Contour Enthusiasts Group Archives Forums Modifications Forced Induction price for power???

Originally posted by Dan Nixon:

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On an SVT, EITHER system has been shown to make near 300 FWHP. So, EITHER system is then making just about as much power as you want to make with stock internals...something to consider. If you are upgrading rods/pistons (but most are not) that is another story...

Will ANY (modified or not) MTX-75 survive a 300+lb/ft with a clutch drop???

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More on that story to come...

Originally posted by TommyBoy:

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Rara: I challange you to rev your turbo'ed engine to 2000rpms and look where the boost gauge is and then tell me the turbo is not RPM dependent!!!!!

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Hmm, I'm not sure you're understanding some of the concepts here.. My GTI makes 17lbs of boost at 2800rpm, and peaks at 21lbs at 3400rpm. Redline is 7000rpm on this 20-valve engine..

..where did you see the engine had to spin up to make boost?

Originally posted by Ryan Lewis:

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Originally posted by TommyBoy:

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Rara: I challange you to rev your turbo'ed engine to 2000rpms and look where the boost gauge is and then tell me the turbo is not RPM dependent!!!!!

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To sum up what warmonger said, how do you get to 2000rpms? Do you mash the gas pedal or do you go up to that point as slow as you can? That's what will make all the differance, not that fact that you're at a certain RPM.

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I am fighting a losing battle even though I know for a fact that I am right!!!
Rpm's are Rpm's no matter how you get there!!!!

Just a few Q & A's
What does it take for a turbo to spool?
Answer: Exhaust Gases

How do you increase gases??
Answer:Increse in RPM's!!!

What some of you are trying to apply is that a turbo is a 100% efficent which is imposible because there is no machine in the world capable off running at a 100% eff.

Where a blower creates drag a turbo creates lag!!!!!

Read my post just above yours.

You seem to think that boost should rise with the revs! That is very wrong! Am I reading you correctly?

Here's some good reading for people that don't want to dig into the thick books.

Difference between a Turbochager and a Supercharger on a car's engine.
How Turbochargers Work

Originally posted by Pascal:

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Here's some good reading for people that don't want to dig into the thick books.

Difference between a Turbochager and a Supercharger on a car's engine.
How Turbochargers Work

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Ahhhhh, thank you, although you just put your foot in your mouth!!!!!

There are tradeoffs in both systems. In theory, a turbocharger is more efficient because it is using the "wasted" energy in the exhaust stream for its power source. On the other hand, a turbocharger causes some amount of back pressure in the exhaust system and tends to provide less boost until the engine is running at higher RPMs. Superchargers are easier to install but tend to be more expensive.

Let's not move away from the subject at hand. More over, let's not get agressive on this one.. I don't know you and I just need to make sure we discuss on equal terms. I'm no turbo expert like Rara and RedSVT for instance, but I have a fair share of experience with boost on small engines.

I didn't put my foot in my mouth as I never stated that a turbo didn't waste anything.

We are trying to make you realize that turbo spool-up is NOT dependant on RPM's but on exhaust energy. A large engine with a small turbo can make max boost right off idle. The only thing you need from the engine is enough exhaust "power" to spin the turbo at a speed where it produces boost.

.. Which is why you can drive a turbo engine at very high revs, with the throttle partially closed (like cruising on the highway) and it won't make much boost. On the other hand, when you go to WOT, exhaust energy is very strong even in lower revs. There is an "exhaust pressure" threshold where the turbo will start to make boost.

Make sense?

Originally posted by TommyBoy:

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How do you increase gases??
Answer:Increse in RPM's!!!

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This is where you're getting mixed up I think. You increase exhaust gasses by increasing the throttle, not by increasing RPMS. You increase RPMs by also increasing the throttle. But, you dont increase exhaust gasses by increasing RPMs....both of them are the product of the same stimulant (terrible word choice but I'm preocupied)

Exhaust velocity is RPM dependant.

Originally posted by RedSVT:

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Exhaust velocity is RPM dependant.

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I retract ALL previous statments....I'd edit them out but I can't..