Promising better fuel economy for AFM engines, the Range

[Zane]

Zane & Josh Merva

Copyright, GM-Trucks.com

 

GM’s Active Fuel Management technology is somewhat controversial. Some people love it and some people hate it. There’s been long discussions regarding how to turn the system off but almost no mention of reprogramming AFM to run more often for increased fuel savings. However today, we unbox and give our first impressions of a product designed to do just that… the Range.

 

What does it do?

Range works with the active-fuel-management system (or AFM for short) in your GM truck or SUV. The device will work on nearly all GM vehicles with AFM technology. That includes engines in the Chevy Silverado, GMC Sierra, the Cadillac Escalade, as well as the Yukon, Suburban, Avalance, and Tahoe.

The Range attaches to your OBD-II diagnostic port. Through the port, it temporarily modifies the software that runs the active-fuel-management system in your engine. Without any permanent modification or software flashing, the device allows your AFM engine to run in V4 mode more often. When plugged in, the system forces four-cylinder operation through a wider range of load. When unplugged, the engine reverts to stock and nothing is left changed.

Range Technology describes it best:

The backbone of the Range fuel economy device is a conditioning algorithm which expands the definition of “load” on the vehicle allowing users to drive in V4 mode as much as 90% of the time. Typically, the AFM vehicles from GM will operate in V8 mode 65% of the time, while most users only need all 8 cylinders a small percentage of their actual driving time. Below is a graph which shows – directly from the factory – that the engine “should” be in V4 far more often, but does not change.

 

 

The theory is by forcing your engine to run in V4 mode more often, you can get better fuel economy in your truck. Range says an average owner can save 65 gallons a year, more than paying for the device’s $199 cost.

 

The product comes from the former CEO of Superchips, so the engineering and development behind Range appear to be of top quality. The Range is clearly not an enthusiast’s garage hack. Instead, it’s a quality product that has undergone comprehensive testing.

Because the Range does not override any engine safety parameters, Range Technology claims the device cannot harm your vehicle at all.

Unboxing

Good packaging is always important for any new product. When a consumer is paying nearly $200, the look and feel of a product’s box is critical. Range Technology seemed to recognize this and made unboxing the Range a satisfying experience.

The Range comes in a high quality soft-touch cardboard box with minimal exterior logos and stickers. Just a silver range logo and product serial number adorn the outside. Cutting two clear stickers allow the top half of the box to separate from the bottom. Inside, you’ll find the Range front and center. A simple instruction card is slid behind the device. The product is displayed nicely and is easy to access. In short, the Range is packaged in a modern manner you’d expect from a $199 device.

Installation

Installing the Range is super easy and takes only a couple seconds. Just take the range out to your vehicle and open the drivers door. Look under the steering wheel and find your diagnostic port. Plug the Range into the diagnostic port while the vehicle is off. You should see a blue LED light up on the device and you’re good to go!

Uninstalling the Range is just as easy. With the vehicle off, just unplug the device. Your vehicle’s active-fuel-management system will revert back to stock operation.

First impressions

As with any product that only takes a few seconds to install, it’s initially hard to believe that the Range could make any negligible difference. With the claims being made, we were initially skeptical.

A few miles behind the wheel and down the road, our skepticism dissolved. Once the 5.3L V8 in Project Sierra warmed up, the Range kicked in. Our Sierra’s engine kicked down to V4 mode, just as always, but there was a noticeable difference in the time the system would stay engaged.

No longer does a slight tip of the throttle “deactivate” AFM. The Range device held V4 mode longer, through more throttle, and even allowed us to travel up hills and accelerate. It’s a huge difference from stock, when any little incline or acceleration used to kick the engine into all eight cylinders with ease.

Staying in 4 cylinder mode substantially longer does come with a few drawbacks. With only half the engine running noise, vibration, and exhaust drone are increased. It’s not harsh but very noticeable. These are the standard complaints we’ve heard of active-fuel-management in the past and part of the reason why some people detest it. We’ll consider these compromises as we continue to test the Range.

Does it actually work?

It’s immediately obvious that the Range does substantially increase the time Project Sierra runs in four-cylinder mode. Will that work out to increased fuel economy? Current Range customers say yes but we’re going to find out for ourselves firsthand.

During the coming weeks we’re going to run the Range on Project Sierra. After a couple tanks of gas and a few calculations, we’ll see what effect it has. Because we’ve kept records of every single fill up in our truck any change in fuel economy, good or bad, will be easy to see. We’re report back when we have our final results.

While we’re out testing, check out the product on the Range Technology’s website for yourself.

We’ve also got a discussion going on this article in the GM-Trucks.com forum. We’ll be updating forum members with fuel economy numbers on a tank by tank basis, so cruise on over to our Project Sierra section and get the inside scoop on how things are progressing.

[Morgan1986]

Interesting .

[2005LT]

Curious to see those fuel economy results. I bet it will help to some degree. I can certainly relate to the slight "tip" or bump of the throttle that knocks it out of V8. As soon as I get over 40 mph mine won't hold V4 at all on flat ground.

[jimbrown1]

I'm curious as to the feedback this product will get. I personally hate AFM which is why I disabled it below 60 so it will work when crusing on the interstate and I don't need V8 power. I can hear the V4 mode with the Borla exhaust and it's not annoying, but if i wanted a 4 cylinder truck I would have bought a Toyota or Nissan. Just my opinion.

[kilbornf]

What size of motor you talking about 5.3 or 6.2

[MikeNH]

What size of motor you talking about 5.3 or 6.2

 

 

5.3. The 6.2 in the pickup does not have AFM.

[neilbedwell]

Will this product increase oil consumption in the 5.3?

[tsbrewers]

I will be honest and say I don't own a vehicle with this, and obviously don't fully understand how it all works, but won't this (and the factory gm tune) basically wear out half the engine faster than the other half? Just wondering.

 

Brew

[tanked_darren]

I will be honest and say I don't own a vehicle with this, and obviously don't fully understand how it all works, but won't this (and the factory gm tune) basically wear out half the engine faster than the other half? Just wondering.

 

Brew

That's a great question!

 

Sent from my Nokia 5190 using Tapatalk 2

 

 

[Range Technology]

I will be honest and say I don't own a vehicle with this, and obviously don't fully understand how it all works, but won't this (and the factory gm tune) basically wear out half the engine faster than the other half? Just wondering.

Brew

 

 

Nope. GM actually did a well engineered system and mechanically everything is basically still "moving up and down". The system just shuts the valves for the deactivated cylinders completely and turns off the coil (no spark) and injector (no fuel). That makes those cylinders like an air spring so you don't lose energy pumping air through them (pumping losses). You still have the same mechanical friction and such (actually slightly less since there's no combustion causing side loading). It's a sound basic design (and Chysler has a similar system for their hemi).

 

There's nothing to cause any excessive wear or oil consumption or anything, except the additional moving parts that turn the lifters on and off.

 

 

[SILVERADOSC540]

 

 

Nope. GM actually did a well engineered system and mechanically everything is basically still "moving up and down". The system just shuts the valves for the deactivated cylinders completely and turns off the coil (no spark) and injector (no fuel). That makes those cylinders like an air spring so you don't lose energy pumping air through them (pumping losses). You still have the same mechanical friction and such (actually slightly less since there's no combustion causing side loading). It's a sound basic design (and Chysler has a similar system for their hemi).

 

There's nothing to cause any excessive wear or oil consumption or anything, except the additional moving parts that turn the lifters on and off.

 

While I understand the "even" wear in theory, I can't help but wonder what the difference will be looking at the valves after 100,000 or so miles. With the valves full-time on one half of the motor and part-time on the other I wonder about proper seating, difference in carbon build up, etc I will say that I never had an afm issue with my 6.0, but traded it in with only 42,000 miles on the ticker.

[Range Technology]

This idea has been around for quite awhile, interestingly enough. The ancient ancestor in production was the Cadillac v4-6-8 in the early 80s. It basically pointed out you needed better controls (both mechanical and electronic) to make it really effective. In late 2003 the Displacement on Demand (DoD) system was launched with the advent of the incredible computing power and precise control afforded by the ECUs being fielded with the latest round of LSx family motors. The advent of drive by wire throttle allowed for control of the engine at a whole new level without having the driver involved. It allowed for optimization during switching between modes to include air flow management which was missing in previous implementations.

 

It has been refined over the years and renamed as AFM and the controllers are another evolution advanced with the E67s (and variants ). It's about to progress to the next generation with the new Gen V small block with AFM and VVT and I suspect it will be even more prevalent on more GM platforms. Makes my personal vehicle LS2s look "old school" While more moving parts and complexity can mean more failure points, I think this one is pretty well sorted out and has been around in the current guise for at least 9years on millions of vehicles.

 

Perfect? Nope. But it's like a lot of vehicle technologies, it here to stay until something better pops up. Drive by wire, coil on plug ignition, VVT, AFM, etc. are the way the manufacturers are using to meet the ever more hostile MPG and emissions requirements while still providing us with decent torque, horsepower and drive ability so we can drive real trucks that tow, haul, and do what trucks should do. It's interesting that GM and Chrysler have chosen the AFM (Chrysler calls it MultiDisplacemnt System MDS) for this, while Ford chooses the small displacement with forced induction (EcoBoost) path. Same goal (small displacement under light load) but totally different ways to gain big displacement torque and horsepower (with its own drawbacks and challenges). Interesting times for car and truck enthusiasts like myself!

[BlackZ71Silverado]

Nope. GM actually did a well engineered system and mechanically everything is basically still "moving up and down". The system just shuts the valves for the deactivated cylinders completely and turns off the coil (no spark) and injector (no fuel). That makes those cylinders like an air spring so you don't lose energy pumping air through them (pumping losses). You still have the same mechanical friction and such (actually slightly less since there's no combustion causing side loading). It's a sound basic design (and Chysler has a similar system for their hemi).

 

There's nothing to cause any excessive wear or oil consumption or anything, except the additional moving parts that turn the lifters on and off.

 

 

When they are deactivated (not working) there is NOT the same amount of friction because there is no load, that's not possible. They are just moving up and down like you said, unloaded. The cylinders that stay active will definately see more wear due to having full load 100% of the time. I would rather have all of my cylinders operating at 100% all the time and full temp. rather than drastic changes this longer duration of cylinder shut down will cause.

 

Not doubting your idea on this product but it doesn't sound like a good idea from what our race engine builders have show us and tell us. The original AFM didn't sound good, having half the engine shut down even longer than designed sounds really scary.

[Range Technology]

I hear you and respect the concern, and don't necessarily disagree with the logic.

 

However, I believe it might be overstated for a street motor (race stuff ... totally different domain). The SAE and GM testing have shown the whole family of LS platform motors (including the AFM stuff) to have excellent wear characteristics in all their forms well past the 100,000 mile mark, so any wear difference will be pretty much negligable for all practical purposes. The biggest areas of weakness has been in the oil squirter/lifter design (and they have revised the lifter to prevent oil splash back carboning up the oil control ring). Of course, building a high horsepower motor, you usually throw out the valvetrain and replace with lighter lifters, cam, and springs and do away with the more complicated AFM gear. I'm not an AFM fan boy, or claiming it's the end all/be all ... but it's here to stay, since they continue it in the GenV motors too. Personally, I'm a boost junky at heart!

 

Total aside ... Engine builder friend of mine has a 5.3 previously AFM motor that had 138,000+ miles on it ($300 junkyard core ... score!) and it was amazing how good it looked on teardown. Still had cross hatching in the cylinders, which he was remarking about. He ported and polished the 243 heads that were on it, new valves, injectors, rockers, springs, cam, roller lifters and oil pump. Bottom end is basically all stock (he calls it his "throw away motor") and rigged up a Chinese 76mm turbo on it at about 7-8 psi boost. The crazy thing cranked out almost 580 HP on his engine dyno with a pretty rough HP Tuners tune in the stock ECU. He basically did a very similar build to the one that Hot Rod did (dug up the article here ... http://www.hotrod.com/techarticles/engine/hrdp_1104_594hp_53l_gen_iii_small_block_for_3252/viewall.html) except he started with the later Gen IV 5.3 (I think his was a out of a 2005/6?). It's supposed to go in an old beater disco era Nova as a street fighter. Should be a blast!

Not bad for a bunch of eBay/junkyard parts!

 

I know that's a personal sample of just one that I've seen first hand, but it backs up what I've researched with the engine builder publications and all the SAE/GM docs. YMMV ...

[BlackZ71Silverado]

"weakness has been in the oil squirter/lifter design (and they have revised the lifter to prevent oil splash back carboning up the oil control ring)".

 

NOT all the AFM trucks have had the lifters replaced with any updated parts. There has been no recall because of this issue, they deal with it as it happens by putting a band aid on the issue. Having the older design is problem enough as seen on many trucks with AFM switching on and off all the time. Having the older design and having the AFM keeping half the engine shut down twice as much just sounds scary to me.

 

The fix for the issue is for GM to install a splash guard (bandaid) to deflect oil.....That is done before replacing lifters or any other parts. The lifter replacement is a last resort. It costs them money so they install the splash guard to hopefully hold people over until the warranty is expired. After that, you are on your own when it comes time for the big money rebuild.