Quote:
Originally Posted by s346k
i believe on NA motors it's widely accepted that one can consistently manipulate the map kpa with air intake modifications. ie if you see 100 kpa @ the start of a pull (2500 rpm) and 90 at the end (6500 rpm) there's a good chance you have a restriction, presuming the car has no other obvious issues.
my question is... is there an accepted horsepower value assigned to the kpa drop? i'm presuming it varies by engine and is a percentage based value.
i know it's not a one size fits all definition of scenario, but other cars i've had showing a drop like that really didn't gain much at all after correction. after comparing logs, my car now shows 96. im on the fence about a cai, as i am still using the stock one. it does very well with insulation and general function. the car picked ~67 whp / 73 wtq on the dyno with only a ported stock intake, full exhaust and e85. stock air box and stock tb still. the car runs hard, i hope to put a number on it at the track soon.
any of you guys with similar mods and rotofabs showing a similar kpa loss? i'm moving up to an msd/95 mm tb soon and don't want to leave 20 whp on the table by using the stock air box. but truth be told, i don't think there's much gain to be had at all with only bolt ons: rotofab vs stock.
fun fact: i saw kpa values as low as 93 before i cut the air box.
is this something anyone even looks at anymore on stockish cars?
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Bain Racing has some fantastic [free] videos on youtube about engine airflow. In one of them, there is talk of a rough equivalence in air intake restriction based on a certain pressure drop/restriction. I can not recall at the moment though.