The "Official" Evo Modding for Dummies
Newbie
Joined: Mar 2011
Posts: 20
Likes: 0
From: san antonio, tx
So I have a question and it may have been asked already but I'm just to lazy to look through all the pages. But will an aftermarket recirculated bov cause issues for the car. Thanks for the help.
For driveability and smooth power delivery at part-throttle, low boost, nothing beats the OEM Evo9 (metal, not plastic) bypass valve.
Pretty much every aftermarket bypass valve or BOV designed to hold higher boost levels will compromise driveability. Maybe not a big deal for someone whose only concern is 1/4 mile times, but it is a big concern for people who drive their cars on the street, or do performance driving events where part-throttle and smooth power delivery is paramount, e.g. autocross, track days, or road racing. You cannot effectively put down power at part throttle—or maintain maximum grip in a corner—when the bypass valve is making the entire car buck and stutter.
I certainly haven't used every BOV/bypass valve on the market, but I can say from direct experience that the Forge RS valve is absolutely awful for part-throttle driveability (regardless of how you adjust it), and the Synapse Synchronic DV diverter valve is the best I've used (it's small too, which makes it easier to fit in tight locations and it's lighter to boot).
Nice
this Sticky is great i figured out why my car will not allow shifting in the higher RPM range (anything past redline) even though i have cams exhaust, intake piping and a tune i learned a lot thanks all you guys for your time you took to create these there awesome.