Exhaust Back Pressure

[brbauer2]

Can a few people check what their AP is reading for Exhaust BP? I'm getting ~14psi at idle and ~18-19psi WOT. Seems high.

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[JDG]

Can a few people check what their AP is reading for Exhaust BP? I'm getting ~14psi at idle and ~18-19psi WOT. Seems high.

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This is perfectly inline with my 30 mile commute home last night in my stock 2016 Fiesta ST (14.5-20 PSIG). High back pressure is typically a result of a smaller turbine, which is usual spec'd for a turbo where quick spoil up time is desired. This link was helpful in explaining this:

https://ls1tech.com/forums/forced-induction/911023-turbo-sizing-backpressure-explained.html

 

[JRifold]

Can a few people check what their AP is reading for Exhaust BP? I'm getting ~14psi at idle and ~18-19psi WOT. Seems high.

Yo. I have the same readings (stock exhaust). I'm wondering if you have an aftermarket, and if so, which one? I'm debating whether to get one. My only issue is I don't want lose back pressure.
- JR

 

[M-Sport fan]

Can a few people check what their AP is reading for Exhaust BP? I'm getting ~14psi at idle and ~18-19psi WOT. Seems high.

Yo. I have the same readings (stock exhaust). I'm wondering if you have an aftermarket, and if so, which one? I'm debating whether to get one. My only issue is I don't want lose back pressure.
- JR

Given the tiny size of the factory snail's exhaust outlet port/flange, combined with the factory catted down pipe diameter, it probably would not make any back pressure difference if you went to a 4" CBE system on these cars.

 

[JRifold]

Given the tiny size of the factory snail's exhaust outlet port/flange, combined with the factory catted down pipe diameter, it probably would not make any back pressure difference if you went to a 4" CBE system on these cars.

Interesting. I had a muffler delete on my previous FiST, and I lost low end power.

- JR

 

[letitreign]

Can a few people check what their AP is reading for Exhaust BP? I'm getting ~14psi at idle and ~18-19psi WOT. Seems high.

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That's totally normal dude. Atmosphere pressure is ~14.5 psi, so at idle you're barely moving any air so the sensor basically read atmosphere. At WOT, you're only 4-5 psi above atmosphere, which is fine. I think what's throwing you off is that you're comparing the pressure to the turbo. Your turbo might spool up to 25ish psi, but the pressure coming into your turbo isnt at 0 psi, its slightly below atmosphere (12-14 psi) due to bernoulli's principle.

 

[brbauer2]

I completely forgot to factor in standard air pressure

>.<

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