Ok, i've been doing a little research on our m45 supercharger and have seen a few different approaches to improving them. "TheOldOne" closes off the two small ports in the supercharger outlet and fills the space ontop of it. "M7" leaves those ports open, and increases the size of the main port. Both of these designs claim to increase effiency, but both use completely different ideas. Which one does what? and which produces better results?

TheOldOne:





M7:




I like the porting job that m7 performed on the supercharger inlet, but i'm not sure how the enlarger opening on the outlet will affect things. If you look at the inlet to the supercharger on "theoldone's" supercharger it still has very large sections of square material right at the inlet which is horrible for flow.

I'm truly lost with these outlet designs and am looking for some real facts as to which one is better.

 

Don't know, but would love to, as well.

Matt

 

Call Larry Widmer at ENDYN and ask him why the inlet is shaped that way.

 

I'll take a look tomorrow, but it think it has to do with the outlet on the runner that mates to the SC; no point in making the SC hole bigger than the runner outlet.


Larry makes a big deal out of carefully matching the case openings to the 120 degree timing of the lobes, but I don't understand the theory behind this.

 

I wanted to post here first to see if anybody knew why. I'll give both companys a call tomorrow.

 

If you look at the picture of the m7 outlet, you can see the rotor with its 60 degrees of twist. See how the sealing edge follows the lines of the triangle part of the port? Look what happens once it gets into the hogged out portion.... if you imagine how the two rotors mesh together, you'll see that there is nothing happening down on that end. I dont think anything bad happens by porting it but I dont think anything is gained either.

Those little triangle ports trade a little bit of efficiency for quieter operation. Its definately noticable I think jlm's sounds great with them filled but I dont think anyone has any idea how much power its worth.

 

I have an Endyn modified blower. The intake area has more material removed than shown in the photo you have. I had a supercharger intake duct that I had modified and then cut into six sections for measurement analysis which I let him (Larry) have for a few months last winter. He used the end piece to do an exact match for me and probably has incorporated the shape into later versions. Remember the entrance is designed for the stock supercharger intake duct interface if you choose Endyn for the SC mod and your duct has a larger exit, Larry and Josh can customize the entrance if you request. There is a great deal more workmanship involved in the modification than what is seen on the outside. He showed me different cases in various stages of porting and the details are many.

Larry has looked at the other M7 re-badge version and thinks that shortening the path to the exit would be less efficient than the concentrated exit his style provides. Larry has a great deal of experience with quality of flow and has all the tools to quantify and qualify anything he does so some things I have to trust him with.

Having measured the internals in the intake system myself I don’t see the point in hogging out the intake duct side when everything has to squeeze through smaller portals downstream or sucked through small, but efficient, orifices upstream but this is a subjective opinion.

 

I'm looking into different porting opptions as i'm making my own TB to SC tube. In my design the outlet matches the Supercharger's inlet. so having it ported as the M7 sc has been will create a smoother flow. I undertsand now why endyne hasn't ported their SCs as m7 has as the stock SC inlet tube is quite horrible.

What really has me thinking is the outlet of the supercharger though. I'm going to give endyne a call tomorrow to discuss that.

 

I have the M7 blower. I cannot comment on the efficiency of the design, but I would personally guess that it might allow less heat production. I looked long and hard at the SC, rotated the vanes, etc, and it seems to me that by removing the area and opening up the sc output, it allows the same amount of air to be flowed, but forces the air out of a larger opening. My guess is that this requires the air moved from down there to face less friction. Boost stays the same since it flows an equal quantity of air, but I would guess that it runs cooler that way. Again, this is just my conjecture, but I did stare at that thing mighty hard before it went on !

 

Ingsoc,

Did you see any differnce in boost before and after the instalation of the blower? were you able to take before and after temp readings?

I need to find a few extra blowers to test out these different ideas.
I already have 4 extra engines sitting here....

 

autoxguy305: I'll trade you a blower for a spare engine

How does one end-up with 4 spare engines ???

JP

 

I have a friend that has access to engines after they are no longer needed. I then pick them up for a very low price. Its just to bad that 99% of the time they're from a regular cooper. The engines i have now are regular cooper engines. Pay for shipping and i'll trade you

 

I took a look and the SC step could be at least 1/8" larger and still not retrict the flow from the stock runner. Knife edging the opening would require a completely different runner design, and without it, the abrupt section change, even if increasing, is a turbulator, significance unknown.

As far as the outlet opening, the large triangular shape is matched to the line defined by the impeller edges, however, that could be a yet larger triangle and with less rounded ends. For that matter, the entire top surface could be removed. so the point is, how much of the captured volume is required? that being the volume created from when the impeller seals as it leaves the intake to when it starts to break into the opening?

cheese...any opinions?

 

Thanks for the offer! I unfortunately need a block with the forged crank! Let me know if you get an "S"

JP

 

Do you need the S connecting rods? I could supply a good block with just an S crank.

 

Unfortunately, my car has not yet been outfitted with boost and temp gauges- I sorta got power-greedy and had the goodies installed before I bought the extra telemetry . I have them, but have had no time to install yet. So, I can't really provide any data, sorry . I know that Madness was apparently trying out the Endyn blower. M7 might be able to comment on theirs, but I'm not sure if anyone else around here has one....?

 

From a purely theoretical perspective - i.e. not with reference to the particular Mini design - there's more to be gained from opening up a S/C inlet than its outlet. Airflow, which we're seeking to maximize, is determined by pressure difference. If the S/C had no leakage and could draw a perfect vacuum, then there would only be normal atmospheric pressure of 14.7 psi or so to drive air through whatever obstructions to flow there might be. But on the outlet side, and assuming for the sake of argument that the engine can also draw a perfect vacuum, then there's 14.7 psi plus the S/C boost pressure.

So other things being equal there's more bang to be had from making sure the intake is freed up than the outlet. Whether theory carries through to practice would presumably be a function of this actual design and whatever compromises may have been made with it.

Neil
05 MCS
96 M3

 

I always have an opinon I think the reason for the traingular shaped port is for efficiency. The rotor to rotor tolerance is probably a lot tigher than the rotor to wall tolerance on a standard blower, just by nature of the manufacturing process. The rotors are precision pieces and the case is a pretty rough casting.

I'd guess that the triangle is there so that only one volume per rotor is being displaced at a time. If that triangle wasnt there, the other side of the impeller would experience the manifold pressure and that pressure would force its way along the case wall causing some lost of boost. The triangle reduces that possiblity and probably allows for a more controlled compression of the air before it enters the manifold. I'd guess thats why larry adds that aero profile to the triangle's opening. He called it a "cow lip" when I spoke with him? Probably adds some local velocity to reduce the pressure of forcing the air through a smaller cross section.

Definately not the facts, but thats my opinion of why/how

 

I believe, though, that by opening up the output side, as we see with the M7 blower, you'll be letting the given amount of air that your vanes would turn escape without forcing it to flow further along, to the output area. I think that this would reduce the heat imparted overall, since it would no doubt encounter less friction, no?

 

Neil,
Theoretically, there is no compression going on inside an Eaton Blower. It works by displacing a fixed volume of air faster than normal. The "stack" of air on the output side ends up pressurized because it has nowhere to go. I think the point that jlm and k-huevo are making is that the intake volume is already sufficient but I dont know how they measure it!?

 

I don't know about this. Since part is obviously closed off by the area around the triangle, it seems to me like there would definately be extra compression, since air must make a perpendicular turn to find the exit.

 

What?

 

Since there is partial occlusion of the supercharger exhaust side [only a 'triangle' is cut into the side], you are restricting the passage of the air out of the supercharger. Air that is moved at the edge of the impellar where there is no direct escape must travel down the length of the impellar to exit from the opening. Therefore, it must turn 90 degrees from the orientation where the impellar pushes it. In doing that, it encounters other air which is being pushed out. It competes for the space, and it gets compressed, right?

 

That is exactly why roots blowers are so inefficient. The air being moved through the blower is at atmospheric pressure right until the exit when BLAM! It runs smack into compressed air that has stacked up in the plenum. Pressurized air actually goes back up into the vanes until it it is squeezed out again in the center where the rotors mesh. This "beating" of the air is what heats it up so much relative to other supercharger types.

The roots blower moves volume. Pressure builds up as volume "stacks up." On the other hand, Whipple screw-type/Lysholm superchargers also use rotors but smoothly compress air internally as air travels down the rotors. At the output the air is already pressurized so there is less turbulence to heat the air.

The wide triangle is pretty typical for twisted rotor roots blowers; that mirrors the lobe opening presented by the rotors. Superchargers with straight-cut lobes use narrow rectangular ports.

 

how about this: you can't let the output edge of the impeller break into the charged side air until the edge of the impeller on the intake side rotates enough to seal the charge it is pushing. Maybe this is the 120 degree timing and what defines the shape/position of the triangle. The small openings would be allowing pressure side air back into the intake side, as would the extra rectangle on the M7 version.

PS:
I took a look and the rotor location at the input is not related to the location at the output as I suggested above