454s - What kind of MPG are you getting?

[my name is alex]

Was getting tired of searching through this thread in hopes of finding some fellow 454s to compare mileage with. Seems like everyone here has 350s.

Looks like I'm getting around 9, maybe even less. That's all city driving, mostly slow-poking it and keeping the rpms under 2 (give or take). I'm refilling at about 1/4 tank to avoid over-heating the fuel pump, and I've only done a few partial tanks, so I'm sure my numbers aren't exact. But whatever I'm getting, it ain't that great (not that I was expecting much, but a man can hope).

I've got a stock '99 2500 Burb 4.10 with 265/75/16s on her.

 

[454cid]

...Seems like everyone here has 350s.

Yup

Looks like I'm getting around 9, maybe even less. That's all city driving, mostly slow-poking it and keeping the rpms under 2 (give or take). I'm refilling at about 1/4 tank to avoid over-heating the fuel pump, and I've only done a few partial tanks, so I'm sure my numbers aren't exact. But whatever I'm getting, it ain't that great (not that I was expecting much, but a man can hope).

I'm getting around that....9 or 10. I haven't actually calculated it carefully for a long time. Since gas has been going down, I've actually been filling up, Though, so I should start writing the numbers down.

I wouldn't worry about the gas level saving the pump. I'm pretty sure that's an urban legend. My OEM pump went out during a time that I was constantly filling up because of the miles I was driving. I've been putting minimal amounts in the tank for the last several years, keeping the tank quite low, and I think I've had the second pump longer than the original, now. I have almost 250K miles on the truck.

I've got a stock '99 2500 Burb with 265/75/16s on her.

Are you correcting your mileage calculations for the tire size? You're rolling further than your odometer tells you, unless you've changed the PCM programming.

 

[volunteerff21]

According to Torque I'm getting 13.5, but my math says around 12 babying the crap out of it when I'm not towing.

 

[my name is alex]

Yup

I wouldn't worry about the gas level saving the pump. I'm pretty sure that's an urban legend. My OEM pump went out during a time that I was constantly filling up because of the miles I was driving. I've been putting minimal amounts in the tank for the last several years, keeping the tank quite low, and I think I've had the second pump longer than the original, now. I have almost 250K miles on the truck.



Are you correcting your mileage calculations for the tire size? You're rolling further than your odometer tells you, unless you've changed the PCM programming.

Good to know about the pump. I'm not correcting for tire size, but I believe it's a fairly minor correction - like 3-4%. So yeah, I suppose I'm getting slightly better mileage.

According to Torque I'm getting 13.5, but my math says around 12 babying the crap out of it when I'm not towing.

Nice volunteer! Is that mostly city or highway? Did you notice any improvement in MPG from your custom CAI or other mods?

 

[Crummins]

I used to average 8-10 which was 70% in town.

The best I ever got was 15 that was all freeway and keeping it at 60.

I averaged 6 towing a ~10k trailer.

 

[dr_goodwrench66]

Pretty much 10-12 all the time. Combination city and hwy driving. 285/75/16 tires and 3.73 gears. EFI Live tune. At the very best I've scored 14.5, but you gotta want it!!

 

[SCOTTYINWV]

This upsets me, I'm only getting 11-14 in my zr2 blazer. Guess I better get a big block...

 

[my name is alex]

Well I guess my 9 is about inline with the rest of you boys, though a bit on the low side.

This upsets me, I'm only getting 11-14 in my zr2 blazer. Guess I better get a big block...

That seems pretty bad for a Blazer Scotty. Heavy foot?

 

[SCOTTYINWV]

Heavy foot and I think my fan clutch is staying engaged. I run at like 150 degrees on the interstate.

Plus its not exactly stock.
.

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[454cid]

Heavy foot and I think my fan clutch is staying engaged. I run at like 150 degrees on the interstate.

That sounds more like a thermostat stuck open, to me. On the highway, you're already getting a lot of airflow. The fan clutch isn't going to over cool the engine.