First Fire: Banks Supercharged Duramax 871S

[bankspower]

IT'S ALIVE — First fire of the Banks 871S race engine

We fired up the race engine on the dyno. These initial runs are easy since we need to break the engine in before hammering it. Once we have the engine properly broken in, we will begin the REAL tests and share those with you!

For now, watch the first fire and enjoy!

[richardsnelson]

THE 871 IN NEW FORM.  I CANT WAIT TO SEE THIS THING IN ACTION.  I LIKED HOW THE OLD 8-71'S SOUNDED BUT THIS THING IS WAY BETTER.  I WANT ONE.

[Romans--bobr]

From what I'm seeing & hearing here... this supercharger - Really IS a true "Supercharger" and NOT an "8V71" type of Rootes Blower.  What's the difference??  The Rootes Blower (like you see on most fuel, alchohol & pro-mod drag race engines, etc, etc.) was originally taken from 2 cycle Detroit Diesels (which was originally designed by Rootes Connersville for industrial applications in the 1800's)... and are NOT true "superchargers" meaning that they DO NOT - COMPRESS Air... they are nothing more than Air PUMPS -or- Air "Movers"... they merely draw air in and move it out.. in pre-determined volumes according to case size, the number of rotors / lobes (2 or 3 normally), whether helical or straight & rpm's turned.

Originally, when utilized on the 2 cycle GM Diesels (brand name was changed to Detroit Diesel in 1965.. and is No Way connected to what some refer to as the "detroit diesel" associated with the duramax & older pickup & light / medium duty diesels) the "rootes" was Necessary to provide air for the engines to be able to run.. as of course, an "intake" stroke is Non-existent in the 2 cycle..and when everything is "new & tight" they would generally provide 4 -6 lbs above atmospheric pressure... but, NOT due to Compressing of the air.. but because the "rootes" would provide a slightly greater amount of air VOLUME, than the engines could assimilate throughout the rpm range... so, "above atmospheric pressure" would result from "BACK PRESSURE".... and NOT by actually Compressing the air -or- "supercharging"... and that is the very same way that they perform when adapted to "4 cycle engines", whether gas, alchohol, nitro, or diesel.... they DO NOT, in & of themselves produce "Boost" by compressing air... like the well known "Turbochargers" DO... where air is taken in & then "accelerated" through an incrementally smaller passage way (in laymans terms) thereby exiting at a much greater Force, than when it "entered".

Having said all that... what I'm seeing & "hearing" on this new Banks "Max" is yet a different breed of "blower".... enter what is known as the "Lysholm Screw Blower".... which actually DOES, intake air and compresses it to an elevated flow rate upon exit... much like the well known & common "Turbocharger"... But, WITHOUT TWO of the turbochargers equally well known "drawbacks"... ie: "Turbo-lag" (though they've come along way in helping to at least minimize it over the years), AND all of the  attendant / associated "Plumbing" that goes with "Turbocharging".  

The Lysholm Screw design has been around for over a 100 yrs now.. and was used on very Large industrial & marine diesel engines... their drawback to being used in much smaller applications was that no one had figured out how to manufacture them with the "tight" tolerances needed and at the same time, be able to "live" (re: stay Together) at the rpms utilized by hugely smaller engines other than what they were originally designed for...diesels that rarely operated much over 300 rpms !  

An "engineer" by the name of Bob (if I remember correctly) Gray, back in the early 1980's took it upon himself to see if the "Lysholm" could be made to work in the high rpm enviroment of "small" engines... primarily, Drag race engines... and after Much trial - error & failures... but, with a lot of tenacity.. he succeeded... and today, almost ALL of the Top Alchohol Dragsters & Funny Cars in the class, are running Lysholm Screw blowers.... which is the main reason why their running the et & mph numbers they are, these days... and as a "side note" - personally, I think it's absolutely Ludicrous that the NHRA - STILL has them locked into a "sportsman class" and not.. PRO.

The Lysholm Screw blower.. works essentially as the name implies.. by turning two (in simple terms) "worm screws" positioned "opposite" .. meaning if were to (say) take two sheet metal screws with "heads" and lay them down, side by side, but... at "opposite ends" from each other... you will get the idea (however simply illustrated) of the layout of the internals.. they intake air at one end, and "screw it" to the exit end, with elevated / increased.. force or pressure at the "exhaust" end, thereby "Supercharging" the air.... UNlike, the common Rootes blower, which intakes air from the Top Center and passes it out the bottom center in large Volumes... but, WITHOUT COMPRESSING the air, in Any Way, Shape or Form.

The Lysholm Screw Blower... when compared to the more common Turbocharger is really the way to go.... in terms of being a LOT SIMPLER & "Cleaner" installation... the main thing that the "Turbo" has in its favor, is that there is NO "Parasitic" loss or "drag" on the engine, to drive it.. as it is exhaust driven of course.... whereas, the "Rootes" and the Lysham types makes use of the term.. "it takes power to Make power" as they are, of course.. Both mechanically driven in one form or another, by the engines crankshaft.   So, why do they use them (Rootes & Lysham Types) in drag racing as much as they do ??... because they have several things In there favor.. 1) Simplicity & "cleanliness" of installation. 2) Capable of pushing greater quantities of air into the engine - very necessary on fuelers & Especially on Alchy engines.  3) Mechanically induced engines produce the Instant throttle response SO necessary in drag racing (especially).... and 4) Rootes / Lysham induced engines will "generally" produce not only More torque... but a "fatter" torque curve over a broader rpm band, than when compared to "most" Turbos.

Turbos, however.. reign supreme when used on OTR (Over The Road) / Semi- truck diesel engines (also used in industrial & marine applications) because they are a much more "sanitary" installation (and therefore, lighter) with Much less "plumbing" as when compared to most "high & ultra high" performance "small engine" (re: automotive / various racing) configurations.

Just some (in very simple terms) "blower" Trivia for some of you "out there" who may have Not known some of the "differences" in the "world" of "forced induction" for engines.    Have a Great day.

[johnsmithfakename]

Supercharged Diesels interest me, I wonder what numbers she made.

[mightyfinejonboy]

feeding the supercharger with a couple of turbo's would be nice...

[BlakesWrld]

need to put that duramax in a chevy silverado

[gavincayan]

Question for you know it all's here and I'm not trying to start an argument here. If you were to take a stock duramax (397 hp and 765 tq at 1600rpms) and removed the turbo and put a supercharger on and nothing else, what would be the differences in performance and power band?

[jasonstuck]

I dont know if I would have gone with only a supercharger. Diesels dont have enough rev range for one you wouldnt think. I would slap at least one turbo on there for boost after the start.

[BigRig]

Can't really call a duramax a 871. Detroit coined those terms a long time ago.

[briandavis]

That is Gayle for yah... complicated piece of shit, for a rich mans game!! Fuck motorsports these days!!

Why it is supercharged? isn`t it wasting of free energy of exhaust gases?

[bhearts]

whats with the shitty looking design exhaust log manifold.