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Discussion Starter · #1 ·
Hey guys just wanted to ask to see if any of you guys have noticed any fuel economy difference having the BMS blow-off valve installed. I feel like it might've but I wonder if it's just all in my head.
 

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2021 Kia K5 GT-Line AWD
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If anything, I would think it would actually do the opposite.

In stock form, the diverter valve redirects extra accumulated air back into the intake, providing a smoother, more constant boost pressure for the turbo. This also prevents the turbo from over boosting and causing turbo flutter, which would damage the turbo over time. It also helps reduce turbo lag as the turbo is kept spinning from the constant pressure.

Replacing the diverter valve for a blow-off valve means you're just venting the extra air pressure out of the system and into the atmosphere. This means you're losing the back pressure that the diverter valve was originally putting back into the system.
 

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Discussion Starter · #3 ·
So having the bms blow off valve you think helps with mpg? I don’t know if it’s just me then because I kind of feel like it’s lowering it
 

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I'm actually saying the opposite.

As this gas is being vented instead of being put back into the system, that means the turbo is losing pressure at the start and therefore less air getting into the engine. Burning the same amount of fuel for less power and efficiency that the car had been tuned for from stock.
 

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Hey guys just wanted to ask to see if any of you guys have noticed any fuel economy difference having the BMS blow-off valve installed. I feel like it might've but I wonder if it's just all in my head.
there’s a loss of about 2 mpg with it installed but i didn’t notice a power difference at all
 
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