he600wg turbo for cm870

[Konstantin]

Hello, I also read couple of articles about cars which claim that wastegate turbo is better for mpg. I have an old truck with cm870 and thinking of experimenting with turbo setup. Yes, I am aware of engine brakes , where I drive I don't really use them often. HE600wg is what I was thinking about. What are your thoughts? Will mpg suffer or stay same or be terrible. Right now I get around 6.6 mpg driving 65mph.

[Rawze]

going from a VG turbo to a non-gt turbo will cost you a LOT of fuel milage. The optimum fuel-air mix for the ISX goes to s$it when you do this.

Also, the bigger the turbo, the lower the fuel milage will be overall due to having to spool up a much heavier turbine.

stop listening to the idiots over on socal medai... they will steer someone down the wrong road in a hurry.


you want to save more fuel.. learn to drive by your boost and pyro gauges and learn to not press the fuel pedal so hard up the hills. No amount of modifications can can beat how the person drives their truck when it comes to fuel savings.

[Konstantin]

(06-28-2022 )Rawze Wrote:  going from a VG turbo to a non-gt turbo will cost you a LOT of fuel milage. The optimum fuel-air mix for the ISX goes to s$it when you do this.

Also, the bigger the turbo, the lower the fuel milage will be overall due to having to spool up a much heavier turbine.

stop listening to the idiots over on socal medai... they will steer someone down the wrong road in a hurry.


you want to save more fuel.. learn to drive by your boost and pyro gauges and learn to not press the fuel pedal so hard up the hills. No amount of modifications can can beat how the person drives their truck when it comes to fuel savings.

Thank you! I had an impression that cm870 is not as precise control as cm871 and therefore they are inferior and can be changed to waistgate without much sacrifice, but maybe I was wrong.

[Rawze]

(06-28-2022 )Konstantin Wrote:  ...
Thank you! I had an impression that cm870 is not as precise control as cm871 and therefore they are inferior and can be changed to waistgate without much sacrifice, but maybe I was wrong.

You are correct on that. it is not as precise.. and a bit on the wonkly side as the turbo gets old.. but it is still superior by far vs. a mechanical turbo.

You know there has been a person or 2 in the past, who swapped out their CM870 ecm and wiring harness to a CM871 ecm + harness so that they can run the newer electronic VG. This does in fact help them quite a little bit from what I understand. I think maybe even 'running rough' did this to one of his trucks too.. so maybe u can ask him about how it turned out>? .. but I don't think he did it for fuel mileage though.


(just the beer talkin')...
- Who knows.. maybe I could break high 9's with a 400-series turbo setup like that, as I already do low 9's and high 8's regularly w 80,000lbs in the box.


If i wanted to go for all fuel mileage on an ISX and keep the power range to something reasonable.. I would have a CM871 (or cm870 w cm871 turbo and ecm) and have one of the newer 400-series turbos adapted to it. That would be the best setup someone could get for fuel mileage but the power range would only likely be about 485 HP or so... which would be fine by me, as that is all my truck is set to any ways.

[Konstantin]

Thank you very much for thorough explanation! I will think about it. Meanwhile will contact that guy, it is very I terested how his mods turned out.