Intake and turbo function question

Apr 7, 2023 | 05:19 AM

MaverickC43

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From: Plainfield IL

Amg C43

Intake and turbo function question

I’m not doubting the science, but we want colder air going into the turbos; is that bc if we’re sending hot air we’ll get less psi boost?
or is it that colder air is denser and will have more oxygen to burn in the engine ?

is this correct in theory
12psi of 40 degree air will result in more power than 12psi of 90 degree air?
thx
Edit

Apr 7, 2023 | 07:14 AM

4npower

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2019 GLC 63, 2020 C43 coupe

Quote:

Originally Posted by MaverickC43

colder air is denser and will have more oxygen to burn in the engine ?Edit

You got it. Denser/colder air has more Oxygen, and the more oxygen you can add to the fuel and spark, the more power you will make. Nitrous Oxide is like 1.5 times denser than ambient air, which is why it's a "power adder". Same idea with meth, it basically cools the charge air by adding a mist of water/methanol to cool the charge air, and water molecules contain oxygen atoms and same with methanol.

Apr 7, 2023 | 07:20 AM

MaverickC43

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That’s what I was thinking. Bc I was getting the same boost psi readings at cold & hot IAT
But should be getting more power ( hp or tq?) or both?
I understand the science just not sure I get exactly what our cars do?
Do all the computers effect this? Put Limits on power we can make ?

Apr 7, 2023 | 07:39 AM

4npower

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2019 GLC 63, 2020 C43 coupe

Quote:

Originally Posted by MaverickC43

Yes, the engine sensors constantly monitors the air/fuel mixture along with intake temps to control timing and many other parameters affecting performance. The problem is, when you compress air/increase boost, it becomes hotter and less dense. Obviously the higher the pressure, the hotter the air becomes, then less power. Then comes things like intercoolers, nitrous, and others like meth to cool the charge air back down and create more oxygen molecules. So yes, if you run the same boost in say 30 degree ambient air temps versus 80 degree ambient, you will make more power in the 30 degree weather just from the lower temps/denser air but same boost levels.

Apr 7, 2023 | 07:51 AM

ygmn

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2015 E400 Sedan

Normally the intercoolers are after turbo.

Since compressing a gas (air in this case) will drastically increase its temperature.
TO see this happen find an air compressor for say your Garage and feel the outlet line from the compressor - gets very hot.

Cooling before turbo helps a little but not as much as after air is compressed.

Apr 7, 2023 | 08:17 AM

MaverickC43

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So the larger intake tubes make more air available
So the engine doesn’t waste power trying to get air?

like when a supercharger provides 300 hp but it takes 100hp from the engine to run the charger
easier flow gives less stress and less loss hp?

Apr 7, 2023 | 10:04 AM

Adam Chambers

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From: Wake Forest, NC

2014 C63 Sedan (SOLD), 2011 SLS Gullwing (SOLD), 2009 SLK55 (SOLD), 2015 C7 Z06 7MT, 2016 C450amg

Question related to this. With OBD Fusion running off a bluetooth OBD adapter I can see IAT but this is from the sensor in the intake box. Where do these cars see intake temp after the turbo and intercooler just before entering the throttle body. would like to see what the temps are as it enters the engine.
On my C7 Corvette I have 3 IAT readings. intake, after intercooler and after throttle body. Only seeing 1 AIT on the Mercedes though.