Fallstar01

I'm pretty sure the Eaton has 3 fins while the Lysholm(Whipple)/Kenne Bell (Autorotor) designs have 4. I'm not sure how that equates to more power however, it has been shown that the Eaton is more prone to heat-related power loss than the others. Feel free to correct me if I'm wrong on this.

Birdieman4

Ok, now my 2 cents. For street oriented applications, screw type blowers outperform roots units, period. The reason why, is screw units are considerably more thermally efficient that roots units, and tend to generate considerably less heat when spun fast, for longer periods of time. This is due to the different impellor design, and hi helix impellors tend to have better tolerances, over longer periods of time. You really can't compare true street oriented blowers to street/racing blowers and their applications. For street oriented purposes, screw technology kills roots technology.

PR Man

I looked up gaseous screw type pump design in one of my old texts. The fins are generally called threads on a screw type. 3 versus 4 is ins't a biggie. Some designs have as many as 6 or even 8 in non-automotive applications. As the engineer you can varyi the diameter of the rotors, the number of threads on each and their pitch, their heighght, and the length of the screws and case, to vary the displacement (volume pumped) and to hit a certain RPM-pressure-drag (heating, efficiency) curve, trading that against power requirement (a big blower of this type probably consumes close to 90 HP when pumping 12 lbs into 427 cubic inchs) and cost. The Eaton M-112 and Lysholm (I think its 122 cubes) are pretty close over all with the Lysholm being a bit more capacity. Both probably have heat loss that begins saturating them at around 14000 RPM, as the typical design for an engine would apply them running 2 - 3 times engine RPM. One might be engineered for lower heat losses but it wouldn't be solely the number of threads (fins) on the rotor that determines that.

This is neat stuff - why I became an engineer 35 years ago.

Lee Willis

I agree. for the street the screw type is really best overall. Much much better than a roots, and in my opinion preferable to a centrifugal because its more linear pumping-versus RPM curve means it delivers more of its boost lower down inthe RPM range. The E-112 I had in the Magnusn kit I had on the'ette was the best blower I've ever owned. The Procharger I now have on the vette blows a lot more air at the top, but I would have gone with an Eaton if they were available in around a 140-150 cubic inch range (again, the times three rule) but a consensus of several folks I checked with at Ligenfelter, MTI, etc., all felt the M-122, or even the big Lysholm 122 for the Ford GT, would be really challenged putting out the final targeted 800 HP I want. The D1SC is proven capable of that on other 427s, so I went with it.

This shows the D1SC, which is actually smaller than the Eaton was (I'll post a picture of that when I had in on the original 350 when I can find one the size it will let me post).

[IMG]local://upfiles/25496/C563F1484A654A2A865AAB22202326D6.jpg[/IMG]

Lee Willis

It seems to let me upload only one picture per message. This is the M-112 that I had on the original stock LS6 engine in my ZO6 for about two years. diversified Performance In apex NC put it on, largely guessing, and the instructions are the time were incomplete: this was the third private Magnusen Corvette kit in the country and the first Lingenfelter sold that was not installed by them - so early in the manufacturing cycle it was made before they even put the nipple for a boost guage on the manifold. Eventually did right at 475 RWHP. It had a really nice low end torque curve and a great wail at full bore - louder than the exhaust.

[IMG]local://upfiles/25496/F06A3D7968274305BC5C7F92205C20AE.jpg[/IMG]

Fallstar01

The Autorotor 2.4L should also be capable of putting out that 800 hp if you could mate it to the right intake manifold. (It's slightly larger than the 2300A Whipple in the Ford GT and should fit your times 3 rule). And it could do so with a much better low end than the centrifugal. Just a thought.

Lee Willis

That wasn't available when I was putting the engine together and I don't know if a manifold and pulley bracket kit for it is available even now. And you are right, it does fit the 3x rule. It is an intrigueing though, and I may have to revisit this down the road. But I have to say the Procharger is working out well. I really can't complain.