Miata Turbo Forum - Boost cars, acquire cats. - Turbo manifold styles- Absurdflow lowmount vs ramhorn, which for maximum power?

Quote:

Originally Posted by sixshooter (Post 684941)

Fluid dynamics favors a design with the fewest bends from a drag and loss of impulse energy standpoint. You want very few 90s and no 180s if you want to maximize the effect of energy pulses on the turbine and not slamming into a corner and being dissipated as heat or rebounding. I don't have access to the fluid dynamics programs that some of you were using for intake manifold design, but many of the same principles are applicable. I recall that each 90 creates as much drag as 20 feet of straight pipe of the same diameter. If you must bend, use wide sweeping arcs.

You're ignoring one very important factor, merge angle. That is the reason a ramhorn outperforms other designs. It's the only manifold design I've made so far that pulls a vacumm (exhaust scavenging) on the non firing runners. Any other manifold does the opposite. Packaging, makes it impossible to make a low merge angle manifold without introducing bends, many of them, so for best flow, low merge angle is more important than the amount of bends. And as mentioned earlier in the thread, just take a look as some of the top performing engines in any type of racing. They can't all be wrong.

As far as spool, shorter runners=faster spool. Full race, with their extensive experience in manifold building, agrees, even though saying otherwise would help their sales. They have no reason to lie. Sorry Bob, but I think you're wrong on that one. There may be other factors contributing to your fast spool, if it is indeed faster with the same displacement.

A low angle merge manifold with the shortest possible runners is the ticket. Tim, your designs look awesome. Have you started working on one yet?