SO what Kill's a Motor, Boost or Power?

[TRXboy]

Alright, May be a dumb question, but a friend and I were talking the other day and it really became an interesting topic that is kind of hard to find information on. You hear all these people say "2003 Cobra's piston's are on borrowed time at 500rwhp" and "the GT500 rod's are toast at around 600rwhp".


But here's the question, is it really the actual power that Kill's the pistons/Rod's? Or is it the boost level/something else. For example, There’s an 03 Cobra in the Vid section making north of 550RWHP on a ported Eaton with Cam's and all the goodies at only 9#'s of boost were as other people go the easy root and just boost the hell out of the motor’s, and still don’t see that power level (and they have toasted there stock motor’s). So is it boost, or power that kills the motor?


Another Example...


A turbo charged stock 3v at say 5 PSI would make the same power as a pro charged stock 3V at say 10 PSI. Now say the Pro charged car is maxed out the stock internal’s making 430RWHP on 10PSI. If you crank up the Turbo's boost to 10psi and you make (making numbers up) 500RWHP, would the engine throw a rod because of the power? Because the Boost level is the same, so in theory, if boost kill’s the motor, it should be just as fine as the pro charged car, just with more power.



Hope it makes sense, and it's not too stupid of a question, but I was hoping some of the real engine guru's in here could discus.

 

[SID297]

Cylinder pressure.

 

[Riddla]

Power does...

:read: :shrug:

 

[thomas91169]

well a turbo generally makes more airflow than a SC at a given psi. airflow equals power, not PSI. PSI is just the force it takes to move a certain amount of air, bigger turbo's require less force to move the same amount of air as smaller ones do.

generally what destroys engines is usually one of two things (or both)

1) Heat
2) Pressure

stock internals can only take so much heat and pressure before giving way. forged is better, its usually more resistant to heat and pressures. The stock internals on a 03/04 cobra motor can take quite a beating, their main weakness is piston to wall clearance that ford gave them, limiting high speed runs due to the piston expansion rate when things get heated for longer periods of time.

and the 3v turbo vs sc question: IMO taking the turbo to the same psi levels the procharger was at should be fine on the motor, depending on how well the tune is (to keep heat down) and how strong the internals are, i dont know if they are any different internally than a 2v GT motor. If it were me, i would use the middle ground, take the PSI max you can run on a SC, and the psi that it takes the turbo to make the same numbers, and then use the middle, you will be making more power while not putting as much stress on the motor, so everyone is happy (you and the motor).

 

[SID297]

(P1 x V1)/T1 = (P2 x V2)/T2
PV=nRT

That should help you figure out the general behavior of gases.

 

[droptopsnake01]

heat kills the motor.

 

[Midnight_Cobra]

Lack of tune, bad gas, idiot driver, vibration, air/fuel, knocking, could be a number of thingss.

 

[customperforman]

according to Richard Holdener (a mod engine expert) neither. or, of the two, excessive boost as boost creates heat. he claims high RPMs kill rods and heat cracks ring lands and burns pistons. he dislikes the claim of 400hp as the max for a 2v engine and states most failures are due to detonation and overspinning. detonation will kill any engine; forged pieces just withstand it for longer. Ryan T. (ryan98gt) was running 613 on a stock bottom end just to see how much it could take on his S Trim car. it lived because he shifted at 5800 religiously.

also, two notes for your information: the cobra at 9.5 lbs making that power was on nitrous. and more importantly, you cant compare boost from turbos/blowers as apples to apples. they are two different animals. it does take less boost for a turbo to make the same power as a blower.

 

[logan_yomtov]

I heard if you complete a motor at the exact moment all the 9 planets of our solar system align, that motor will be indestructable and have the highest performance of any engine known to man(that wasn't built the exact moment all 9 planets aligned.)

 

[NewKid]

I heard if you complete a motor at the exact moment all the 9 planets of our solar system align, that motor will be indestructable and have the highest performance of any engine known to man(that wasn't built the exact moment all 9 planets aligned.)

Isn't that the LS1?:shrug:

You know, the motor built by God.

 

[01cobravortech]

Neither one kills a motor. In fact, a motor should last you 1 billion miles no matter how much boost or power its making.

 

[Double"O"]

RPMs

 

[TacticalKaos]

There are so many variables and contradictions this could go on forever. For instance, say a .............Supra......makes 900whp at 40 PSI and it blows up. Was it because it had 900 hp? Perhaps but it wouldn't have had that power had it not had the boost. I don't know if that makes sense but that's the contradiction part.

In essense though there are so many factors. Say you increase only boost and change no other variables (timing, fuel, etc...). More than likely you won't make much more power but the engine is put a much greater risk of detonation. Playing devils advocate lets say you add every bolt on imaginable to a stock motor and get a great tune and put down 700 rwhp (making up numbers). How long is that gonna last on a motor intended to have 400?

All I am saying is that it isn't necessarily one or the other. They compliment one another so essentially they both contribute.

 

[01cobravortech]

You could have something not properly torqued to spec that could lead to failure. Infinite possibilities.

 

[TacticalKaos]

HAHAHAHA this is getting so out of hand already. Playing devils advocate.......the lack of octane kills motors. If we all ran 200 octane we'd be in great shape. Damn OPEC.

 

[svtcobra2k3]

Isn't that the LS1?:shrug:

You know, the motor built by God.

No. God built the 2JZ-GTE.

 

[TacticalKaos]

No. God built the 2JZ-GTE.

Zing!!!!!

 

[blumnday99]

(P1 x V1)/T1 = (P2 x V2)/T2
PV=nRT

That should help you figure out the general behavior of gases.

You may need a chem book...look up combined gas law and ideal gas law.

 

[Smokey1226]

No. God built the 2JZ-GTE.

your damn right! Name another stock boosted engine that can last 200k+ miles and any stock engine that can last 100k+ miles making 800hp +

I have yet to find one ever built as well as the 2jz

 

[TRXboy]

Alright, some interesting responses. But then explain why it is not recomended to go over 400RWHP with my motor on stock internals. If the Tune is safe, and it is getting enough fuel, what would cause the stock internals to go if neither boost, nor power kills the internals.