flynbludream

iTrader: (1)

Ok so there are 3.0 liter supras running 4 digit HP, 5.0-5.2 Gallardos running 1500 hp, lots of little displacement engines making big power with big turbos. Skinnies has proven a junkyard 5.3 can push 8-900 hp or whatever he is at. The heads and parts available for chevy engines is second to none. Displacement is not a requirement for huge HP.

So what does it take to run a 5.3 to 1500+ HP? The 5.3 platform has more sealing surface than other LS engines so that should help. Obviously you probably want a thicker deck head to prevent lifting. Outside of that, what do you need to push 30lbs of boost+ through these things? Stock cranks are stout as hell. You can push 1K HP on a 400+ CI engine at less than 20 lbs of boost, I want to see a 5.3 at 30+.

Why hasnt anyone done this? Lets hear what it would take to build a reliable 30lb 5.3.

Fbodyjunkie06

iTrader: (10)

First off, get an iron block. Second, your going to need a stout rotating assembly. Oliver Billet rods (or some other comparable billet rod, maybe a stout I beam) Diamond pistons(or the like). I'd use a forged crank for that power level like a Callies Magnum or a custom crank. Then your going to need a 6 bolt head like a mast small bore head, or a trick flow, or all pro head. I'd have the block o ringed, pin the mains, big 1/2" main studs and head studs also. Maybe even hard fill the block 1/3 the way up, rpm will be a deciding factor here and the engines power band.

Now that you have the hard parts figured out, all you really need to decide is what type of cam (hydraulic or solid) to use, intake type and style(tunnel ram, carb style with an elbow, fast, or stock style intake), fuel type, turbo size, converter, rear gear, and transmission to go with it. I'd use E85 or methanol to fuel an all out combo of anything turbo, 2 injectors per cylinder, and have a marcella tunnel ram with burst panels made for the motor. Have the cam custom spec'd then time to choose a turbo.

Turbo selection would be a PT91, GT55-91, or comparable, maybe even a 94 for a little extra over that 1500hp we are looking for here. A 4500-5000rpm stall converter, and if we were 1/8 mile racing a 3.90 rear gear and 3.50 for 1/4 mile assuming a powerglide is being used. That's no where near all of it, but that's a start to what it would take.

Sarg

iTrader: (6)

Been wondering this as well. Also curious what the block itself is good for.

71 chevy

iTrader: (18)

pull out a blank check and give it to a top engine builder. done

tim99ws6

iTrader: (31)

uuuummm....WTF would you put a 6bolt head on a 5.3 motor?


At about 1200, i'd swap out that stock crank for a nice aftermarket piece. Being FI, I'm a fan of Aluminum rods to take the beating off the crank a little too, but with a nice aftermarket crank, you can go billet rods too. Obviously pin the mains and ARP stud everything

Turbo or S/c is pretty simple, so no need to discuss there.

For heads, definitely an aftermarket casting is a necessity. I'd probably do a pyramid ring setup with a 1/2 stud and MLS gaskets.


The nut-cracker is RPM on a 5.3. If you are going to make the power, it's going to have to rev well. That means a really excellent flowing head and intake package, solid roller and high rpm valvetrain stability.

LS1x2

iTrader: (11)

Those smaller motors making all that power are turning much more RPM. They push more air than you ever will on a 5.3L at 7krpms. This means they can spin turbos higher as well.

flynbludream

iTrader: (1)

So this is the cookie cutter response for all LSX (usually bigger CI) engines to get to 1k HP. Skinnies is doing 850 with a stock 5.3 with ARP hardware upgrades on a junkyard aluminum block. So is all this necessary? Theoretically the 5.3 should die around 700+ rwhp. With the extra sealing surface do you need to o-ring? Or $1200+ rods? What empirical evidence is there to justify the need to fill the block? I remember seeing some magazine putting down 1k HP on a mildly modded 5.3. Granted that may not last long, but who knows? Tune seems to play a tremendous part of how these things stay together. Thanks for the feedback though.

flynbludream

iTrader: (1)

The LSx heads all seem to flow exceptionally well and the aftermarket ones even more so even "as cast". Any suggestions on heads? What are the max valve sizes you can fit on a 5.3? I'm in the "let the turbo do the work" camp for power. Cam selection would definitely be key as would the valvetrain. Wondering how well aluminum rods would hold up? Maybe we should shoot for a 1khp goal.

Would you need to spin it much past 6500-7k rpms?

NemeSS

iTrader: (127)

I guess I would try my luck with nuttiest stock crank, precision balancing of crank with hbeam steel rods, thick crown pistons. Appropriate ring package and assembly with precision machine work on block. Doweled main caps with studs, precision clearances with appropriate bearings. Heads studs, with 205 afr heads. Custom grind, jesel rockers, TT tc78s

71 chevy

iTrader: (18)

This 1500+ hp engine is going in your street strip warrior right? and is it going to have an overdrive transmission and AC? do you also want it to get 20 plus mpg.

I dont know your knowledge level and I shouldnt assume, but honestly not a lot of people would even know what to do with 1500+ hp, and not a lot of people have the drivetrain to support that.

how much do you have for the trans?
have you budgeted for the rear end to support it?
how about stiffening the chassis and the rollcage you need
how about the fuel system to support that much power


and as far as knowing what it takes to run 1500hp in a 5.3, I know of only one person doing it ,ultimate 346, you should ask him.

Bobsmyuncle

iTrader: (32)

I don't think it would require all those high dollar parts u guys think it will. There's hardly been ANYONE that has broke a stock crank. How many blocks have u seen fail? I've never seen one fail. I don't think it'd be all that tough really. It require a few certain things....

Stock bore- I think this is fairly important, for the cylinder pressure, and for sealing.
Boost pistons- diamond like mentioned before
Billet rods- i wonder sometimes how underrated the rods are on the market. But any billet rod should hold 1500.
Crank- I'm sure 1500 is possible w a stock crank, but obviously won't last too long. I thing a callies or any off the shelf forged crank will hold. Guys r making 1100+ w em all the time.
Obviously the other biggest task besides the bottom end is sealing the heads under 30psi. In my opinion, It wouldnt be that hard. I've seen stock sized studs, with regular gm gaskets seal 20+psi many times. I think it'd take a few key things..
1/2" head studs
Super flat deck surface
Super straight head surface
Double oringed. WITH receiver grooves. One oring inside the other and I think if u did one on the head, and one on the block, it'd seal just about Anything.
And of course use an aftermarket head. Somewhere 245cc range.

Turbos, the easier part of this equation, I'd go for billet bb 70-76mm range.

I've been wondering what that cheap 5.3 sittin in the garage is capable of.,..

Bobsmyuncle

iTrader: (32)

A 5.3 litre will move more air at 7k rpm than a 3.0litre at 9k Rpm any day.

tim99ws6

iTrader: (31)

That's adorable you think a 76mm on a 5.3 will make 1500

Bobsmyuncle

iTrader: (32)

turboS with an S, means plural. Or more than one. Pretty adorable huh? U will never be able to spool a 1500hp turbo on a 5.3. Atleast not by 7500rpm.

1fast bird

iTrader: (22)

No need for 2 injectors per cylinder when they make ridiculous sized atomizers. Also if you are making the said 1500hp, then you would want a tighter converter than that. Pretty sure Fireball was running a converter stalled below 3000 on his old 366 setup making 1700hp give or take.


I think a gt47-88 would be a kick *** turbo for the small cubes maybe even a gt55-88.......

stock48

iTrader: (17)

I've seen a 5.3 spool twin billet precision 67's. Two of those on kill would have to do something, it would definitely want to rev.

SS4Matt

iTrader: (4)

These Supra's and Lambo's and other high revving vehicles have over head cams, Making a pushrod motor run as high (RPM) as they are capable of is the issue you will have, especially making it more than just a 1/4 mile at a time piece.

tim99ws6

iTrader: (31)

My bad,

So you're saying twin 76mm ball bearing turbo's is how you would budget build a 1500hp 5.3?.....


Sorry, I was confused!

71 chevy

iTrader: (18)

are you quite sure about that?

slowride

iTrader: (3)

Rpm, the engine needs some. Solid roller, single plane, some sort of intake and camshaft combo that works in the correct powerbandr. Trying to do this on a hydraulic roller will keep power under 7k rpm for the most part, will result in a short powerband and a lot of torque (which tears up things the most).