Need opinions of my injectors (those with larger injector experience please look)

[monster50iii]

I have 200k miles on my rig. Injectors have never been out, and my balance rates are great. Worst one is a -1.9. Most are under +-1.0. Truck seems to run good, but my mpg towing sucks. I can hardly get over 8.5-9mpg. Its been this way for a long time, but seems it may be getting a bit worse with time. My dilemma is I have a set of DDP +20% LBZ nozzles ready to put on. I cant decide if its a good idea to swap nozzles, as the injectors seem good, or if I should replace them. I don't want to spend money to have them tested, just to get bad news and spend more money on a new set. And IF I get new injectors, where do most find the cutoff to be where the larger sizes start yielding worse mpg? Of course tuning makes a big difference, but putting that aside and just focusing on the size of nozzle where is the cutoff? This can is more of an opinion, but please share!

P.S. I can get 18-19mpg empty at 60, but my mpg has always stunk even at 70...drops to 16-17 easy even on stock tires.

 

[gmduramax]

You have to have something else going on. That’s terrible mileage. The 20% tips are a waste of time you should do at least 60’s. I never noticed a drop in mpg with 100’s

 

[monster50iii]

That towing mpg was traveling at 75mph, towing 14k roughly. And I agree with you, I would expect to get atleast 10. Balance rates dont give much insight of course. Hence why I'm debating new injectors.

That's interesting info on the 100s. I was worried about mpg tanking if I went too big. I like the idea of backing the tune off with bigger nozzles. I tried doing abunch of searching but I found mixed feelings. Think a NEW set of injectors are worth it on a 200k rig or remans?

 

[zakkb787]

That towing mpg was traveling at 75mph, towing 14k roughly. And I agree with you, I would expect to get atleast 10. Balance rates dont give much insight of course. Hence why I'm debating new injectors.

That's interesting info on the 100s. I was worried about mpg tanking if I went too big. I like the idea of backing the tune off with bigger nozzles. I tried doing abunch of searching but I found mixed feelings. Think a NEW set of injectors are worth it on a 200k rig or remans?

Have you checked the rest of your fuel system and main rate and all that already? Like you said balance rates don’t tell a lot.

 

[monster50iii]

I haven't really.. My rail pressure runs at desired, and it starts pretty decent in the cold yet. There really aren't any issues that stand out at all. I'm sure my cp3 is getting tired, I'm not really sure if that could cause a loss in fuel efficiency. I'm sure it can if bad enough, but I can get close to holding rail on a 3000us tune. And that's calling for 198-199mpa. The other night I started it to warm up, and after a few minutes there was a bit more ticking going on the RH side of the engine vs the LH side. Once the engine warmed up it wasn't noticeable. But while it was warming up it was pretty easy to hear a good difference side to side.

As far as main rate what are you asking? I watch my calc fuel rate at all times, its just a habbit for tuning purposes for me. All looks normal there. Idles in the 8-11mm3 area at idle when warm.

I think I'm going to see if DDP will take the nozzles back and buy some LBZ 60% injectors and go that route.

 

[clrussell]

Honestly mileage doesn’t seem extra terrible towing 14k running 75.

What kind of trailer? Race trailer?

What’s your exact set up?

 

[Bdsankey]

I have 200k miles on my rig. Injectors have never been out, and my balance rates are great. Worst one is a -1.9. Most are under +-1.0. Truck seems to run good, but my mpg towing sucks. I can hardly get over 8.5-9mpg. Its been this way for a long time, but seems it may be getting a bit worse with time. My dilemma is I have a set of DDP +20% LBZ nozzles ready to put on. I cant decide if its a good idea to swap nozzles, as the injectors seem good, or if I should replace them. I don't want to spend money to have them tested, just to get bad news and spend more money on a new set. And IF I get new injectors, where do most find the cutoff to be where the larger sizes start yielding worse mpg? Of course tuning makes a big difference, but putting that aside and just focusing on the size of nozzle where is the cutoff? This can is more of an opinion, but please share!

P.S. I can get 18-19mpg empty at 60, but my mpg has always stunk even at 70...drops to 16-17 easy even on stock tires.

I'm wondering if you couldn't benefit from a revised tune/different tuner. These trucks are picky in terms of what RPM they are most efficient at and each one seems to be different.

Honestly mileage doesn’t seem extra terrible towing 14k running 75.

What kind of trailer? Race trailer?

What’s your exact set up?

I'm with you on this one. Grossing 24k my LB7 averaged 10.2mpg from Wisconsin to Colorado and back at cruise speeds from 75-85 with a gooseneck. If you have a large enclosed trailer I could see the mileage definitely going down.

 

[DAVe3283]

Does your truck still have the DPF? I know the LB7's always got the best mileage, but yours does seem low to me. Not crazy low, but lower than I would expect. Towing the same weight at the same speed, I get 10.5+ MPG, and it jumps to 12+ MPG if I drop the average speed closer to 70.

This is on an open deck trailer with a tractor and some junk on it. If your trailer is enclosed, then honestly, that MPG is probably about right.

Your empty mileage is pretty good if you still have a DPF, and not too bad if not. I get about the same on my LB7, but on larger tires.

Finally, I agree with the guys on here: don't bother with anything less than +50-60% injectors. My last set of injectors were +60%, and they were a cakewalk to tune. Now running SAC75% injectors, and those aren't too bad to clean up either. For your truck, I would say +60% would be great.

 

[S Phinney]

60 to 100 overs work fine. Towing heavy and big injectors doesn’t seem to last as long either if you’re running the temps up high b


Sent from my iPhone using Tapatalk

 

[Dozerboy]

Heck I’ve never got any better then 10mpg pulling a bigger trailer on my LBZ. God my last trip with the camper I mentally blocked out whatever mpg I was getting it was so bad. I’m thinking new 100 overs are coming soon as my balance rates ain’t that good.


Sent from my iPad using Tapatalk

 

[monster50iii]

60 to 100 overs work fine. Towing heavy and big injectors doesn’t seem to last as long either if you’re running the temps up high b

How so? If anything I would think itd be easier on the engine. Less pulse, less timing. I havent had any luck at controlling pilot quantity at all so not sure how that's going to over. I can add pilot but theres a limiter that stops me from pulling any away in cruise range etc. I'm sure someone like Kory has found the tables to control it for himself. Maybe he would share these tables now?

 

[S Phinney]

How so? If anything I would think itd be easier on the engine. Less pulse, less timing. I havent had any luck at controlling pilot quantity at all so not sure how that's going to over. I can add pilot but theres a limiter that stops me from pulling any away in cruise range etc. I'm sure someone like Kory has found the tables to control it for himself. Maybe he would share these tables now?

I’m talking about durability of the injector. Larger you go you have less materials from the extruding and high temps make them less durable. That’s for heavy towing. Tuning isn’t a problem. I was talking about parts life.


Sent from my iPhone using Tapatalk