intake manifold pressure

[Dan Lentsch]

Hey, I'm not sure if anyone will be able to answer this question (or if it is even a valid question), but what are some typical vacuum readings behind the restrictor on the intake manifold. We are just starting to design a restrictor / intake, and just got access to a nice flow bench, but I'm not sure what kind of vacuum to expect since we have never run our engine before. (We have a '07 GSXR 600) Also, if anyone knows what kind of CFM to expect that would be awesome.. I'm pretty new to some of this, so any help is highly appreciated! Thanks.

[Dan Lentsch]

Hey, I'm not sure if anyone will be able to answer this question (or if it is even a valid question), but what are some typical vacuum readings behind the restrictor on the intake manifold. We are just starting to design a restrictor / intake, and just got access to a nice flow bench, but I'm not sure what kind of vacuum to expect since we have never run our engine before. (We have a '07 GSXR 600) Also, if anyone knows what kind of CFM to expect that would be awesome.. I'm pretty new to some of this, so any help is highly appreciated! Thanks.

[Dan Lentsch]

anyone?

[Wesley]

Well, you can run the choked flow calculations to figure out what you should be shooting for as far as upper-limit CFM goes - but getting it close to that is going to take plenty of work on your restrictor design.

As for vacuum on a typical engine, I'd say a hell of a lot. That restrictor doesn't play nice with the pistons being greedy. Sorry I can't be more specific, but I don't have numbers for you. http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Charlie]

This is a pretty simple calculation to get a ballpark CFM number, and that's all you really need for flowbench work. Do some math, engineer. http://fsae.com/groupee_common/emoticons/icon_wink.gif