Question about V4 mode

[Grumpy Bear]

11 hours ago, pronstar said:

Let’s say these trucks average 16 mpg.

One group of folks state they notice a 5% improvement in MPG with AFM.
That equates to an improvement of 0.8 mpg.

Another group of folks state they don’t notice even a 1 mpg drop when they disable AFM.

It’s entirely possible that both groups are making accurate statements.


Sent from my iPhone using Tapatalk Pro

As a group Fuelly says the National average is 17 and small change and it matters not if it is a 4.3 or a 6.2. Millions of miles, thousands of trucks. K2** only. 

 

There's that, then there is Pepper. 27 mpg LIFE TIME average. BTW I fat fingered the percentage. It was good for 8% not 5%. 25 before + 8% or 2 mpg = 27 mpg. Since 7/13/2018 the 24 tank AVERAGE has been 29.0 mpg or better. Calculated not DIC. 

 

Believe it or not...why would I care. 

[swathdiver]

I went on Fuelly too the other day and took the average economy of every GMT900 SUV for all years.  Average of averages the 5.3 equipped trucks average 14.37 MPG.  Long or short, 4-speed or 6-speed didn't matter, they all averaged 14.3X mpg.

[KARNUT]

As a group Fuelly says the National average is 17 and small change and it matters not if it is a 4.3 or a 6.2. Millions of miles, thousands of trucks. K2** only. 
 
There's that, then there is Pepper. 27 mpg LIFE TIME average. BTW I fat fingered the percentage. It was good for 8% not 5%. 25 before + 8% or 2 mpg = 27 mpg. Since 7/13/2018 the 24 tank AVERAGE has been 29.0 mpg or better. Calculated not DIC. 
 
Believe it or not...why would I care. 

I get confused easily I guess. I read all your posts on pepper, I thought your mileage improvements where tied to temperature manipulation and driving habits, not cylinder deactivation. I guess I missed that.


Sent from my iPhone using Tapatalk

[Grumpy Bear]

8 hours ago, KARNUT said:

I get confused easily I guess. I read all your posts on pepper, I thought your mileage improvements where tied to temperature manipulation and driving habits, not cylinder deactivation. I guess I missed that.
 

Sorry Stan. Confusion was not the intention but I see how it happened. 

 

How much we get from the AFM is tied directly to how much of the driving cycle it is actually on. Agreed? If you drive in such a way that is never or rarely on or on only in a situation such as down hill when the decal fuel trim has the injectors shut off then the AFM can not contribute anything to fuel savings and it is as you have experienced nearly useless. 

 

If on the other hand you are attempting to keep it on nearly always and your improvement programs are centered on this goal then it is of much benefit. The temperature manipulation allowed, in my case, the use of less viscous and more lubricous fluids which reduced load which keeps the AFM active allot. My driving habits are aimed at the same goal thus the synergy is keeping the unit active during periods and speeds that would have had it disengaged otherwise. They work in symphony. In the end I can drive faster to a better result than the factory tune allows. She can now run up a 2% grade into a light headwind on a 65 F day and remain activated while doing 60 mph. I needed dead air and 85 F or better and dead flat roads to do that at 45/50 mph before the tweaks. 

 

Hope that removes the confusion. I'm just not a person who is riding the "Oh my, the AFM is going to kill my motor" buss. I'm sure the reputation is well earned but I also believe that there are reasons beyond the fact it exist for that reputation that are more user related than equipment related. As you noted in an earlier post....time will tell....right? Let it rain!!!!!

[batman900]

^Good info. I recently got the AFM delete and noticed about .5mpg loss. Your post explains why it wasn't more, 90% of my driving is hilly highway. Going down V4, then back up V8 over and over and over. Almost no flat roads. I just got tired of feeling the change over.

 

 

[Grumpy Bear]

11 minutes ago, batman900 said:

^Good info. I recently got the AFM delete and noticed about .5mpg loss. Your post explains why it wasn't more, 90% of my driving is hilly highway. Going down V4, then back up V8 over and over and over. Almost no flat roads. I just got tired of feeling the change over.

Hilly terrain and/or elevation is a tougher nut to crack but yes that would be the explanation. One suit doesn't fit everyone. 

[Donstar]

53 minutes ago, batman900 said:

^Good info. I recently got the AFM delete and noticed about .5mpg loss. Your post explains why it wasn't more, 90% of my driving is hilly highway. Going down V4, then back up V8 over and over and over. Almost no flat roads. I just got tired of feeling the change over.

I have now owned a V8 and a V6 with AFM and live in a hilly region.  The transmission gearing up and down sometimes annoys me.   Tow/haul mode will reduce this annoyance especially with a load.    I still have not noticed the transition to V4 by any other means than the DIC display.  I suggest that if AFM is annoying,  then owners should take advantage of their warranty and get it repaired.  You paid for this feature and you should reap the benefits.  Losing 1/2 mile  for every gallon (on average) is significant, imo.

[diyer2]

We have been at our new to us mountain home in Colorado for over a year now.

The roads we travel most vary in elevation from 9500 feet to 8500 feet.

Very little flat roads.

Lots of grade changes.

6th gear is useless, rarely gets into 6th gear when in D. 

Removed the Range device shortly after the move. 

When it was in 6th gear it was for a short time and V4 would not stay activated very long.

It would shift up and down a lot on some of the drives due to grade changes.

I just run it in 5th gear manual on some roads, 4th on others and 3rd on some to stop the trans from shifting so much.

Lots of shifting causes heat I believe.

Truck is stock except for a K&N air filter.

Averaging 15.8 MPG with some towing included, the boat.

87 octane Top Tier fuel.

[Grumpy Bear]

5 hours ago, diyer2 said:

We have been at our new to us mountain home in Colorado for over a year now.

The roads we travel most vary in elevation from 9500 feet to 8500 feet.

Very little flat roads.

Lots of grade changes.

6th gear is useless, rarely gets into 6th gear when in D. 

Removed the Range device shortly after the move. 

When it was in 6th gear it was for a short time and V4 would not stay activated very long.

It would shift up and down a lot on some of the drives due to grade changes.

I just run it in 5th gear manual on some roads, 4th on others and 3rd on some to stop the trans from shifting so much.

Lots of shifting causes heat I believe.

Truck is stock except for a K&N air filter.

Averaging 15.8 MPG with some towing included, the boat.

87 octane Top Tier fuel.

Can I ask what ration the diff gears are? ( a chance to learn something) 

[diyer2]

3.42's Grumpy Bear.

 

[Grumpy Bear]

Would you care to offer an opinion on how 4:10 or even 4:30 gears might effect performance (transmission/AFM/fuel efficiency) in your particular driving region?  (yes I'm fishing) 

[Centex14]

Tuned out afm. Still getting between 15.5-16.5 just like before. So in my case, no difference with or without. I don’t like complicated machinery so I eliminate it when I can.


2014 z71 LTZ
Volant Intake
Borla Exhaust
Diablo
Bilstein 5100
Rough Country Level

[CadillacLuke24]

I can understand some people's frustration with AFM.

 

I left it on, and boy do I love it.

 

It is useless on the interstate. No doubt there. 

 

Get on state highways (70 mph here) and it comes into play. Enough to make a decent difference. I tend to get 21-22 mpg very consistently on primarily highway trips.

 

When I absolutely NEED good gas mileage, drop down to 55 and AFM SHINES. Regularly 23-24 mpg at 55 mph, and my record is 26.1 mpg. Over 120 miles. 

[KARNUT]

I can understand some people's frustration with AFM.
 
I left it on, and boy do I love it.
 
It is useless on the interstate. No doubt there. 
 
Get on state highways (70 mph here) and it comes into play. Enough to make a decent difference. I tend to get 21-22 mpg very consistently on primarily highway trips.
 
When I absolutely NEED good gas mileage, drop down to 55 and AFM SHINES. Regularly 23-24 mpg at 55 mph, and my record is 26.1 mpg. Over 120 miles. 

I can see that. My question is how do you get away with 55 in a 70? My Camry shines at 72 MPH with 33-35 MPG and drops pretty good higher. My truck would go as high as 24MPG at 60 MPH with out cylinder deactivation going up HWY 17 at the speed limit. If try that on interstate 10 from Texas to the east coast they’d play bumper cars with me.[emoji2]


Sent from my iPhone using Tapatalk

[diyer2]

16 hours ago, Grumpy Bear said:

Would you care to offer an opinion on how 4:10 or even 4:30 gears might effect performance (transmission/AFM/fuel efficiency) in your particular driving region?  (yes I'm fishing) 

As far as the AFM, it doesn't get used. There are 2 roads where it will engage if I let it. One going down hill for maybe a mile and the other road about a mile of flat area.

The gear change would raise the RPM's but I don't know if it would keep it in the power band more. Mileage may suffer some due to more RPM's at a given speed.

I did my playing with motors, transmissions in the 70's racing quarter mile. Now reliability and getting high mileage out of my vehicles is a priority.

 

I'll add this. 

To the best of my knowledge my 1970 Nova SS, 350 C.I., 4 bolt mains, high compression pistons, fuely heads, 411 gears, 4 speed tranny set up by B&M lived in the 5- 6 K rpm range at the track. Street driving 2-4 K rpm's. It got terrible gas mileage.

My truck lives in the 1500 to 3 K rpm range now. I like that, less wear.