Killer_Z

iTrader: (1)

yes the crank can. but not rod's and pistons. theres some procharged and turbo ls1's running pretty solid in the 600's but still even they say its a time bomb really. most build to 500's to stay reliable. atleast from reading the last 8-10 years.

Cody Strife

iTrader: (1)

Good info, so from what I get the only way you can really risk your stock internals is with power adders such as turbo, supercharger, or nitrous.

A head and cam LS1 with 105 intake and throttle body should be fine on factory connecting rods...

95maroz28

iTrader: (21)

^should be fine if you upgrade rod bolts or keep the rpm down. Ive ran my 98 turbo ls1 around 500-550 rwhp last year or so with no problems

Killer_Z

iTrader: (1)

yeah w/ power adder ur typically looking at 550+ easily, so it obviously adds more to the risk factor lol. look up katech for rod bolts. theyre stronger material while utilizing stock tension or something along those lines.

cals400ex

iTrader: (27)

I have seen numerous stock ls1's blow. I am currently around 500 rwhp and mine is still going. now, i don't drive it much and i try to not keep it pegged for long periods of time. my personal gut feeling is that higher rpm will hurt you more so than more power. i keep the shift points at 6200 to try to keep the bottom end together.

A.R. Shale Targa

iTrader: (2)

As others have agreed...the production shortblock has reliably dynoed 500
plus rear wheel several times (camscam and chris1313 to name a few) yet
they do have to spin them to 7200-7400 which elevates the stress loads on
the pistons (speed in ft./sec.) as well as the limits of the powdered metal rod
even if upgraded with aftermarket bolts.
Even Car Craft (IIRC) just sprayed a junkyard LQ9 w/cam and FAST intake
using a direct port fogger, like 20 degrees of timing, and 109 octane for like
750 dyno horse at I believe 6500 rpms. Again keeping the tune right AND the
rpms down helped it live. For the record it had 190,000 miles on it.
Now the reason you can safely make a bunch more power with forced induc-
tion is twofold. The rpms can stay in the 62-6400 range and they make peak
power just after top dead center (with regards to the piston location) this is
much easier on the stresses to the stock pistons and rods, whereas peak
with NA and NOS is right at the ragged edge of detonation (almost trying to
back the piston up)
A simple Borg Warner S480 on E85 can dyno 1000 flywheel (perhaps just shy
of 900 rwhp) with quality heads, the right cam, a FAST intake, and BIG injec
tors. I'm not saying this is a daily driver however there are plenty of people
on the turbo forums running high eights and low nines with combos like this
in G body or Fox chassied cars; and having decent longevity.

Z28Drifter348

I understand that being able to make power at lower Rpms is going to keep stress off the rods/pistons. But let me ask you this. For the few thousand dollars that it cost to build an ls motor with some forged Rods and pistons. Is it really worth risking? In my opinion it is not, I learned the hard way. When you spend 400$ on a cam ,150 on ls7 lifters and 1800 for a set of heads and all the other misc things needed and after a rod beats the **** out of the cam and some valves get bent and there's a hole in the block the size of your fist. You realize that you just lost faith in trying to make 300whp more than what the car made from the factory on a factory rotating assembly. Don't get me wrong nothing is forever but a forged bottom end is going to Handel much more abuse, high shifts and other factors involved with initial tuning lean conditions/detonation etc. than a stock bottom end.

A.R. Shale Targa

iTrader: (2)

FIXED 4YA
I only answered The OPs question. Please don't assume that I'm advocating
using stock parts for mega-horse builds. Some people are cheap and some
just don't give a F#CK.........case in point
http://www.hotrod.com/techarticles/h...g_bang_theory/

Detoxx03

iTrader: (14)

I had two pistons let go at 602rwhp

Z28Drifter348

^1000 engines my ***. Who the f**k quotes a post and makes changes to it. Haha. I pity the fool who takes this that seriously. 1000 ENGINES!!

Cooldude5231

iTrader: (6)

friend of mine has a completly stock bottem end ls2 pushing 811whp to the tire through a th400
hes now upgraded injectors (since he maxed out his old 160lb's) and is running 8.7's in the 1/4
he beats the hell out of it.
he keeps trying to blow it up seeing as he has a complete forged rotating assembly sitting on the bench, but cant.
hot rod mag, did a article on a 150k mile twin turbo 4.8 truck motor that help up 60 dyno pulls at over 1000hp.
heres the link
http://www.hotrod.com/techarticles/h...g_bang_theory/

A.R. Shale Targa

iTrader: (2)

I can only imagine that the BTUs of heat kicking the slugs of your mill @ 600
rearwheel or 700 crank was enough to close the factory .018" ring endgap
which then pops the dense part of the cast flattop off and all hell breaks
loose then. If you manage to shut her down quick enough and the piston is
still connected to the rod the area usually broken is right near the exhaust
valve section of the slug (highest heat temperature)....sorry to hear this
The silicon content of hypereutectic pistons is so high that it tries to
reject the cumbustion heat back into the chamber to create more TQ
and consecuently causes the top portion of the piston to run hotter
which closes the ring end-gap.

gto866

there is no one number, but over 500 and things do tend to break. conservative is nice - you get to actually drive the thing and not sit in the garage all the time doing repairs

MikesTA2002

iTrader: (1)

that write up was really cool..

95ONE

iTrader: (1)

Those blocks also have crazy thick cylinder walls and amazing I or H beam Connecting rods with full floating wrist pins... Big difference from what the 5.7 LS has. They didn't mention this in the article. Here are the rods that came out of my 5.3 liter.. compared to some LS6 rods and pistons. The thicker rods are from the 5.3.

Cody Strife

iTrader: (1)

It's sounding more to me like the limiting factor on rods and pistons is the maximum torque they are exposed to...

This would explain why I have always seen engines go in the meat of their torque band and not 1000 or less rpms before hitting their rev limit.

I am betting the reliable horsepower limit is much higher with a centrifugal supercharger vs a turbo or positive displacement blower. Simply because your not exposing the engine to longer durations of increased torque...

For example, they may both reach the same peak horsepower, but one (turbo) is making alot more peak torque earlier on...

disc0monkey

iTrader: (10)

doesn't the rotating assembly see much more power on a supercharged car vs turbo or nitrous?

A.R. Shale Targa

iTrader: (2)

The blower drive hub needs the crank to be keyed...sometimes double keyed
Then as boost escalates the amount of horsepower needed to turn the blower
increases which causes belt slip...more ribs on the belt or a cogged design
helps this but then an extreme tensioner is needed putting added stress on
the crank snout which then becomes a weak link.....every engine combo has
it's pros and cons....compromises

disc0monkey

iTrader: (10)

we might be saying the same thing(parasitic loss), but for example on a supercharged engine making 650 crank hp(around the stock short block limit) the rotating assembly will be seeing 700-750 hp worth of heat and load.(way past stock short block "safe" limit)

mrstepheneades

I put down 755rwhp at Tick on a cam only s475 fed 130,000 mile ls1 with them letting off before the peak power at only 5800rpm on the Dyno because of a glitch on the computer. Seen the number and told them not to make a full pull lol because I had no idea it was putting down that much power. It was just a Dyno day and wasn't really concerned about making another pull to the full 6600rpm. Figured I may of picked up closer to the 800 rwhp number if did though. I realize the ls1 is on a prayer but with low timing and enough fuel( 11.0 AFR with 100% meth) it will live a while long as you don't drive it like your average Honda owner the barks his gears and twist 9000rpm and thinks he has 300 HP but really 150 lol.