Need exert advice

DuramaxOnTheBrain · 07-21-2008, 07:34 AM

Hey ya'll,

I have a mostly stock 04.5 LLY that I would like to put a better flowing air and exhaust system on but I am not really interested in it being able to do extreme stuff, you know what I mean? I think all of these very powerful mods are way cool but I just want to be able to tow my camper (28 ft travel trailer about 8000lbs loaded for now, probably a 5th wheel at some point in the future) without overheating and get better gas mileage all around. I also want it to be as quiet as possible while still flowing better than stock. A few questions...

Is there a better flowing exhaust that keeps a muffler that is even worth swapping?

Would just a cold air intake and maybe the turbo inlet mod be enough air flow for an aftermarket exhaust?

And finally, could I do these two mods (air and exhaust) and still be ok if I don't get a tuner or chip or is that a must?

I want to stay as close to stock as possible and get some better performance. Thanks for all of your help!

Brain

**Meyerperformance** · 07-21-2008, 07:57 AM

Yes with those two mods you will be fine. I would do a MBRP 4" turbo-back exhaust, and a PPE airbox mod. The 4" exhaust flow will help lower egt's and give you a couple ponies to boot. The 4" with muffler is not much longer than stock it has no drone on highway.

**Diesel Nut** · 07-21-2008, 08:39 AM

I have a couple of the Injen Air intakes out there with good results so far. They are pretty sweet units. Combined with a good 4" system you should pick up a decent amount of performance, more so when towing because you are working the motor more and the extra airflow will be more notable.

Here are the Injen Intakes.

gr8shot · 07-21-2008, 08:59 AM

IMO, no need for a CAI, just do the turbo mouthpiece mod. That by itself will help a good bit. If you want to stay stock, then obviously no need for a tuner, but a mild one will really help out with fuel economy, and a little extra power on the hills would be nice when towing a trailer. Your stock tranny will hold ~90hp extra without any probelms, so why not take advantage of that?

**Meyerperformance** · 07-21-2008, 09:42 AM

I have never had a problem with my aluminized exhaust, and it gets salted heavy here. Maybe im luck though. One thing i tell customers is look how long you keep your truck, that plays a big factor in what exhuast is best for you.

Tyler

DuramaxOnTheBrain · 07-21-2008, 09:48 AM

Thanks guys,

What is the stock exhaust made of? If its alum I should be ok because even though I live close to the coast we don't have any rust problems down here in SC unless you neglect something really bad. If I could afford only part of the upgrades would you all go with intake/exhaust first or just a programmer first? Thanks again.

Brain

Hook'em_Horns! · 07-21-2008, 12:32 PM

First, pulling only 8k lbs behind a D-Max LLY will not give you overheating problems, but it will run hotter than other D-Max versions.

Second, the biggest limitation on the LLY is the reduced sized Turbo mouthpiece and the biggest reason for any overheating issues. Other intake/exhaust mods can show improvements, but none of these address the real problem, which is the mouthpiece restrictions along with the change in the induction plumbing.

Killerbee goes into a more technical explanation in the flaws of this design here:

http://members.cox.net/beekiller/GMC...verheating.doc

Quote:

The resistance that can be found in the LLY intake box, element and tube, combined is only 16% of that found in one simple piece that these companies ignored altogether. That means that 84% of the intakes restriction was left in place, unattended to. It's pathetic actually, and a waste of a "million dollar flowbench facility".

My simple CAI modification also discussed here (lots of pictures);

cold air intake

and here:

cold air intake

has increased my throttle response and acceleration with a small improvement in mpg, but the biggest change has been lower engine temps and far less fan activity. Performance does drop though, when outside temperatures reach the mid 90’s and above pulling heavy in the Hills, Heavy as in 2.5 times as much weight as you’re anticipating for a pull.

Try this simple mod first, then look at changing the compressor mouthpeice for your best overall improvements.

After addressing these, then you may want to look into more mods from supporting vendors here.

DuramaxOnTheBrain · 07-21-2008, 12:41 PM

Roger that. Thanks. I have read all of your stuff and killerbees and It is all great info. The fan issue has been my biggest concern yet because that thing screams so loud I can't hear the radio and that is towing the 8000lbs on flat lowcountry roads. I'm gonna mod the mouthpiece myself. I already took it off once but I went into panic mode thinking I might have the wrong piece off or something and put it back LOL!

Brain

**Meyerperformance** · 07-21-2008, 12:58 PM

i would do a exhaust first, then programmer, and the stock exhaust is ss. Let me know if i can help with any questions.

Tyler

Hook'em_Horns! · 07-21-2008, 01:06 PM

Quote:

Originally Posted by DuramaxOnTheBrain

Roger that. Thanks. I have read all of your stuff and killerbees and It is all great info. The fan issue has been my biggest concern yet because that thing screams so loud I can't hear the radio and that is towing the 8000lbs on flat lowcountry roads. I'm gonna mod the mouthpiece myself. I already took it off once but I went into panic mode thinking I might have the wrong piece off or something and put it back LOL!

Brain

Gasketing the airbox with the additional hole has pretty much eliminated my fan noise. When it does engage now, it is VERY quiet. Give us an update on your results.