CFM Continued...

[Bruce Plecan]

Er, this looks like it's assuming 100% VE, True?.
If so wouldn't 130-140% be a tad closer?
is there any intercooling?
Sneezy

> Then, the engine will be trying to breathe in 434 x 5400 x 0.5 x 1/1728 ,
> or 678 cfm at the highest speed you will be turning it. The runners to
each
> cylinder will be wanting to flow 1/8 of this much, or about 85 cfm each.

> The trick is to size everything in the flow path so that you do not have
> excessive pressure drop at any one point in the path at the amount of flow
> the engine wants to draw in. What the guy talking to you is missing is
that
> with a pressurized intake--the pressure drop in the runners is
proportional
> to the density of the air flowing through them!
> Of course--you will also have proportionally more pressure you can afford
> to lose with the turbo motor, So whatever will work well with the same
size
> and speed range  NA motor is pretty close for a turbo motor. Going maybe a
> fuzz BIGGER than what you would use for a similar size/speed NA motor will
> tend to lower backpressure from the turbo on the motor, and lower EGT's
> some.
> Going any smaller than what you would run on an NA 434 would hurt
> performance some, and durability more.
> Flow on the inlet side of the turbos will be the amount of air the engine
> breathes times the manifold density ratio--a LOT more cfm. Everything on
> the inlet side of the turbos should be sized accordingly, and also to have
> VERY low pressure losses at this design flow The amount of back pressure
> which the turbo(s) will put on the engine to make a given amount of boost
> is EXTREMELY sensitive to losses in the inlet tract to the turbos!.
> Regards, Greg

>