Turning up the mechanical pump

[dds92780]

Sooo, i found a guy that said he could turn up my pump by turning the screw and moving the rack forward more and weakening the spring on the aneroid valve for 150 dollars with it all on the truck if i drive there. He has been in business for 30 years and i heard a ton of good things about him. He said that i would be very happy when he is done with it.

I currently average 5.7mpg in the last 20 days and on some of those days i got over 6. Yesterday i got 6.5! I do mostly 18 wheeler dump work where i gross 72k and have stop and go traffic. I wonder what it will be when i get all that done. I heard that its best to have a turned up pump so you don't have to wait for boost to build up as long thus making the pyro temps lower. I usually never go over 825 or 850 on a long hard pull and get close to 30 psi of boost, have seen 32 in winter.

A little history too - (I had my pump rebuilt 6 months ago at midwest fuel injection bolingbrook and the shop said they could only put it on the high end of spec which i have no clue the number is maybe 365 or so right now) So i feel a pump hot rodder guy is the way to go...

So even if the boost builds quicker it will probably never exceed 32 psi because i wouldnt be changing the turbo or injectors, (injectors were rebuilt last year too)

Just to be clear ( i am the only driver of the this truck and i own it) (E7 350 mechanical with 442 rears) (Truck has 370k on it now)

I feel by turning up the pump more, i would be benefiting from it and maybe using less throttle, looking out my window to see if smoke comes out the stack and lay off on it, but when i want the power its there for hills and just to get better mpg maybe? Does anyone see anything wrong with this or is my way of thinking on this seem to be correct?

I also am not trying to make this a tractor pull truck, just give me a little better mpg if possible, get the turbo and torque to come on a little sooner and maybe hopefully keep up evenly with a 427 or so, Ok lets here your feedback and maybe tell me if you have done it yourself and what results you got. Thanks a bunch to my mack bulldog family!

[brutus998]

I would especially if you are going to be the daily driver on it. Watch your EGTs. You could actually benefit from a holset turbo and a size over injectors will make it run a lot better and get great mpg

[Superdog]

I have a set of takeout E7-400 injectors I'd sell really reasonable if you are interested.

[dds92780]

How would getting bigger injectors help vs just turning up the pump? And wouldnt having bigger injectors making it spray more meaning i would use more fuel? Could you please explain?

[felicello122]

turning it up will make a big difference if you are stock now, like brutis said keep your pyro below 10 and you will pass a 427.

[rsb502]

Adding bigger injectors helps the fuel system run more efficiently, with a turned up pump and bigger injectors it will make more power and therefore you use less throttle, less throttle=less boost and that equals better fule mileage. I had one cranked way up in the past and I got better mpg when I got done because I wasnt holding the throttle down to maintain speed I could lug it around and it would pull the hills a gear higher and 300-500 rpm lower making better mileage and running cooler.

[oilburner]

If it doesn't have a pyrometer in it you will need one, drove a 300 mack once that was a dang hot puppy and had to keep a eye on it.