The Old One - Energy Dynamics : Damaged Roots Type Blower
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Hey, let's boost a 7 psi kit to 12 pounds and see what happens...

How to reduce Boost From 12 psi to 3 psi

We proudly announce our latest modifications, which are designed specifically to reduce boost in any close tolerance roots blower, regardless of application.

The process is quite easy and all you need is a "small" diameter blower pulley that will increase boost to 12 psi, with your non-modded blower. Completely disregard our advise and drive the heck out of it for several months, wait until it's performance has rolled off a bit, then send it to us for rework and mods.

We'll take it from there and when you receive the modified unit, it's likely to be no better than it was when you removed it from the car.

These photos are documentation of "the" most famous blower that we've done to date. Some might wonder why we took pictures of it and the answer is simple. We'd never seen a blower that had been abused to that extent and a picture is worth a thousand words. Especially so, when people want to use our "good faith" and "free" work against us.

Figures 1-3 : These three pictures are of the, yet to be disassembled blower, as received. Note the greasy filth of the exterior, as well as the discoloration, both externally and internally from the extreme temperatures that this abused unit was exposed to.

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Figure 1 : The blower as we received it. View of well worn supercharger with manifold removed. Note the abundance of crankcase oil present on the discharge outlet and the heat discoloration.

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Figure 2 : A different view. The reasons for the the nasty conditions are both a function of many miles of abuse and running a 3" pulley without proper blower modification. Increased RPM require the blower modifications to keep excessive temperatures under control. Excessive heat is just like excessive RPM, They each ruin peoples" motors.

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Figure 3 : Another view from the manifold side of the blower displaying the overall nasty condition of the unit.

Having provided performance-related services for over 35 years, we've long come to associate the external appearance of components with the condition of internal mechanisms. Abuse outside always means abuse inside.

Figures 4-5 : These two pictures clearly show the damaged rotors and the amount of case damage that occurred, when the components were both attempting to occupy the same relative space at the same time.

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Figure 4 : View of the rotors after removal from the case. Note that the rotors became so hot that the epoxy finish was "blown" off. The epoxy is simply another component that the engine must eat. Please notice the serrated edges of the rotors. These are designed and machined to be self-clearancing as the engine runs.

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Figure 5 : The innards of the blower case. Note the (hard to see) shapes of the inlet at the rear and the exit on the lower side. The case also displays considerable scoring resulting from the self clearancing design and the temperatures which caused some of the epoxy to fly off.

Note that the super heated rotors expanded, literally exploding their epoxy sealing layer off. Also, note that the rotor edges that have been chewing up the blower case walls. Please keep in mind that the epoxy and aluminum that's produced by the contact ends up in the engine's cylinders, so the blower itself isn't the only victim of this abuse.

The blower case shows that there are no areas that were spared from contact, while the expanded blower rotors were chewing away.

As the case has been "re-machined" by the larger rotors, there's absolutely no way that the clearances will ever be tight enough for suitable performance again.

Figures 6-11 : These next six photos show our attempt to revive anything that was left to function. We did not do our full aeroport configuration due to the shape of the components. We did elect to perform the standard "S" mods that have been available from OJ and Magnusen Products for several years. The pictures show where the mods were performed on this damaged case.

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Figure 6 : This view shows some internal detail of charge exit area. Note the area increase and the radiusing on all the surfaces to curtail turbulence.

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Figure 7 : This internal view shows the expanded and carefully shaped air entry at the back of the case. The shapes are designed to work with the charge exit area to provide 120-degree case to rotor timing and are, therefore, critical.

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Figure 8 : This view provides a good overhead look at the the amount of material removal necessary in the blower charge exit area. Note that the (front) of the opening is tapered to a sharp intersect for greater escape cross section. All surfaces are carefully radiused.

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Figure 9 : Another similar upper view of the charge exit area.

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Figure 10 : This view shows that the rear area on this particular application required only minor reshaping which was really simply to get a good match to the bypass housing.

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Figure 11 : Another view of the reworked entry area of the rear of the blower.

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Figure 12 : The blower's rotors in this picture exhibited considerable warpage and wear damage. We massaged them where necessary to prevent future contact and erosion. The rotor's heat-treat was also destroyed by the heat from the extreme RPM and abusive driving conditions. We went ahead and stripped the remaining epoxy off using water and an ultrasonic cleaning process. We felt that we could possibly prevent the engine from eating any more debris by removing it while we were able.

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Figure 13 : This is a look into the bypass housing showing the minor radiusing that is necessary to properly allow pressure equalization. Many people spend a lot of time carefully shaping this area, but there's in fact very little flow at this's only a pressure balance and the bulk of the flow still passes through the blower rotors. Don't waste too much time working here, the gain is not measurable.

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Figure 14 : This picture shows the "finished" blower just prior to packing and shipping back to it's owner. We did perform the "S" mod to the case, while cleaning the components and reshaping some parts so their warpage wouldn't cause part to part collisions in the future. We did our best to help revive something that was already dead and, if nothing else, there was no longer any debris available for the engine's consumption.

Finishing statement:

Our "free" work (including shipping) was all for naught and continues to be the subject for a lot of conversation. Readers can all see the photos and draw their own conclusions.

The question of "would we do it again" comes to mind and, although I'm tempted to say "NO", we'd still attempt to help anyone we can with their individual problems. Sometimes manufacturers don't go that far and our willingness to help those in need is simply one more reason that our company is different. Most people who've been in touch with us over the years can verify that there's not a day that passes where we don't answer questions and provide advice to all those with problems. Our philosophy is fairly unusual in this day and time, but if we know the answers, we are ethically obligated to pass the best correct information on in a manner, which is fully understood by the enthusiasts or businesses asking the questions.

  • A little tidbit regarding our purchases of other's blower kits. We have purchased some and we'll continue to do so, as long as other customers need our help.
  • If we are to provide personal support, as well as additional components, i.e. high quality air boxes, induction systems, improved "S" tubes, boost / traction controls, and headers, it should be fairly evident that we'd need the "real thing" to begin with. Making sure that there are no surprises, when the customer installs the components is paramount in our view. The kits are also a necessity in developing modification packages, as we don't ever practice on our customers' components.
  • Many feel that these purchases "say" that we use the other kits as the base for our own. My response to that is easy, "We sell systems, not kits."

- The Old One

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Hey, let's boost a 7 psi kit to 12 pounds and see what happens...