petert 586 Posted April 13, 2006 (edited) Whilst looking for inlet runner calculators, I found this interesting HP calculator. Hand up if you have a head that can flow 250cfm @ 28 in.? Answer - every Mi16 owner. So if you enter the data, your head/engine can make up to 257hp! And if you have a head that can flow 300cfm? 308hp. http://www.bgsoflex.com/flowcalc1.html Dig around. There's plenty of interesting automotive calculators on the site. and if you can only make 150cfm @ 28 in., most 8V owners, you're limited to 154hp. Sensible results? Edited April 13, 2006 by petert Share this post Link to post Share on other sites
TEKNOPUG 3 Posted April 13, 2006 computed rpm at peak power = 2254????!!!!! Share this post Link to post Share on other sites
petert 586 Posted April 13, 2006 Yes, the RPM is a bit off, but I think the hp is reasonably accurate. Take a big valve 8V for example. It would flow approx. 170 cfm from a good one - that's 175hp. Share this post Link to post Share on other sites
Dom9 2 Posted April 13, 2006 So, for what it's worth CFM = BHP... Sort of makes sense, just seems a little too ideal for my liking! Share this post Link to post Share on other sites
petert 586 Posted April 14, 2006 So, for what it's worth CFM = BHP... at least for a 122 ci engine. Share this post Link to post Share on other sites
smckeown 1 Posted April 14, 2006 (edited) Dave Baker has been saying this forever though, there's a post on there somewhere where he comments on dave andrews flow development work and states that power is directly proportional to something, it's in the area of flow though, it's not valve size but in that area. But here's the killer as i've just found out, you might be able to gain X bhp with Y flow, but at what rpm ? it may be that the rpm is too high for your engine to cope with Edited April 14, 2006 by smckeown Share this post Link to post Share on other sites
petert 586 Posted April 14, 2006 But here's the killer as i've just found out, you might be able to gain X bhp with Y flow, but at what rpm ? it may be that the rpm is too high for your engine to cope with And what if you do have an Mi16 head that can flow 300cfm? It doesn't mean you'll make 300hp, the limiting factor will be something else. Share this post Link to post Share on other sites
veloce200 3 Posted April 14, 2006 Dave Baker has been saying this forever though, there's a post on there somewhere where he comments on dave andrews flow development work and states that power is directly proportional to something, it's in the area of flow though, it's not valve size but in that area. I think this is Valve Curtain Area, which is why an 8v engine with the same valve area as a 16 engine will produce less power. It's a good calculator and I guess demonstrates why motorbike engines end up using throttle bodies that you would think are way over size - eg 38mm should be good for 180 bhp and they end up on a 600cc motorbike producing 100 odd hp. Share this post Link to post Share on other sites
Guest slindborg Posted April 17, 2006 ive got a formula for calculating RPM @ max power but it does require some assumptions lol. Ill get it ported over to my site asap (the forumula is at work and im off till wed.) Share this post Link to post Share on other sites
