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MPG loss from changing injectors


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Ok I changed my injectors a few years back thinking they were causing my surging problem when towing. I think it ended up being alternator with excessive ac noise. The injectors I had were 8 holes and said bosh on them, I didn't know any better thinking they were stock I got a set from DAP that are 60hp thinking I'll be gaining some hp and mpg, And actually lost hp and mpg. And when talking to DAP they said that my injectors were not factory and couldn't use them as core so it costed me another $150, and I asked for my old injectors back and instead of my old ones they sent me another set of theirs that were new and said 75hp on the bag. So I guess I got another set of injectors for $150 that's nice but they are not 8 holes that I gave them.  The ones in the truck now are still 60hp and from beginning I noticed a bit more smoke not much, but towing egt's are now higher and mpg went from 20 on hwy to 17, and 15 towing to 12.5 or so. I tried different speeds and power levels on quad, but the highest I can get out of it is about 17-17.5 empty. When I asked DAP what size were my old injectors they said about 75 hp and that's the reason for them sending me a set of 75hp. So I guess my question is do 8 hole injectors work better even though they were bigger I did 3 mpg better and had more power and less egt. Who makes a good 75hp 8 hole injectors as I'm getting ready to pull these out. Unless my vp is getting old and mpg is going down, but I noticed it right of way when changing injectors. Maybe I'm crazy, but always hand calculate my mpg and usually not that picky of mpg on a truck but I was trying to make it better not worse.  

Edited by Dieselfuture
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8 hole was likely giving you better mileage because it atomizes the fuel better. 7 hole don't atomize as well but usually make more power. That's why the 6x.013 is pretty popular in the performance world

I have no idea who makes a set of 8 hole though....

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Maybe I got more things going on then just injectors, but I know for a fact that I lost some mpg, like I said before it's not a huge deal for a truck I don't use much but I wish I could figure out what I'm doing different to lose almost 3mpg. I tried my quad on level 1 which is supposed to be best mpg and drove 200 mile round trip going 60-65 and got 17.3 mpg empty, then I tried level 5 on a 150 mile round trip 60-65 mpg and got 16.1 mpg, then I tried level 7 another 150 mile trip same average speed and got 15.8 so it seems consistently getting lower the higher level I use. I have not tried 55 mph on any level as I don't have that much patience. I did tow our boat 200 ml one way on level 0 which is factory setting and got 13.6 mpg and on the way back had it on level 5 and got 12.5 mpg power was noticeably better but lost 1 mpg not a big deal. But I can't get my 20 mpg I did before switching injectors and that was done with 65-70 mpg on different occasions. Maude I need to plan on getting somewhere an hour later and try 55mph, according to Mike and other people that's where mpg is at, but my lieometer even though it's off by about 3-4 mpg still tells me that going 55 is less mpg then going 65.  

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55-60 MPH

Edge Comp set on 5x3 with +50 Injectors

This will net roughly 22-23 MPG fairly easy.

I'm going to give it a shot and see what happens, but how come before i was able to get 20mpg at 65-70, the only other thing i can thin of is my home made front bumper is not as aerodynamic as the original was, and another 150 lb heavier. One more thing i changed are tires but went to a size smaller for better mpg and take offs with my 3.55 gears. So if anything my speedo should be counting more miles per gallon. I heard that when vp's get tired they waste more fuel, so would that mean it doesn't compress it as good and it's not atomizing as good? 

Also where do you keep your rpm closer to 1800 where the torque is?

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No. At 55 MPH it down to 1689 RPM's.  Which is better for MPG but then when I need torque I can down shift and it puts me roughly at 2k of the tach. Excellent torque for steep grades. Where I'm at in Idaho the average speed limit is 45 MPH to 65 MPH. All local towns are 25 MPH. Then all residential is 15 MPH.

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what speed do you se 22 mpg at, and what level on tuner.  I'm starting to think my vp is wearing out, but it's still seems to run well. 

I am usually at 65-70 and run 5x3 on the edge.

 

Took a while to comment something funky was going on with this site.

Edited by gh0stman
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