How to Build a 425 WHP Duramax LLY!

[@g-man4412]

I would advise anyone doing tuning to the LLY. If you go big there MAKE SURE YOU INSTALL HEAD STUD KIT or you run the huge risk of blowing head gaskets!!!! Then you will be tearing down the motor (& trust me). then the real money starts flying out the door....

[@8020Media]

G - Not a bad shout. Thanks for sharing this insight!

[@josephheasley615]

Need to think about building the transmission at that time

[@8020Media]

J - True.

[@ynotjf]

My 02 LB7 is stock except for a Banks Six-Gun tuner. I pull a 7000lb trailer on power level 5 (about 100 extra hp above stock) and I’ve been researching cold air intakes that Bank (and everybody) recommends. I’m starting to believe that CAI are simply a sales pitch and not really needed, here is my logic: 1) ACDelco says the stock paper air filter filters down to 3 microns while the oil K&N and Banks filter filters to 5-7 microns so the stock filter is superior from a filtration standpoint. Oil filters have better flow but additional flow is not necessary as even under full load the vacuum gauge on the air box never indicates a vacuum is present with a clean filter. So if no vacuum is present with the stock filter & air box then adding a larger flow airbox is not solving anything as the engine can only absorb a certain amount of air volume.

[@whitepowder8838]

Transmission tuning will do nothing to hold power for 01-10 trucks. Line presure can only be adjusted manually internally on these. Custom EFI tuning can help save your transmission by defueling shifts. Trans tunes waste of money unless you have large tires or giant turbo, as the only thing u can change is shift point and tc lock up

[@lukedougherty7078]

Fuck.. stock turbo supports 530 to the tire with very minor intake upgrades but makes some back pressure which results in some EGTs with that turbine and housing

[@8020Media]

Luke - yep!

[@g-man4412]

I've been at this since I was 15 years old... I'm 67 now my friend. seen & done a lot over the years.... built & serviced a crazy amount of machines.. race cars, boats & trucks & even motorcycles. Cheers & hope you enjoy what you do as I love it myself.....

[@8020Media]

G - Thanks for the feedback and support! Sounds like you’ve got a ton of experience.

[@nolanyaun3843]

thanks man just bought an 05 duramax fully stock and wanting more power appreciate it

[@8020Media]

N - Thanks for the feedback! Keep us updated on your build.

[@bassdaze]

nope... the stock air box is perfect, untape the fender well and add a strip of foam around box... this becomes a true CAI... especially if you duct it outside the engine bay... this is proven... after market CAI are a joke and just look pretty... my inlet mouthpiece cost $60... LBZ mouthpiece and DONE

[@8020Media]

R - Interesting, but don't see how it wouldn't work! Idk if I would say "they're a joke", but to each their own. Thanks for sharing your experience.

[@pierce_arrow1798]

I have the zf6 manual. Does anyone know how much power they are good for stock?

[@jaymetimmerman3541]

TCM tuning doesn't help the 5 speed hold power.

[@g-man4412]

Well that's without saying if you put more to the Motor then the tranny will become the new weak spot. Myself I am putting a GEOREND master kit with the triple disc torque converter & changing the valve body to a 6 speed & new TCM for my LLY from Calibrated tuning in Woodstock IL. Nic can help you out if you are thinking of going that way.

[@8020Media]

G - Agreed. Thanks for sharing your experience!

[@konnorcook5918]

425 can be accomplished easily with an lly with just a tune. Reliability is the problem, supporting mods are key.

[@8020Media]

Konnor - Correct.

[@g-man4412]

I am doing a stud kit right now on the LLY as we speak.... this is happening to a lot of folks who are getting carried away without that being considered... probably need a valve job anyway right.... Lol;;;;;;

[@8020Media]

For sure, good move on your end! Preventative mods are some of the best and a lot of people think they can get away without them.

[@thefloridacrew1473]

Best Intake I’ve found for my LLY is a Banks Ram Air. Best inlet is going to be the LBZ imo. Bout to pick up the banks automind 2 and then leave it there. Nothing massive. Just need a good streetable truck that’s quick but reliable. My trucks also been studded

[@8020Media]

T - Thanks for taking the time to share your experience. Sounds like you've got a good build!

[@Djmedic23]

to build any dmax to 425 is a tune thats it thats all they will hold 450 on stock trans all day

[@8020Media]

Dj - Thanks for sharing the insight.

[@HollywoodJack509]

I have an 05 lly with ppe downpipe, s&b turbo mouthpiece, s&b cold air intake, efi live, and fass lift pump. On tune 4, they advertise 80hp and 147ft. Do you think with these mods I'm in the reliability category with a stock transmission? Only asking because there is no proven hp numbers for the modifications I've done without a dyno. Thanks.

[@Clutch_Kick187]

I hope you got rid of the cat.. and get a custom tune from someone who knows what they are doing.. don't push the power, you will destroy the trans and motor with canned tunes.. Don't screw around with high hp tunes bud, You will end up with bills much higher than the truck is worth..

[@8020Media]

H - You are probably getting close. Hard for us to tell exactly without dyno numbers.

[@hamilton9339]

Got an 05 w\ 32k got intake, inlet, dp, an a 4" cat dump only lacking tuning. Got plans for trans, lift pump an turbo to sit around 600

[@8020Media]

Awesome, nice low miles! I'd do the lift pump the same time you do the tuning, but overall sounds like a good build.

[@CT9905.]

You forgot to include the EGR valve.

[@8020Media]

C - Thanks for the insight.

[@markthomas4083]

I think the Cold Air Intake is a waste of hard earned money.

[@8020Media]

M - These always seem to be a topic of discussion. We will always push for aftermarket intakes.

[@jacobkolba5751]

i have a 05 lly with 3 inch dual exkaust and thats all. i just put a 4 and half inch lsp intake on. its like a new truck. throttle response is amazing

[@8020Media]

J - Nice! Thanks for sharing your experience.

[@wilhelmpeters6054]

I just bought a 2005 lly that was studded and had the transmission built 10,000kms ago. It has an s&b cold air intake but not an upgraded turbo intercooler pipe. Four inch exaust straight piped not sure what down pipe is on there. What kind of tune and modifications would you recommend me to do to get to 500 whp?

[@8020Media]

W - We have great LLY content on our ChevyTrucks website for this: chevytrucks.org/?s=lly

[@axeyplayz1052]

Does this video apply to the 2006 lly?

[@8020Media]

A - It applies to all LLY's

[@turbosupra2jzdragracingtob249]

Larger trans cooler also

[@8020Media]

T - True!

[@victorelizalde333]

Mods to my 05 lly ,, airdog lift pump ,, Magnaflow down pipe, magnaflow 5” exhaust ,, egr deleted ,, arp stud ,, afe exhaust manifolds ,, eBay up pipes ,, eBay turbo mouth piece ,, s&b cold air intake ,, banks air intake scoop,, pusher hot and cold inter cooler pipes with Y bridge,, bd diesel throttle booster ,, duramax tuner 6 speed transmission conversion kit .. never programmed non tuned never seen a dyno .. can anyone guess my horse power gains ,, cause I don’t have an idea if I gained anything although do feel a whole different truck with all add-ons

[@8020Media]

Victor - Sounds like you've got quite the build! You've certainly gotten some power gains, but not a crazy amount.

[@heywatsup671]

Non cuz ur not tuned.

[@victorelizalde333]

@@heywatsup671 from the dig @ red light,, I’ve smoked 2014 f150 ecoboost about a year ago with half the parts it got now 😉

[@heywatsup671]

@@victorelizalde333 love it just smoked an sti last week in my lly. id deff get some nice efi live tunes from reputable vendor, dmax tuner, ppei good local diesel shop! you wont regret it, will b a whole new truck.

[@8020Media]

A - Sounds like you've got a good build too! What do you have?