need another blow by question answered. last one I promise

[Kibby]

Last one. Installed the fmic and piping the other day. Absolutely no blow by at all. The dipstick didnt move at all and there is a huge, huge noticiable power gain. My question is: is the amount of pressure reduced in the engine from a fmic vs stock ic and piping? Either way it peaked at 20 psi on both setups. My assumption is the lower intake temps from the fm, even though its making more hp and tq, is making less pressure in the cylinders vs the stock ic thus no blowby? Idk

 

[ApexHunter]

Need to distinguish between pressure in the intake tract and pressure in the crankcase. Blow by is directly related to pressure in the crankcase. Not the intake tract.

That being said, if you are making more power due to higher intake air density, that power (think cylinder pressure) could potentially increase blow by thus increasing crankcase pressure.

 

[Kibby]

Idk if you read my post thoroughly but I said im making more power and have no blowby now. My assumption was lower intake temps making less pressure in the cylinders from swapping to a fmic. Ex: 20psi @300 degrees is more pressure than 20psi @100. More power less pressure. I was only getting pressure in the crankcase because the rings are on their way out. I wasnt expecting the car to completely stop blowby with a fmic.

 

[ApexHunter]

I did read your post thoroughly. "pressure in the engine" leaves some room for interpretation.

Quoting Kibby:
My assumption is the lower intake temps from the fm, even though its making more hp and tq, is making less pressure in the cylinders vs the stock ic thus no blowby? Idk



Air charge is approximately 20psi before and after right? 20psi is 20psi? Maybe i'm missing something?

Quoting Kibby:
My question is: is the amount of pressure reduced in the engine from a fmic vs stock ic and piping?



The vast majority of blow by occurs during/after the combustion process, when cylinder pressure is at its peak. Torque is a product of cylinder pressure. Being that HP is a function of torque, it is pretty safe to assume there was an increase in cylinder pressure if there was a gain in power.

 

[Kibby]

It was 20psi stock ic vs 20psi fmic. Higher temps on stocker vs aftermarket fmic. My question was: 20psi stock ic was putting more pressure in the cylinders than 20 psi with the aftermarket one. If so less pressure eliminated blowby?

 

[prove_it]

In theory, based on the higher inlet temps.

 

[4g6Tree]

Quoting Kibby:
My assumption was lower intake temps making less pressure in the cylinders from swapping to a fmic. Ex: 20psi @300 degrees is more pressure than 20psi @100. More power less pressure. I was only getting pressure in the crankcase because the rings are on their way out. I wasnt expecting the car to completely stop blowby with a fmic.



That would be true if the air never ignited. You can fit a lot more cold air into a combustion chamber than hot air. With a colder charge your combustion chamber has more air in it even though you're still at the same boost pressure (hot air takes up more space than cold air). But once this cold dense charge ignites all the air that's packed into the combustion chamber explodes and makes more cylinder pressure than a hotter intake charge would. More air combustion, greater cylinder pressure, more horsepower.

As for the dipstick not popping out anymore, I'm not sure why. If you have worn rings I'd think increasing hp would create more blowby.

 

[coyotes]

My dipstick would pop out sometimes when i still had the stock intercooler. After my FMIC kit, no more popping out. Even with a bigger turbo now.

 

[Kibby]

^^^ I shall continue to increase horsepower until it runs better lol.

 

[manikbastrd]

I have good compression on my car (which would indicate good rings) and I still get my dipstick to pop without a spring to keep it in...

 

[ApexHunter]

If we are talking about pressure here, 20 psi is 20 psi, period. Now density on the other hand, that is something else. Yes, a colder charge is denser. But 20psi hot and 20psi cold are both still 20psi.

Let's say you have a jar filled with air. Now seal it and apply heat. As the temp increases and your air expands, the pressure will increase.

If you had a regulator on that jar, and you set it to 20psi, the density of the air would change depending on temperature, but the pressure will remain the same.