B'klyn9C1

As I ride out Hurricane Sandy I see all these threads on this forum about putting turbos on stock 5.3 liter LSx's (LM7) and producing these hellified RWHP numbers like 600 to 800 RWHP.

I am new to this FI game and I want to do a LSx conversion on my 1995 Caprice 9C1. First I was going in the direction of a LS3/L92 based 416 ci N/A stroker. Then the concerns of Daily Driver driveability and fuel economy pulled on my coat. Then friends of mine with turbo cars like Buick GN's and Prochargered Impala SS's said that FI cars are better DD/weekend track car combo vehicles. Because you don't use the gas until you step in it. So I went in the direction of SC stock displacement 6.0 liter LSx and now this these stock internal 5.3 turbo motors has got me really intrigued!!

So please guys tell me why is the 5.3 liter so magical in producing high horsepower over let's say a Force Induction 6.0 to 6.2 liter LSx e.i LS2, L76,LQ4, LQ9, LS3/L92???

Why are the 5.3 stock internals better in surviving boost than the 6.0+ liter LSx's????

a4ls2goat

Nothing special.
They are cheap to come around and make the same power as a 6.0/6.2 will make.

And also, you don't need a really big turbo for a 5.3 as you would need on a big cubic inch motor to be efficient.

B'klyn9C1

Okay what you are saying it is a combination of just the right amount of cubes to the available turbos that are commonly on the market that are more efficient (and less costly) to what you would need for the 6.0/6.2 LSx's???

BTW I just finished reading Richard Holdener's article from the Sept. 2011 issue of Hot Rod magazine, "The Big Bang Theory" . WOW!!!! He just could NOT kill that thing with twin turbos and pushing 1300 HP!! And to find that the motor was really a 4.8 liter than the 5.3 that they originally thought it was!

To a4ls2goat and others who are in the know do you think that the extra meat and small bore lends to the 4.8 and 5.3 liter's (LM7's) boost indestructibility as compared to their larger displacement LSx cousins??

Ferocity02

iTrader: (60)

They are cheap, and hold together pretty well. I heard the newer 5.3's have better rods that will resist bending with high power and boost. Not sure what year those started on though.

a4ls2goat

They started late 2004.

I have a 2009 4.8 with a 260$ turbo gt45 making 580whp through a 3600 unlocked converter with more to go.

B'klyn9C1

580 RWHP through a 3600 stall unlocked TC?!?!?!?! DAMN!!!

a4ls2goat, do you think that a combo similar to yours will work on a 4000 LBS daily driver such as mine and still get reliably 550+ RWHP/500 RWTQ???

a4ls2goat

Lol. My setup is on a 2005 GTO. Which is around 4000lbs also.
With the right fuel/tune, yea it can be reliable.

Check out my build thread.

pwrtrip75

iTrader: (8)

I dont think the stock inerds would hold together at the point in which you would have to worry about cylinder wall thickness comparison between a 5.3 and 6.0..

B'klyn9C1

a4ls2goat, I did check out your build thread. Very interesting.

Why did go with the 4.8 liter rather than turbocharge a the LS2 that came with the car or even a LS1 which first came in the first year of GTO(Monaro) importation????

BTW did retain your AC with your single turbo setup??

a4ls2goat

Long story short. I broke a ring land on my stock motor

B'klyn9C1

Under boost??

a4ls2goat

Yea. My fuel system wasn't up to task. So now I switched to e85.

Cronic_Moronic

From what I have been reading the weak link in the lsx family of engines are the factory connecting rods. The rods are shared with all the engines in the family so people who plan on keeping the stock innards go for the less expensive engine since they all will let go at around the same HP level.

silver_82

No one is being truthfull the real reason everybody does all the 5.3 engines is because the internals are a special alloy made with unobtainium, black rhino horn and uni-corn main. Its all voodoo **** man. Some say Thor forges the rods by hand.

jridenour31

This, but you're forgetting adamantium.

I8UR4RD

iTrader: (16)

yeah cuz a 408 turbo wont really be any better. make the same power with the 5.3 and a smaller one. same torque too!



they are magical because its good power, with fairly good reliability on a budget. if you pop one...you can go buy another 12 pack on special at motor mart.

B'klyn9C1

LOL Great response to my question and I love your avatar too!!!

N2OBaby

The Magic is using a Stock $350-700 motor if you break it you can afford to replace it try that with an LS9,LSA,or LS7.

NightmareTA

iTrader: (20)

WRONG! Lizard skin. Children's tears.

This is the magical makeup of a 5.3's internals.

But in reality, the 5.3 is just a cheap affordable motor and the power they make with boost is unbeatable for the cost. The smaller bore and piston also makes them slightly less susceptible to damage from detonation over a large bore engine.

B'klyn9C1

I get the part about how the 5.3 and to an extent the 4.8 are way cheaper and easier to obtain from a junkyard than your typical 6.0 or 6.2 liter LSx. There more of them out there etc. etc.

But how do you explain those stratospheric RWHP AND RWTQ numbers that people post here on this forum about their boosted 5.3 liter budget builds?? You know 600 to 800 RWHP on little more than 1 bar of boost. Should there be at least typically 1000 FWHP from a boosted LS3/L92 stroker(408+ ci)???? After all the LS3/L92 based strokers have at 90 ci more displacement and way better heads than the 5.3 liter LM7???? Right??? Or am I missing something here???