Tuning an engine to do Active fuel management

[LSJRL07]

Is it possible to tune my 2007 Yukon SLE 4.8L to have Active Fuel Management? Currently, it has a Volant CAI, and that is it. I am in San Antonio, and know that Nelson Performance does good work, but I wanted to know if this is even possible...I am wanting to get more MPG out of my Yukon and I know this helps a lot... thoughts?

 

[JennaBear]

It is possible, however, don't expect huge MPG gains. I actually have AFM left on, but changed the settings on it.

 

[felixgun]

Jenna,

I found that I got better gas mileage in my Tahoe with active fuel management. The escalade's didn't get AFM until 2010. So you are saying there IS a way to add it even if the car didn't come with it?

 

[JennaBear]

No, you can't add it if you didn't have it from factory. I have it on my 2010 Denali.

 

[04ctd]

beware, thread drift....but here goes: FWIW, it only seems to work at lower speeds, because at higher speeds, the % of load required on the engine to overcome wind resistance, keeps it in V8 mode.

with a CAI & 3 inch exhaust on a 5.3 2007 tahoe, i got 18.5 on 3 diff tanks hand calc'd between SC & NY. that was running slow (~70mph due grandbabies in car)
hold it 75~80mph and the mpg goes down ~16.

around town, it gets worse. (15~16~18) because of the stop & go.
i think the 4.8 will get lower mpg due to being at higher % load to move 5k lbs, ??


HTH

 

[JennaBear]

I would have to check with Justin on this, but if I remember correctly, we were staying in V4 mode while cruising at 75 on the freeway (with cruise control). This could be due to the setting on ours though.

 

[ChevyGuy]

My 2008 cruises in V4 mode also at highway speeds, with no mods.

 

[SgtTexas]

beware, thread drift....but here goes: FWIW, it only seems to work at lower speeds, because at higher speeds, the % of load required on the engine to overcome wind resistance, keeps it in V8 mode.

with a CAI & 3 inch exhaust on a 5.3 2007 tahoe, i got 18.5 on 3 diff tanks hand calc'd between SC & NY. that was running slow (~70mph due grandbabies in car)
hold it 75~80mph and the mpg goes down ~16.
around town, it gets worse. (15~16~18) because of the stop & go.
i think the 4.8 will get lower mpg due to being at higher % load to move 5k lbs, ??


HTH

i can attest to this as well. with cruise set, it seems that as soon as i hit the slightest resistance (hill, wind, bird poop, etc..), my engine goes into warp mode to get me back to 70 from 68mph...

 

[domin8]

I don't know the specifics, but I'm willing to bet a good tuner could adjust something like fuel trim tables to keep the engine in V4 longer in order to improve fuel economy, but they'd have to adjust throttle % to greater than 6%, which is the setting from the factory. This also requires the engine to burn more fuel and increase air intake as V4 to make more power to compensate for increases in drag (air density, slope/gravity, traction coefficient, etc). Will it save when compared to V8 fuel economy? That depends on the settings. There is a line that can be crossed to where that makes this a less favorable. Where this is I'm not sure and would have to defer to my tuner and HPTuner beta tester BennyHHR on the HPTuner forum. If you ask him I'll sure he'll blow your mind on his wealth of knowledge in this area due to a Master's Degree in Mechanical Engineering and experience that comes with 3 decades.

OP, sorry for the above thread jack. I'm really not sure if what you are seeking is possible. You might want to ask BennyHHR at the HPTuners forum.

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[millsdk]

Thanks, great info!