Fuel rail pressure

2004LB7

Super Moderator
Staff member
Dec 15, 2010
8,551
3,058
113
Norcal
So far, I’m running a stock turbo and probably will until it gives out. i’ll probably just go with the 30 overs then in the long run I think it will be best. Also, they’re cheaper than the stock ones currently. The biggest thing I’m running into is finding guys for tuning. I know guys who will do it, but I’m not quite sure where they get their tunes from, which would be nice to know. The ideal tune I want would have minimal horsepower, would work great with 30 overs, and also would have a special feature in it that would stop exhaust gas from leaking into my engine. Also, I guess I’m not completely sure how much tuning you need for 30 overs or if you can just put a normal 40 horse tune on and call it good. just some of the questions I’m having.
You might be better off learning to do it yourself. What you're asking for should be easy to learn compared to higher HP tunes. All the information on learning how to do it is throughout this and other forums. Loads of threads discussing tuning. Just start reading
 

PureHybrid

Isuzu Shakes IT
Feb 15, 2012
3,886
800
113
Central OH
Kennedy must be living in the past. Lots of shops would tell you to run 100% over for 600hp goal. If you're going to keep it at a lower tune 9/10 and just have something spicy for showing off then a smaller injector won't hurt. But on the flip side there are no negatives to running a large injector either
 

Bdsankey

Vendor
Vendor/Sponsor
Feb 1, 2018
4,817
1,862
113
Larsen, Wisconsin
So far, I’m running a stock turbo and probably will until it gives out. i’ll probably just go with the 30 overs then in the long run I think it will be best. Also, they’re cheaper than the stock ones currently. The biggest thing I’m running into is finding guys for tuning. I know guys who will do it, but I’m not quite sure where they get their tunes from, which would be nice to know. The ideal tune I want would have minimal horsepower, would work great with 30 overs, and also would have a special feature in it that would stop exhaust gas from leaking into my engine. Also, I guess I’m not completely sure how much tuning you need for 30 overs or if you can just put a normal 40 horse tune on and call it good. just some of the questions I’m having.
Personally, I think Kennedy is stuck in the past, as that is not something anyone recommends today. He's a smart guy but I do not share his opinion.

As for injector sizing, I wouldn't run anything smaller than a 60% if you're going above stock output, as 30% doesn't really gain you anything.

How do you want to use the truck? What elevation do you live/drive at most? What else is done to the truck? What are your goals for the truck?
Kennedy must be living in the past. Lots of shops would tell you to run 100% over for 600hp goal. If you're going to keep it at a lower tune 9/10 and just have something spicy for showing off then a smaller injector won't hurt. But on the flip side there are no negatives to running a large injector either
Bingo! For a 600whp goal I would go to a 60% at minimum but the customer who wants 600whp usually wants more later which is why most shops will go to a 100% as there is minimal downside (if any) at that point.
 
Last edited:

BM06lbz

Member
Feb 11, 2026
40
6
8
coon valley, Wisconsin
That all sounds great yeah I’m at 1000 for elevation here in Wisconsin. I haven’t done really any major upgrades to my truck besides just some random small stuff like ported valve and fuel plug. Also, I did the transgo Junior kit and an exhaust. Right now I just want a decent small tune, but if my tranny ever goes and I get a built one then I would like to run 500 horse , and also still be able to tow with it. The thing that keeps me from getting bigger injectors is the tuning and technically I can run 30 overs without tuning right away
 

Bdsankey

Vendor
Vendor/Sponsor
Feb 1, 2018
4,817
1,862
113
Larsen, Wisconsin
That all sounds great yeah I’m at 1000 for elevation here in Wisconsin. I haven’t done really any major upgrades to my truck besides just some random small stuff like ported valve and fuel plug. Also, I did the transgo Junior kit and an exhaust. Right now I just want a decent small tune, but if my tranny ever goes and I get a built one then I would like to run 500 horse , and also still be able to tow with it.
I'm in WI as well (Fox Valley area here). While I'm not a fan of rail plugs, they do work to solve a weak FPRV. The Transgo Jr definitely helps them hold a little bit of extra power and increases life on a small tune if the trans is healthy to begin with.

Sounds like you've got a pretty solid roadmap to your build!

The thing that keeps me from getting bigger injectors is the tuning and technically I can run 30 overs without tuning right away
Personally, I don't agree with this statement. Most shop owners don't agree with this statement. If you're going to run an oversized injector, you really should install a proper tune for it. Have guys gotten around it? Sure, but it's not anything a shop will ever do.
 

BM06lbz

Member
Feb 11, 2026
40
6
8
coon valley, Wisconsin
I'm in WI as well (Fox Valley area here). While I'm not a fan of rail plugs, they do work to solve a weak FPRV. The Transgo Jr definitely helps them hold a little bit of extra power and increases life on a small tune if the trans is healthy to begin with.

Sounds like you've got a pretty solid roadmap to your build!


Personally, I don't agree with this statement. Most shop owners don't agree with this statement. If you're going to run an oversized injector, you really should install a proper tune for it. Have guys gotten around it? Sure, but it's not anything a shop will ever do.
I called a diesel shop yesterday and sounds like they’ll incorporate what I want into a tune including tuning for 45 overs.Also yesterday I pulled my fuel tank and cleaned it out. As you can see in the picture I’ll attach,the fuel sending unit has some flaky rust/sludge on the metal surfaces. When I cleaned my fuel tank out, there was quite a few rust specs in the bottom of the tank. i’m guessing this is normal and most guys just don’t know about it, and trust the fuel filter to do its job? Or is it something I need to be worried about and buy a new fuel sending unit.
 

Attachments

  • IMG_2799.jpeg
    IMG_2799.jpeg
    301.3 KB · Views: 10
  • IMG_2782.jpeg
    IMG_2782.jpeg
    190.7 KB · Views: 10

2004LB7

Super Moderator
Staff member
Dec 15, 2010
8,551
3,058
113
Norcal
I called a diesel shop yesterday and sounds like they’ll incorporate what I want into a tune including tuning for 45 overs.Also yesterday I pulled my fuel tank and cleaned it out. As you can see in the picture I’ll attach,the fuel sending unit has some flaky rust/sludge on the metal surfaces. When I cleaned my fuel tank out, there was quite a few rust specs in the bottom of the tank. i’m guessing this is normal and most guys just don’t know about it, and trust the fuel filter to do its job? Or is it something I need to be worried about and buy a new fuel sending unit.
That is from water in your fuel.

I've inspected both of my trucks and they where spotless inside. What filter are you using? Is it a coalescing filter?
 

2004LB7

Super Moderator
Staff member
Dec 15, 2010
8,551
3,058
113
Norcal
I prefer the Racor PFF50216 with the coalescing media inside. Are you able to inspect yours to see if it has it? It appears from a little googling, that TP3018 may or may not have it depending on versions, dates and manufacturer

If it doesn't, that might explain why you have rust in your tabk
 

Bdsankey

Vendor
Vendor/Sponsor
Feb 1, 2018
4,817
1,862
113
Larsen, Wisconsin
I prefer the Racor PFF50216 with the coalescing media inside. Are you able to inspect yours to see if it has it? It appears from a little googling, that TP3018 may or may not have it depending on versions, dates and manufacturer

If it doesn't, that might explain why you have rust in your tabk
This is the filter I stock at my shop for the same exact reason. For ages Racor made the TP3018 but when the LML came out they switched manufacturers. I do not know who makes them now.
 

Dozerboy

Well-known member
Jun 23, 2009
5,088
682
113
TX of course
I've had worse than that in my tanks, but I've fueled up out of drag up tanks. So I kind of expect it. I do run good dual fuel filters because of that.

You might look at 1 of our supporting vendors like Brad for injectors. Not sure if you were gonna use LDS or not but I hear their service is gone downhill from where once was.
 

BM06lbz

Member
Feb 11, 2026
40
6
8
coon valley, Wisconsin
Kind of late I guess as I’m picking them up this afternoon. it seems like a stock injector is a stock injector no matter where you get it from but maybe I’m wrong. maybe i maybe it’s the difference who bores them that makes the quality. Also, it seems the reviews are pretty good as well.
 

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
16,914
3,418
113
Mid Michigan
Kind of late I guess as I’m picking them up this afternoon. it seems like a stock injector is a stock injector no matter where you get it from but maybe I’m wrong. maybe i maybe it’s the difference who bores them that makes the quality. Also, it seems the reviews are pretty good as well.
You are definitely wrong about the bolded. As for oversize, yes it matters who makes them.
 

PureHybrid

Isuzu Shakes IT
Feb 15, 2012
3,886
800
113
Central OH
Genuine Bosch reman / new SHOULD be equal no matter the place. But obviously there's lots of shady dealers or shops selling garbage in nice Bosch boxes. As far as oversized nozzles I'd say you can count on one hand the number of injector builders who have the equipment comparable to an OEM to properly test after modifying. Exergy, S&S, Dynomite, Dan's Diesel. Not sure who's doing injectors for Lincoln Diesel anymore
 

Bdsankey

Vendor
Vendor/Sponsor
Feb 1, 2018
4,817
1,862
113
Larsen, Wisconsin
Genuine Bosch reman / new SHOULD be equal no matter the place. But obviously there's lots of shady dealers or shops selling garbage in nice Bosch boxes. As far as oversized nozzles I'd say you can count on one hand the number of injector builders who have the equipment comparable to an OEM to properly test after modifying. Exergy, S&S, Dynomite, Dan's Diesel. Not sure who's doing injectors for Lincoln Diesel anymore
This I don't know.

I had a customer here locally drop his set of 45% injectors off at LDS (they were LDS injectors). They had to send them out to be turned into 150%. I can understand maybe not having a wire EDM in-house if QC on incoming parts is awesome BUT that would've meant he should've been charged for new nozzles, put on their flow bench and calibrated, then returned to the customer in a day or two not a week+ (especially when you tell the customer it'll be fast).


This has me wondering a few things...
 

BM06lbz

Member
Feb 11, 2026
40
6
8
coon valley, Wisconsin
So I pulled my lower valve covers off to check valve lash. Just had a question when I put valve covers on, is it fine if I buy new bolts that match my old ones at a hardware store or is it special kind of bolts they take. my old bolts should still work as well. but I figured why not buy new if I can get them pretty easy?