lq4powereds13

iTrader: (7)

Trying to decide which way i want to go Ive found a 90k mile lq4 i can pick up for about 800 or a 50k mile 5.3l lm7 i can pick up for around 650-700. Which would be better for a whp goal of 550? Whichever i go with will have katech rod bolts, arp head studs, speed inc tu1 cam, 317 heads with proper valve springs for the cam, 60lb injectors, ls6 intake, new oil pump and timing chain, and custom front mount t76. Will i be able to achieve the goals easier with the lq4? Thanks for any input ya have. Will be going in my 240 hb with a 4l80e stalled.

MY99TAWS6

iTrader: (3)

Why would you build a 5.3 when you can build a 6.0. Build the 6.0.More displacement is almost always better. Take less boost to make same power as small engine and spool up turbo quicker as well. And 6.0 is very strong but of course at 550whp strength is not that big a deal. Also not sure if this is mostly street driven but the 6.0 will also have a lot more power and torqe off boost.

MUSTANGBRKR02

iTrader: (91)

Either would be a good choice. But if you have plans for more later on the 6.0 would better suit your needs.

Blownz28man

iTrader: (2)

I'd say 6.0l as well. If you want to make sense of your purchase.. Look at a 6.0l Block new. 750.00. 5.3ls used blocks can be had for 100-200. So a few hundred more for an engine is a great deal. From what Ive read 550hp would be well within your grasp for a 6.0.

cjmatt

iTrader: (4)

it looks to me like he is asking which stock motor, he said nothing about pistons, crank, or rods.

I prefer the 5.3, its gonna make the same hp as a 6.0 at limit, if not a tiny bit more, plus theyre cheaper and easier to find. if building a forged motor, id go for the 6.0 though.

lq4powereds13

iTrader: (7)

Yeah stock for the moment except for the upgrades in the first post, if it fails i will pick up another and build it. Would the tu1 be a good cam for the 5.3l?

lq4powereds13

iTrader: (7)

well looks like im going with a 5.3l found one with 15k on it. Any input on speed inc's TU1 cam? Ill be going with patriot dual gold valve springs as well.

Camaro Chris

iTrader: (1)

5.3l FTW they take to boost better. they have a better rod to piston ratio. Thicker cylinder walls, higher revving motor

MY99TAWS6

iTrader: (3)

This is urban legend comments. There are plenty of 408 iron blocks running big power. In fact before the LSX iron blocks came out if you search the old FI lists you can see some of the very fastest cars running 6.0 iron blocks. They are plenty thick and rod to stroke is engineering mumbo jumbo.

Its nothing for a well built 6.0 to spin to 6500 or 7000. You don't need to spin an engine to 10k if you can make more power and torque lower down. The bigger cubes will spool up the turbos faster as well and make much better power and torque off boost which is like 95% where most street cars usually will be. But hey whatever floats your boat. But disagree strongly that a 5.3 is better in any area than a 408 expect for maybe the ability to pick them up for cheap.And a 6.0 iron block is pretty cheap and easy to find as well.

Not to mention you will have to run way higher boost to make same power on smaller motor. This can cause some problems of its own in terms of heads staying down,etc. And late spool up depending on the turbo used.And narrower power band.Or worse power band for street use.Track use not as important if the power band is maybe narrow and at higher rpms.

MUSTANGBRKR02

iTrader: (91)

I believe OP is wondering about stock set ups. If i did it again i would do a 6.0 first so you have room to grow later.

pwrtrip75

iTrader: (8)

When dealing with stock parts, the top of a piston with a smaller bore will have more structural integrity than that of a larger bore.. How much??? No idea. Both have the same stroke so the only significant difference would be the bore....the force on the the piston. I know a stock 5.3 piston can handle quite a bit....I will soon test a stock 6.0 setup.


Boost is the replacement for displacement....

MY99TAWS6

iTrader: (3)

WELL YES AND NO!
Lets say we have my 2.4 litre talon with its 650 hp max turbo.
Pretty much going to be impossible to get it much past that 650 range ,few guys have done it but certainly no potential to get say 1500 or more hp out of it like has been done on current LSX 427 or so cubic inch builds.
Now the 2.4 revs like a demon with its dual overhead cams and it can do 8000 or 8500 rpm like nothing. A built 2.0 talon engine can do 10,000rpm in a flash.
Does that mean these 2.0 or 2.4 are better than a 427? or my built 408 with its "terrible" rod to stroke ratio??

Define better. My powerband on the 2.4 is not the best. The big turbo spins up around 4000 rpm and carries power thru to 8000 or even 8500. Sounds good but around town going up thru the gears the car is not really that great to to drive. It has very little torque being such a small engine under the spool point. And very little torque feels pretty crappy to me as most of the time you are in the city you are not really going to be going over 4000 in normal driving. If I am in third I can gear down to second ,step on it and spool up pretty quick. Car is a manual. If on the highway in fifth I can gear down to fourth and again spool up pretty quick. Going up thru the powerband sucks the most on small engines.

Off the line at track I can do strategies to get off the line under boost. Two step and antilag are two of them or nitrous with small shot.
But in normal day to day street driving the 2.0 or 2.4 is just not that great.
Now if you don't like torque or much power down at the lower rpms and this can help traction issues then ok the smaller engines are not too bad.
And once full up on boost it can still be a nasty quick ride. And can give the tires a challenge even with awd.

Now on the street to me at least more displacement is still better. More torque,more power off boost and you don't need to run as much boost to get similar power and you have less potential from the smaller engine usually. While it might seem on paper you can just run say 25psi to put out say same power the bigger motor can get at 15psi the heads may not stay on the car at 25psi. The turbo might not like putting out 25psi to name a few reasons.

And since most of the time most street cars would be in light boost or no boost unless racing people or trying to get huge tickets again the bigger displacement engine is to me much nicer to drive. Yes it can be hard on traction. But that comes down to suspension,boost ramping,traction control strategies,tires...

So given all that I would love to have a 427 LSX build or a 454 LSX in my car right now. But the 408 will have to do. Even with its bad rod to stroke ratio..

Engineers..I think they still can't explain how bumblebees can fly!

Its also interesting to see the argument that little motors can't turn the fast times that big ones can. They can turn some amazing times but it does take big boost to do it and usually the powerband and area under the curve is not too great. Go drive an s2000 NA honda. Then drive an NA ls1 right after that.
I think most of us of course would prefer the ls1 powerband.

pwrtrip75

iTrader: (8)

^ Your preaching about nothing relevant.... this is STOCK parts im talking...as is everyone else but you.

If you pumped the same amount of air through the 2.4 as you did the 427 they would probably make close to the same power... Thus boost is the replacement for displacement. Would it hold? Pry not.... who cares.

pwrtrip75

iTrader: (8)

^ Your preaching about nothing relevant.... this is STOCK parts im talking...as is everyone else but you.

If you pumped the same amount of air through the 2.4 as you did the 427 they would probably make close to the same power... Thus boost is the replacement for displacement. Would it hold? Pry not.... who cares.

MY99TAWS6

iTrader: (3)

Ok stock parts..The 6.0 cranks are very strong. The 6.0 has more cubes. Don't give a crap about rod to stroke ratio its engineering mumbo jumbo.The 6.0 will make more power and torque off boost. The 6.0 will make more power at lower boost than the 5.3.And way more torque.
The 6.0 will spool up the turbo ,whatever turbo is used quicker. The 6.0 will have a better area under the curve. Only possible downside would be if the 6.0 was much more money than the 5.3.

And as already said if and big if you could move the same air thru the 2.0 built or not as a built or not 427 the peak power might look to be simlar although don't think seen hardly any reliable much over 500 engine stock 2.0 engines talking bone stock no forged pistons,cranks,rods.
But again the area under the curve would be crap compared to the bigger motor.

I am mostly arguing with anyone that thinks the 5.3 is superior in any way to the bigger 6.0 engine. Its a cheap alternative maybe thats it. Price is only real reason didn't go up to a 427 LSX and also didn't think needed over 1000rwhp on any sane street car.Heck 600rwhp is more than new z06 or zr1.

MY99TAWS6

iTrader: (3)

Ok lets talk stock pistons..they are crap.hypercrap. Seen a lot with blown out ringlands. Several from hardly any boost at all just a bit too much timing,too lean,..KABOOM. might even take a turbo with it when it grenades. One reason went right to forged motor after seeing few local guys wipe out the stock ones..one procharged ls1,one sts forged lt1 to name too.
So rod to stroke is least of the worried here. And guy is using some mods already just keeping crank, rods, pistons for now. At least he is dropping compression with the 317s which is good idea.

All I know is my 6.0 is much more fun to drive around over even my 5.7 95% of the time when am off boost and just street driving. 5.3 off boost with lowered compression..weaksauce but should make for better traction and will take a lot longer to spool up the chosen turbo.

Anyway he said he had found a 5.3 so not big deal. Its not the end of the world he can always do a different engine later on. And a 5.3 even stock can still be fast with enough boost going thru it.And of course its still a v8 not some little four banger.

pwrtrip75

iTrader: (8)

Who builds a turbo engine to run good off boost?
<-----not this guy

355TurboLT1

iTrader: (11)

98Z28cobrakiller is running a 370ci LQ9 and has run a best of 9.1 in the 1/4 and is looking like he will hit 8's any time now. He is right under 9 to 1 compression. Granted he is running AFR heads,forged pistons and rods. But it shows you dont need a 408 to go fast. Check out his setup.

ninetres

iTrader: (35)

Stock internals for stock internals the 6.0 will make more power/torque ON AND OFF boost. It will also spool the turbos faster.....AND leave room to grow to a 370 or 408 one day.

No real world advantage of the 5.3l over the 6.0 platform besides cost if you can find one cheap.

(I know a lot of this was said already but I figured I'd verify the opinion.....or is it fact???)

lq4powereds13

iTrader: (7)

haha thanks for the info guys, ended up buying a 07 5.3l l59 with 15k on it for a pretty good deal. Not going to push it too hard until i pick up a extra block to build anyways. Would it be better to go with a custom cam spec'd out by pat g or say the tu0 from speed inc?