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Discussion Starter #1
Hello I am new to the forum.
I have the choice to get an 04 gmc with the LB7 engine with 80,000 miles on it and the injectors have not been replaced or a 2005 gmc with the LLY engine with 60,000 miles on it. Please give me some feedback on what my best choice is. Any information is appreciated thank you!
 

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LLY hands down. throw on a new mouthpiece and you're golden. ~250 for a mouthpiece vs 3k+ for injectors 20-60,xxx miles from now
 

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i love my lly, but you cant go wrong with either they both have there ups and downs
 

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get a lbz dude you wont be dissapointed
 

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Connects your intake to your Turbo
 

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The general rule of thumb is to purchase the newest Duramax that you can afford. The LBZ engines are highly sought after, and for good reason. In this situation I would go LLY personally.
 

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As far as comparison..

LB7, known for injector issues, the more filtration you add to your mix the better your chances of prolonging the removal/replacement down the road (which is inevitable) Lb7 trucks have no emissions unless it is an old fleet truck/ CA emissions model, so egr is not an issue, and the pcv system was actually effectively done on these models so the pcv reroute is not completely necessary. Just plan to have around 3-5k sitting around just in case for injectors, depending on if you do it yourself of it you pay to get it done. However these are great motors, and you can't beat the sound of a straight piped LB7, its what all the duramax guys go for sound wise.

LLY, known for head gasket issues. This is about a 2kish job depending on the parts you go with. The 05's seem to have a few less issues with this than the 05 models did, however depending on how it's been run/beat on this has to be on the back of your mind. When doing the r2, just bite the bullet and go with arp studs so you won't ever have to do it again down the road. They lly rigs have a variable vane turbo, getting rid of the wastegate the lb7 trucks had. GM improved their injector issues, and the only thing you have to worry about in that category for the lly rigs is the injector harness, otherwise known as the "icepick fix". I should also add in the restrictive factory turbo mouthpiece, as they are very poor for air flow. They are very strong engines and can go maintenance free for many miles (just like any diesel really)

Either truck you will be happy with as they are great rigs :thumb
 

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He speaks truth! I miss my old straight piped lb7. That was a beautiful sound!
 

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I don't know if Jake198 is wondering this, but how do the variable vane turbo's work?

I've been searching the forum with the search feature and I haven't come up with diddly squat. I own an '05 LLY and have just been curious how and why they were the turbo set-up to have when it was brand new.
 

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I don't know if Jake198 is wondering this, but how do the variable vane turbo's work?

I've been searching the forum with the search feature and I haven't come up with diddly squat. I own an '05 LLY and have just been curious how and why they were the turbo set-up to have when it was brand new.
When the load on an engine is low, the vanes on the turbo charger remain closed. Little exhaust causes flows across the turbine impeller, or rotor, producing little turbo charging effect

When the load on an engine is high, the vanes on the turbo charger are opened by an actuator This allows a stream of exhaust gases to flow over the impeller.
 

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When the load on an engine is low, the vanes on the turbo charger remain closed. Little exhaust causes flows across the turbine impeller, or rotor, producing little turbo charging effect

When the load on an engine is high, the vanes on the turbo charger are opened by an actuator This allows a stream of exhaust gases to flow over the impeller.
So basically it helps boost build quicker by causing the restriction?

Sorry, I may be going to school for diesel but I don't know of any big rigs with variable vane turbo's so I don't think I'll be hearing about it there and I just want to know how my truck works.
 
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