Anyone gets >40mpg consistently in his/her xb?

[Z man]

Originally Posted by xbUser

One thing I've learned in a hard way, don't put away your spare tire. And remember to leave the jack inside your car. Sometimes, a can of liquid won't save you. My tire broken into pieces. Tire wall has holes. I am glad I have spare tire and jack. I save $75 for not calling toll truck to change the tire for me. If I don't have a spare tire, it definitely cost much more..... And remember to buy road hazardous insurance for tires. I regretted I didin't.

Did you hit something or was it because of the pressure being beyond wall max psi? I have my spare tire and jack mainly as a good luck charm.

[xbUser]

The tire guy shows me that it hits something on freeway. For some reason, I found it harder and harder to keep 40+mpg on freeway, especially after the upper grille was gone. I will put the grille back on the lower grille tomorrow.

The speed I've got the best mpg, according to SGII, is 35mph w/ 5th gear. I get over 50mpg easily. Sometimes it goes 60mpg. Same trip, I only get 33mpg at 60mph. What a big difference!!

[Z man]

Originally Posted by xbUser

The tire guy shows me that it hits something on freeway. For some reason, I found it harder and harder to keep 40+mpg on freeway, especially after the upper grille was gone. I will put the grille back on the lower grille tomorrow.

The speed I've got the best mpg, according to SGII, is 35mph w/ 5th gear. I get over 50mpg easily. Sometimes it goes 60mpg. Same trip, I only get 33mpg at 60mph. What a big difference!!

What happened to your grille?

Wow only 33mpg @ 60mph? Geez I hope I get better than that!


I overfilled about 14 cents worth of gas,

I don't know if that's the reason but my quarter tank is 130 miles!

[xbUser]

I don't know if the bad 60mph mpg is given by the uncalibrated SGII or not. Holding 60mph with 40+mpg is very difficult. The first tank is rather easy. After filling up 2 tanks, it gets harder and harder. I also see the mile meter is not matching to my odometer. I am very confused. But even the SGII is not calibrated, it shows cruising at 35mph saves more gas than 50 or 60mph. That is tough to drive because I can only drive this speed in town, where has traffic lights and stop sign. That is not many chance to have long cruise. Freeway is impossible to drive in this speed....

Another interesting find out today. We all know drafting saves gas. Today, I did an experiment. Cruising 55mph, no vehicle ahead, require holding 21tps, getting 33mpg. Drafting behind a big truck after 8 cars length, driving 65mph to 70mph, require holding 20 to 21tps (less gas used, faster speed), getting 39 to 41mpg. That means, drafting gives me 15% fast speed & 20% mpg. Great!!

Another experiment, blocking lower grille is cooler than the upper grille. Both reach 204F max (where the fan clicks in). Lower grille blocked goes up less frequently. Without block, max water temp is 194F. I will try few more days, then block the upper grille again. See if the result still same and see if mpg goes up. I am trying to do it in the same tank of gas so that mpg won't get affected by gas factor.

Also, I observed going beyond 65mph has dramatic higher air resistance. That explains why slowing down to 65mph from 80mph will jump from 32mpg to 38mpg. That makes xB not very good in pulse and glide because driving to 70mph uses much more gas and it doesn't have a lot of time cushion before stepping on the gas pedal again. (maybe 55mph) For me, I will neutral cruise only when the hill is deep and long enough. Neutral cruising gives me 350mph @ 70mph, 300mph @60mph, 279mph @ 55mph. Those figure is from my current SGII. The number may not 100% accurate, but it is good for reference.

[Z man]

Yeah I tried blocking the lower grille. Maybe I should tape that one up again.

I find that going between 40mph and 60mph is perfect for most roads. I only pulse up to 60mph anyway. I have a few good places on my road for 1 mile glides maintaining 50mph though corners. I hate it so much when people brake and get in my way when I am coasting in neutral. It really helps to have a good handling car. Just to think that I'm getting 200mpg and they are probably getting 25mpg while in my way! Gahhh!

Have you thought about a belly pan yet, and the material and everything?

[whokilledthejams]

@xBuser:

It's good to see all these different things quantified. I still haven't gotten around to getting an SG2 myself, sadly. Even if yours isn't 100% accurate, you can still get a good handle on what's working and what's not.

I blocked the bottom grille because A) I thought it looked better, and B) very little of the radiator is actually behind it. I figured that the upper grille would do more good, just intuitively. It's good to know I happened to be right.

Same with driving over 65mph-- instrumentation or not, you can really feel the drag. I wish I had the nerve to drive a little bit slower on the interstate, since that would get me over 40mpg easily. I generally keep it as close to 64-65 as I can.

[xbUser]

I saw the xB bottom few days ago. The middle part is pretty good. It is not smooth as silk, but not bad at all. The worst part is the rear. I saw someone did a good job in another forum. I am still thinking of the material. Looking for coroplast, but no luck in home depot. I saw window screen, like 48"X84" for $13. that is good for blocking grille, but too soft for belly pan. I would buy that later and test out any affect to water temp. Usually, it reaches to max in 2 situations. 1) traffic in local or jam 2) going up the long hill.

[xbUser]

Today, I found out the problem of low mpg these 2 tanks. That is GAS!! I refill in costco rather than Valero today. Instead of reporting 33mpg @ 60mph/22tps, today, I got 43mpg @ 60mph/21tps. Yesterday, 21tps can't cruise @ 60mph. I have to gas more until 22tps. That's the main reason of lower mpg. The second reason is the adjustment of SGII. Everytime I refill, I press the fill up button on SGII and enter the amount of fuel refilled. SGII will adjust the difference. Today, I am happy, because better gas let me lighter my foot in cruising and adjusted SGII gives out higher mpg number.

[Z man]

I want an under tray for the rear, but its too much work for me! Gah!
I always fill up at Shell, no matter what. I should try V Power, haha.

[whokilledthejams]

You know, it's funny you mention that-- I'm starting to suspect the gasoline on this current tank is going to keep my mpg down a bit.