I'm interested in buying a JRSC from a friend of mine and installing it on my sohc powered civic. I drive alot, 26k miles per year so fuel economy is important to me. I'm under the impression that the JRSC has a bypass valve so the intake manifold is not pressurized under light throttle, so MPG is not adversely impacted while cruising. Can anyone share their MPG before and after the JRSC install?

 

Your right under light throttle you wont have boost and milage should stay the same for most part. Tuning of course makes all the difference. You won't be disappointed with milage. I have large injectors too and still mpg is not bad.