Tested Valence MPG Before/After

amxguy1970 · May 16, 2016

Just as it says, wanted to take it off and see the impact while I was at it. Picked a route, all highway, never below 60 mph or above 70 just sticking at the speed limits with cruise control. Ran back to back with in an hour, this was between 11 pm and midnight, light traffic and didn't impact the test speeds. Route was 40 miles with a u-turn to change direction. Started once I got to 70 mph speed limit and set cruise unimpeeded (reset trip mpg then too), dropped to 65 shortly there after (the speed limit and cruise) and kept that until the bridge where I dropped to 60 and kept it until shortly there after made the u-turn. Gently accelerated back to 60 and set cruise where I continued to adjust it according to the speed limit and back tracked.

Before mpg with the valence was 23.3, after it was 22.1. Noticed it not going in to 4 cylinder mode as often with it removed.

I never thought it would have that much impact, thought maybe half an mpg at highway speeds. I did hear an engineer state it was 1 mpg that the valence gained them on the Colorado / Canyon but thought that was a little far fetched.

Either way I knew I didn't want it stock on there, removed looks good but unfinished so I always wanted to trim it which I will be doing. Like the more finished look and hope to get half that difference back.

I know there will be some who say it is a truck who cares, well truth be told it is a big thing to many shoppers and it they can save a little fuel who not? Why anyone would just want to piss money away is beyond me, I will save anything I can get because that is how I operate (not that it will make a difference to me).

Truck is a 2014 CC 5.3 4wd Silverado with the 3.42 rear end and 8k miles on it, all stock including tires and added a tonneau cover and bug deflector. No AC on during the test, just the fan, windows up, temp was upper 60's. All tires were around 37 psi during both tests. This was in the DFW area so pretty flat other than a small incline or bridge. Truck didn't down shift at all and on some of the hills with the valence it kept 4 cylinder mode engaged, without valence not so much.

Hope that helps, this isn't scientific but it is a pretty good indicator. Designers spend tons of money on design and testing so it sure had to account for something. Those have have removed it and say it did nothing probably don't drive highway much. If you do a lot of city driving and see an overall average you won't see much a difference. On a ton of highway miles or a road trip you will be able to see it.

That and 4 cylinder mode does make a difference, easily visable the mpg difference each time it goes in and out (which is probably why the mpg dropped, less 4 cylinder mode because more of the truck was in the air holding it back and needing V8 to keep speed).

That is my 2 cents and unscientific test, discuss...

Tyler

Perseus · May 16, 2016

Interested to see results after trimming

camcamaro1991 · May 16, 2016

"valance"

Our truck's valance was cued from the Vettes, engineers already confirmed it lowers aero drag. They pointed out the outsides hanging lower for the tires, and center being a bit higher made the biggest difference. In the same video it also showed a 2nd valance under body panel (prototype valance/panel) frame mounted I believe its transmission mount section. I guess it never made it to production.

Since your own findings prove it works why would you remove it? I guess if your going to trim you're valance, keep the same GM design and just shorten it in ratio.

fondupot · May 16, 2016

I know you tried your best to keep both runs as close as possible, but the difference of 23.3 and 22.1 is 1.2 mpg. Which is about 5% difference. That 5% difference could have been attributed to a pick up in wind, or slightly different acceleration. I would have to see more thorough testing to support a claim that the valence improves mileage.

I'd say about 5 runs with the valence and 5 runs without the valence, and then average each side out. Then compare.

Neat experiment tho.

Donstar · May 16, 2016

Tyler's test may not be 100% controlled but it does support keeping the valance attached to your truck. I believe like many others that a truck looks better without it. I also believe gm puts it there for a purpose and if it saves me money, it looks better to me!. A saving of only a fraction of a mile per gallon makes it worthwhile in my opinion.

b1gted · May 16, 2016

I didn't really buy my truck to get good gas mileage. There are far more options for that. But I agree that every little bit helps, I believe if you like the valance, leave it, if you don't like the looks of it, take it off. It is your truck. :-)

Rkaroll953 · May 16, 2016

mines been ripped off since day one. at 70 with no wind i get 21-22 and thats leveled 2 inches with no v4

ragin_cajuns · May 16, 2016

Took mine off this weekend. Had it off on my previous truck as well. I think it looks better without but to each his own. If it makes a difference in mpg its so minor that it doesn't matter to me.

tnchevy · May 16, 2016

I keep a spread sheet of my mpg's from every fill up for my truck. I went the first year with the air dam on and have had it off now for 7 months. When I get a year with it off I will let you guys know how it turned out. The mpg's lost will vary for different people due to the average speeds in which they drive, the faster you go the more drag and the more fuel you will save with the air dam on compared to with it off. I figured one year with it on and one year with it off will give a good idea but I rarely drive on the interstate so my results will be different than others.

Shu · May 16, 2016

That is about the same mileage I think I lost when leveling the truck so while it may not be a huge amount of controlled variable runs, I'd say it is pretty accurate given how much you were able to control the variables. Thanks. At 1 mpg average, for me it amounts to about $175 per year in additional gas expense.

Rock1500 · May 16, 2016

I keep a spread sheet of my mpg's from every fill up for my truck. I went the first year with the air dam on and have had it off now for 7 months. When I get a year with it off I will let you guys know how it turned out. The mpg's lost will vary for different people due to the average speeds in which they drive, the faster you go the more drag and the more fuel you will save with the air dam on compared to with it off. I figured one year with it on and one year with it off will give a good idea but I rarely drive on the interstate so my results will be different than others.

I agree and let us know but couldn't you comply 7 months for now and see a difference or not?

Sent from my SM-N900V using Tapatalk

brmudd · May 16, 2016

The first year will be during the break in period. Maybe take similar periods following break in to try and keep the variables to a minimum.

Be interesting to see.

crushNchowda · May 16, 2016

I took mine off after lifting/leveling it w/ bilstein 5100's & adding 1" more block to the rear.

#1 - GM trucks are the lowest 1/2 tons on the market from the factory, and this relatively huge chin spoiler/valance whatever you wanna call it clearly amplifies the already low ride height of the truck.

#2 - If you're looking for some added rationale for removing the ugly thing, most people get a tonneau cover for their trucks, I believe a solid/semi-solid tonneau cover would offset the fuel mileage loss from removing the valance.

#3 - My now 11,000 mile 2015 6.2 8 speed CC 4x4 short bed that has the level & valence removed is averaging .3 mpg BETTER than my now totaled w/ 40,000 miles '14 5.3 CC 4x4 std bed truck that was NOT leveled and had the valence on. Both trucks got 93 octane. My driving habits remain the same - 16.1 for the 6.2 leveled no valence and 15.8 for the 5.3 stock - more rationalization for ya.

Shu · May 16, 2016

Actually a tonnaeu cover does not improve fuel mileage.

amxguy1970 · May 16, 2016

I took mine off after lifting/leveling it w/ bilstein 5100's & adding 1" more block to the rear.

#1 - GM trucks are the lowest 1/2 tons on the market from the factory, and this relatively huge chin spoiler/valance whatever you wanna call it clearly amplifies the already low ride height of the truck.

#2 - If you're looking for some added rationale for removing the ugly thing, most people get a tonneau cover for their trucks, I believe a solid/semi-solid tonneau cover would offset the fuel mileage loss from removing the valance.

#3 - My now 11,000 mile 2015 6.2 8 speed CC 4x4 short bed that has the level & valence removed is averaging .3 mpg BETTER than my now totaled w/ 40,000 miles '14 5.3 CC 4x4 std bed truck that was NOT leveled and had the valence on. Both trucks got 93 octane. My driving habits remain the same - 16.1 for the 6.2 leveled no valence and 15.8 for the 5.3 stock - more rationalization for ya.

That is anomaly...

Actually a tonnaeu cover does not improve fuel mileage.

Actually it does, how much is up for discussion but independent tests as well as manufacturers have shown otherwise.

Thanks for the correction on Valance, since there are two spellings auto correct didn't catch which one.

I will try to remember to do another test (though it will be different weather) after I trim it.

Remember this is strictly highway, no city. If you run averages with any city mixed in the difference will be less pronounced, much less depending on the amount of city driving/idling.

The reason I would remove are a few reasons. One because this truck leaves the pavement and it is a hindrance, two it looks better and three it has already been scratched up a few times around the city and I don't want this to break and have it rip out the center "skid plate imitation design thing" piece at the bottom of the bumper that it is attached two. It was 16 bolts and clips to remove, if it gets ripped out other pieces very well might come with it.

Doing multiple runs to average no doubt would have been best but I wasn't investing that much time in to this. I think just over 5% is a little out of the error range but it certainly could be much closer. Weather shouldn't have changed much as storm were long past and it was fairly calm.

Some good ideas out there fellas.

Tyler