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2021 Silverado Trailboss 6.2L Bad MPG?


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Hey, just wondering if anyone experienced bad MPG from a 2021 Silverado Traillboss 6.2L using the Pulsar LT?
 

I have a these modifications on the truck:
Closed Box Air Intake from Volant Performance
Borla S-Type Cat Back Exhaust system (Dual Pipe Exit)


Before installing the Pulsar LT to disable the Auto Start/Stop & DFM. I was averaging about 10-13MPG (Roughly 11.0 MPG AVG). But soon as I install this Pulsar, I can't get any better MPG than 9.5MPG. I don't drive as aggressive and I don't got any performance modifications aside from the exhaust/intake. Am I doing something wrong here or possibly something wrong with my truck? I do run Premium Fuel (93 Octane) since its a 6.2L. And Throttle response is set at Level 2.

Also Keep in mind, I do drive more city then highway, but I don't think my MPG should be this BAD compared to highway.

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Occams Razor applies here?  "The simplest explanation is usually the best one."  You defeated autostop and DFM and this is the result, worse mileage.   You need to make a decision, better mileage or mods. 

 

My 2021 Sierra 4wd Denali CC 6.2L has averaged 19.4 mph over its first 23,000 miles.  100% stock truck except for AMSOIL synthetic Lubes throughout. 

Edited by elcamino
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City driving kills our mileage.  I'll drive a little further to run steadier speeds with less traffic/lights.  Less wear on the truck and better mileage.  

 

We only get 9 mpg on E85 with 100% city driving, 13 mpg on 93 octane but our trucks are older and unmodified but do not have AFM/DFM or start stop.

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Set the throttle response back to stock.  You are opening the throttle further with your current setting.  More air through the throttle body means more fuel to the cylinders.  All 8 of them, all of the time.  When I had it on my 2019, I would get around 13mpg in town, and 23-25mpg on the highway.  My only settings were AFM/DFM off and auto start/stop disabled.  It was an otherwise stock truck.

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Disables fuel saving measures, then complains about poor mpg. Is this a serious thread? 

 

Let's do a little math here. Both AFM and stop start are said to save between 5-10% depending on conditions each. So, lets say each saves 7.5%, that is 15% in fuel savings (or lost if you defeat them). If you were averaging 11 mpg and now averaging 9.5mpg, that is almost exactly 15% difference before and after. Granted it all depends on driving situation, but those percentages are optimal really on the high end and suboptimal on the lower end. 

 

Either way, that is exactly where you should be after defeating those two devices. No, nothing is wrong with your truck. 

 

Tyler

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On 2/22/2023 at 4:48 AM, elcamino said:

Occams Razor applies here?  "The simplest explanation is usually the best one."  You defeated autostop and DFM and this is the result, worse mileage.   You need to make a decision, better mileage or mods. 

 

My 2021 Sierra 4wd Denali CC 6.2L has averaged 19.4 mph over its first 23,000 miles.  100% stock truck except for AMSOIL synthetic Lubes throughout. 

 

That's a modification though that significantly improves mpg and hp, so you can't say that with those mods. It's like someone saying they are just bolt ons but have heads/cam set up, that is just misleading...

 

Tyler

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Well I decided to return my throttle response to STOCK and I kept Auto Start/Stop & DFM Turned off through Pulsar. Still was getting Avg 8.5 to 10MPG (City Driving Of course). So After a few days of not seeing a improvement, I turned DFM back on and still left the auto start stop off. Now my MPG went back to Avg 11MPG. I just feel like I'm supposed to get better MPG with having a air intake (Which advertises it increases MPG by 3 supposedly). I did throw some Octane Booster to see if helps but not seeing much of a difference other than my normal MPG with Stock Throttle/DFM ON.

Just crazy to see other people in the internet saying they're getting 16/20MPG with similar mods and I'm getting the worst of it. Maybe Sparkplugs?

Edited by MathewB75
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More air in the engine means more fuel as well. The computer is going to compensate and adjust the amount of fuel as it reads higher airflow. This also isn't the old days where you can throw an intake on and get decent power gains anymore. Computer controls every aspect of engine operation and is going to continually adjust to follow the parameters the stock tune demands.

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Just crazy to see other people on the internet saying they're getting 16/20MPG

 

Well, pretty sure no one has ever lied on the internet. Think there are rules about that everyone must follow to be allowed on it.

 

Example, I am on my original tank of gas, so my 6.2 is getting around 5-10k to the gallon, not too shabby for almost 57000 miles😁🤥

Edited by JimCost2014
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This is my actual calculated mileage, not the DIC because that is not accurate.

That one huge spike is a cross country trip to the high plateau. Almost all the rest is at sea level in Florida.

2022 5.3, 10-speed and one of the lucky ones without DFM from factory. Everything else is oem.Screenshot_20230301_113229.thumb.jpg.b05b692ac65d9e9bfc3ecb1c7974659b.jpg

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On 2/22/2023 at 5:48 AM, elcamino said:

Occams Razor applies here?  "The simplest explanation is usually the best one."  You defeated autostop and DFM and this is the result, worse mileage.   You need to make a decision, better mileage or mods. 

 

My 2021 Sierra 4wd Denali CC 6.2L has averaged 19.4 mph over its first 23,000 miles.  100% stock truck except for AMSOIL synthetic Lubes throughout. 

Not around town it won't, my 6.2 will get 20+ all day long on the highway but it drops to 13-15 around town depending on fuel blends and weather. This engine gulps fuel in a stop and go environment but that is the case with any v-8 engine in a truck really.

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Check and see if you have any vacuum leaks on the intake and if you havent, add some clamps for the valve cover connetion to the intake tube. Its minor but worth  a check and its easy to do.

 

I had a small vacuum leak on mine unrelated to the intake. I noticed power and economy were up after i put the stock intake back on and fixed the vacuum leak for a dealer visit. I still haven't put the volant back on but if/when i do ill be putting hose clamps on that hose from the valve cover to the intake tube.

 

And when i say power and economy were up after, i didnt even notice power was down until after this was fixed. I chalked the lost economy to more time i was flooring it to hear the intake 😬. I had no check engine lights and anything obviously wrong

Edited by dram1983361
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