6.9 fuel economy after turbo add and fuel screw increase

[gretatuneberg]

Just put a factory ATS turbo on my 86 6.9 with c6, 3.54 diff, 3" exhaust, running waste veg oil diesel blend.

I turned up the IP fuel screw almost a full turn.

Gray haze at WOT. No coal rolling.

Still not getting much better than 15mpg.


If the fuel screw is turned up too much, could I be wasting fuel, even though it's not smoking?

I typically drive 90-105km/h on the highway (60mph).

Would love to see closer to 20mpg.

 

[BlindAmbition]

A turbo won't give you more MPG, but it'll make better use of the fuel you're already burning via improved power. Best thing you can do is swap out that C6 for a ZF5 if you want mileage.

 

[Nero]

To answer your question about the fuel screw, the exhaust may still be clear, but keep an eye on your egt's, the higher the screw is thr faster you'll hit peak temps.

 

[Kevin 007]

Yes, under towing or high altitude situations, that's when you'll see a bit of an improvement in MPG with a turbo compared to N/A, but day to day putting around you won't notice much.

 

[XOLATEM]

Wait a minute...is your odometer calibrated for miles or kilometers...?

How are you calculating your 'miles-per-gallon'...?

I am totally ignorant of the instrument panels and guages that are available in Canada...

As an aside...I am planning to do the same thing you did...put an 093 on a 6.9 and I am particularly interested in how it works out...

So...please pardon my 'dumb' question.

Thanks...

 

[Old Goat]

That slipamatic C6 is your problem.
Even a T-19 4-spd you will do better.
Last Saturday drove from here in Nevada, 4 - 5K ft range over to Santa Cruz, Ca.
going over the Sierra 8K ft and down to seal level and back, Over 500 miles.
got 18.8 mpg.
2 tanks before that putzin around here was in the 15mpg range. Not sure why,
maybe the fuel I got? Winter fuel usually less mpg compared to summer fuel
where I can get to 20mpg.
Pretty same truck as yours except for the manual gear box, and NA.


Goat

 

[gretatuneberg]

Wait a minute...is your odometer calibrated for miles or kilometers...?

How are you calculating your 'miles-per-gallon'...?

I am totally ignorant of the instrument panels and guages that are available in Canada...

As an aside...I am planning to do the same thing you did...put an 093 on a 6.9 and I am particularly interested in how it works out...

So...please pardon my 'dumb' question.

Thanks...

It's in km but I do the conversion to US MPG for this forum. I always do a calculation based on distance travelled vs fuel added.

The ATS kit seems alright if the price is decent. Installation isn't too hard. There are factory instructions online in one of the forums. I noticed a fair power increase with no exhaust on which was reduced slightly with the addition of a free flowing 3 inch exhaust. Haven't tested it towing yet. Am looking to get my gauges set up next.

 

[BlindAmbition]

What is your timing set to?

 

[KansasIDI]

Wait a minute...is your odometer calibrated for miles or kilometers...?

How are you calculating your 'miles-per-gallon'...?

I am totally ignorant of the instrument panels and guages that are available in Canada...

My 91 F-Super Duty was from Canada originally, has a metric speedometer and odometer. I just convert it to miles in my head while driving, not difficult, for me at least.

Fuel mileage, I just do the math at the fuel station, and I always reset my trip meter when I get fuel in that truck.

That truck is extremely heavy, so my fuel mileage is terrible, also it is detuned/derated alot, I am pretty confident that it’s the slowest truck that I have ever driven…

I love everything about pulling trailers with it, except the lack of acceleration… the brakes are awesome, handles turns great, doesn’t squat at all with 15k bumper pull trailer.

Needs a turbo… but I use the truck all day every day and have tons of other projects going on when I do have time… getting the air conditioning fixed early next week, that in itself is gonna be a mess…

I have an ATS 088 kit that I’d like to put on it, I’ll get to it eventually… but I’d really way rather have a Hypermax kit on it… I absolutely love the one on my 86… can’t seem to find many of those out there, unless I bought a new kit, but that seems unnecessary since I have a complete good 088 kit sitting on the shelf in my shop…

Sorry to go off on a tangent

 

[KansasIDI]

As an aside...I am planning to do the same thing you did...put an 093 on a 6.9 and I am particularly interested in how it works out...

I sure hope you put head studs on first…

 

[WrenchWhore]

I agree with @Old Goat. That C6 is going to kill your mileage potential by at least 2 MPG IMO from a T19 and close to 5 MPG if you had a ZF5. I have a similar truck with NA 6.9 4x4 3.54's T19 and 35's. I was calculating about 16 MPG highway (60-65 MPH) and then got about 17.5 MPG after a set of injectors from R&D. My new refurbished motor I just put in 7.3 with 093 turbo (fuel turned up 3 flats) 3"turbo back downpipe to 4" straight pipe. I was anywhere from 14.5 - 17 MPG BUT its pretty smokey under WOT. More gray haze then black. I definitely need to check timing and probably turn down the fuel. The higher 17 MPG's I got was with cruise set at 60 MPH.