Live: V8 MPG (1 Viewer)

[90 Weight]

Currently in the midst (first 6 days) of a 70 day, 5,000 mile roadtrip in the 40.... This is the first major driving he has seen and so I was not exactly sure what MPG to expect....

he has:
new crate 350 w/edelbrock 4bbl 600cfm

three speed automatic TH350

33x12.50's

Hardtop w/roof rack and RTT

Tire carrier

and a FULLY FULLY loaded cargo area.....I mean to the cap fully loaded....

I was expecting something around the likes of 12-15mpg....


drum roll.....


after 600 miles, we are averaging 5.7MPG

is something wrong? should I check the tuning? he is running fine but maybe he could be tuned for economy? or do you guys think that should be expected for a fully loaded flying brick?

On open stretches I keep the rpm's somewhere between 2500-3000 on the top end (60-73mph) but the majority of the driving has been along the PCH (california coast line) so the speeds are up and down hills at around 35-50....

what do you guys think?

 

[middlecalf]

I wouldn't be happy with that, but it's hard to say what's the main reason, there could be a lot. My ancient 283 w/carter afb (old version of edelbrock), 31x10.5 was getting 7.5-9 mpg with driving speeds from 45-60 mph. I've since replaced the even ancient-er dizzy with an HEI and just measured at 14.8 mpg! No other changes. What are you running on the electric side of things? Are you compensating for the different revs in you mpg calcs?

BTW, if/when you significantly improve your mpg, "he" will no longer be a "he," he'll be a "she." trust me.

 

[FJforty]

Edelbrocks love to pour gas in, racers love them. A Quadrajet might be a better carb for you. OH! and where the heck are you?

 

[BrianSanDiego]

Dang, I would think it would be better than that! Sounds like its running very rich or the timing is way retarded. Maybe pull a couple spark plugs to see if its too rich?

 

[Poser]

Currently in the midst (first 6 days) of a 70 day, 5,000 mile roadtrip in the 40.... This is the first major driving he has seen and so I was not exactly sure what MPG to expect....


new crate 350 w/edelbrock 4bbl 600cfm

Is this engine even broken in yet, or are you in the midst of that currently?

 

[lcwizard]

In this day and age why didn't you do a injected motor and a 700r.
You'd more than double the mileage

 

[toddslater]

Also, would be interesting to see the build/spec of that crate motor. Does it have a hilift long duration cam ? For comparison, I just logged my 5.0 HO (injection) mileage to and from CMCC. Mixture of 60 mph highway, two lane hilly roads, and some one and two horse towns. Running 35x12.5 muds, stock trans, tcase, and gearing...16 mpg. I'd say 50% loaded with crap along with my fat a$$.

 

[fieldsken1]

i have the same setup as you do with 35 inch tires and i get about 10 to 11 mpg and i kept my foot in it about half the time. go get it dyno

 

[MtnClimber]

Just wanted to ask... You didn't poison your rig with E85 did you? My Titan was getting 18PMG highway on a trip we took two years ago with regular. My Titan, being a Flex Fuel equipped truck, I stopped in Boulder City NV and gassed up with some E85 since that was all they had.

I got just under 5 MPG with that crap! Stay away for the E85 and if at all possible, try to find the stations that still have real fuel and not the E90 (most popular 10% Ethanol gasoline).

Break in and tune go hand in hand. Let it do it's thing and try to run it with different loads and RPM during this break-in period. Hills are good at this point. Once broken in, then it can be re-tuned and I bet the MPGs and power will improve.

 

[antFJ]

call your truck a 'she' and you'll see immediate improvement...

on a tech note whats the exhaust look/smell like?

 

[MtnClimber]

It's got a V8. V8s have balls. You don't call something with balls a she unless you're queer.

 

[Hugh Heifer]

In this day and age why didn't you do a injected motor and a 700r.
You'd more than double the mileage

IIRC it was injected for a bit but he was having nothing but trouble with it.

 

[Elbert]

I would think something at least close to 10 mpg.

I get somewhere around 13 MG on the hway...9-10 in town.. V-8 with 5 speed, fuel injected, 6000lbs, 4.11 gears with 33 tires.

 

[Fast Eddy]

From your description I would've guessed 9mpg or a bit less. You didn't list your average cruising speed, but from your rpm I'm guessing your running at almost 70mph sometimes. Slow down or pay up. You're driving a brick with 50s technology. I'll bet you can get it up to almost 10mpg with a very constant 55mph. Lose the RTT, get FI and overdrive and you can probably get it up to almost 14mpg.

 

[GarageRat]

It's got a V8. V8s have balls. You don't call something with balls a she unless you're queer.

Uhhhh...enjoying being in a "he" is the definition of that connotation of queer isn't it?

Is there black smoke? Smell like fuel? How much weight of cargo are we talking? What gearing? Is the tranny downshifting a lot?

 

[bikersmurf]

Last highway trip I got 13-14 mpg(us) with a shot vacuum advance, tired carb, a 40 year old 350, and 33x12.50 AT tires.

Auto transmissions are some what harder on gas, but that seems way low. Even running at 3000rpm all day long on the I5, I was still seeing good fuel economy.

hope you can figure out why.

If it ain't broken in that will also be a factor(as others have stated).



Truck and passenger 5400 lbs... Although it doesn't seem to matter.

 

[FJforty]

I got a dump truck that gets 5-6 mpg, you could put the cruiser in the bed. Hmm. Uneven tire pressure in the rear can work the rear diff. pretty hard. Brakes dragging? You might drive awhile and feel all your brake hubs for heat. Wheel bearing? Did you put oil in it or someone else. Wrong oil. New engine can suck some fuel. As a side note, this is a great way to break in an engine. When you take all that stuff out it will haul butt.

 

[GarageRat]

The carb doesn't concern me as much as the others, I've got an AFB on my '63 and get the same mileage I got with a Q-Jet on the exact same motor. They can be finicky to tune, which could very well be your issue, but they're good carbs. Most people don't take the time to mess with the metering rods and jetting, not quite as easy as your average Holley.

 

[numby]

I think Poser's question is spot on.

What's the stall rating on the torque converter?

 

[numby]

I think Poser's question is spot on.

What's the stall rating on the torque converter?