Hypertech Tuner Installed Today = No More AFM!!!!!

GRN69CHV · September 10, 2016

Responded to a post earlier today talking about this same topic. Have been considering this for a while. Ran out to pick up oil for the tractor today, sure enough Auto store I went to had Hypertech Max Energy #32501 marked down 25% (last one) to $247.00. Checked on-line real quick, this had all the features I wanted, so took it. Installed the prepackaged premium fuel tune, increased trans shift points by 50%, adjusted tire size to 32" for the new shoes and the biggie, turned off AFM. Why did I wait so long to disable AFM. Truck was low on fuel so filled it up with 93 octane, then took it on a 20 mile drive. Even with the crappy 3.08 gears, difference in 6th gear at lower speeds (ie 45 mph and below) when running in V8 mode ( as compared to having it try to run in 6th gear and V4 mode and not do either well) is night and day. There is the option to set a minimum MPH to enable AFM (say 60 mph), but I'd just as soon keep it firing on all 8 cylinders all the time. If I can average 16 mpg in daily rural driving and just touch on 20 mpg highway I will be happy.

mrhonestlyinsane · September 10, 2016

Afm is been gone for a year on my truck. Probably the best mod yet.

snowman44 · September 10, 2016

How is the performance feel of program?

GRN69CHV · September 11, 2016

Overall feels much better. Hypertech 32501 doesn't have option to change TQ management, yet throttle seemed more responsive. Might be combo of fuel/timing curve combined with eliminating AFM and firming up trans shifts, seem to be working together. I wouldn't say night and day difference, but yes noticeable. To the point where I am really pondering, what would this run like with some gear out back!

protovack · September 11, 2016

If you had 3.42 you probably wouldn't have needed a tune!

GRN69CHV · September 11, 2016

Probably would have done it anyway if just to disable the AFM. I have been driving it around in M5 for the past year, maybe 80% of the time. 3.08 gearing really didn't bother that much, my big complaint was when the engine went into V4 mode and trans shifted into 6th gear at 40-45 mph. Little driving I did so far, 6th gear is much smoother.

Also, not discounting a gear swap, if so, needed a way to calibrate the speedo anyway.

mrhonestlyinsane · September 11, 2016

I have 3:42 and still tuned . Well worth it imo

KARNUT · September 11, 2016

I did the same and did a write up on it a couple years ago here. I left the engine alone I was running e85 locally and reg on trips. No v-4 50 per cent on TM. I did raise the mph to 130 and shift points a bit loved it.

GRN69CHV · September 11, 2016

I did the same and did a write up on it a couple years ago here. I left the engine alone I was running e85 locally and reg on trips. No v-4 50 per cent on TM. I did raise the mph to 130 and shift points a bit loved it.

What rpm did you raise shift points? Best I can tell factory setting is about 5500 on 1-2 and 2-3, haven't been able to run out 3rd.

Per the calculators, shifting at 5500 RPM, with "0" converter slip

1st = 42 mph

2nd = 72 mph

3rd = 110 mph

4th = 147 mph

.

Even if I factored in 5% slip, the numbers only drop to 40, 68,106, 140. Have the top speed limiter set at 99 mph, 3rd gear could really be dropped to 5100 rpm shift point. If I was tuning a trans to race, given the gear ratios and peak hp and tq at 5600 / 4100 respectively (GM spec ,max RPM at 5800), I'd probably reprogram the trans to shift 1-2 at 5800 and 2-3 at 5600 netting an rpm drop to 3405 going into 2nd and 3757 going into 3rd. Regardless of the gears out back, the 1st and 2nd trans ratio spread is pretty severe. Ideally, you'd need to run 1st to about 6400 to keep the motor at/near peak torque. A 6400 rpm 1st gear shift point drops the motor to 3757 rpm going into 2nd. Not going to happen and truthfully, for most of us, no need to beat on it like that.

KARNUT · September 11, 2016

I raised the sift points to about 6K and raised the RPMs as high as it would go before cut off for Manuel shifts. On E85 I was satisfied with the results. My weekend truck is a 383 stroker with a whipple, in a 92 Chevy and I was still happy with the performance of my 14 GMC. People who say the 5.3 underperforms makes me laugh.

What rpm did you raise shift points? Best I can tell factory setting is about 5500 on 1-2 and 2-3, haven't been able to run out 3rd.

Per the calculators, shifting at 5500 RPM, with "0" converter slip

1st = 42 mph

2nd = 72 mph

3rd = 110 mph

4th = 147 mph

.

Even if I factored in 5% slip, the numbers only drop to 40, 68,106, 140. Have the top speed limiter set at 99 mph, 3rd gear could really be dropped to 5100 rpm shift point. If I was tuning a trans to race, given the gear ratios and peak hp and tq at 5600 / 4100 respectively (GM spec ,max RPM at 5800), I'd probably reprogram the trans to shift 1-2 at 5800 and 2-3 at 5600 netting an rpm drop to 3405 going into 2nd and 3757 going into 3rd. Regardless of the gears out back, the 1st and 2nd trans ratio spread is pretty severe. Ideally, you'd need to run 1st to about 6400 to keep the motor at/near peak torque. A 6400 rpm 1st gear shift point drops the motor to 3757 rpm going into 2nd. Not going to happen and truthfully, for most of us, no need to beat on it like that.

GRN69CHV · September 11, 2016

KARNUT, don't think I will run mine to 6000, if anything, I'd consider dropping shift point to 5200-5300 for 1-2 & 2-3. Video on Hypertech site shows Dyno session of stock '14 5.3.

Rear Wheel HP/TQ were:

Stock: 314HP @ 5600, 334 TQ@4300

Low Octane Tune : 318HP@ 5550, 339 TQ @ 4350

Premium Octane Tune: 322HP @ 5550, 344 TQ @ 4450

More important, biggest gains were +13HP @ 4600, +15TQ @ 4600. Those are nice gains further down in the power band where it's a lot more useable. Think if I do anything further it will be to concentrate on increasing power in the mid range. Will see, put a few miles on it today running around, typical Sunday rural driving, nothing wide open, at most some mid throttle up to about 3500-3800 rpm, a lot more responsive. FWIW, fuel mileage is hanging right in there at 16 mpg.

GRN69CHV · September 12, 2016

Couple days in, fuel mileage has increased. Driving habits are the same, if anything I might have gotten into it a little more in 1st and 2nd.

Pic 1 22 mile highway run today up I95 to Phila Intl Airport - 70 mph with cruise on, shows 25 mpg

Pic 2 Trip A, set at last oil change 7,095.6 miles at 16.0 Avg (reminds me, I need to reset this, )

Pic 3 Trip B, reset to "0" on Saturday after installing tune. 93.2 miles averaging 17.6 Only highway run was the 22 miles on I-95 today, Came back home a different way that was mixed rural driving.

Pic 4 Last 25 miles (coming back from Phila) mixed rural driving, shows 18.0 mpg

Trip A was prior to tune and disable AFM. Also, about 6500 of these miles were with the stock Bridgestone 265.65-18 RH-S. Last 500 miles were on the Michelin Defender LTX M/S, which is a LRR tire. Slight taller at 32" (speedometer was corrected when installed the tune). Most impressive is the recorded 25 mpg. And once again, even with the 3.08 gears, this truck is a pleasure to drive down the road now in 6th gear when running as a V-8.

Someone please tell me, why do these trucks come with AFM? Makes no sense does it. I disable AFM and tune it to run on premium fuel. Power is up, average fuel mileage is up 10% and I can tell you, it has never recorded a highway average of 25 mpg. Factory rating is only 22 mpg, that's a 13.6% improvement. Yes, I will be paying 20% more for fuel, factor in the improvement in fuel consumption and the difference in fuel costs are 7-10%. I can live with that. Heck, I would have been happy if (and fully expected) the fuel mileage to drop to 15/20. Factory is 16/22, tuned for premium with no AFM and it goes to 18/25? Even if this first 93.2 miles is an exception. it is promising.

So, Someone please tell me, why do these trucks come with AFM? Makes no sense does it

GM, are you listening?

mrhonestlyinsane · September 12, 2016

My guess is they do it for emissions laws. I think your results for mpg is an anomaly. My daily commute mileage went up but my highway mpg went down considerably. Although it is still reasonable at 20mpg seeing I am lifted and have larger tires. I don't believe 6.0 liters in the 3/4 tons run afm...because they don't have mpg constraints...but I could be wrong.

Dnt · September 13, 2016

I cannot figure out which one would be best for a 2016 6.2 with the 8spd? My new GM Borla exhaust has a ugly tone to it when at slow speeds it changes to 4cyl mode. I would love to set AFM to only come on at highway speeds and also have the option to turn it completely off etc. as i wanted to. I see several different kinds Hypertech / Bully Dog / super chips etc etc and they all claim to work miracles LOL not sure what to believe. I would go for around 250 bucks for a decent hand held programmer.

GRN69CHV · September 14, 2016

Not one to leave things alone, programmed a different settings this morning. I like this a lot better.

1. Moved down to regular fuel tune. After running it around for a few days and noting the rpm range I run it at, was I really going to miss a 4 HP loss as 5550 RPM.

From Hypertech website

Rear Wheel HP/TQ were:

Stock: 314HP @ 5600, 334 TQ@4300

Low Octane Tune : 318HP@ 5550, 339 TQ @ 4350

Premium Octane Tune: 322HP @ 5550, 344 TQ @ 4450

2. AFM = Still Disabled

3. Trans Shift firmness = +50%

4. Trans shift points: Lowered shift points from factory settings

1-2 & 2-3 ( -300 ) Now shifting at 5200

3-4, 4-5 & 5-6 (-400 ) Don't know actual shift points, haven't been able to run out 3rd

5. Increased top speed from 99mph to 106mph. Not that I really need this, but if I get a chance would like to run out 3rd gear just to validate the shift point.

Observation: Truck accelerates hard to 5200 then immediately shifts and seems to get right back in the powerband. When you look at the dyno sheet on Hypertech site (2014 5.3 Silverado), you can see the HP plateau. Stock setting, it would shift at 5500 but to me it felt like it was nosing over trying to hit that 5500 shift point. Also felt with the increased shift firmness, shift was a little harsh. At lower shift points, shifts are real crisp. I like it.