LLY: Where To Draw The Line? - Actual Experiences Wanted

04LB7yz

New member
Aug 16, 2013
120
0
0
Way North Minnesota
So it seems that it is my turn to do head gaskets on my LLY... I knew it was only a matter of time, so I am not shocked. The reason for this post is to figure out where I should draw the line. I watch this forum very closely and have seen a ton of new threads on getting the most out of a stock bottom end truck, some knowledgeable and some not so much. I have also seen a lot of people making 700+ on their stock bottom ends. I don't see this as realistic. So I am looking for people that "have been there and done that" to give me real world advice. I realize anytime you modify something you run the risk of breaking things.

Those people that have added more fuel and bigger turbo/turbos to there stock bottom ends, are you glad you did so? Do you wish you would have left it with stock fuel and air? What is the best option or options in order to keep my bottom end healthy if I choose to add fuel and/or air? I have read countless posts with conflicting ideas on how this is best achieved. A lot of it is very old and out dated at this point. Hopefully we can get current real world information on the subject so people stop asking all of the uneducated questions that arise for this topic. :thumb:

I have seriously thought about just building my motor but then I am afraid that everything will spiral out of control. My father owns an engine machine shop and has built a few of these engines. So my machine work bill would be next to nothing but that still does not mean it would come cheap. Those that have built their motors, would you do it again? What would you have done differently?

Any insight is greatly appreciated! :thumb:
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,123
4,865
113
Phoenix Az
no one regrets adding more air or fuel to their stock bottom end........... till they hurt or break the engine.

if you want to keep the bottom end alive, you need to keep torque low. twins and lots of fuel down low will kill a stock bottom end quick. a bigger single turbo generally moves where peak HP is made higher in the RPM range and can reduce torque due to that but thats not to say you cant again hurt the engine.

your also on stock pistons and while they are stronger than 06-10, they can still crack. it has been theorized (just like reduced torque) that a smaller pluse width/ larger injector that gives you the same amount of fuel as a small injector/ large pulse injector would give is healthier for the pistons. on top of that, if you use the turbo/s to clean up the fuel to get your max HP, EGTs will be better and will help longevity. using lots of fuel to really drive a turbo to get your HP your after will add more stress to the pistons.

As for building and regretting on an engine. i had my times where i regretted it. more of "i could have used that money for such and such". that lasted about 2 years and now that i have the truck running like i want, i have 0 regret about it. i enjoy the hell out of it.
 

cdbright

JUST RENT IT
Dec 16, 2008
1,009
6
38
43
Salt Lake City, UT
i can run circles around my uncles LML but all he does is drive it and drop it off for warranty issues (if any) and i spend weekends working on my truck :(:(:(
 

NRA223

New member
May 20, 2015
288
0
0
I've seen a lot of trucks making 6-700 hp on stock bottom ends and living with abuse. I've seen a truck with banks exhaust and 6 gun blow. A lot of factors involved from how and where the power is made to how it's drove and maintained. Like said above the consensus is easy on the torque down low. I have a mild turbo/pump/injector set up that I'm guessing is around 600 whp. I dd it on the big tune but haven't been to the track and I don't pull. I don't regret adding fuel or air but I know it could blow tomorrow and I'd have nobody to blame but myself. Sometimes I think I could have spent the money elsewhere but then I drive the truck and forget about that.
 

melms23

Member
Jul 30, 2011
253
0
16
WI
My lmm is fun to drive, makes good power, and has been super reliable (knock on wood).

Needless to say I'm a big fan of the s475 over stock, plus you don't even have to remove the stock turbo.
 

dirtydmax

<---up shit creek
Sep 1, 2013
1,072
0
0
45
muskoka,Ont Canada
Slippery slope man when building one,It will start as a mild build but it can and will get out of control.If its a dd DONT TOUCH IT and enjoy having a running truck.Just my :2cents:
 

A. Stock Lbz

New member
Aug 13, 2013
342
0
0
spokane wa
The lly I sold had a hsp 475/over stock twin kit 40% nozzles on a stock bottom end 250k miles. The tuning was de-torqued a ton but it made all its power up top for the most part. It was pretty doggy down low but I knew that going in if it had any chance of not taco-ing the rods.it dynoed 680/1005 on 2 different dyno's, never took it to the track but it would gap my buddy's mid 12 sec Cummins in a hurry. I wish I could of buit the motor but decided to sell it cause I didn't want to drop 10k on a build. If you got the cash to build it and can get machine work for a little or nothing go for it, or run detorqed tuning and hope it doesn't kill itself.
 

clrussell

pro-procrastinator
Sep 23, 2013
5,906
363
83
Slippery slope man when building one,It will start as a mild build but it can and will get out of control.If its a dd DONT TOUCH IT and enjoy having a running truck.Just my :2cents:

I'll second this 100%%

Read my thread
 

Burn Down

Hotrodder
Sep 14, 2008
7,093
28
48
Boise Idaho
5+ years @ 600 hp with twin turbo's before I pushed a head gasket... Run's mid to low 12's has made several 5K mile trips to the states and back with no issues. It does sit in the driveway a lot from me dicking with it all the time:D
 

carter_44

...
May 11, 2010
575
0
0
AZ
I don't regret my engine build. I regret spending that much money. Put a nice hole in an LBZ piston with stock air and fuel. What started out as a budget build ended up as an everything build. My advice to anyone considering modding these trucks is this...build the trans, max effort tunes from a reputable tuner, lift pump....drive it. It costs a shit load of money to go from a 12 second truck to a 11 or 10 second truck and reliability and drivability suffers.
Now I'll go drive my truck and change my mind.
 

A. Stock Lbz

New member
Aug 13, 2013
342
0
0
spokane wa
I don't regret my engine build. I regret spending that much money. Put a nice hole in an LBZ piston with stock air and fuel. What started out as a budget build ended up as an everything build. My advice to anyone considering modding these trucks is this...build the trans, max effort tunes from a reputable tuner, lift pump....drive it. It costs a shit load of money to go from a 12 second truck to a 11 or 10 second truck and reliability and drivability suffers.
Now I'll go drive my truck and change my mind.

Agree 100% built trans stock turbo and fuel lbz was the funnest truck I have owned.
 

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
15,308
1,597
113
Mid Michigan
If your machine shop bill is zero, then why are you even asking? Put a set of Carillos or Crowers in it, stud the heads, and have fun with your fuel/air setup.
You sure dont NEED 1000hp to have fun with one of these trucks. 650-800 would be more than most people need for what they actually do.....

As to my experience, I guess I'm now one of those "old and out-dated" guys, with absolutely no current relevant information on the subject. :rolleyes:
Funny, though...there havent been any new stock bottom/stock turbo setups that have bested that 5 year old 12.14. Just sayin' ;)
 

Ne-max

I like turtles
Nov 15, 2011
3,361
64
48
Lincoln, Ne
Just remember. A true 650hp truck is way funner then a 900hp dyno queen. Usable power is what matters. Not something that can spike a dyno.

Also stock bottom ends live longer with lower torque but torque is what we need to make these heavy trucks fast.
 

Bustedknuckles

Honey Badger
Sep 25, 2010
1,309
2
38
32
Hagerstown MD
I just turned over 206,000 miles tonight. Stock motor with studs and a S366 and 30% over injectors. I drive it to work every day and have towed heavy multiple times no problem. I think its a very good combo if you want more than tuning but dont want to have to build the motor.

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