srt-killer

I was just thinking......If the tubo 2.0 really makes 206hp. at the fly like gm claims and it's not underated, than technically it's only making about 10-15hp more than ours stock. Cause every one already knows were on average dynoing in at 215-220 to the wheels stock, given a 15% loss, were right there with the turbo 2.0. Maybe that motor isn't under rated, and gm is doing it from a business stand point, cause a 55hp incresse does sound really good on paper. And the average persone not knowing what the sc 2.0 are really making, they will go out and buy it. One whay to find out if it's under rated sooner than 2008 is just to wait for the solstice gxp to come out and see what they are dynoing in at.

alleycat58

The motor wouldn't be underrated, as it will fall into the new SAE guidelines. The LSJ S/C'd got in under the old guidelines, underwhich companies routinely under and over rated engines. So with this LSJ with the turbo instead, it would have to be re-rated and would fall under the new guidelines.

srt-killer

So with this said than the T 2.0 and the S/C 2.0 are making the same amount of hp. Right?

Nocturn

No,

the 2.0 Turbo has VVT, Direct Injection and no supercharger to turn. Put in the same application the 2.0T will ALWAYS put down more power than the 2.0SC.

That said, the 2.0SC doesn't have 15% drivetrain loss, the engine makes around 230HP +- 5Hp. Modern FWD cars have barely over 10% drivetrain loss, RWD cars will be aroun 14-15%. Autos will have more than manuals, but only about 1-2%.

alleycat58

^^^^ What he said.

mi6_

True, but the 2.0L Turbo also runs more boost than the LSJ if I am not mistaken. Also, it is somewhat of a misconception that superchargers experience more power loss than turbos because they are belt driven. A turbo also looses potential power because of the restricted exhaust having to be routed through an impeller.

Stock for stock, I would imagine the 2.0L trubo is more powerful. I would venture a guess that a Stage II LSJ would have more or less the same output as the 2.0L Turbo.

srt-killer

Ok than given a 10% loss were still making about 240hp, only 20 shy of the T 2.0. Thats still only ruffly 20hp difference for vvt, direct injection and a Turbo thats making more boost. Thats sad!

Nocturn

Most SS/SC don't dyno over 220, The average is around 190-210 being on the high side. They are underrated, but not by more than 10-15 HP.

That said, even if the 2.0T was running the same PSI as the LSj it will always put down more power due to the blower on the LSJ. I'm not a turbo person, I just know cars. The restriction in the exhaust is far less of a parasitic loss than the extra pulley that the belt has to turn.

The 2.0T will be approximately the same as a GM STG 2 LSj.

This is the reason engines are switching to electric water pumps, electric fans, and so on. My car is old has both a belt operated fan and waterpump. I could see probably 15-20 more HP if I switched to electric systems.

SilverSS/SC

I cannot find the gear spread of the astra's 6 speed trans so I cant accurately comment on how it may contribute to the 2.0t's acceleration in the 08 Cobalt SS . But , there's performance to had right there over our 5-speed . The trans we have is good and strong , but the gear ratio's absolutely SUCK for our powerband .

06black

I know this is a little of topic but it does tie in here...

my buddy Tom's dad just got a sky RL from the GM test flet and myself and him are going to have a friendly little grudge match...

I know this is by no means a stock for stock comparison due to my car but I'll be able to give you all some kind of a heads up and pics!

back on topic now....

Nocturn

True but I'm not sure if the 2.0T will get a the new transmission or not. I know the Solstice will, but its RWD so..

torrin1234

Err... Who cares.

That's 2008 - no offense but all of this omg omg it's going to be turbo stuff is sad. Be happy with what you have, until it's gone. Really.

mattyfinch

no the engine wont be pushing a supercharger, but it will have to spool causing turbo lag, i mean really we can go back and forth all night and day if we want, but until the car is out, dyno'd and proven its simply speculation really.

Remember when the stage 2 kit was supposed to have a 2.8 pulley? then it came out with the 3 inch... dont get too ahead of yourselfs.

Gm isnt stupid and wouldnt revamp the cobalt that drastically only 3-4 years into its production, not to the point of making hte previous tuned model obsolite. The 2.0L turbo at best will put 230 to the ground, and normally a turbo pushes LESS boost the obtain ewual amounts of h.p. ....not always though.... but mostly, and if the engine is the same, u should assume the boost levels off the new turbo to be LOWER stock, then the superchager is omiting.

Nocturn

I've never seen a balt dyno 230 to the wheels.

I thought the stage two kit did have a 2.8 pulley...but I don't own a balt so.

The point I'm making however is that even if the turbo does have to spool, it will make more power simply because it doesn't have to turn an extra pulley. The parasitic loss is higher on a SC than a TC.

SSKING

thats good and all but what do gm plan on doing on it,are they going to keep it fwd or make it rwd

mi6_

1) Most of the six-speeds out there use the 6th gear as an overdrive gear (i.e. it is too tall to be used to reach top speed). Having it would not make your car faster. The Corvette, Viper, Civic Si, and other cars use this type of system. Their transmissions sort-of are 5-speeds, because you only use 5 gears when performance driving.

2) The Cobalt's transmission has good gear ratios. The short first is what allows you to get moving so quick. I have had no problems. My car doesn't bog badly in second if you shift just before redline in 1st. I have driven a car for years with shitty ratios. Trust me, this car has a good transmission.

astrocrep

Check my sig.

Edit Heres link to my dyno scan.
https://www.cobaltss.net/forums/2-0l-lsj-performance-tech-47/another-awesome-dyno-stock-05-ss-sc-8440/

-Rich

Nocturn

In which you show the corrected numbers to be 217, in essence discredditing the 230 since those are "uncorrected" numbers. 217 is about the high end of where most are dynoing...

Either way the point remains, that the parasitic loss on a TC is less than that of a SC, factoring in all the upgrades to the 2.0T, there is no way a stock LSj is going to put down the same numbers as an 2.0T.

05YELLOWSS

I'm just gonna say no to the question, most simply because of the parasitic drag caused by a supercharger being crank-driven...

phxSS

I can't believe no one has made an electric a/c motor yet (except for the Toyota Prius and Camry hybrids). That would save a lot of hp.

grindpunk16

turbo > sc

turbo will make more torque than the supercharger. less parasidic drag and alot easier to upgrade.

WopOnTour

It would be pretty damn close IMO if the LSJ was adjusted to achieve the 20psi boost the turbo-charged LNF is getting.
Wop

Nocturn

Well to answer the original post, there is no way a stock lSj will make stock 2.0T numbers.

But can an LSj make those numbers easily, sure thing.
Is the LSj a better engine? I would say NO, not because of the TC but because of the direct injection.

The two engines are very similar and I really don't see a point in comparing the two, you can get good power out of either, its just going to be easier to do with the 2.0T because it has more to start with.

To the electric AC blower,I presume its beacause the hybrids have the battery power to run it, a regular cars alternator wouldn't be enough to run one, which would require a bigger alternator pulley...and thus eliminating the original point of an electric ac blower.

zinner

SIDI might get better fuel economy but I dunno if it makes more power.

Peak HP numbers aren't everything, if there were the RSX-S would be a faster car.

WopOnTour

Exactly Z
It's still a 2.0L Ecotec
SIDI and even VVT are essentially emissions/economy systems (well with some mid-range bolstering in the case of the VVT) and given the reciprocating aspects of these 2 engines are essentially identical- both would make similar PEAK power NA and at identical boost levels IMO. You can't really compare peak power on 2 near identical engines with an 8psi difference in boost. Furthermore, the slight amount of parasitic loss associated to the SC would be somewhat offset by the 0.3 lower compression ratio of the LNF as well
Wop