What did you do to your NNBS GMT900 Tahoe/Yukon Today?

[iamdub]

Ive been trying out mileage of the gas tanks fulls for the different octanes myself. I can tell you that 93 has lasted me almost 3 days longer than with a tank of 87. I also towed a trailer with the 93. So maybe its worth the couple dollars more for the 93.

Yes i know its a very scientific method i have

I got the same results when my 5.3 was stock. No pinging, more power and better mileage. Even if the cost per mile doesn't outweigh the cost per gallon, it's still worth it for the extra power and no detonation. Of course, now I HAVE to run 93 or higher octane.

 

[mikeyss]

So am i being too picky if i bring my truck back and have them straighten out the steering wheel (its crooked enough to notice) after they just did an alignment yesterday?

That is the alignment guys job, to set the steering wheel centered and then do the alignment. After they're done, they are supposed to drive it after to make sure the wheel is centered. Absolutely take it back and have it corrected, you paid for it to be done correctly.

 

[Drok]

Since i work at the dealer, i didnt drive off till the end of the day. Ill definitely be saying something when i go back.

 

[iamdub]

So am i being too picky if i bring my truck back and have them straighten out the steering wheel (its crooked enough to notice) after they just did an alignment yesterday?

Hell no. Having the wheel straight is part of an alignment. You paid for an alignment, they owe you a straight wheel.

 

[gooffeyguy]

Had a hectic work week so I took it out for a drive last night to chill out and put some more shakedown miles on it. I've also been trying to burn off the tank of 93 to refill with E85. I only got it down to 1/4 tank so I filled it up from there. Fuel mileage dropped 4-5 MPG and I can't tell if there's any more power. What I can tell is that it was about $.81/gal cheaper and I found a solution for the catless exhaust smell. The exhaust smells almost like it did with cats.

It takes like 7 miles of driving after a fillup for the computer to figure out the alcohol % and adjust to the higher octane tune tables.

Did you have a custom tune done or just using stock? If custom, did they do anything to the E85 spark tables?

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[gooffeyguy]

Also, on E85 my exhaust smells "sweet", kinda like, uh, corn.... lol

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[Sam Harris]

So am i being too picky if i bring my truck back and have them straighten out the steering wheel (its crooked enough to notice) after they just did an alignment yesterday?

Picky?!? No. That’s 100% part of the job!

 

[iamdub]

It takes like 7 miles of driving after a fillup for the computer to figure out the alcohol % and adjust to the higher octane tune tables.

Did you have a custom tune done or just using stock? If custom, did they do anything to the E85 spark tables?

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Right. I just cruised after filling up on I-10 for eight miles before commencing any "testing".

I do have a custom tune for the cam and raised compression. I had it tuned on 93. My thought, since E85 is nowhere nearly as available as 93, was to have it tuned to the max on 93 and let the PCM advance it from there when it detects the elevated alcohol content. I went this route since the actual net alcohol content varies wildly (or so I've read) from source to source. Had I tuned it to the max on E85 (or whatever % I netted), it'd retard the timing should I get a lower % of alcohol, including running E10 with 93. Also, it adjusts for time elapsed between refueling events due to fuel losing it's octane rating as it ages. My Tahoe sits a LOT and I usually fill up once every month or two. All considered, the amount of available power is more stable, I have a reduced chance of detonation, I'm really not sacrificing a whole lot of power at all, if any and I still have the convenience of running 93 if E85 isn't within range.





...I am kinda tempted to get my own tuning program and playing/learning, though.

 

[George B]

Also, on E85 my exhaust smells "sweet", kinda like, uh, corn.... lol

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Mine too! Too bad the cost difference doesn’t offset the mileage

 

[gooffeyguy]

Mine too! Too bad the cost difference doesn’t offset the mileage

Yeah, around here lately it's kinda been a wash. $2.26-2.30 for premium and $1.65-1.75 for E85

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[gooffeyguy]

Haven't done anything yet today, but reading some threads on the site I'm thinking of ordering a remote transmission filter kit. Keep me from having to mess with dropping the pan again, and allow me to change the filter easily about every year or so.

 

[iamdub]

Yesterday:

Measured for exhaust ideas

Changed the oil

Checked the tire air pressure

Checked for leaks

 

[CaptainAmerica1]

Got the 240+mi round trip finished without incident. PF TPMS sensor is giving me fits...Brand new Ac Delco... gonna have to replace it. Otherwise uneventful trip and got 15.5 mpg...

 

[swathdiver]

My thought, since E85 is nowhere nearly as available as 93...

True, but E85 stations keep popping up in your area on Gas Buddy, mostly Racetrac. Seen a new one on US1 in Addis for $1.64, one downtown on Florida Blvd for $1.62, and 4 more to the south and east and even more out near Slidell. What really surprised me was that one just west of the Mississippi river. Some of the same and some different Racetracs also carry E15 or Unleaded 88. I mix the two and wind up with 91 octane for the price of 87, or usually less, with higher knock protection and get better gas mileage usually.

 

[George B]

I wish e85 was more than 5 cents cheaper here.

 

[iamdub]

True, but E85 stations keep popping up in your area on Gas Buddy, mostly Racetrac. Seen a new one on US1 in Addis for $1.64, one downtown on Florida Blvd for $1.62, and 4 more to the south and east and even more out near Slidell. What really surprised me was that one just west of the Mississippi river. Some of the same and some different Racetracs also carry E15 or Unleaded 88. I mix the two and wind up with 91 octane for the price of 87, or usually less, with higher knock protection and get better gas mileage usually.

Maybe it was my search criteria, but Gas Buddy wasn't showing much. It was a RaceTrac where I filled up the other night (BTW, best gas station coffee ever!). I've been to that new RaceTrac in Addis. It's probably the closest to me, or at least the most convenient. Thanks for pointing these out. I'll try Gas Buddy again- I probably fat-fingered something in the drop-down boxes when searching.

I'll investigate the mixing trick!

 

[iamdub]

Put about 80 more miles on it today running around in the 93 degree heat. No issues other than the noise. I'll be embarking on a 260+ mile trip with it tomorrow morning.

 

[swathdiver]

Put about 80 more miles on it today running around in the 93 degree heat. No issues other than the noise. I'll be embarking on a 260+ mile trip with it tomorrow morning.

Safe Travels! From the list I made for my father and I:

Racetrac 1975 SW Railroad Avenue Hammond Louisiana 70403
Racetrac 1417 Youngsville Highway Broussard Louisiana 70518
Racetrac 7332 LA-1 South Addis Louisiana 70710
Racetrac 27877 Juban Road Denham Springs Louisiana 70726
Racetrac 16703 Old Jefferson Highway Prairieville Louisiana 70769
Racetrac 5015 Florida Blvd Baton Rouge Louisiana 70806
Racetrac 18313 Highland Road Baton Rouge Louisiana 70809
Racetrac 7648 Perkins Road Baton Rouge Louisiana 70810
Racetrac 8008 Airline Highway Baton Rouge Louisiana 70815
Racetrac 11677 Coursey Blvd Baton Rouge Louisiana 70816
Texaco 15972 LA1 Simmesport Louisiana 71369

 

[avalonandl]

Going to haul the boat to the ramp and launch.

 

[iamdub]

Safe Travels! From the list I made for my father and I:

Racetrac 1975 SW Railroad Avenue Hammond Louisiana 70403
Racetrac 1417 Youngsville Highway Broussard Louisiana 70518
Racetrac 7332 LA-1 South Addis Louisiana 70710
Racetrac 27877 Juban Road Denham Springs Louisiana 70726
Racetrac 16703 Old Jefferson Highway Prairieville Louisiana 70769
Racetrac 5015 Florida Blvd Baton Rouge Louisiana 70806
Racetrac 18313 Highland Road Baton Rouge Louisiana 70809
Racetrac 7648 Perkins Road Baton Rouge Louisiana 70810
Racetrac 8008 Airline Highway Baton Rouge Louisiana 70815
Racetrac 11677 Coursey Blvd Baton Rouge Louisiana 70816
Texaco 15972 LA1 Simmesport Louisiana 71369

Thank you! I'll bring my portable tool kit just in case. lol

You guys will be traveling around those areas? Most are in/around the BR area, but then you threw a Simmesport and Youngsville in there.