If you want to keep a diesel running cool it needs to have good air flow through the engine. I would recommend getting a boost and pyrometer gauges to be safe. If you don't like the A pillar pod mounts PPE makes an overhead console mount thats pretty slick.

As for the PPE tuner I would go with the PPE economy and run it on level 1.

While you are replacing the injectors you could replace the drivers side exhaust manifold with one for a 2011+ LML diesel engine. It doesn't have the big kink cast into it and will help the front 3 cylinders on the drivers side breath as good as the other 5 and will help the turbo spool a little faster. It would also be a good time to port match the turbo inlet elbow to free up some air flow and its supposed to help it spool faster and keep the EGTs down a bit.

I would get a PPE boost valve too. On a 40 hp tune its not going to have a huge effect but it should still get the boost up closer to 28-30 psi from the stock 18-20 psi and clear up any smoke, build a little more torque and hp and keep the EGT's cooler.

Exhaust is up to you. AFE is supposed to fit the best. I've installed a few and they weren't bad and had the most stock like fitment. I've got a Diamond Eye QT on mine and its fairly quiet but not as quiet as I thought it would be. 4 inch is plenty. 5 inch is overkill for what you're doing and isn't worth the extra cost.

I could be way off but thats what I would do. Add a little 40 hp tune, add some boost, keep the air flowing freely through the engine and drive it sane. The Allison should do just fine but keep it in tow haul. Everyone here seems to slip the Allison on the 4-5 upshift but I got mine running too powerful of a tune rolling into the throttle in 5th gear. Once the torque converter locks the line pressure drops roughly 100 psi and the holding power goes out the window. The 5 speed Allison is good for an extra 100 hp over stock so you should have you a good 50 hp buffer zone to work with. A good healthy Allison like yours is a perfect candidate for a transgo shift kit but it requires removal of the transmission on the 5 speed Allison.

 

Trpshoot,
I would put and EGT and Boost gauge on, especially when towing. I have the PPE boost valve installed and use the Dr. performance predator tuner run on towing, which is 65 hp. You do have to be careful when towing even with a lower setting, I will limp my trans in OD if I let the engine hit its torgue peak when toeing my 5er up a grade, have to kisk it down to drive and everything is fine. You will be suprised at the increase in power from the new injectors.
Frank

 

I would suggest going with Lincoln for injectors also.
Where I got mine, I would also agree about Brent great guy from what I delt with him.

The idea of a tuner worries me with a stock trans. Even a Transgo Jr would be a big improvement. Seems like all the limped threads I read, or posts have a tuner. Stock can and do break but it's almost always the tuned trucks.
Even Franka548 says his limps if he's not careful with a 65hp tune.

My question is do you want to worry about limping the trans with your trailer in tow?

 

We've go similar trucks! Mine is at 57000 right now, just got it last October and love it. Get gauges! EGT is a must when towing, and it combined with the boost will be handy for evaluating the results of your mods. I'm putting in Isspro EGT & Boost on the piller right now.
Simple relativly easy and cheap mods with bang for the buck is exhaust and air intake mods.
I saw somewhere where a guy using the stock exhaust and replacing the stock muffler with a 4" muffler had very good results for the money.
Before working the electronic mods have gauges.
Jim

 

My recommendations are as follows:

NEW stock injectors, my choice is dealership. I'm sure other places sell the same product.

A single EFI Live economy/tow tune (sometimes called optistock) from a credible place. I would recommend "Idaho Rob" at ATP trucks. His were pretty damn good, and have only required some tweaking on my end.

4" or 5" exhaust, muffled or straight pipe, whichever you prefer.

You most certainly do not need gauges, especially with such a mild tune. They are useful for several reasons, but not necessary in applications such as this.

A boost valve will yield minimum differences, perhaps very slightly better turbo spool up. The engine will only create as much boost as it needs, you might gain 1-2 lbs of boost with one of those valves with your setup. You would be further ahead to port, or get your turbocharger horn ported.

I might add, that there is certainly nothing wrong with the PPE tuners, in fact next to EFI Live (or HP Tuners) I consider them the very next best one. If you want a plug in tuner, then yes, PPE is the programmer for you

 

You most certainly do not need gauges, especially with such a mild tune. They are useful for several reasons, but not necessary in applications such as this.

Disagree strongly with this.

I run my Edge on 2 while towing and have had my EGT warning go (1250) while pulling uphill. Truck still had oomph but I backed down. My trailer is about 8000 so I'm lighter than the OP.

 

My turn: With your low mileage, there is a good chance you only have a few bad injectors. I would give consideration to only replacing the bad ones. If it makes you feel better do them all.

I would choose a ppe standard and skip the exhaust or just add a free flowing 4 inch muffler (that is what I have on my truck) wifes truck has stock exhaust and PPE on level 3 and it runs very hard.

Gauges, ABSOLUTELY, know where you are and not have to worry.

Towing with extra power, 1st choice install full transgo in your tranny. Second choice, lock out overdrive when towing unless driving on flat type roads. Don't allow full throttle 4-5 shifts with a tune.

PPE airbox mod works well.

 

Thanks for bringing up the mileage, stop by your favorite GM dealer and see if they might help cover some injector costs. 9 times out of 10 they will not, but some have got lucky and had most of it covered (yes, even well out of warranty).

How much power do you plan on adding?

With the exhaust, look at dropping EGT's about 200F and a 5hp increase (Don't worry, you won't feel the difference).

Anything to beef up the transmission is solid advice, and I approve

 

Thanks to everyone for the advice! I will have to digest the info and may have more questions.

 

O.K., I know NOISE is subjective to individuals, but Oldred95 says that his Diamond exhaust is not as quiet as he thought it would be...

Oldred95, how much louder than stock?

Everyone else, any suggestions on 4" exhaust leaning towards the quiet side? Just looking to lower some exhaust temps as quietly as possible.

 

The noise really depended on engine speed. The diamond eye started out on my dads LBZ and it was pretty dang quiet on it but after 600 miles would still bother the person riding in the back seat. On my LB7 it is a little louder but the rpms at highway speed are higher too. When I was running 265/75-16 tires, on a trip to Dallas I was running 80 at times at like 2600 rpms and it was pretty noisy in the cab. I could still maintain a conversation or talk on the phone but there was a constant roar in the background. Now with 20s and taller tires the engine speed is down some and the exhaust is a little quieter at highway speeds and the tires hum a little so it masks the exhaust a little.

They say the Diamond Eye QT system with I believe a Corsa muffler is just as quiet as stock though. For what its worth I've heard a few stock exhausts with just the muffler cut out and replaced with a piece of pipe and they are surprisingly quiet inside. Honestly the stock exhaust isn't that bad on the LB7 because its just a muffler. We put my stock exhaust on my dads LBZ so it would have a muffler and no cat and it works well.

 

I've pulled 2 different 5th wheels since 2004-current one is 12,167lbs. for 29,783 miles. I've had zero problems with the Allison despite running Edge Atitude on lvl 2(60hp 180ft lbs) the whole time. Not saying that some type of trans. upgrade wouldn't be a good idea, but not sure it's necessary with a mild tune. My PPE boost valve added 1-2lbs. not much, but not much $ either and easy to install. Gauges IMO are a must with added power. Anytime the intake and exhaust are swapped for after market the noise level in the cab goes up. I tried 6 different mufflers(yes 6) including welding 2 of them together after some machine work to make one 40" long(had to shorten pipe & relocate front hanger) built a resonator to go behind trans crossmember, built a resonater tip and still could not get it quiet enough, especially in 1500-1800 rpm range. Finally gave up & put stock exhaust back on. If your '03 has a cat on it, then a cat back would not be so loud-that's what my nephew has on his '03. With stock exhaust and added power gauges are an absolute must. In the mountains, I have to downshift to keep the egts below 1250 degees on a long pull with the stock exhaust-egts weren't a problem with 4" exhaust. Hope some of this helps in your decision in how to proceed with your mods.

Rich

 

I don't have a cat on my truck, how does that figure into the equation? I understand that I will need gauges.

 

Boy do I got some cool numbers for you!

If you remove the stock muffler and straight pipe your current exhaust, you are looking at a 5hp gain and a 200F EGT drop. I found this at both stock power levels, and at 450 RWHP.

So for towing (if a straight pipe does not bother you) then you may go that route and yield good results.

On Edit: I should let you know that this was done on a Dynojet chassis dyno, with 20 runs to get these numbers. I also have a factory catless LB7

 

I'm not sure what you mean by how does that fit into the equation. If you say you don't have one, then it doesn't, but I thought all '03's came with a cat. Look forward of the trans cross member to locate it. I maybe wrong and I'm sure someone will correct me if I am. Anyway, a cat(besides cleaning the exhaust) acts like a resonator and quiets the exhaust somewhat.

Rich

 

but I thought all '03's came with a cat. Look forward of the trans cross member to locate it. I maybe wrong and I'm sure someone will correct me if I am.

Rich

On the Lb7's, only the California emissions and some fleet emissions came with a cat. Together they represent a small minority of the Lb7's that were produced. LLY+ (2004.5+) all came with a cat.

 

I got a 5" flopro exhaust and I think it is pretty quiet. If you have a long bed make sure you tell them that when you order because the hangers will be in the wrong place. They were great to work with sent me the right kit and were super cool to work with. I would recommend a tuner with on the fly tuning and a monitor with a temp probe so you can have at least electronic readouts of EGT and boost. Brent is great to work with I sent him text questions or called him whenever I had a problem or question and he provided awesome customer service. If you are handy with a wrench and have somewhere warm to work changing the injectors isn't that hard just make sure you follow the tutorials and take your time.

 

Yeah it's kind of confusing. But the good news is you don't have a cat to hold you back.

 

Thanks for the info. With my hearing loss, background noise makes it almost impossible for me to have a normal conversation.. So straight pipe probably won't work for me. I guess I am looking at either a 4" muffler back, or down pipe back. Need to figure out what brand. I am one of the lucky ones, I definitely do not have a cat on my exhaust...

 

Sounds like you are on the right track :thumb: I'm sorry, but I do not have numbers for other setups. It's too cold to dyno, have to wait until spring.

 

From the factory I did not have a cat. Would it be really loud if I replaced the muffler with a straight pipe?
Thanks
Jim

 

My exhaust dumps out the side, right before the muffler.

I hear it inside, but can talk on the phone
Idle, the engine clatter will be louder than the exhaust
High idle @ 800 RPM, you will have to speak up to talk beside it
High idle @ 1200 RPM, you will have to yell to talk beside it
Cruising windows up, can hear it inside but still talk normally
Cruising windows down, gets loud with an object beside the truck
Full throttle, very loud (you don't want to be the car beside you)

I imagine a full system would be quieter inside, maybe someone with that exact setup could chime in.

 

That really does answer what I've been wondering. I'll see how the EGT's go when I start pulling the camper and let that drive my decision. For right now I'll stick with stock.
Thank you
Jim

 

That really does answer what I've been wondering. I'll see how the EGT's go when I start pulling the camper and let that drive my decision. For right now I'll stick with stock.
Thank you
Jim

Jim

You're going about it the right way. Just downshift if your EGT'S go higher than you want. See my post #14-I should have added especially when pulling concerning the noise of an aftermarket 4" exhaust.

Rich