Useless Information

[swathdiver]

Man with all the up and down hills bere I’m at 14.3 MPG average. But thats with my cam and leveling kit so I’m not doing too bad. Do you have the 4 speed or 6 speed?
Edit: turning phone sideways shows ur sig, which states 6 speed.

can you upload that spreadsheet?

14.3 MPG is the average for ALL variations of the GMT900 SUVs, long and short, first year to last save for Hybrids.

Upload it to where? Send me an email, I'll clean up the file and send it over.

 

[Big Mama]

this one. I don’t have flex so I’m wondering if you fill up with different types of gas. Interesting

That tank had a remnant of 5 gallons of 96octane mixed fuel along with 4 gallons ofE85 and 22 gallons of Unleaded 88/E15.

 

[Thauber]

14.3 MPG is the average for ALL variations of the GMT900 SUVs, long and short, first year to last save for Hybrids.

Upload it to where? Send me an email, I'll clean up the file and send it over.

Interesting, I would have assumed it would have been better than the NBS being these have the 6-speed tranny. Known reason for the low mpg?

 

[R3cord303]

Interesting, I would have assumed it would have been better than the NBS being these have the 6-speed tranny. Known reason for the low mpg?

Could be that they’re heavier, bigger, and more powerful.

 

[gooffeyguy]

Does a leveling kit affect mileage?

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

 

[Thauber]

Could be that they’re heavier, bigger, and more powerful.

Compared my '04 to an '09 equivalent. The nnbs is only 300 lbs heavier, 15 more HP, and 5 more torque. Extremely minimal difference.
Is it maybe tied with the use of E85? Mine is a flex as well, but I only use plain old 87 octane.

 

[Sam Harris]

Compared my '04 to an '09 equivalent. The nnbs is only 300 lbs heavier, 15 more HP, and 5 more torque. Extremely minimal difference.
Is it maybe tied with the use of E85? Mine is a flex as well, but I only use plain old 87 octane.

Yes, E85 yields approximately 3-3.5 MPG less than standard 91 octane.

 

[R3cord303]

Compared my '04 to an '09 equivalent. The nnbs is only 300 lbs heavier, 15 more HP, and 5 more torque. Extremely minimal difference.
Is it maybe tied with the use of E85? Mine is a flex as well, but I only use plain old 87 octane.

Yes, E85 yields approximately 3-3.5 MPG less than standard 91 octane.

Is the 14.3 mpg average part of the EPA quoted rating or user supplied real world testing? Because I don’t think the EPA rating would use E85

 

[Thauber]

Is the 14.3 mpg average part of the EPA quoted rating or user supplied real world testing? Because I don’t think the EPA rating would use E85

I can't speak for where Swathdriver got his numbers, but I'm guessing experience and research. The link below does show EPA for an '09 on straight E85. Interesting to see his custom mixtures fall in line with those estimates for E85. Awesome he took time to make the spreadsheets.

https://www.fueleconomy.gov/feg/bymodel/2009_GMC_Yukon.shtml

 

[HiHoeSilver]

Does a leveling kit affect mileage?

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

Probably not by itself, but the 60 lb, 33" × 10+" tires that usually go on sure do.

 

[R3cord303]

Does a leveling kit affect mileage?

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

Probably not by itself, but the 60 lb, 33" × 10+" tires that usually go on sure do.

it does effect milage, you get more wind under the car blowing on suspension components. Same reason why lowering a car gets better mpg i.e. Teslas and their air suspension lowering the car above x mph

on our SUVs how much does it effect things? Don’t know. On mine? Clearly not much. It was averaging 14.3 when I bought it with lots of highway by previous owner, now that I’m doing lots of highway again, even with the cam and level, its still at 14.3, despite not having AFM.

 

[swathdiver]

this one. I don’t have flex so I’m wondering if you fill up with different types of gas.

The alcohol content of that mix was 20%. Supposedly your L92 is not supposed to have enough injector for alcohol content greater than 15% but such a mix yields equal or better gas mileage than straight high octane gasoline.

Interesting, I would have assumed it would have been better than the NBS being these have the 6-speed tranny. Known reason for the low mpg?

Data was gleaned from Fuelly which at the time recognized no difference between fuel and octane types. I think however, that the real difference is because people just drive them faster. And then the folks with K2s drive even faster yet! We make regular trips to Grandma's house and rarely do I pass a K2 or 900 at 71 mph. But they fly by us all the time like their hair is on fire!

Does a leveling kit affect mileage?

My research seemed to indicate, gee I'm forgetting now, that around town no, and it was minimal or no loss on the highway.

Is it maybe tied with the use of E85?

Is the 14.3 mpg average part of the EPA quoted rating or user supplied real world testing? Because I don’t think the EPA rating would use E85

I can't speak for where Swathdriver got his numbers, but I'm guessing experience and research. The link below does show EPA for an '09 on straight E85. Interesting to see his custom mixtures fall in line with those estimates for E85. Awesome he took time to make the spreadsheets.

Maybe, data at the time came from Fuelly looking at all 2007-2014 5.3 Tahoes, Yukons, Suburbans and Yukon XLs and Avalanches. In the grand scheme of things, the 6-speed wasn't that big of a game changer MPG wise, it was the introduction of VVT in 2010 that sets them apart from the earlier years.

Notice that the EPA shows no Fuel Economy ratings for the 2009 or 2010 GMC Yukon XL 4x4 or Suburbans. No idea why and when I asked them, they had no idea either. My original window sticker is blank with regards to mileage ratings.

 

[kbuskill]

Compared my '04 to an '09 equivalent. The nnbs is only 300 lbs heavier, 15 more HP, and 5 more torque. Extremely minimal difference.
Is it maybe tied with the use of E85? Mine is a flex as well, but I only use plain old 87 octane.

What rear end gears did you have in your '04???

What gears in your '09???

I believe most of the 6 speeds got the 3:42s but not 100% sure.

 

[swathdiver]

What rear end gears did you have in your '04???

What gears in your '09???

I believe most of the 6 speeds got the 3:42s but not 100% sure.

Most of the 5.3s have 3.08 gears unless they have HD Towing package. Those with 3.08s are the ones that get 21-22 MPG doing 70 mph @ 1,500 rpms!

 

[wjburken]

Thought this sticker was an interesting example of full disclosure on a fuel pump for E85. Surprised by the range of ethanol percentage they could have.

 

[swathdiver]

Thought this sticker was an interesting example of full disclosure on a fuel pump for E85. Surprised by the range of ethanol percentage they could have.
View attachment 236180

They have been slow to establish industry standards but this is one of them. E70 or E75 is the winter blend of E85 for enhanced starting in cold weather. But they are calling it all the same. E51 was the old cold weather standard for a time if I remember right.

Must contain 2% denaturant (hydrocarbons) I guess so tweakers don't drink it. If anyone gets really bored: https://www.nrel.gov/docs/fy13osti/57590.pdf

 

[swathdiver]

Finally got that busted bolt out! Or rather, I paid some professionals to do it for me! They replaced two of the swaybar bushing bolts and installed my new bracket and used a blind nut again on top. I'm going to replace that with a Heli-coil. Another bolt should be replaced so I'll order one up.

I also wanted an alignment done but they told me that I needed new ball joints on both sides. Gee, I just checked the left lower with a dial indicator and it was good. Wondering how they checked mine, I reviewed the dash cam footage while it was in the shop, and they did indeed jack up each side and press down on the wheels with a long cheater bar. Once home, I looked at them more closely and the rubber is cracking though they are not leaking yet.

So if anyone was wondering, that explains my post about Ball Joint and Control Arm life. 152K and I'm a little past due!

Also noticed that the alignment cams still have the plastic inserts from the factory, the truck has never had it caster or camber adjusted. The outer tie rods do not appear original.

The transfer case rear output seal is leaking and needs to be replaced. The rear differential's pinion seal is starting to sweat. Also noticed that the engine oil cooler block above the oil filter is leaking. The 10 mm wrench tightened each bolt only slightly, I've got to get that changed, no more waiting James!

Have only fueled up 4 times since October, the truck has not been driven much. Battery charge just now was 54% and 11.54 volts. It was in the 30s a few weeks ago and barely kicked over. Time for a new battery or time for a long run on the highway to charge it up? Battery is 40 months old now, 40K miles and almost 1500 hours. Cadillac has a coupon for a 48PG for $180 installed. If they'll do the 48HPG I'm game.

Transmission. Had its first fluid exchange done at 117K miles with 31% or so showing on the Transmission Oil Life Monitor. Doing a little math, it was very likely never done before, about 1700 miles per percent. Now she's at 78% and it's been 34,240 miles which is about 1556 miles per percent. Makes sense, the previous owner lived in a more rural area than me. So now I have another choice to make, do another fluid exchange or drop the pan and change half or all at 36K? I shall send off an oil sample (transmission) soon for examination. Should I decide when the results come back?

If we're going to replace the controls arms, we're going to replace the struts, shocks and springs too. All GM OE, not even AC Delco if I can help it. Costs more but should make it to 300K miles.

Oh, installed the transfer case shield with bolts purchased from a member on here. Cleaned them up, painted them red. Even though I read that they were self-tapping, I insisted on threading the holes with my tap. Dumb idea, that one hole is not as tight as the others and they didn't need much torque to tighten up, 15 ft lbs. Have to get the other shield.

Wanted to pull the front tow "hooks" out and paint them red. Bolts are not easily accessed like the Suburban or Tahoe. Have to remove that hard plastic and pull away wheel liner to get a wrench or socket in there. Another day.

Almost thought we had enough rain-free weather in the forecast to do the mirrors with the Gruven gears. Close but not yet. Been waiting over two years!

If we go through all this suspension work and level the truck, by then it will be time for tires. If I do go up in size, I am thinking about a 20 x 8 wheel with 275-65-20s, a 34" tire. Not too wide to require trimming or getting stuck in the mud. KO2s again but those red Grabber letters are cool. Most wheels are an inch wider. Not for me.

 

[BG1988]

The alcohol content of that mix was 20%. Supposedly your L92 is not supposed to have enough injector for alcohol content greater than 15% but such a mix yields equal or better gas mileage than straight high octane gasoline.




Data was gleaned from Fuelly which at the time recognized no difference between fuel and octane types. I think however, that the real difference is because people just drive them faster. And then the folks with K2s drive even faster yet! We make regular trips to Grandma's house and rarely do I pass a K2 or 900 at 71 mph. But they fly by us all the time like their hair is on fire!




My research seemed to indicate, gee I'm forgetting now, that around town no, and it was minimal or no loss on the highway.








Maybe, data at the time came from Fuelly looking at all 2007-2014 5.3 Tahoes, Yukons, Suburbans and Yukon XLs and Avalanches. In the grand scheme of things, the 6-speed wasn't that big of a game changer MPG wise, it was the introduction of VVT in 2010 that sets them apart from the earlier years.

Notice that the EPA shows no Fuel Economy ratings for the 2009 or 2010 GMC Yukon XL 4x4 or Suburbans. No idea why and when I asked them, they had no idea either. My original window sticker is blank with regards to mileage ratings.


View attachment 234825

the VVT has the

Deceleration Fuel Cut-Off Mode works great just barely press the gas on down hills (you have to train your self with a OBD2 reader to watch the O2 sensor Bank1 sensor 1 )and you can speed up to 80-85MPH to crest the next hill ..@ 60mph



when it's showing 0.000V it's running lean or Deceleration Fuel Cut-Off...

when I do this on the hybrid I do a FORCED Regeneration on the down hill at the same time to MAXIMIZE efficiency


i can accelerate while it's Forced Regeneration and run "lean" as shown by the instant reading 70-99 "while increasing the speed"

radio Headunit shows power going from the wheels to the battery )



25.58MPG ... the only way to MAXIMIZE efficiency is to use 91 octane or higher with the VVT (timing will advanced upto +42 degrees )I also noticed it's more efficient to go 70-75 mph on the uphills the instant reading is about 15-16mpg (as long as you keep it in 4th/6th gear) compared to 9-13 instant reading @ 60-65mph as it may drop to 3rd gear..


91oct is required other wise your timing will drop and you will downshift to 3rd gear



I think once she has a new battery I could get 30-35mpg out of it that is the only thing holding me back is the 11 years old degraded battery that only has like 15-20% capacity left

Have only fueled up 4 times since October, the truck has not been driven much. Battery charge just now was 54% and 11.54 volts. It was in the 30s a few weeks ago and barely kicked over. Time for a new battery or time for a long run on the highway to charge it up? Battery is 40 months old now, 40K miles and almost 1500 hours. Cadillac has a coupon for a 48PG for $180 installed. If they'll do the 48HPG I'm game.

walmart has the H-6 AGM battery with 5 years/60 months free replacement $149 including install.. how is that better then having to wait 2-5 hours for a dealer to install it?

 

[swathdiver]

the VVT has the

???

walmart has the H-6 AGM battery with 5 years/60 months free replacement $149 including install.. how is that better then having to wait 2-5 hours for a dealer to install it?

My truck gets GM OE or ACDelco parts! The other ones in the driveway are fed Walmart and local auto store parts!

In 30+ years of driving, mostly in Florida, I've only had two car batteries last more than two years. The one in my truck now and the original one that came in one of my Pontiacs. That one lasted about five years. Curiously, both are the only two vehicles that have RVC and EPM.

Too bad about your main battery. Pretty cool about going down hills. I remember when I first bought mine, running the hills between Winston-Salem and Charlotte, never seen gas mileage like that since! Our hills down here where I live are highway overpasses.

48PS is current equipment. ACDelco does not recommend the AGM battery because of the way our trucks charging system works. I don't need the higher CCA of the 48PG but would like the higher reserve capacity of the 48HPG, such as when I'm airing up or down the tires with the engine off or running the Tech-2.

 

[BG1988]

VVT equipped engines have Deceleration Fuel Cut-Off it cuts the fuel supply..... they claim it saves 2% but you can squeeze more out of it.. if you run the down hill parts correctly you can hit near Zero fuel usage. while increasing speed .. it's perfect for long down hills. that is how I was able to achieve 28.7MPG... combined I found a road that is nearly 100% 8.5 miles of "down hill"

I could keep it in Auto Stop or DFCO/ mode..


to simplify it :

the only thing coming of of the exhaust is air from the atmosphere the CAT drops from 550c to 175C(guess that is the lowest value?)