[nastyblacksrt]

So you're saying if I take 2 identical SRT-4's.....leave one stock and put one at 40psi. They will last the same amount of time.
Not taking a 10psi engine and a "similar" 15psi one, taking the exact same engines and testing them against each other, the exact same engine and components a 10psi version isnt going to have more power than the 15.

Yeah I am sure you can take one engine, port and polish everything, balance and blueprint everything, add water/alky injection, map clamp, injectors, different intakes and exhaust, other components the 10psi may have more power, but the exact same engine/car setup.....how will the 15psi car make less power.
Boost leaks don't count.

and boost does not equal power? so how are people going from stock boost turning it up to 19psi and they are getting quicker times or showing more hp on the dyno? are they cutting down wind resistance?

Gotta give it to us SRT guys to start some shit. But i concur.

the motor wont be able to hold much with that kind of compression, and then an engine rebuild on a brand new car to get some decent power??? nope not me, last time i checked i dont have a money tree growing in the back yard. I say the cobalt with max out at around 260whp with a gang load of mods....exhaust, fuel tuning, pulley, intake...etc. 260 is still not a bad number for a fairly light car.

 

[DanM]

So you're saying if I take 2 identical SRT-4's.....leave one stock and put one at 40psi. They will last the same amount of time.
Not taking a 10psi engine and a "similar" 15psi one, taking the exact same engines and testing them against each other, the exact same engine and components a 10psi version isnt going to have more power than the 15.

Yeah I am sure you can take one engine, port and polish everything, balance and blueprint everything, add water/alky injection, map clamp, injectors, different intakes and exhaust, other components the 10psi may have more power, but the exact same engine/car setup.....how will the 15psi car make less power.
Boost leaks don't count.

and boost does not equal power? so how are people going from stock boost turning it up to 19psi and they are getting quicker times or showing more hp on the dyno? are they cutting down wind resistance?

Well yes, of course, EVERYTHING else being equal, if you just slap on a smaller pulley, you get more boost and more power. But you'd be pretty stupid to do that, wouldn't you? If that's what you're talking about, simply sticking on a smaller pulley with no fuel/calibration/other upgrades, then yeah, maybe at 14psi you top out and start to go lean. But again, you'd be pretty stupid to do that, wouldn't you? What you want is high flow, not just high boost. Boost by itself means nothing.

I have neither the time nor inclination to start into a whole physics lesson here. But boost is a measure of RESTRICTION. Boost is pressure as a result of air NOT making it into the combusion chamber, and so no, it absolutely does not equate to power. The simple "crank up the boost & go faster" thinking is way too general and simplistic. That's the way most Honda kids w/o any knowledge of how forced induction works talk... "I'm gonna put 45psi in my VTEC!! R0x0rs!!". The "crank up the boost & go faster" thinking is like saying more voltage always equals more power. Well.... uhh... generally, I guess, but that's pretty simplisitic and really doesn't take all the information into account.

Cobalts will easily make more than 260hp, and you'll easily see ones at more than 14psi of boost. In fact, I'll bet you now that you'll see one at some point making 300hp on LESS than 14psi of boost.

Whatever. If you think the way to make more power on an F/I engine is just to crank up the boost till it pops, go nuts. And if you think a 9.5:1 static CR is going to prevent serious power, then by all means, leave your engine stock. I'll see you in my rear view mirror.

 

[mm_omega2]

No, the point was that you said a 10psi engine would have more power than a 15psi similar engine....
So here's my scenario. (Just using the srt in this one because that is the only F/I car I have until we get the Cobalt next year)
The SRT runs around....13-15 lbs stock give or take. They can also run up to around 17-19 without running too lean (Some SRT's run really rich stock)
So take a stock srt, tune down to 10psi....tune one to 19psi. You don't have to worry about fuel flow, it can handle it. Which will dyno more power? Which will win in a race, 1/4 mile?
Never said turn it up til it pops, I was saying crank it up because you said it makes zero sense saying a motor break at a certain boost pressure. Now you say crank up the boost til it pops which is saying turn up the boost until the engine breaks...same thing right?
So boost makes absolutely no HP...then why does adding a turbo add horsepower....so its the restriction of air not going into the engine that adds power not the addition of air going into the engine.
Then you say putting on a pulley will make more power and boost but it's stupid to do? I'm jsut not following you.
You won't really have to worry about new fuel systems until you start getting into big increases in boost, adding 2-4 lbs is not a huge increase, significant but not huge.
Top fuel dragster's making real serious power...compression 6:1.1..running 54psi, why do they use such a low CR? Lower compression with higher boost reduces your chances of detonation.

 

[WRicerX]

More boost always equals more power. It's more air being forced into the cylinders. Granted, that air has to be compensated with gas. But unless you have exceeded the efficiency of your s/c or turbo, then I can't see why it wouldn't make more power. In fact, as a very general rule of thumb, for every 1 psi increase in positive pressure, it can up the power 15 hp. Obviously that can vary with engine setup, size, modification, etc.

 

[mm_omega2]

More boost always equals more power. It's more air being forced into the cylinders. Granted, that air has to be compensated with gas. But unless you have exceeded the efficiency of your s/c or turbo, then I can't see why it wouldn't make more power. In fact, as a very general rule of thumb, for every 1 psi increase in positive pressure, it can up the power 15 hp. Obviously that can vary with engine setup, size, modification, etc.

Exactly.

 

[DanM]

Gah. You're completely missing my point. Read carefully.

So here's my scenario. (Just using the srt in this one because that is the only F/I car I have until we get the Cobalt next year)
The SRT runs around....13-15 lbs stock give or take. They can also run up to around 17-19 without running too lean (Some SRT's run really rich stock)
So take a stock srt, tune down to 10psi....tune one to 19psi. You don't have to worry about fuel flow, it can handle it. Which will dyno more power? Which will win in a race, 1/4 mile?

Of course this is true. I'm not arguing this.

Then you say putting on a pulley will make more power and boost but it's stupid to do? I'm jsut not following you.

You said that the most the LSJ can handle is 14psi. I said no, it's not that simple, it depends on 100 million other factors. Perhaps this is true if you change NOTHING else and just slap on a smaller pulley. But that's stupid. Now read carefully. I didn't say a smaller pulley was stupid, I said JUST a smaller pulley was stupid. There are already people making 18+psi on the LSJ with a smaller pulley AND fuel AND calibration upgrades.

THAT's my point, and THAT's why you can't just look at boost by itself.

So boost makes absolutely no HP...then why does adding a turbo add horsepower

If you're asking me this, then you really don't understand how compressors and an F/I engine works. More air FLOW makes more power. Boost is not air flow. Boost is pressure.

I'm not typing anymore, but I have a really informative link somewhere about how compressors and F/I engines work. I'll post it when I get home, for anyone that's interested. I'm done now....you can have the last word.

 

[mm_omega2]

1st I never said an LSJ can only handle 14psi....only statement I made about it was that stock I believe they are pushing around 12psi, but I had heard different stories of what absolute stock boost pressure was. On post #22 you said 14psi and you top out and go lean.
Yeah I know boost is pressure, I could get that much by looking at my boost gauge where one side says vacuum and the other half says pressure.
and yeah I also know boost is pressure, what kind of pressure ...AIR.
To get more power overall you need boost and flow....you can take the stock CobaltSS crank up the boost and get more horsepower.... increase flow, do the K&N drop in filter...more power.
Boost alone will make more power because you are forcing more air into the engine.

 

[DanM]

I apologize, it was someone else that said the engine will "break" at 14psi, not you. See post #19. My mistake. Either way, what I'm saying still applies, that statement is over-generalized and incorrect.

 

[WRicerX]

DanM, Wheelburns said:

Spoke to Chris White online tonight. Hes in research and development for the high perforamcne engines center. He said that the cars break at 14 lbs of boost. Pistons and Rods being the biggest contributors.

Now, I don't know who Chris White is, or what research center this is (GM?), or how true that statement is, but I would assume they are working on a stock car. That given, if a car breaks down at 14psi, then it breaks at 14psi. The constant here is that it's stock. So, other than production variances, they are going to run similar HP.... once again all things stock.
I do understand what you are saying about boost vs Hp. I had a turbo that maxed out at 17psi and had x amount of horsepower. I upgraded to a better, higher flowing turbo. This thing actually made more power at 14 psi than the smaller turbo made at 17, due to the fact that the newer turbo was capable of more flow at any given rate. You can blow 14 psi through a straw, and 14psi through a PVC pipe (well, maybe not really ) and the amount of air that comes out the end of each one is different, and that's where the HP would be different. It's a weird analogy, but is this what you are getting at, or am I still missing the point?

 

[nastyblacksrt]

this conversation really needs to end. no one know yet the capability of the cobalt. but from owning and tuning SEVERAL F/I cars, i know 9:5:1 is not and ideal compression radio. Look at the NA honda motors with a 10XXX compression, the most the can run without and engine rebuild is 8-9psi MAX on a small garret turbo, but remember with that kind of compression there is more use of the air being fored into the engine. I retract my statement earlier about 260whp, im guestimating 350-400MAX>>> bot not on that stock supercharger, EFFICIENCY is the word of the day... Also isnt the IC mounted inside the intake manifold?

 

[WRicerX]

this conversation really needs to end.

WTf? Why, that's what these forums are for..it's just speculation at this point, just like your guestimated horsepower predictions.
What really does need to be known, though, is true, hard physical evidence of the engines capability/strength.

 

[nastyblacksrt]

some needs to donate a cobalt to me, i can blow it... the only motor that i just kept throwing boost at that wouldnt blow was a rb25det on a stock turbo.

 

[WRicerX]

the only motor that i just kept throwing boost at that wouldnt blow was a rb25det on a stock turbo.

That would be a challenge I would be happy to undertake.

 

[wheelburns]

WELL CHRIS WHITE WORKS FOR GM. hE HIMSELF HAS A 524 RWHP GTO WITH A PROTOTYPE PORDYNE S/C STOCK MOTOR, ID TAKE THIS GUYS WORK AS GOLD. THE 14LBS OF BOOST CAME FORM HIM THEYVE BROKEN MANY MOTORS AT BOOST AS LOW AS 14 LBS OF BOOST THATS ALL I WAS SAYING. i WAS JUST RELAYING THE MESSAGE I GOT WASNT SUPPOSE TO BECOME THE BULLSHIT U 2 STARTED JUST STATING A SIMPLE FACT FROM ARELIABLE SOURCE TAKE IT OR LEAVE IT YA KNOW

 

[WRicerX]

WELL CHRIS WHITE WORKS FOR GM. hE HIMSELF HAS A 524 RWHP GTO WITH A PROTOTYPE PORDYNE S/C STOCK MOTOR, ID TAKE THIS GUYS WORK AS GOLD. THE 14LBS OF BOOST CAME FORM HIM THEYVE BROKEN MANY MOTORS AT BOOST AS LOW AS 14 LBS OF BOOST THATS ALL I WAS SAYING. i WAS JUST RELAYING THE MESSAGE I GOT WASNT SUPPOSE TO BECOME THE BULLSHIT U 2 STARTED JUST STATING A SIMPLE FACT FROM ARELIABLE SOURCE TAKE IT OR LEAVE IT YA KNOW

Bullshit?

 

[wheelburns]

the back and forth stuff i was just sayin theyve broke them at at 14 lbs and he come out with the here we go again boost and power blah blah blah i wasnt sayin u need more boost or less boost i was sayin theyve broke them at 14lbs nothing more nothing less oh yea its a procharger not a powerdyne my mistake

 

[WRicerX]

That's cool, I gotchya.

 

[cobaltss93]

does anyone know what stage clutch i can go with on the stock thrust bearings in the cobalt ss?

 

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