Boost Question

[joker]

Ok let me say I have no idea about s/c's othger than how they work on a basic level. I have a few questions though.

1)How does your h/c/i setup effect the amount of boost you get from a s/c? For example, say you have a s/c that flows 1500 cfm at maximum output. Could not not possibly see more boost on a restrictive engine than your would on one that flowed monster numbers? Say would an s trim s/c make more boost on a stock motor than it would on one that was running afr 205's track heat intake and a monster cam?

2) Can more boost = less power and less boost = more power ? Just as above, the more boost it makes my thinking says the more power you would get out of the s/c alone. However, if you have more n/a power would that make up for a lack of boost from having the same s/c installed on a more free flowing engine?

3)Is it possible on a s/c'd motor, just like it is an n/a motor too have your internals flowing too much? I know stock internals would be a bottle kneck for a s/c but at what point does it go to far to the other end of the spectrum?

Hope I phrased these where someone besides me can understand what I am trying to figure out :jester:

[Italian LX]

1)How does your h/c/i setup effect the amount of boost you get from a s/c? For example, say you have a s/c that flows 1500 cfm at maximum output. Could not not possibly see more boost on a restrictive engine than your would on one that flowed monster numbers? Say would an s trim s/c make more boost on a stock motor than it would on one that was running afr 205's track heat intake and a monster cam?
Yes, it effects it just like described above. Perfect example is Lee's Cobra. He's running a 20# pulley, but due to his less restrictive induction, he is only seeing around 14psi. (Although the intercooler accounts for a boost loss, it's probably only a pound or two.)

2) Can more boost = less power and less boost = more power ? Just as above, the more boost it makes my thinking says the more power you would get out of the s/c alone. However, if you have more n/a power would that make up for a lack of boost from having the same s/c installed on a more free flowing engine?
Yes, more boost doesn't always mean more power; it all depends how you're geting the additional boost. If you have more boost because of a restrictive intake, then you're pissing in the wind. With additional boost also comes additional heat which, we all know is, effects performance in a negative way.

3)Is it possible on a s/c'd motor, just like it is an n/a motor too have your internals flowing too much? I know stock internals would be a bottle kneck for a s/c but at what point does it go to far to the other end of the spectrum?
I would think it would be hard to acheive a motor that is so efficient that a blower has little or no effect on the performance. But I'm sure there is some sort of "law of diminishing returns" in effect.

[QWKSNKE]

Ok let me say I have no idea about s/c's othger than how they work on a basic level. I have a few questions though.

1)How does your h/c/i setup effect the amount of boost you get from a s/c? For example, say you have a s/c that flows 1500 cfm at maximum output. Could not not possibly see more boost on a restrictive engine than your would on one that flowed monster numbers? Say would an s trim s/c make more boost on a stock motor than it would on one that was running afr 205's track heat intake and a monster cam?

Yes. Boost is a measurement of restriction.


2) Can more boost = less power and less boost = more power ? Just as above, the more boost it makes my thinking says the more power you would get out of the s/c alone. However, if you have more n/a power would that make up for a lack of boost from having the same s/c installed on a more free flowing engine?

Within certain paramters a well flowing engine with less boost could and would make more power than more boost on a more restricted engine

3)Is it possible on a s/c'd motor, just like it is an n/a motor too have your internals flowing too much? I know stock internals would be a bottle kneck for a s/c but at what point does it go to far to the other end of the spectrum?


Yes you can run out of blower on well flowing engine.

One thing to remember is that compression ratio, intercoolers, heads, and intakes can affect boost #'s.

Does that help any?

[TheJeanyus]

Yes, a better flowing engine will make less boost and more power. Look at QWKSNKE's setup - the blower is pullied to make 20 psi, but only makes 14 - 15 on his engine. I'm pretty sure a stock motor with 20 psi wouldn't make that kind of power, either.

[coupe]

Joker, you're on the right track. It's the reason compressor sizing is so critical to your engine. The first things I ask when someone wants a turbo and a certain power level is what their camshaft and heads are like. Then I ask if they have a good block. :nice:

[Craig K.]

In the recent MM&FF (I think it was) they should the effect of adding in the intercooler, as I recall it cost them 3-4 PSI and around 50 hp (?) Don't have the magizine in front of me so I'm going off of memory.

As the others said to your ?'s you really need to match everything together.

[Italian LX]

In the recent MM&FF (I think it was) they should the effect of adding in the intercooler, as I recall it cost them 3-4 PSI and around 50 hp (?)
Yeah, but it's a known fact that an air-to-air intercooler will typically lose horsepower on a dyno due to the boost loss, but gain horsepower on the street.

[Craig K.]

Yeah, but it's a known fact that an air-to-air intercooler will typically lose horsepower on a dyno due to the boost loss, but gain horsepower on the street.

Yeah they stressed the point that you then (after adding the air 2 air) have to go back and re-tune.

They had wanted to prove the point that 1) you loose boost because your adding more distance and resistance for the boosted air to go through, and that 2) Just by adding a air 2 air doesn't gain you anything unless you retune.