Measuring intake flow restriction in cars

[@ema1671]

This video deserves more attention.

[@JulianEdgar]

Thnaks you! Spread the word.

[@africankat1]

so glad i found this channel. thank you Julien

[@JulianEdgar]

Thank you - spread the word.

[@tallerflash]

Thanks Julian

[@enterBJ40]

Hi. There's any formula to calculate air restrictions based on displacement or hp?

[@JulianEdgar]

You'd need to know all the restriction of the complete intake system first - measurement is the key.

[@enterBJ40]

Hum...my closest guess would be to measure vacuum immediately after air filter ( once a new air filter has been installed) . That would provide a base line restriction index. Then all I have to do is multiply by 3 that initial number. That would be my maximum air restriction for that specific engine.

[@JulianEdgar]

@@enterBJ40 I have no idea why you would take that approach!

[@enterBJ40]

I must multiply by 3 because that is maximum restriction amount allowed by major Diesel engine manufacturers. The minimum base number can be determined by measuring the amount of vacuum in ideal conditions: X amount of RPM using a brand new stock air cleaner in a stock air box and air ducts.

[@andrewleonard9257]

Hi Julian. Have you done much testing of pressure drops across throttle bodies at wide open throttle? What about from the TB exit to the intake manifold of NA engines? I'm wondering why you generally stop measuring prior to the TB. Is it safe to apply high vacuums to a Magnehelic gauge? Also, what benefits have you seen - on a gauge or dyno - from gasket/port matching? I've heard that protruding edges aren't as bad for flow as might be assumed, because they typically only effect flow at the slow boundary layer.

[@JulianEdgar]

I haven't done any gasket matching measurements. I usually show measurements only up the throttle body as a different technique is needed for measuring pressure drops across the throttle butterfly.

[@andrewleonard9257]

@@JulianEdgar Even at WOT? Does the answer have something to do with velocity?

[@JulianEdgar]

@@andrewleonard9257 Nothing to do with velocity. It's just harder to measure this pressure drop without being able to hold full throttle, full load constantly.

[@levilambert8068]

good video my man!

[@JulianEdgar]

Glad you liked it!

[@albertsantosTP]

Thank you sir!

[@therandomrobert1842]

Would this work on an intake manifold I took off my airbox so it gets free flow and how would I do it would I have to drill a hole and then cover it after? I have a 1nz fxe in my Prius c I’m going to do a camshaft swap and can’t find any manifolds that would fit since they face the hybrid drive but the earlier version with the aluminum manifold would fit but I don’t want it to restrict it more than the one on it already

[@JulianEdgar]

It's normally done prior to the throttle body ie before the intake manifold. Intake manifold vs power is a different ballgame.

[@greg4909]

hey julian, what are your thoughts on forward vs rear facing snorkels on 4wds?

[@JulianEdgar]

Forward facing. Should easily be enough aero pressure built-up to negate the flow drop through the filter. (Take about 5 minutes to measure the pressure difference of front-facing versus rear-facing.)