Improving 454 HO gas mileage

[1987_chevy]

I've been driving my truck for about a month now and have gotten way worse gas mileage than I expected. I have calculated somewhere between 7-10 mpg. This is a little bit of mixed driving, keeping it around 60 on the highway.

My setup is an sm465 with 3.73 gears, and a 830 HP carb. I realize the the carb being a performance carb could hurt gas mileage, but it's not running rich. I like the gearing of the truck, and I plan to pull it and i think that gearing will work well.

Any other experience with a similiar setup? or any suggestions?

 

[Jims86]

I've been driving my truck for about a month now and have gotten way worse gas mileage than I expected. I have calculated somewhere between 7-10 mpg. This is a little bit of mixed driving, keeping it around 60 on the highway.

My setup is an sm465 with 3.73 gears, and a 830 HP carb. I realize the the carb being a performance carb could hurt gas mileage, but it's not running rich. I like the gearing of the truck, and I plan to pull it and i think that gearing will work well.

Any other experience with a similiar setup? or any suggestions?

Put the TBI back on for starters, and then have a custom tune done
Tire pressure and driving habits for the rest of it. Could probably bring the rear gears to the next step up for hwy mpg. Skinny tires help as well.

If you want to keep the carb, i would suggest getting a wide band O2 sensor monitor to mount under your dash, that will allow you to fine tune the jetting.
What carb exactly do you have? Q-jet is best OEM, Holley is best aftermarket.....Edelbrock and the carter copy are ****.

 

[1987_chevy]

Put the TBI back on for starters, and then have a custom tune done
Tire pressure and driving habits for the rest of it. Could probably bring the rear gears to the next step up for hwy mpg. Skinny tires help as well.

If you want to keep the carb, i would suggest getting a wide band O2 sensor monitor to mount under your dash, that will allow you to fine tune the jetting.
What carb exactly do you have? Q-jet is best OEM, Holley is best aftermarket.....Edelbrock and the carter copy are ****.

The carb is a Holley 830 HP. The motor is the 454 HO crate motor, not the original one. So TBI isn't really an option. Do those O2 sensors for jetting a carb really work, I have looked into them.

 

[Jims86]

The carb is a Holley 830 HP. The motor is the 454 HO crate motor, not the original one. So TBI isn't really an option. Do those O2 sensors for jetting a carb really work, I have looked into them.

Ok...its an 830 cfm, not HP.
The Carbed 454s came with 750 cfm q jets. But with some tuning, your holley could work just fine.

 

[1987_chevy]

It is this carb- http://holley.com/0-80511-1.asp

And this engine- http://www.jegs.com/i/GM-Performance/809/12568774/10002/-1

I was thinking maybe 4.10 gears if i avoided interstate, but i don't know if there'd be any noticeable gains over the 3.73s

 

[Jims86]

Ideally, you want to cruise betwix 1800 and 2200 rpm. Sorry I forgot to answer the rest of your question...yes, the wideband kits work great, they use them in dyno cells to optimize engine combos.
And that carb....hmmm, i dunno.
I would step down to a 770cfm truck avenger.

 

[1987_chevy]

I've looked at a chart and entered my tire size and gear ratio and at 35 i should be around 1400, and at 50 i should be around 1900 rpms. I just figured being easy on it I'd be closer to 13 mpg. Not that I'm complaining because I love the motor, just a little expensive to cruise around in lol

 

[Jims86]

I've looked at a chart and entered my tire size and gear ratio and at 35 i should be around 1400, and at 50 i should be around 1900 rpms. I just figured being easy on it I'd be closer to 13 mpg. Not that I'm complaining because I love the motor, just a little expensive to cruise around in lol

Yeeeeeaaahhhh....you MAY see 15 if you fine tune a truck avenger, but thats pushing the boundaries for a 454.

 

[1987_chevy]

Yeeeeeaaahhhh....you MAY see 15 if you fine tune a truck avenger, but thats pushing the boundaries for a 454.

Yeah well i put it together for power so I can't complain too much, maybe someday when i have the money I'll try a smaller carb

 

[woodsrider250]

Don't drive it for a week, and you'll have the dough