuel economy the more my mpg improved. This is not just the 3 tanks.

I don't care about deviation, statistics or anything else. If it works then I'll keep doing what I'm doing. If it doesn't work then I'll change it.

So far I replaced some ignition components, did aero mods, and inflated my tires 25psi more than I had them before. Now I'm getting 6mpg more than when I did nothing.

I'm not trying to get a science grant, I don't have to show any data. I'm only stating facts. I did this and that which changed this and that. I don't want to nerd up this tire issue. I'm only posting this so other members see that when I increased tire pressure my fuel economy improved. And to show what happens when you increase tire pressure.

I'm sorry but this is not an experiment, If I wanted to do this on a experimental basis I would of posted this in the experiment section.

[Matt Timion]

I would like to remind everyone to keep the rules of the forum in mind when you post. We really don't have time or room for mean spirited posts.

[MetroMPG]

I agree that it's important if you're making strong claims about a technique or modification that has changed your FE, you have to have solid data to back it up.

I AM a nerd. And I want the data from a test that's as controlled as possible. Claims made without good support automatically go in my "doubtful" pile.

The fact that people here generally seemed to agree to that point was one of the things that interested me in this site originally. I think we would be doing each other (and the site in general) a favour if we are constructively skeptical of each other when appropriate.

PS - If you had a ScanGauge or other FE instrumentation, you could conclusively prove/disprove your theory in about an hour.

[Compaq888]

Originally Posted by MetroMPG

I agree that it's important if you're making strong claims about a technique or modification that has changed your FE, you have to have solid data to back it up.

I AM a nerd. And I want the data from a test that's as controlled as possible. Claims made without good support automatically go in my "doubtful" pile.

The fact that people here generally seemed to agree to that point was one of the things that interested me in this site originally. I think we would be doing each other (and the site in general) a favour if we are constructively skeptical of each other when appropriate.

PS - If you had a ScanGauge or other FE instrumentation, you could conclusively prove/disprove your theory in about an hour.

PS- you want to send yours out so I can prove it for you or maybe just do the experiment on your car. My fender bender was $700, there is no way I can afford a scanguage.