3500 Dually MPG

[jpaitala]

I think this has been discussed many times before but I wasnt able to find the info I want.
My friend has '94 Chevrolet Dually and is getting 12-13MPG while running empty. He has exhaust system done and intercooler added and he does no towing. The rig is at 250 000km at the moment and is running real nice.

Is this right or should he be getting better MPG out of his Dually??

Thanks.

[Johnny B.]

I would say that he is in the ballpark. I get 12-14 really "13.6 mpg" all around mileage. I tow a 30' loaded to travel travel trailer 7000 lbs and get 8-9 mpg.

[Kollin Syverson]

I get a pretty consistant 12 MPG. Doesn't seem to make much difference if I am empty or pulling.

[HudB1]

I get 14-16 on regular basis of mixed hwy and city empty with 96 dually with the f code 6.5 and 4.10 gears. Just upgraded to taller tires and soon 3.73 gears just to reduce the rpms at cruise.
later
hudb1

[Don Boland]

After adding Kennedy's 3 1/2" exhaust, removing the Cat (for as long as I can get away with it!), and new injectors, I am running a little over 15 empty, 12-13 with a full load of firewood, and about 9 towing my 24' pontoon party barge, which is like pulling a big blocky brick behind you (not so cool wind resistance wise). So I don't think you are far off. I run 235/85's with no speedo correction so I get mine by adding about 7%. I get about 14 1/2 on the clock.

DB

94' CC Dually 4x4, 6.5td, Kennedy 3.5" exh, FSD cooler mounted on firewall outside of hydroboost - plug down! 195,000 miles. Going for a chip and boost mods (and gauges) next along with fan clutch!

86' Suburban 4x4, 6.2, bad head-gaskets (they're next!), run's great but loses coolant! Wife hates it - I love it! 310,000miles

[ktmracer]

2000 4x4 crew cab auto dually. 14.6mpg om hwy. empty. 6.5 to 8 mpg towing 40 ft. high profile,about 13,500lb. 5th wheel. these figures are at 65mph or lower. over 65mph and mpg goes out the bottom,towing or not.

[ucdavis]

Gears seems to be the big variable w/the dually's. What ratio rear end you got?

[gwaidman]

I have a 94 dually 4x4 with f code engine, 5 spd trans 4:10 gears, and 287,000km on the clock. I have a yard of crushed limestone in the box for winter traction and get 17mpg average. I dont drive it too hard and 110kmh is as fast as I go. They key lies with RPM, keep it around 2000 for max economy and anything higher than 2400 is going to empty your wallet.

[jpaitala]

Myself I'm looking on two trucks now... The other one is '94GMC Dually and the other one is '97Chevy Suburban. So the suburban would kick the Duallys butt by 3-4mpg's?? Am I on the right track with this estimate.

I'm not sure yet which of these two trucks I will get(hopefully I can get a truck before christmas).

Thanks.

[kowsoc]

I'm thinking if the dually had 3:73 gearing it would be close to the same fuel economy of the burb. There would be extra weight with the dually though. However, I have hauled 1000-1500 lbs. on my 94 2500 extended cab numerous times with only a slight hit with mileage....maybe 1/2 mpg.

Maybe someone with a 3:73 geared dually will chime in. smile.gif

[jeffreydmet]

I have a 99 K3500 DRW with AT. 235/85 tires and 3.73 gears. I pull more than don't but the trailer weight is about 3000 lbs and low profile. I usually get about 13 mpg. I have got 17-18 mpg unloaded after a few modifications. I have done some testing and my duals cost me at least 1-2 mpg. The 17-18 came with the outer duals off.

I had the stock tires and 4.10 rearend when I got the truck and it would only get about 15mpg empty. The gearing change at most helped 2 mpg but does make the truck much nicer to drive. I have been using fuel conditioner which I think helps a little. Typical for me towing a lot is around 14-15 mpg.

[LanceW]

'94 F-code extended cab dually here, automatic w/ 4.10 rear. Empty, I get anywhere from 14.5-17 depending on speed and conditions- 17 is the very top limit, not typical. I just completed a round trip from Richmond VA to Baton Rouge LA with a 3 horse gooseneck, probaby 7,000 lbs or so, mostly at 70 mph and averaged 11.05 mpg over the 2,400 mile run. I've been using Power Service additive with cetane boost and think it makes a difference. Depending on how your buddy drives it, I think his mileage is a little low. Just my opinion. As they say, "your mileage may vary".

I got back tonight from a round trip to Salisbury MD, and going down rte 50 and back to annapolis I was travelling at 60-65 most of the way. I think (but am not positive) that I got a little better than 12 mpg WITH TRAILER for that part of the trip. Speed makes a huge difference.

[gerickson]

Just my two cents worth. My 96 longbox crewcab K3500 with a very tired 6.5 with cracked heads and block and with the smallest O.D. tires I

[1bad383]

just curious, I have noticed some Big Block 3500's, 2500's and so on came factory with an airdam in front. A friend of mine broke his on a 1500 mileage went way down...... Replaced it and went to normal. What normal is, I dont know. But is there a reason we cant try an air dam? Cuz I would like to get better than 11.5 on my 3500 4.56 crewcab dually @ 206,300 Miles........

[jeffreydmet]

I've been thinking about putting one on my truck (99 K3500 3.73, 235/85 tires) too. I think it will make a difference. My truck had a bug sheild on it which is not very aerodynamic. I took it off and think it helped the mileage significantly. Others have said this too.

However 1bad383 you probably won't see much results from the airdam on your truck because of the gearing. I would say a lot of your bad mileage comes from that.

[mike micklich]

10 regardless of action no cat kenedy exhaust phazer k&n 4x4 dually 410s taller tire fill it every 250

[jpaitala]

Anyone with 2wd dually?
Does 18-19mpg sound right for '96 dually?

[Johnny B.]

I was told by the previous owner that he got 16mpg with my truck. He was 60 and didn't have to be anywhere, but I really doubt he got 16. I would love to squeek a solid 14 mpg with mine. I would say it could be realistic with 3:73 since I run 225 75 16 tires.

[pgoldstein]

With slightly oversized tires and a 4:10 gear my truck is now getting about 15-16 mpg. If I keep the tach at 2200 rpm which equates to about 68 mph.

[rjwest]

Ditto: 15-16 empty on 96 k3500 4.10 and 12.5-13
with 2700-3000 truck camper, ( average over 30K miles
with truck camper ) swaped in 3.73 gears.
still 12.5-13 with truck camper, ? empty.
not enough mile to tell.

DRIVES Much better with 3.73 loaded at 65 to 70 mph
pulls 2 lbs more boost ( 2000rpm at 65 )
PROOBLEM: TCC use to lock at 45 mph and pull hils at
60mph in OD. Now locks at 50 MPH , and down shifts or unlocks TCC with 1/2 throttle... I think it's
losing milage gain of higher gears with ( Slush )
mode at 60mph.....

It appears that TCC lock up is not afected by speddo, but Tranny speed.

Going to try the poor mans torque loc as posted in fforum.

If I can Get the TCC to lock up in 2nd and stay locked longer in 3rd and OD . I Think MPH will go Up..