454 FUEL injected guys!!!!!

[Grim-Reaper]

Ok I feel like a horses pitute asking this. What kind of MPG you turning on a relativly stock 87 up Fuel injected 454?
I'm shopping for a Burb I was hoping to find a 90 or 91 with a 4l80 OD tranny but not that common. It will be a pull truck for a Airstream camper a couple weeks a year. Running into a lot of TH400 trucks. I know the TH400 is near bullitt proof so not out of the question. THis pig will be my DD so It has to get like 15mpg or better on hwy at 75 mph (We fly in GA and I'll still be getting passed often at that speed LOL).

 

[OL14BLAZ]

[ QUOTE ]
THis pig will be my DD so It has to get like 15mpg or better on hwy at 75 mph

[/ QUOTE ]

Haven't had one of my own, but a coupld of my friends have owned 1/2 ton 2wd suburbans with 5.7L in them and the best they ever got was around 13 to 14 mpg on the hwy. So I think a 3/4ton with a 7.4L would get best at 12mpg on the road.

Just my .02 worth.

Eric /forums/images/graemlins/usaflag.gif /forums/images/graemlins/k5.gif

 

[Sandman]

My pull truck is a '92 xtra cab dually 4x4 with the 454. I have the 5 speed manual and unloaded on the freeway, I get a little better than 13. In town its more like 11.

 

[beater74]

My 98 454 crewcab gets 12/13 highway

 

[AnthonyG]

That beats the 6 or 7 i get with my bilt sb buy its not tbi

 

[Grim-Reaper]

[ QUOTE ]
My 98 454 crewcab gets 12/13 highway

[/ QUOTE ]
You have the 4L80 right?
Well that's scaring me but if the 5.7 isn't getting much better then I would rather get more motor then I need 95% of the time then have less motor then I need when trying to pull some long hill with 4500lb of trailer behind me ( or worse 8500lb of K5 on trailer) and 4 passengers and camping gear for a week.
Sounds like the OD is not a big gain in average driving.
What sort of RPM's are folks turning on the hwy with say a 31-32 inch tire?

 

[yellowK20]

I have an 86 k-20 with a NV4500 4.10 gears 315-70-16 BFG Mud Terrains 4" suspension lift with an 87 tbi 454 stock except for hooker headers 3" pipes with 40-series 2 chamber flowmasters I 've gotten as good as 17 Mpg highway with a 25 mph tailwind But I usually get 10-12 in town and 14-16 on the higway /forums/images/graemlins/truck.gif

 

[JK5]

My 91 C 2500 gets around 17 mpg... /forums/images/graemlins/smile.gif
Highway speeds...around 60-80 mph..

It has 4.10 gears...
4L80E
7.4L with over 200,000 on it..
Also....I have a cap on it....so there isn't that much wind drag!!! /forums/images/graemlins/smile.gif

 

[beater74]

I'll have to check my tire size they are some weenie street tire but i have 4.10's and i seem to run in the low 2000"s at 75 mph.

 

[yunit]

Towing a trailer with a 454 truck you will get about 8mpg. /forums/images/graemlins/eek.gif

 

[Grim-Reaper]

The airstream is light and areo dynamic. I posted this over there as well. The guys with Airstreams of simular size get about 12-13 towing on the flat and about 10-11 in most hills unless they get in the high passes.

Some place did a study and on average it take about half the power at hwy speeds to keep an airstream going as it does a simular size box trailer.

Now if I pull Dollar I fully expect 8 but that's not much worse then Dollar get's all by it's self so no real loss LOL.