codyss

Without reading all of the GM article I was just wondering exactly how the LSJ is only good to 300HP?

Are the pistons really that weak? It isn't like eveything else has super duty pistons.

Since HP is derived from TQ I would see certain parts of the drivetrain being the weak link before internals.

UtOhCop

I wouldn't push the LSJ past 300 horsepower without some Forged Pistons and rods.

MarcS

The rods are okay, I would say it's safe to push past 300hp on stock internals. The book on the engine build for the 300+ hp did not say how much power it would be actually making. It may be 380 for all we know which could be the threshold on the pistons.

We can probably get near 300 with a stage 2 and some bolt on's alone.

BLKSS

Arent they already forged?

Waylin22

Im never goin above 300 hp with my SS/SC, it will put too much stress on the engine alone....i want this engine to last me a long time so I can avoid putting in a new one down the road later.

glockglade

I would think that since the LSJ is already supercharged, and the stage 2 upgrade for it puts it to 15 pounds of boost I think this engine can put well over 300 and still run well. You might not want to run it everyday, but a once in a while WOT seems like it would be ok.
Current Mods
Custom 3" exhaust, sportline springs, and intake mod
Future mods for my SS S/C
Fujita CAI
TOG headers w/downpipe&cat
stage 2 upgrade, with SFPH smaller pulley to put boost around 17 pounds
And hopefully Brembo will get in the game for some serious Brake Kits.
That should put u right around 300hp and unless you r a fulltime racer that should be plenty for a daily driver 4 cyl.

R33P3R007

I think 300 to 350 is plenty for this motor. any more then that and I would want to do motor work.

SilverSS/SC

I dont remeber where I read it , but it was a tech article on the 2.0 SC engine . that article stated the shortblock was rated to withstand 475 hp . The internals are already forged .

BullDog71ss

I remember hearing or reading that 400hp was fine for the stock internals/head on the 2.0.
I also remember that all the internals were forged, not just the crank. What the hell is true and what isnt? I cant imagine GM putting hyperuetectic pistons and cast connecting rods in a high boost, high revving engine.

ExHondaMan

Article says the stock pistons are hypereutectic not forged.
*EDIT* I believe the pistons are forged.
The article does not specify whether they are refering to 300hp or whp. People with psifi kits are putting down around 235-250ish on dynojet... with a modest 8-10% for drivetrain loss your looking at 255-280ish at the crank... I find it hard to believe that another 20-30hp is all it can handle... who knows though.. Well have to wait and see how things progress...

wesmanw02

Well considering the internals of the stock 2.2 Ecotec are good up to 280HP, I can't imagine the 2.0 S/C engine being only 300. GM tested the 2.2 Ecotec themselves and found out that at approximately 280HP, the connecting rods simultaneosly and catastrophically fail.

So considering that, I'd say the LSJ should be good to at least 375HP on stock internals.

Chevy4Life85

yeah form what IO have read/heard over the past year about the car the 2.2 engine is good up around 300 and the 2.0 is well over that

Maximus

well guys HP does not magically kill your engine.....adding power actualy will do very little to your engine....adding 300 whp over stock is less stressful then trying to spin your motor an extra 1500 rpm.....RPM kills engines HP doesn't..........read maximum boost for a good description of why this is....................Also when your upping the HP the power itself is not what kills the engine, what kills the engine is that when you up the boost there are alot more things that can go worng, such as detonation and running lean etc............but adding raw HP in itself does not kill your engine, as the loads are not directly transfered to your rods like you would think, ............................with good tuning and good mechanical knowledge this motor will hit 400 whp easil;y on stock internals..............My V-6 was apparently a very weak engine, but after a few years of know how we can hit well over 300 whp on stock internals, and we only have cast pistons and rods on a motor never meant for boost...........If the 2.0 Ecotec cannot handle 400 whp on boost friendly stock internals there is something wrong........................you guys really need to do some reading before you all start speculating on something nobody here knows anything about

Jmc007

Maximus you got some right points; and my opinions is there is no problems to make some mod like header, intake, exhaust and a few PSI more with a pulley. All these mods (except for the pulley) won't add HP by themself, but will remove some restriction, which will release some horsepower. It won't stress the engine too much.

Self

Why not? And when is 12-13psi considered high boost?

codyss

12-13 PSI is alot for a S/C application.

12-13 PSI is not alot for a Turbo application.

Maximus

Stock the Cobalt SS is only using 50% of the blowers capacity........PSI means nothing, impeller speed of the blower is most important..........for the Cobalt to be pushing 12 psi stock and only hitting 20 whp tells me this car either has terrible flowing heads or it needs some serious intake and exhaust upgrades..................On 4 psi the Tiburon makes more WHP then a stock SS

UtOhCop

You use an M62 on your Tibby? Also does your Tibby have the same compression ratio as the LSJ?

codyss

210-220whp isn't less than a Tiburon @ 4psi.

Maximus

actualy I will show you a 230 whp Tib at only 3.5 psi..................and for reference my buddies 4 psi SC Tib put down 206 whp on a loaded dyno where we only dyno 135 whp stock........

a stage 1 Tib(4psi) and a Cobalt SS are likely evenly matched with the Tib likely being slightly faster of the two as many stage 1 cars will run very low 14's...the Tib is geared better

But my point is a stage 1 Tib is making 210 whp and a SS/SC is making 210 whp except the SS/SC is at 12 PSI and the Tib is at 4 PSI.......but my bet is the impellar on the superchargers are spinning very close to the same RPM...as 200 WHP needs X amount of air regardless of what motor, and each SC is pushing enough air to make 200 WHP...except the Tib's setup seems to flow better hence it has lower PSI......

MarcS

Also take into account the cyl compression. The Cobalt's is very low which is more boost friendly as opposed to the higher compression ratio of the tib because it was manufactured as a NA motor.

ExHondaMan

Whats the LSJs compression ratio ? 9.0 ? 9.5? its not that low..

*EDIT*... ya its 9.5...
98 tibby w/ 2.0L is 10.3

MarcS

You're right, I read what I wrote and "very" is too stong of a word.


I'm not sure what it is. I'll look it up now.

MarcS

The stock compression ratio for the SS is 9.5 according to the 300+ build guide.

I found 10.3 for the Tiburon at http://www.internetautoguide.com/car...undai/tiburon/

UtOhCop

The LSJ's compression ratio is 9.5:1? WTF. GM is really retarded. It should be 8.5:1