Since our car comes with a s/c would it be a waste of money and time to take out the s/c an add a turbo. Or will I just have to wait and see what the aftermarket comes up with?

 

No it wouldn't be a waste. I think everyone will agree that a turbo has more potential. But most people on here want the low end grunt of a roots style blower, and for good reason. But yes a turbo would make more peak power and torque, but maybe more area under the curve.

Just to look at it this way, in the GP community, the fastest cars are ALL turbo cars. Even the ones with huge Whipples or Eatons just can't keep up with turbos. Food for thought.

 

the top end on a turbo just cant be touched. only get more efficent as the rpms rise.

 

Even if you put a turbo on and held it to the stock boost level of 12.5 psi , you would make more power than the roots blower . Do your homework and choose the right compressor , and lag should be minimal to non-existent. I think your gonna find the cars that are gonna keep up with the modded power levels of a STI , EVO or SRT-4 are gonna be turbocharged . Apparently GM even felt so with the phase 5 turbocharged SS . All of GM's high powered Ecotecs are turbocharged . I'd like to feel a little more optimistic about the blower(SC) , but the blower , in a serious combo ....seems to be the first thing to go .

 

just by adding the turbo you'd be in the power range of the saab there are down sides thoe if you raced a cobalt ss with s/c vs your "turbo" you'd probably loose in the begining every time, DETONATION (more money and tuning to get rid of) SRT-4 guys get detonation with bolt ons and stage 2 problem is we cant tune these cars yet so your car would run like crap for a while (hurts car ) you will have to upgrade internals just to turn boost up or BOOM to mush power on stock pistons not good lol SAAB also has a 7000RPM rev limit
and i think there transmission is a six speed correct me if im wrong

Ide rather twin charge but ill wait til it is perfect before i try anything

youd probably be

Engine displacement: 2.0L
Engine horsepower: 210hp @ 5,500RPM (really round 250hp) do to the 7000 rpm rev limit!
Engine torque: 221 lb.-ft. @ 2,500RPM

 

It depends what you want your car for.

If you want reliability, driveability, warranty and low end grunt = Keep the S/C

If you want a pain in the ass, drivability issues, tuning issues = Turbo it

Despite what PsiFi thinks a Turbo or twincharged setup will never run correctly with a piggy back, hell it can barely trick the ECM enough to run a smaller pulley.

I never been in a car that had a tubo added that didn't have a list of tuning issues.

 

Turbos arn't that much worse to tune than blowers. They have the same principles behind tuning. BUT without some type of complete PCM editing software (LS1edit, HPTuners) you'll never get it right. So no piggyback or retuned PCM will work. You'll need a standalone period.

Turbos are just as reliable too. You'll even get better gas mileage since you can run around in low boost all day at low rpms. Or turn down the boost for 87 octane, then pump it up for 104 octane and the strip.

Turbos have also been proven to give as much and in some cases MORE torque than a roots type blower. It will however be at a little higher RPM. You'll be able to launch harder with a turbo without torching the tires too.

But don't get me wrong, I think theres plenty of potential in a larger roots blower.

 

Well that may be slightly exaggerated, but overall what Cody is saying is for the most part correct. Its widely known that Superchargers are easier to install, maintain, tune, and generally provide better driveability than turbos due to zero lag and no cool-down period. Guys who install aftermarket turbos tend to always be tuning and tweaking them, because it is next to impossible to get them set up perfectly.

However, there's no denying that turbo's have more potential when it comes to high boost levels and top end power. Turbos also have less parasitic loss, since they are not powered off of a belt run by the engine.

Bottom line is that they each have their advantages and disadvantages, and its ignorant to claim that one is necessarily better than the other. Superchargers provide more low end torque, instantaneos boost, better driveability, and more linear power, while turbochargers allow for more top end power and more tuning options.

Personally I prefer Superchargers, because of the fact that boost is always ready, they have more low end, and they sound awesome

 

Just to add to my previous post I was only speaking of applications where a turbo was not stock.

And since the Cobalt PCM is sealed tighter than a chastity belt good luck tuning it.

 

So what you are saying is that cars that came from the factory turboed are the only cars that will not have trouble out of a different/bigger turbo?

 

I dont really see how the car would have to many tuning issues. It is set up for FI already it wouldn't know if the compressed air was from a turbo or if it was from a blower. This is a topic that has been on my mind since I drove the car home and I still toil with it trying to figure out how I should proceed (i.e. turbo it or go with a different SC)

 

All your tuning issues with a Turbo revolve around driveabilty at low rpms . In a very basic explaination .....boost comes on progressively with a supercharger to where as in a turbo car it is very realistic to see FULL boost at a very low rpm . Thats why the guy thats doing the tuning has such a tough job . It may be cake to tune the WOT parameters , now lets compensate for several different boost levels at any given rpm under numerous load conditions .


I think there are alot of shops out there that are jumping on the Turbo wave that dont have the expirience to properly tune a street driven turbo car . A good friend of mine has a single turbo( 76mm) 91 mustang gt in the neighborhood of 800 rwhp , and its more of driver than ALOT of heads/cam cars Ive been in . Reliability in Turbocharged street cars are not the fault of the turbo , its typically the fault of mix-matched parts and/or a bunk PCM tune .

I agree on the on the piggy back , but not on the re-tuned pcm . If the LSJ had say hp tuning software avail. , Im sure it wouldnt take someone too long to convert the stock pcm to speed density and use a 3 bar map . Their are quite a few 1000+ hp LS1 combo's using a stock pcm with LS1 edit and a 3 bar map in speed density . IT would be interesting to see how high the LSJ pcm reads RPM . That may also dictate how far the aftermarket will go with the stock PCM . The LS1 pcm for example will go to 8K rpm .

 

If someone could figure out if you could use an LS1 MAF with a MAF Translator (used on DSM's and even Turbo Buicks), you wouldnt need to convert to a speed density system. Theyve been very effective on some pretty quick DSM's and Buicks, and if they could be used on the LSJ it would be a very viable option and make tuning a bit easier.
When it comes down to the almighty dollar and ease of use, the S/C route would be cheaper and easier. When it comes to overall power and potential, the turbo wins.
cvenom, your response hurt my whole head to read

 

What I am wondering is why wouldn't the stock tune be able to handle it? It can real boost, it has tables on how much fuel to add for the boost. I need some more explanation.

the car has a 3 bar stock.

 

Isn't the engine cammed way wrong for a turbo? I would think that the car would be useless till the snail spooled up.