Question How a turbo works
08-06-2016, 06:25 AM
#1
Member
Thread Starter
Question How a turbo works
Ive seen Engines with a cone filter directly fitted to the Turbo How does this work with the intercooler. Ive been looking for an answer for time.
I was watching this.
I was watching this.
08-06-2016, 08:25 AM
#2
Senior Member
He seems to have bypassed the intercooler all together cant see it or the pipe work....although its difficult to see....not the best idea.Especially as it sucking in nice hot under hood air. I suspect that mod is good for 20 or 30 horse power......loss! But if it is there the IC is between the turbo and the intake so whether the filter is in a box or straight onto the turbo intake will not make a lot of difference...imo .... apart from the warm air going in rather than nice cool air from the front of the car. Funny thing is that where the filter is, is the output of the turbo rather than the intake....at least on my Turbo jeep....I guess they are not all the same!
Last edited by ALFAitalia; 08-06-2016 at 08:34 AM.
08-06-2016, 10:51 AM
#3
MBworld Guru
These cone-style filters are marketed as allowing a greater volume of air into the engine. The problem with them is that being under the hood, they are sucking in hot air. And on top of that, they are often no more efficient than factory filters in terms of air volume.
A normally aspirated engine performs better with cooler air, such as with a cold air intake. This doesn't mean using a device to cool the air, it just means pulling air from outside the engine bay that is cooler. Most all modern cars do this. MBZ generally uses intake ducts that pickup air from right behind the front grille, before the air has a chance to be heated by the engine, radiator, evaporator, etc.
Forced-air induction engines (super/turbo charged) need cooled air. Pressurizing the air causes it to be heated (Boyle's Law). Intercoolers are used to lower the temperature of the incoming "cold" air which allows for an increased volume of air into the engine.
A normally aspirated engine performs better with cooler air, such as with a cold air intake. This doesn't mean using a device to cool the air, it just means pulling air from outside the engine bay that is cooler. Most all modern cars do this. MBZ generally uses intake ducts that pickup air from right behind the front grille, before the air has a chance to be heated by the engine, radiator, evaporator, etc.
Forced-air induction engines (super/turbo charged) need cooled air. Pressurizing the air causes it to be heated (Boyle's Law). Intercoolers are used to lower the temperature of the incoming "cold" air which allows for an increased volume of air into the engine.
08-06-2016, 07:40 PM
#4
MBWorld Fanatic!
Skip to 2:45, look at the grille opening. That big shiny thing is the top of the upgraded intercooler.
The cone filter on the turbo is just fine. Warmer air in the turbo setup makes the turbo work harder, but in reality a 20 degree change at the turbo inlet will barely change anything if the intercooler is working well. The PSI post turbo will be the same because the wastegate will keep the turbo spinning harder to further compress the warmer air. As long as the intercooler is getting good airflow it should cool it right down anyway with no real change.
The airflow to the engine bay once the car is actually moving means that the filter won't see much hot air anyway. It gets normal outside temp air once the car is doing 30mph or so.
The cone filter on the turbo is just fine. Warmer air in the turbo setup makes the turbo work harder, but in reality a 20 degree change at the turbo inlet will barely change anything if the intercooler is working well. The PSI post turbo will be the same because the wastegate will keep the turbo spinning harder to further compress the warmer air. As long as the intercooler is getting good airflow it should cool it right down anyway with no real change.
The airflow to the engine bay once the car is actually moving means that the filter won't see much hot air anyway. It gets normal outside temp air once the car is doing 30mph or so.
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Reanimation (08-08-2016)
08-08-2016, 05:35 PM
#5
Member
Joe and Rudeney have pretty good answers. Its a great explanation, but im not sure if it answers your original question. Simple answer, the intercooler will never go before the turbo or air filter. It will always be downstream or after the air has been compressed. Lets look at why!
The turbo compresses the air. Once air is compressed, the ideal gas law tells us that this will not only compress the air, but it will also increase the temperature. An increase in the temperature of the air means a decrease in power. Hence, an intercooler is always used after the turbo, to reduce the temperature increase from the act of compressing the air.
Another way of looking at it: The air first comes thru the air filter at lets say 80F. Once the turbo compresses the air, its increased to 150F. This increase causes a loss of power and increases the chance of detonation. Then the air travels thru the intercooler where it drops back to say 100F, giving you back some power, but also decreases the chances of detonation.
To continue, there are many setups that dont run any intercooler at all. These setups are limited to how much boost you can run. The more boost you run, the hotter the air will become, which can limit the amount of power. However, more importantly, the hotter the air becomes, the higher the chances of detonation. Many of these non-intercooled setups are limited to 5-7 psi.
There is also the opposite setup, where people will put a massive intercooler on a stock turbo car. An intercooler can only cool the air (at best) down to the outside temperature. An intercooler that is too large will have larger plumbing losses, leading to less power as well.
Maybe that is more information than you need. Does that help at all? If not, or if its confusing, ask more questions and we can help out more.
The turbo compresses the air. Once air is compressed, the ideal gas law tells us that this will not only compress the air, but it will also increase the temperature. An increase in the temperature of the air means a decrease in power. Hence, an intercooler is always used after the turbo, to reduce the temperature increase from the act of compressing the air.
Another way of looking at it: The air first comes thru the air filter at lets say 80F. Once the turbo compresses the air, its increased to 150F. This increase causes a loss of power and increases the chance of detonation. Then the air travels thru the intercooler where it drops back to say 100F, giving you back some power, but also decreases the chances of detonation.
To continue, there are many setups that dont run any intercooler at all. These setups are limited to how much boost you can run. The more boost you run, the hotter the air will become, which can limit the amount of power. However, more importantly, the hotter the air becomes, the higher the chances of detonation. Many of these non-intercooled setups are limited to 5-7 psi.
There is also the opposite setup, where people will put a massive intercooler on a stock turbo car. An intercooler can only cool the air (at best) down to the outside temperature. An intercooler that is too large will have larger plumbing losses, leading to less power as well.
Maybe that is more information than you need. Does that help at all? If not, or if its confusing, ask more questions and we can help out more.
Last edited by 91ser; 08-08-2016 at 05:37 PM. Reason: no!
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Reanimation (08-11-2016)
08-08-2016, 05:44 PM
#6
Member
Rudeney, you are correct that Boyle's law is part of it. Just a quick correction, Boyle's law considers the temperature to be constant. Its simply a pressure/volume relationship. Otherwise, the rest of your explanation was right on!
On a different topic, water - air intercoolers offer an advantage in that you can add ice to the mixture, which makes it possible to run temperatures lower than what an air - air intercoolers can do. This is more popular for cars that will be at WOT for short periods of time, like a drag race. For road racing, the ice will melt quickly and return to its normal effectiveness.
On a different topic, water - air intercoolers offer an advantage in that you can add ice to the mixture, which makes it possible to run temperatures lower than what an air - air intercoolers can do. This is more popular for cars that will be at WOT for short periods of time, like a drag race. For road racing, the ice will melt quickly and return to its normal effectiveness.
08-08-2016, 06:00 PM
#7
MBWorld Fanatic!
Or you adapt something like a Killer Chiller unit, if you run A/C, to cool the air-water unit to below ambient. Not practical on a race car as you don't have a/c but in a race car you have constant movement so the intercooler system doesn't heat soak anyway. Air-air is also usually lighter and simpler with less things to fail.
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08-11-2016, 07:38 AM
#8
Member
Thread Starter
I get it now thanks, I did open my bonnet and have a look what was going on. I understand now how its possible to stick a cone filter directly on the turbo Not that I will be doing it anytime soon.
08-11-2016, 05:43 PM
#9
Former Vendor of MBWorld
Or you adapt something like a Killer Chiller unit, if you run A/C, to cool the air-water unit to below ambient. Not practical on a race car as you don't have a/c but in a race car you have constant movement so the intercooler system doesn't heat soak anyway. Air-air is also usually lighter and simpler with less things to fail.
