LLY: Introduction/results and What next

B_Garr

New member
Apr 30, 2009
1
0
0
St. Louis
I am newbie to the diesel world and wanna say how impressed i am with the amount of power and reliability these motors offer. I bought my 04.5 d max bone stock with 88,000 miles on it and have loved it from the get go. From driving nothing but gas trucks the transition to diesel blew my mind. I wanna first say i use my truck for its purpose, winter months I plow snow sometimes three days straight, pull 5k-8k weekly, and load my bed to the brim daily. After making that known i wanna explain my thoughts of the first few months of owning the truck and information that i have learned. The first thing i was dispointed in was the gas mileage, throttle response, and purges in low rpms. So being who I am begin to inspect all components of the truck and came up with a list of many improvements needing to be done. Being young and owning a small business in these times my funds and time have been extremely limited. These are the results I have came up with while owning the truck.

DAY 1:(stock, 14 mpg avg.) Quote from my own mouth "Im keeping this one bone stock, I'm gonna drive to the ground".

WEEK 2: Forgetting the statement above, I began my mods. First i examined the factory intake and what i have now learned to be called the turbo mouth piece. I took these components off to check for shaft play in the turbo and was surprised in its condition. Noticing the many restrictions in theses parts i grabbed out the dremel and epoxy and drilled out the inner angle of the t.m.p., widened the opening and smoothed everything out and eliminated any restrictions. I then reinforced the area i drilled out with high temp epoxy, sanded it smooth, and painted it black. Impressed with the part i just fab d up i then went to addressed the air box. First I cut the front of the box (behind the head light) open and removed all the ridges and smoothed it out. After doing that noticed a cheap gm fix to the inner fender to stop water, debris and most importantly cool dense air from entering the air box. So of course i removed that. With my air box now free flowing and a new drop in filter i re-installed it, I then came up with the idea of putting a foam weather striping around the opening to try to create some what of a seal to the fender and head light. happy with these results also i then blocked off the turbo silencer and pcv valve. I ran a 1/2 heater hose from the pcv valve down to the frame and put a breather filter on the end to vent. After doing these mods I took it for a test drive and immediately noticed the throttle response and purge problems to be fixed,not to mention lower running temps and bit funner to drive. After these mods and week of driving (16 mpg avg. with quicker throttle response and smoother low rpms)

Week 4: Very impressed with the mpg gain and overall drivability of the recent mods i decided to put a little money out. I found a egr block off plate on ebay $11.00 and a 4" exhaust system turbo back (no cat) system for $375.00. After installing these upgrades the true power petiantial begin to show its self. (my mpg Jumped to 19 mpg and gained an estimated 25hp-35hp

Month 4: After enjoying my now free flowing motor I found a predater tuner w/egr function on craiglist for $150.00 and jumped on it. After slowly working up to the 100hp tune allowing alli to properly learn the power curve i begin to have some real fun. This tuner has opened up in entire new playing field for me, 02 and below cobras and gt's are now at my bed. (now seeing any where from 23mpg-28mpg highway no load 65mph).

Currently: Getting a small taste of power potential this motor is capable of good old Alli began to tell me she has been left out and i experienced limp mode. I have now limped her 7 times and am currently on the 65hp tune and the clutches are pretty much toast. I am now in the process of saving to give Alli her much needed over haul and have really been liking what sun coast offers and want to combo one of there stage iv rebuild kits with the Ats co pilot.

Im beginning to plan out my next upgrades and have taken this to about as much knowledge as i have and am looking for input. I know lift pumps, cp3 pump, and probably efi live but i wanna get into the 750hp range to hang with my buddy's turbo cobra.

Let me know what you guys would recommend.
 

malibu795

misspeelleerr
Apr 28, 2007
8,408
674
113
42
in the buckeye state
750 you going to need a SC4 or better tranny mainly billet hard parts if you plan on going north of that
twins/ large single talking 4094/htt A5k or biger
duel fuelers
rods
head studs
efi live is a must

600hp dmax is low 12s high 11s in the 1/4.
stock turbo will put you mid to high 12s pending weight of truck

since you seriously work your truck ALOT compound twins would be right up your ally. with using a S480/GT4708 as the big charger
 

othrgrl

Diesel Addiction Owner
Mar 10, 2008
2,151
4
38
Wilmington NC
www.mydieseladdiction.com
EFI Live is without a doubt the best investment you can make as a Duramax owner.

Alot of us do not run the co-pilot and some have even removed it and ran better times without it - not saying I'm against it as I have no experience with it. SunCoast Stage IV is my choice for trans.

Upgrading your turbo mouthpiece to one from an LBZ/LMM (06+) mouthpiece is the best option and will get you more flow than your ported LLY MP. If you do this you can either mod your LLY intake to fit or bolt an LBZ intake right up and rescale the MAF with EFI Live or a Tech II.

AirDog is my choice for lift pumps but there are cheaper options. Shimming the Fuel Pressure Relief Valve is basically free and will allow you to hold more rail pressure. With a lift pump and shimmed FPRV the stock CP3 will give you all the fuel the stock turbo will support.

On the stock turbo you can get into the 12s and 500ish hp pretty easy.

A turbo upgrade can take you up to 600 - Cheetah or Danville 68+mm, HTT, small S400, GT40.

At 600 you are starting to flirt with disaster for the rods, pistons, and head bolts.

750 is going to take a budget build motor, dual fuelers and a decent size charger - A5K, S400, GT4094 or GT42, big Cheetah

BTW welcome and good luck - let me know if I can help you with anything along the way.