Well that was for ig109 .. Sorry got lazy to put his name lol..

Coban... If I go with smaller tire will that be better... These truck look ugly if you put anything smaller than 20 inch wheels IMO

Ps.. Here in Los Angeles we already paying $4.15 a gallon 91 octane[/QUOTE]

actually my truck has 22inch rims and 305/40/22 tires.

and yes the tune has a 40rpm slip when in AFM mode.

i took that down to 10rpm, 0 rpm had too much vibration when it enters and exits the mode, during v8 mode, i have the split at zero

 

No- don't start thinking like that.........

 

[QUOTE=Coban;4669160]I don't have HPTuners installed on this computer yet so I can't verify, but I dont think slip does affect AFM... If you reduce the slip it improves the driveline efficiency. Slipping is power that is not being converted to forward motion, just heat.




OK I get that, Thanks ....... so AFM from what I can see on my in cabin scan guage is TPS , Vacuum , Speed or is it more complex than that .......I am trying to track what cause's it to go in and out .....

 

cjg454ss,
Quick question - are you reporting the average mpg shown on the DIC or manually calculating?

 

I'm pretty sure he's using the DIC, note the words "once it was rolling I reset it"

Not sure if he's reporting from the instant or average display though.

My truck only has the average, and I have verified that number to be 100% accurate at the pump every time; however, the average on the DIC just does the simple math of gallons used vs miles driven, just like we do at the pump. The instant MPG display has been proven to be inaccurate, from what I've heard.

 

On a different note, I wonder how the swap to lower gears would affect the fuel economy of none-AFM trucks, especially once bigger rolling stock has been added. I really don't see myself gaining mpgs in a 3.90 or 4.10 swap, but you never know. The extra torque off the line would be nice, but I need to get this thing tuned first so I know how much low end I'm losing to the torque management nannies.

 

Based on this thread ........... I installed 4.11's this week in my 2010 CCSB 4x4 5.3 6spd. stock tires / wheels (was 3.42) only mods headrs & catback ..... so far I am seeing similar results average city stop & go mileage up ....... watchng TPS % on my scan guage definitely using less TP % to get truck rolling and maintain cruise and yes V4 staying in longer you can actually accelerate lightly and it wont kick out ............too early to really qualify absolute results but dont see any reason why I wont see similar type results as original poster ......... and I luv how the truck responds ...... low gear is not too short ......... now to get a tune

 

My 5.3 w/ AFM ('09 SIlverado) had the "instant" feature in the DIC but my '11 does not. I guess they remove it if you don't have an AFM engine since that screen also displayed whether you were in V4 or V8 mode.

The window sticker on my '09 Z71 4x4 5.3/4L60E ECRB w/ 3.73s showed 14/19 for mpg. I was able to average up to 18.1 over the course of a month with mostly city driving but driving like a bitch and using 87. E85 dropped me down to a best of 14.1 in the same conditions.

So far with just 2 weeks in the 6.2 CCSB w/3.42s I can only keep it at around 16.4 babying it, the EPA rating on the window sticker is 12/18. After seeing this I'm really tempted to go with 4.10s...can't imagine gaining performance AND economy. Both of my trucks have had the same 18" wheels/tires BTW.

If the XFE model is designed for maximum fuel economy why the hell is GM putting 3.08s back there?

 

Quote:

Originally Posted by 91Z28

My 5.3 w/ AFM ('09 SIlverado) had the "instant" feature in the DIC but my '11 does not. I guess they remove it if you don't have an AFM engine since that screen also displayed whether you were in V4 or V8 mode.


.

If the XFE model is designed for maximum fuel economy why the hell is GM putting 3.08s back there?

The Instant Mpg / V4/V8 is part of an option package ....if you dont have it easy to add the DIC module apprx 80.00 do a search lots have done it .....

I would not hesitate going 4.11 ........this is my secound truck I changed the ratio my last 2wd I went 3.90's it defintely got better city milege and no worse on hwy .......unless you drive over 70mph then yes it drops off compared to 3.42 or even 3.08's .........I assume GM puts those 3.08's in to get the max mileage at 55mph ..........where nobody drives

3.90 not availalble in the front 4wd diff so just go 4.11 ..... 70 mph is now 2015rpm with stock tires

 

I think you've nailed it - the companies equip and tune their vehicles to get high scores on a computerized EPA lab test routine, NOT the real-world.