Liars! This is RIDICULOUS!!
07-07-2008, 01:18 AM
#71
Platinum Member
Join Date: 05-09-2006
Location: "Upland" Mesa, Arizona
Posts: 6,805
Hey Cleveland.....
I'll tell you what. I'm taking a vacation soon of about 4000 miles. From Arizona through NM, TX panhandle, Oklahoma, Missouri, Illinois, Indiana, and Michigan.
Not sure of the route in return. But this route will provide a variety of exposure for the HHR (was thinking about taking another car, but I'll use the HHR for this purpose), although most driving will be on the Interstates, at the designated speeds. I'll keep a perfect spreadsheet on everything and try to include pictures of dash read-outs vs. manual calculations. Have any ideas of info to accumulate other than the obvious.
I'd be willing to bet that I would see 34-35 mpg in at least one of the tanks of gas....the worst upon leaving home. I need to climb the mountains to the NE section of the state to get access to the Interstate.
Besides, this will also provide some interest while driving across country.
I'll tell you what. I'm taking a vacation soon of about 4000 miles. From Arizona through NM, TX panhandle, Oklahoma, Missouri, Illinois, Indiana, and Michigan.
Not sure of the route in return. But this route will provide a variety of exposure for the HHR (was thinking about taking another car, but I'll use the HHR for this purpose), although most driving will be on the Interstates, at the designated speeds. I'll keep a perfect spreadsheet on everything and try to include pictures of dash read-outs vs. manual calculations. Have any ideas of info to accumulate other than the obvious.
I'd be willing to bet that I would see 34-35 mpg in at least one of the tanks of gas....the worst upon leaving home. I need to climb the mountains to the NE section of the state to get access to the Interstate.
Besides, this will also provide some interest while driving across country.
07-07-2008, 12:01 PM
#73
Senior Member
Thread Starter
Join Date: 03-31-2008
Location: CLEVELAND
Posts: 772
Hey Cleveland.....
I'll tell you what. I'm taking a vacation soon of about 4000 miles. From Arizona through NM, TX panhandle, Oklahoma, Missouri, Illinois, Indiana, and Michigan.
Not sure of the route in return. But this route will provide a variety of exposure for the HHR (was thinking about taking another car, but I'll use the HHR for this purpose), although most driving will be on the Interstates, at the designated speeds. I'll keep a perfect spreadsheet on everything and try to include pictures of dash read-outs vs. manual calculations. Have any ideas of info to accumulate other than the obvious.
I'd be willing to bet that I would see 34-35 mpg in at least one of the tanks of gas....the worst upon leaving home. I need to climb the mountains to the NE section of the state to get access to the Interstate.
I'll tell you what. I'm taking a vacation soon of about 4000 miles. From Arizona through NM, TX panhandle, Oklahoma, Missouri, Illinois, Indiana, and Michigan.
Not sure of the route in return. But this route will provide a variety of exposure for the HHR (was thinking about taking another car, but I'll use the HHR for this purpose), although most driving will be on the Interstates, at the designated speeds. I'll keep a perfect spreadsheet on everything and try to include pictures of dash read-outs vs. manual calculations. Have any ideas of info to accumulate other than the obvious.
I'd be willing to bet that I would see 34-35 mpg in at least one of the tanks of gas....the worst upon leaving home. I need to climb the mountains to the NE section of the state to get access to the Interstate.
Besides, this will also provide some interest while driving across country
07-07-2008, 12:51 PM
#74
Platinum Member
Join Date: 05-09-2006
Location: "Upland" Mesa, Arizona
Posts: 6,805
If you spend anytime at altitude (5000ft and up) try to determine how much altitude hurts mpg. I'm at 500ft above sea level so I have no expeience here. I don't know if you do the down hills in neutral, i know that some states it's supposedly illegal and some feel it's dangerous. But That will probably offset any significant mountain climbsthat you encounter.
Besides, this will also provide some interest while driving across country
Besides, this will also provide some interest while driving across country
I'm not sure, as most people state, that altitude effects overall mileage. As you know, our cars have computers that measure, in one way or another, many things to adjust and provide appropriate fuel mileage. I'm wondering if the computer performs the necessary adjustments for altitude, with the readings from the MAF, and related sensors. I think the drop in mileage at "altitude" is a mindset carryover from the carb. days.
Being summertime, I can't ask the few remaining contacts that I have. They are either on vacation or traveling for GM (including the guy that monitors this forum).
Oh, and as I stated in another thread.....One of the best MPG tanks of fuel that I experienced was in Northern Arizona through Albuquerque to Amarillo. That's anywhere from about 7000-4000 ft.....although gradually downhill. Can't remember what the MPG was....but anywhere from 30-35 because I averaged just slightly more than 30 mpg for that entire 8500 mile trip.....and I included my city driving, at destinations, for the overall MPG.
I also forgot to answer the "in neutral, downhill question". No I don't shift out of gear when encountering large declines, but I do coast by removing my foot from the accellerator (I also disengage the Cruise Control, but sometimes the vehicle attains to much speed and need to use the brakes frequently. I found that using Cruise downhill maintains the speed better, although still increases depending on the decline).
07-07-2008, 01:20 PM
#75
Senior Member
Join Date: 10-02-2005
Location: VA
Posts: 1,245
Snoopy.... First have a great and safe trip!! 
As for altitude, the MAF sensor (which reports Mass Airflow) will compensate for altitude. With the air less dense at altitude, mass per volume is lower, but since the sensor actually detects mass, not volume, the correct values will be reported to the ECU. Consequently, fueling will remain correct.
Now, going "uphill" vs. "downhill" will make a difference! I regularly make a business trip that's right at 200 mi. each way. Net elevation gain is about 1,500 ft. The last few trips resulted in an average of 2.6 MPG difference between up and down.
I've also noted that rain will drop the MPGs, given having to push through the water on the road. It was really noticeable showing MPG while driving through rain at the same speed and watching the mileage dropping. But I have 235 tires that don't help that!
Wish you were closer or coming out to eastern VA. I'd put a tune on your car that would gain a few MPG!!
As for altitude, the MAF sensor (which reports Mass Airflow) will compensate for altitude. With the air less dense at altitude, mass per volume is lower, but since the sensor actually detects mass, not volume, the correct values will be reported to the ECU. Consequently, fueling will remain correct.
Now, going "uphill" vs. "downhill" will make a difference! I regularly make a business trip that's right at 200 mi. each way. Net elevation gain is about 1,500 ft. The last few trips resulted in an average of 2.6 MPG difference between up and down.
I've also noted that rain will drop the MPGs, given having to push through the water on the road. It was really noticeable showing MPG while driving through rain at the same speed and watching the mileage dropping. But I have 235 tires that don't help that!
Wish you were closer or coming out to eastern VA. I'd put a tune on your car that would gain a few MPG!!
07-07-2008, 01:46 PM
#76
Platinum Member
Join Date: 05-09-2006
Location: "Upland" Mesa, Arizona
Posts: 6,805
Hey THANKS Joe....
Wish I was traveling in your direction, I would then BRING THE OTHER CAR
and you could put a performance tune on that.
Thanks again for the thoughts and the offer.
Also agree with your other comments. Rain alone, or with accompanying wind can have a sever effect on mileage.....both in volocity and wheel slippage (although mostly unnoticeable to the driver, but still present).
But I would think it COULD also increase mileage, if no wind is present and rain is a fine mist. You know, cool humid day, kind of thing.
Most of the mountain climbing, as I mentioned, will be in AZ getting to the 7000 ft elevation where I enter the Interstate. But some other are encountered in Missouri that are somewhat challenging for the MPG.
So, regarding that MAF...are you saying...there should be little if any difference in altitude and fuel mileage?
Wish I was traveling in your direction, I would then BRING THE OTHER CAR
and you could put a performance tune on that. Thanks again for the thoughts and the offer.
Also agree with your other comments. Rain alone, or with accompanying wind can have a sever effect on mileage.....both in volocity and wheel slippage (although mostly unnoticeable to the driver, but still present).
But I would think it COULD also increase mileage, if no wind is present and rain is a fine mist. You know, cool humid day, kind of thing.
Most of the mountain climbing, as I mentioned, will be in AZ getting to the 7000 ft elevation where I enter the Interstate. But some other are encountered in Missouri that are somewhat challenging for the MPG.
So, regarding that MAF...are you saying...there should be little if any difference in altitude and fuel mileage?
07-07-2008, 01:55 PM
#77
Senior Member
Thread Starter
Join Date: 03-31-2008
Location: CLEVELAND
Posts: 772
Snoopy.... First have a great and safe trip!!
As for altitude, the MAF sensor (which reports Mass Airflow) will compensate for altitude. With the air less dense at altitude, mass per volume is lower, but since the sensor actually detects mass, not volume, the correct values will be reported to the ECU. Consequently, fueling will remain correct.
Now, going "uphill" vs. "downhill" will make a difference! I regularly make a business trip that's right at 200 mi. each way. Net elevation gain is about 1,500 ft. The last few trips resulted in an average of 2.6 MPG difference between up and down.
I've also noted that rain will drop the MPGs, given having to push through the water on the road. It was really noticeable showing MPG while driving through rain at the same speed and watching the mileage dropping. But I have 235 tires that don't help that!
Wish you were closer or coming out to eastern VA. I'd put a tune on your car that would gain a few MPG!!
As for altitude, the MAF sensor (which reports Mass Airflow) will compensate for altitude. With the air less dense at altitude, mass per volume is lower, but since the sensor actually detects mass, not volume, the correct values will be reported to the ECU. Consequently, fueling will remain correct.
Now, going "uphill" vs. "downhill" will make a difference! I regularly make a business trip that's right at 200 mi. each way. Net elevation gain is about 1,500 ft. The last few trips resulted in an average of 2.6 MPG difference between up and down.
I've also noted that rain will drop the MPGs, given having to push through the water on the road. It was really noticeable showing MPG while driving through rain at the same speed and watching the mileage dropping. But I have 235 tires that don't help that!
Wish you were closer or coming out to eastern VA. I'd put a tune on your car that would gain a few MPG!!