So everyone says the 4g63 can make 600hp and the Audi 5 cylinder 20v can make 700hp. Of course we all know you can slap a Chinese turbo on a 4.8 LS and make 800 daily driver hp. But what's the truth for a true Grassroots junkyard build? 4g63 maybe 400hp without getting into the internals. 20v about the same. Is the LS really that good? Any other engines out there that I'm missing?
Probably depends on how long you need to make power. My experience is nearly anything can make bulk power, just not for very long.
In reply to barefootskater :
Oh about 6 autocross runs and say 3 1/4 mile drags.
4G63 is definitely up there. I had a friend who was pretty well-versed in them, and he said turbo, injectors and a wastegate were all you needed to hit 500hp for a little while. LS motors are also pretty easy to make dumb power on. Look at Cleetus Mcfarland's Ruby. He had a junkyard 4.8L with a jank turbo kit and a cam making 800+whp. Wasn't the longest lived, but it ran like a freight train. I've also seen 5.3Ls shurg off some pretty big shots of nitrous
Isn't theV8Kid making close to 1000hp with his LS turbo?
Pretty hard to beat the LS V8, especially since you can get it for so cheap. The Coyote 5.0 is another excellent motor, but it's big, heavy, and not cheap.
How expensive are those couplers the tractor pull guys use? I'm picturing two LS engines coupled together hoovering down an entire bottle of nitrous every run.
Stampie said:So everyone says the 4g63 can make 600hp and the Audi 5 cylinder 20v can make 700hp. Of course we all know you can slap a Chinese turbo on a 4.8 LS and make 800 daily driver hp. But what's the truth for a true Grassroots junkyard build? 4g63 maybe 400hp without getting into the internals. 20v about the same. Is the LS really that good? Any other engines out there that I'm missing?
Audis can do 1000+, you are pretty much limited by turbo and fuel injector once you have good rods and pistons in it. But on a stock engine, you are looking at about 80ft-lb per hole until you can expect shortened rods. That is about 500 at the crank.
20vs are thin on the ground though... you'd blow the whole budget on getting a longblock unless you found someone who didn't use the Internet.
Pull a 454 out of an old motorhome, cam and intake, headers. cheap turbo and like 8psi and youd have something that would make lots of power and tons of torque and should live for a long time. heavy though.
Answer to the question as posed in the title is pretty simple: S52.
Worth a read to the end
https://www.hotrod.com/articles/hrdp-1109-stock-gm-ls-engine-big-bang-theory/
In reply to barefootskater :
I don't think Stampie wants to hear the word "motorhome" again for a long, long time. 
¯\_(ツ)_/¯ said:How expensive are those couplers the tractor pull guys use? I'm picturing two LS engines coupled together hoovering down an entire bottle of nitrous every run.
One guy used the driveshaft guibo from a Pontiac GTO/Holden Monaro as an engine coupler between two 450hp small block Chevys. It seemed to do the trick.
mtn said:Answer to the question as posed in the title is pretty simple: S52.
Turbo m/s5X for a torquey build. Stock trans can handle plenty of torque. There are some pretty quick stock S52 turbo cars. Fastest stock block/trans/diff car is in the 8s.
Heavy, but there is the obvious 2JZ, and nissan RB motors.
The VG30DETT is not terribly expensive and will make a fair amount as well (~500 at the wheels on stock turbos, a lot more with bigger ones) and it comes bolted to a robust transmission and diff.
IIRC the VR6 can make a decent load of power as well if you feed it boost.
Legend has it that if the bearings aren't wiped out and you have appropriate ring gap the 4.8/5.3 iron block LS motors are tough to beat. I'm not going to pretend I understand why, but the Internet has lead me to believe this to be true. Disclaimer I run a stock weak sauce 295 hp 4.8 so my personal experience is limited.
Suprf1y said:Worth a read to the end
https://www.hotrod.com/articles/hrdp-1109-stock-gm-ls-engine-big-bang-theory/
That doesn't help me want one less.
Suprf1y said:Worth a read to the end
https://www.hotrod.com/articles/hrdp-1109-stock-gm-ls-engine-big-bang-theory/
Came here to reference that article. HRM has always been refreshingly clear about exactly how they achieved power.
In reply to Knurled. :
I came here to point out the same thing. Wonder what you could do if you found one of the new 2.5l 07k engines? My friend was saying apparently some of the early ones came with forged internals, which should lend them to making at least what the old 20vs could in a smaller package (provided you can fab a manifold for the turbo, supply enough fuel, and have standalone). I remember there being a couple builds into older Audis and obviously the TTRS stuff, but not a whole lot of budget work with this engine yet, which is kind of surprising considering the advantages...
In reply to MrRobogoat :
If you go to The Project Pad, you will find much info on the 07K.
Like how its cylinder head flows hurricanes more flow than the old 20v junk did.
And how its valvetrain also accomodates much more radical lift curves thanks to having rockers instead of direct acting buckets.
And how the oil pump is reliable to 9500 instead of exploding over 8000 like the old 034-block engines.
People have made silly power with the cast cranks, too, no need to hold out for a forged crank. By silly power I mean people are finding the limits of the 01E transmissions, and people say things like "I paint a stripe on the axle shafts, when the stripe twists 360 degrees I replace the axle"...
The main problems with the 07K are that it has no provision for a mount on the left side, and it was never available longitudinally so the intake manifolds cause issues. However it is much shorter than an old 5cyl thanks to putting the chain on the back, and it is supposed to weigh close to what a 4cyl weighs despite having an iron block.
The Atlas 4.2 is known to take boost quite well
5.3 LS it’s the most common and easiest to find replacements. Just go on car - part junkyard search I’m sure you can find 100 within 100 miles for under $400.
354 Poly motor.
Hemi Heads
8/71
Nitromethane.
1K Hp
In reply to Knurled. :
There's a 944 swap kit for it now. Might make it usefull in longitudinal chassis. That would make a fun swap engine for other cars if there was a good manual to put behind it.
In reply to Stampie :
Have you ever taken a Jaguar V12 apart?
The crankshaft is forged En 24 steel that is heat treated to incredible hardness. The mains are 3 inch diameter and con rods are 2.30 inches which makes a LS Chevy look pretty wimpy. ( and weighs 78 pounds)
so are the con rods! (EN 24 forging ) then look at the rod bolts and nuts. They look like something from the best NASCAR BINS. pins etc.
the block itself looks like it’s from a Top Fuel engine only it has 12 cylinder bores instead of 8. Speaking of bores. The iron used in the sleeves must be really high grade because I’ve pulled apart engines with 90,000 miles on them and could still see the crosshatch done at the factory. Yes the head studs ( all 54 ) go all the way down into the crank webs. And yes the 4 bolt main caps are forged EN 24 steel There is a great big crank mounted gear driven oil pump. Just like formula 1 uses.
No rubber timing belts, no cheap stamped parts,
Like any other engine under discussion here you would need to boost them a lot, put a decent camshaft in them and use high octane fuel.
They were making 800 + horsepower on French pump gas, normally aspirated, and lasting 24 hours in Listers at LeMans
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