I'm gonna have to agree that you need a tuner mod. My 5.3 with a tune and headers put out 280hp/290tq on a mustang dyno.

tho I don't have a CC 4x4 or big tires.

 

my 361/373 runs where done on a dynojet. zero fudging done.

on the street it will take 21 degree's. thats about it. the dsp/predator handhelds are a waste imho. trying to cram 25 degree's into it on 91 octane isn't going to happen.

as far as the 9.8 afr. you are safer running 13.6 afr than this. running 9.8 is washing down the cylinder walls. this is bad mmmk.

 

I made over 300 to the ground with a 5.3 and small 207/220 cam with 35" tires and 4wd, so I dont want your excuses

 

Are you sure your tuner is familiar with tuning LS motors? Otherwise, I suspect he's confused by the vvt programming, which is probably overriding or compensating for anything he is trying to do with the timing. Just a hunch imho. I would think that the vvt would provide the best max hp and tq adjustments on it's own, therefore you would see little to no room for improvement on a tuners end

 

I have never dynoed my truck, as it is an AWD and we don't have an AWD dyno here, but I can tell you that I saw substantial gains (both SOTP and on the track) tuning the stock motor with just a Volant CAI and the stock exhaust. The only thing on the stock exhaust that needs to change is the mainfolds to good headers, BTW, the stock 3.5" catback is fine for everything except the most serious builds. The E38 ECU w/ VVT are the most difficult to tune of the LS motors, from what I've read. These don't even have a VE table, but a "Virtual" VE table (on EFI Live, at least) that requires experience to tune. 9.8 AFR? I would say that you have a lot of performance left on the table, since leaning that to like 12.8 should make a significant power difference, all other things remaining equal. But, you have to know what you're doing, since messing with some of the tables will throw the whole tune off. I'm no tuner, but I have a friend who is very good with tuning LS setups, but my truck really stresses him out, he says. We learn something new everytime we tune it. It has been impossible for me to get my truck to run any leaner than 12.4, no matter what PE you command, the bitch still wants to run rich. Messing with the MAF tune seems to help a bit, but we haven't quite zeroed in on the best tune yet (because I "keep changing ****", my friend tells me). So far I've been through one Wheatley and two Black Bear email tunes. If you contact either one of them I bet they know how to make your stock truck make more power. Also, as someone else said, tuning the TCM will also improve performance, without even changing power output.

 

I had my 2010 6.2 Sierra 1500 4X4 dyno tuned by a very experienced tuner on a Dyno Jet. The peak RWHP went from 288 to 290. I thought I should see more, but it was not to be. He did flat line the A/F ratio at 12.7 and reduce the TM by 30%. The mid range numbers did improve. Did it make a SOP difference? Yep. I guess that transfer case and heavier wheels and tires on the 4X4's take some additional power. Maybe with some shorty headers and a good CAI, I could get over the 300 mark. Pretty happy with the way it drives right now.

 

here is some more sheets about the rpm and what it all seen. i believe this is what the stock map produced thru out the rpm range.

 

last sheet

 

yeah thats all i seemed to get from the chart was 1 hp. but the power seems to come on way way earlier now and fuel mileage was better also after.

i think im going to try Volant cai with the donaldson filter instead of the oil type filters. the donaldson isnt going to probably flow as much as a cotton filter but it aint going to get the dust get by like the others will either. i will leave the stock muffler for now but that little resonator unit is coming out. a little too quiet for me yet. i like a little rumble.

i would like to go to a supercharger but there isnt no way im going to get that by the wife...:nunchuk1:

 

I removed the little resonator. Sounds perfect with no drone.