2020 2.7 Fuel Economy Issues

[Kenneth Memmer]

Just reaching out for some feelers from fellow owners. I just got a new to me 2020 Silverado with the 2.7. 4x4 with 55,000 on it. It has a 4 or 6 in lift with 35in all terrains. At 75 I can only get 16 mpg. Does that seem right? Also it will sometimes jerk when shifting into reverse pretty hard sometimes as well as what feels like hard up shifting sometimes

[silveradosid]

should normally get 20 mpg or more at that speed, but with the lift and large tires i could see you loosing 4 to 5 mpg. also if the truck wasnt recalibrated for those tires the tranny could do weird shifts

[Silverado4x4]

Your biggest issue is the lift,tires and the little 4 cylinder pushing the wind load and tires, the 4 cylinder is working hard to push the truck. Its the price you pay for lift and bigger tires.

[diyer2]

Service the trans with a quality fluid, Amsoil, Redline.

[newdude]

13 hours ago, Kenneth Memmer said:

Just reaching out for some feelers from fellow owners. I just got a new to me 2020 Silverado with the 2.7. 4x4 with 55,000 on it. It has a 4 or 6 in lift with 35in all terrains. At 75 I can only get 16 mpg. Does that seem right? Also it will sometimes jerk when shifting into reverse pretty hard sometimes as well as what feels like hard up shifting sometimes

 

 

Yes.  Its lifted with 35s and you are doing 75mph.  Take all that off and go back to stock, you will get 20mpg doing 75mph.  

[f8l vnm]

Seems like 14-16 is the range for most half tons with lift and 35s. This also debunks that if the 2.7 works harder , it will waste more gas. I’ve been in 5.3 and 6.2s,  Ford 5.0/3.5 with same modifications and all get around same mpg.  

[customboss]

14 hours ago, Kenneth Memmer said:

Just reaching out for some feelers from fellow owners. I just got a new to me 2020 Silverado with the 2.7. 4x4 with 55,000 on it. It has a 4 or 6 in lift with 35in all terrains. At 75 I can only get 16 mpg. Does that seem right? Also it will sometimes jerk when shifting into reverse pretty hard sometimes as well as what feels like hard up shifting sometimes

AT has issues and it may be too late to correct them with fluid. It's still under warranty so have GM check it out.   If it's solid I agree change out the fluid and filter with high quality ATF. 

 

I use Amsoil ATL in my 22'LTD Trail Boss 2.7T and get an average right now of ~27 mpg  @65 with AC on and no wind 87 avg octane E10.  E15 it drops that a tiny bit.   

 

Confirm ECM  calibration on wheel size so the MPG via DIC is correct.  Check MPG via multiple fill ups manually to confirm what DIC is telling. 

 

Being a boosted engine air filter is critical to good MPG. If it's at all restricted it will affect MPG.  

 

I run an O'Reilly MGA air filter with great results. Live in a really dusty area too. 

 

Use a good synthetic engine oil too.  I have shared oil analysis on differing brands in the 2.7 engine thread. So far Amsoil is tops. 

 

Enjoy your new ride and bet you get it figured out and enjoy it.  

 

 

 

[It's Tim]

15 hours ago, Kenneth Memmer said:

 It has a 4 or 6 in lift with 35in all terrains. At 75 I can only get 16 mpg. Does that seem right? Also it will sometimes jerk when shifting into reverse pretty hard sometimes as well as what feels like hard up shifting sometimes

Is it a ghetto lift? CV & U-joints trashed?

[4banger]

5 hours ago, f8l vnm said:

Seems like 14-16 is the range for most half tons with lift and 35s. This also debunks that if the 2.7 works harder , it will waste more gas. I’ve been in 5.3 and 6.2s,  Ford 5.0/3.5 with same modifications and all get around same mpg.  

exactly, if you ask for v8 power levels you'll get v8 mileage, the 2.7 can suck gas just about as hard as a 6.2 as it will make almost as much power (at least with the H.O. it will no problem, at my elevation of 4000' I have 22 ft/lbs more than the 6.2 but it has a 63 hp advantage, so the 6.2 can still suck more gas but not much), so towing or lifts with heavy fat wheels/tires you're going to eat that fuel regardless of motor, the 2.7 inline 4 has simply traded 4 cylinders for a big ole turbo with 22 psi boost...which does a couple things to note, 1. no more power loss at elevation (3% per 1000' with naturally aspirated), and 2. way more power at lower rpms eliminating hills, handling lifts with heavier tires better, and in conclusion you get a more relaxed calm peaceful driving experience, so you've got the better choice motor regardless, service the transmission and you should be good to go

 

now, one doesn't have to go crazy with huge heavy wheels/tires, I have the refreshed high output 2.7 and did a 4" lift but went lightweight 17" wheels and skinny 33's (same height as stock) and removed my chin spoiler and I'm easily achieving factory fuel economy ratings, I would bet the wheel/tire combo is the bigger killer than the lift...I dropped 4 lbs per corner while going up to snowflake rated all terrains with e load rating, so I'm not being penalized at the pump at all for the choices I made (factory tire was 275mm wide, I went to 255mm so about 3/4"-1" narrower), I remember gaining mpg on my gladiator by tucking the wheels back into inline with the body/fenders fyi, I went from 35's sticking way out like a skateboard up to 37's tucked back in and actually got better mileage so having those fat meats sticking out into the wind is an mpg killer fyi, might give you some ideas but I'd bet if you went some skinnier 35x11.5 or 285 75r18 and maybe not a ridiculous offset you'd likely pick up a couple mpg's easy, and choose lighter weight wheels, they are out there but guys seem to want looks and choose the heaviest dang wheels/tires out there rather than focus on function

 

and for perspective go pull one of your wheels and throw it on a scale...the factory 20's with the all seasons came in at 78.25 lbs fyi...my new 17" combo with e-rated snowflake all terrains came in at 74.25 lbs....I'd bet if your pushing well over 90 lbs per corner, it's not hard to get over 100 lbs per corner with 35x12.50's on some in fashion wheel

 

if I could find some 17" black rhino rapids (I have black rhino chase) I'd save 2 more lbs per corner, one day perhaps, but my accelleration is also fantastic because I went this direction, goes and rides just as good as stock 20's

 

 

Edited August 29, 2022 by 4banger