7.3 IDI Turbo fuel mileage after tuned up?

[DAXTY88]

I have a 94 factory idi turbo 220k,CCLB, SRW, 4wd, E4OD, 4:10, 35in tires speedo been calibrated, just bought the truck and best mpg it’s getting currently is 11mpg it also runs a little rough. I am certain the injectors are due to be changed and I’m looking to replace the pump as well and will then reset timing. My question is if I install a turned up pump like a R&D or Moose what kind of mpg can I expect. Of course I know it depends on my driving and a number of factors but I’m curious of others that have mildly built IDI’s what they have done to there truck, what kind of horsepower and what they can get for mpg with there foot out of it. My plan is a 90-100 cc pump, wicked wheel, studs and inter cooler hoping to get around 250+ wheel horsepower.

 

[saburai]

Welcome to the idi world and the forum! Give us some more details on your truck. Mileage? Auto? 4x4? Dualy? Cab? Tire size if not stock?

 

[Clb]

Fwiw
my bone stock 93 idit (58k original miles) wont break 14

 

[firehonomichl]

If it’s running rough run some hotshot diesel extreme thro it. Mine was having smoky starts idling rough and poor fuel mileage. I ran a bottle of that thro it and put the oil additive in and went for a drive. Thing runs great now I changed my fuel filter. Mines an 88 extended cab 4x4 5 speed and I’m getting 15 mpg in town. I drove it to Billings Montana and was getting 18 mpg mines bone stoke! For now lol

 

[DAXTY88]

Welcome to the idi world and the forum! Give us some more details on your truck. Mileage? Auto? 4x4? Dualy? Cab? Tire size if not stock?

i just edited my post and added info, Thankyou

 

[DAXTY88]

Fwiw
my bone stock 93 idit (58k original miles) wont break 14

wow I’m sure you could definitely do better all my past IDI’s did with stock na pumps and added turbos fuel screw maxed out still could get 15 driving easy

 

[lotzagoodstuff]

Have you set the timing on your current pump yet? I’d set the timing, run a filter full of ATF and then a high dose of Hot Shot, and then get a good baseline. 11 mpg sounds a little low, but not really with a E4OD and 35” tall tires (especially if the tires are wider than stock). My old red and white normally aspirated truck was set up similarly and fuel quality (read cetane additive) and throttle quality (read don’t drive faster than 63 mph on my uncorrected speedo) had a vast difference on fuel mileage.

Get timing set and a good baseline, but I wouldn’t expect much better than 14-15 with new injectors and a pump. The taller tires, 4.10s and automatic are all working against your quest for better mpg.

 

[jrollf]

My 1993 F350 Crew Cab Dually 7.3 IDIT with a Classic Diesel Design 90cc pump, and a Banks Sidewinder Turbo (gen 2 waist gated). (All else is stock). 5spd Manual transmission. 4.10 rear end. LT 235 85r16 tires.

If I drive nice ~65mph I get around 12.5 to 13 mpg highway.

Towing 8,000lbs, relatively flat ground 8 to 9 mpg.

Sent from my SM-N960U using Tapatalk

 

[Big Bart]

Non-turbo, 7.3, C6, 2wd, stock tires, timing 8.5btdc, red mark on speedo at 55mph lol, and I believe a 4.10. (65mph at 2,750rpm.) I average about 12mpg all in not towing. So guessing 13mpg hwy and 11mpg in town. Best mileage is 45mph in third on the hwy due to traffic. Probably 14.5mpg at that speed.

Would imagine a zf5 would get me another 2-3mpg on the hwy to lotzofgoodstuffs point.

These where not designed for doing 70-80 at 15-18mpg like they do today. (4, 5, and 6 speed trannies.) They were made to pull hard and tow slow when we were a 55mph limit nation. I use mine mainly for towing and Home Depot runs. So being a little slow on the hwy has not been a issue for me. If it was a daily driver I might be looking to add a overdrive.

Either way when dialed in these are great trucks!

 

[saburai]

"Either way when dialed in these are great trucks!"

They sure are!

 

[jrollf]

...
These where not designed for doing 70-80 at 15-18mpg like they do today. (4, 5, and 6 speed trannies.) They were made to pull hard and tow slow when we were a 55mph limit nation.

This is very apparent in my truck. It's amazing how much quieter is it 55 miles an hour versus 65 in the cab. And how much smoother it feels. My truck really likes 55 to 60 miles an hour.

Sent from my SM-N960U using Tapatalk

 

[IDIBRONCO]

I'll agree with the ATF/Diesel Extreme treatments. Then I would also agree having the timing checked with the fuel system parts that are on it right now. Unless you know for absolutely certain that one or the other is fairly new, the pump and injectors should be replaced as a set. They wear out at the same rate. You'll get the best performance (both power and mileage) from having the same amount of miles on all of them.

 

[IH-GM IDI]

Mines a 94 IDIT crew cad LWB with E4OD 4.10's and 32.5's I run 50/50 diesel atf on filter changes and a monthly bottle of diesel extreme. 16-18 on highway running 70mph about 2000rpm. With the banks down pipe you can really feel the power band between 1800 and 2400 rpm so I usually run in that and try to keep out of the chug-a-lug zone below 1800 were volumetric efficiency isn't quite working to its full potential

 

[silexis]

I recently switched from Rotellla 15w40 to a synthetic chinese Sinopec 15w40. Was getting around 16-17mpg now getting 18-20 mpg. 4.10 rear and 5 spd, but have Gear Vendors overdrive and doing a pretty easy backroad non-hilly commute w/avg speed around 45mph in 5th. On the highway, I'm getting 16-17mpg unloaded. The worst I ever got was pulling a light boat with a lot of surface area into strong headwinds at 75mph on a 100 degree day: 10mpg. I'll probably send in a oil sample to Blackstone in 1000 miles to see if the oil is working.

 

[The_Josh_Bear]

wow I’m sure you could definitely do better all my past IDI’s did with stock na pumps and added turbos fuel screw maxed out still could get 15 driving easy

My details are in my signature.
I get 14 mpg doing 75+ on our freeway in a very hilly area. Mostly freeway with some city driving. These 33" mud snow tires are not helping. They look good but one is out of round and even with beads it's no good.

From what I've experienced you won't gain MPG from a turbo+hotter pump+CAC. You end up using the power to drive like a normal vehicle instead of like a grandpa.
And from what I've read you won't gain a lot with a wicked wheel upgrade, I can think of 2 guys that did it and they got 1mpg better that was reported.

The biggest MPG gains are driving slower, timing, gearing, hills, wind, etc. But then you jam the skinny when nobody is around because IT'S FUN and then lose 2 days of grandpa driving benefits lol.