So An Intercooler Actually Robs Power If Boost Is Too Low?

[nicholastanguma]

An intercooler actually robs power from my engine if the turbo's boost psi is too low?

If it's true, I'm assuming it's because an intercooler will be responsible for a big intake plenum pressure drop going to the carby, and to overcome that pressure drop the turbo's psi need to be high enough to keep the plenum's air volume flowing properly.

Is all this accurate?

[BLSTIC]

Intercooler pressure drop is largely proportional to volumetric flow rate, so yeah with an oddly shaped core with not enough engine flow area (end tank dimensions) you could have a restriction that wasn't worth the cooling. But unless you're only running 4psi for a drag race an intercooler is almost always worth it overall

If you're running high cfm through a small spot for the core you can have long end tanks and short flow path (for maximum engine flow area) or a thicker core.

There are different style and quality cores too, for different goals.

Typical pressure drop will be 0.5-2psi for "really good" to "a bit restrictive"

[Walter R. Malik]

An intercooler actually robs power from my engine if the turbo's boost psi is too low?

If it's true, I'm assuming it's because an intercooler will be responsible for a big intake plenum pressure drop going to the carby, and to overcome that pressure drop the turbo's psi need to be high enough to keep the plenum's air volume flowing properly.

Is all this accurate?

NO ... there is power in the temperature drop.

[ptuomov]

At zero psi, the intercoolers reduces power because of its flow restriction.

In practice, every gasoline powered engine can make more power with an intercooler than without an intercooler. So you can’t use the above limiting case to convince yourself that you wouldn’t benefit from / don’t need an intercooler.

[RW TECH]

From my own testing, every 10°F increase in inlet charge temp resulted in 7 HP. Cooling is definitely a benefit.

But, intercooler bricks can become flow restrictions that cause less power than the compressor output is capable of.

For fun, this is what a REALLY GOOD intercooler brick looks like & this is where they come from: https://www.mezzotech.com/why-microtubes.html

[nicholastanguma]

From my own testing, every 10°F increase in inlet charge temp resulted in 7 HP. Cooling is definitely a benefit.

Wait, I think you may have made a typo.

You mean for every 10°F decrease of the charge temp you saw a 7 hp increase, right, or am I misunderstanding?

For fun, this is what a REALLY GOOD intercooler brick looks like & this is where they come from: https://www.mezzotech.com/why-microtubes.html

Great linky, thanks. American company, too, yay!

[nicholastanguma]

So you can’t use the above limiting case to convince yourself that you wouldn’t benefit from / don’t need an intercooler.

Copy that.

[RW TECH]

From my own testing, every 10°F increase in inlet charge temp resulted in 7 HP. Cooling is definitely a benefit.

Wait, I think you may have made a typo.

You mean for every 10°F decrease of the charge temp you saw a 7 hp increase, right, or am I misunderstanding?

For fun, this is what a REALLY GOOD intercooler brick looks like & this is where they come from: https://www.mezzotech.com/why-microtubes.html

Great linky, thanks. American company, too, yay!

I actually was increasing temp 10°F at a time, but did not say "decrease" after "7 HP".

Distracted typing..LOL!! Thanks for pointing it out.

[modok]

An intercooler actually robs power from my engine if the turbo's boost psi is too low?

If it's true, I'm assuming it's because an intercooler will be responsible for a big intake plenum pressure drop going to the carby, and to overcome that pressure drop the turbo's psi need to be high enough to keep the plenum's air volume flowing properly.

Is all this accurate?

I don't know about robbery but an intercooler wastes energy.
The purpose of an intercooler is to prevent the engine parts from being overheated or overstressed, and also allows lower octane fuel to be used.

intercooler reduces efficency but improves power output of engines.
the opposite is called a regenerator, it improves efficiency but reduces power output.

If engine was infinitely strong and octane was not a problem we would be heating the air after the turbo instead of cooling it.

But, knowing your area of interest, one and two cylinder engines, I think if you saw such an example of the intercooler reducing power it would be because it changed the intake harmonics, changed the "period" or, "reaction time" of the system in such a way it pumps worse.
What really matters is the pressure and temperature in the cylinder when the intake valve closes, that is the REAL boost pressure, while what the boost gauge shows.... is some kind of average.

[gunt]

so from mem , no intercooler is required under 7psi , in that case the slight flow restriction will cost a small bit of bhp , but note , yoyr area has alot to be considered as the compressor multapilys intake temp to the turbo and passes them on to the inlet , now theres a pretty high strung 2.0 engine in the uk where the temp out of the turbo is 120deg C and the intercooler bring it down to 40deg C , so definatlly required .

go back to Gale Banks love of air density , this is the function fo the intercooler , do the test , if its required , then its gona benefit , but who runs under 7psi , even std high compression engines anre taking more ,

although you could run a bigger turbo [ more lag ] less psi required and make more power

[lefty o]

An intercooler actually robs power from my engine if the turbo's boost psi is too low?

If it's true, I'm assuming it's because an intercooler will be responsible for a big intake plenum pressure drop going to the carby, and to overcome that pressure drop the turbo's psi need to be high enough to keep the plenum's air volume flowing properly.

Is all this accurate?

I don't know about robbery but an intercooler wastes energy.
The purpose of an intercooler is to prevent the engine parts from being overheated or overstressed, and also allows lower octane fuel to be used.

intercooler reduces efficency but improves power output of engines.
the opposite is called a regenerator, it improves efficiency but reduces power output.

If engine was infinitely strong and octane was not a problem we would be heating the air after the turbo instead of cooling it.

But, knowing your area of interest, one and two cylinder engines, I think if you saw such an example of the intercooler reducing power it would be because it changed the intake harmonics, changed the "period" or, "reaction time" of the system in such a way it pumps worse.
What really matters is the pressure and temperature in the cylinder when the intake valve closes, that is the REAL boost pressure, while what the boost gauge shows.... is some kind of average.

even though an engine tends to make its best power just before it melts itself , we still wouldnt being heating the air entering it. the cooler charge is denser allowing more air and fuel in. hot air is less dense, making it less efficient=less power.

[modok]

Well, yes and no
The way a heat engine works is..... air entering the engine, then being heated, then we extract the energy from the expansion.
The turbo is part of the engine.
It would reduce power at the same boost, because of course the intake pressure would go up, but it would increase power at the same mass flow rate.

That is if it didn't melt or explode, even turbine engines have limits.

Trapping the "air", compressing it, then cooling it is how a refrigerator works, which takes energy to make happen.
Heating the trapped "air" it instead of cooling it then makes the refrigerator into an engine which produces energy