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porting blower confusion / how the eff do i do it



We should just let steig test some stock M90's and some "crazy port" M90's and a reasonable port M90. Not that steig or alky would do any of us a favour after that thread.[/QUOTE]

bluegtp91 said:
No thanks because a ported outlet flows better for one.

Allows the blower temp to drop.

Less parasitic loss from the temperature drop.

But we could be here all day and the gains are there but you won't really notice anything...but it won't hurt to do it.

Alky did PM me, but...I didn't reply...so, let's build a supercharger dyno out of cardboard, elmers glue, and popsickle sticks.

Seems relevant.
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matt5112 said:
Based on what?



Based on what? More in the same space means it'll heat up more. Gas laws can't be ignored.



But you said it flows more, which means it costs more power to turn the blower.



How so? If you reduce flow, that does hurt performance. If all you do is reduce flow, then yes, you can run a smaller pulley with the same flow mods.

But its not productive as the blower spins faster it uses more power to turn it. Only benefit is noise.



Blue, y u no reply?

I can think of a few ways to make a blower test bench. The only issue would be it would only be relative, not absolute. But thats like any dyno or flow bench in the history of cars. :th_jester:
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:th_laugh-pointup: :th_laugh-spit: How funny no one here has talked about rotor timing and lead-ins :confused:. There is more too it than just opening up the inlet and outlet to what looks good. Granted, the 3800 M90 does'nt get the huge gains in hp that the Cobra M112 does from a port due to its straight through design, but there are gains to be had. But what do I know? I'm sure another "expert" like copgtp will come in here and chime in. I'd actually like to hear what Reptile has to say about all this ( I respect his opinion), although I'm not sure if he messes with rotor timing at all or just ports the inlet and outlet.

BTW my dyno has about 100 hp to spin the M112 to 18000 rpm. Not sure on the M90 (yet) but it takes a bunch of power to turn these little bastards. Maybe hook one up directly to your transaxle :p.
 
nick, youre talking about adding a beveled edge to the outlet? what gains could that possibly have over just opening it up to what it should be and giving the bottom side a once over with a wire brush?
 
Because all he did was clean it.

He didn't even remove the square bosses at the top of the outlet that protrude into your typical "V" pattern.

So, If I'm wrong...then that means Brian has been doing it all wrong all these years too? I doubt that.
 


but he did remove the bosses where it mattered, the triangle is fully extended. he just didnt remove the entire thing.
 
Triangle didn't move down at all.

Just removed the little bit at the top...

Maybe we should all do it like Stieg does it and end the discussion?

1-_15_-08_050.JPG
 
alkygto said:
:th_laugh-pointup: :th_laugh-spit: How funny no one here has talked about rotor timing and lead-ins :confused:. There is more too it than just opening up the inlet and outlet to what looks good. Granted, the 3800 M90 does'nt get the huge gains in hp that the Cobra M112 does from a port due to its straight through design, but there are gains to be had. But what do I know? I'm sure another "expert" like copgtp will come in here and chime in. I'd actually like to hear what Reptile has to say about all this ( I respect his opinion), although I'm not sure if he messes with rotor timing at all or just ports the inlet and outlet.

BTW my dyno has about 100 hp to spin the M112 to 18000 rpm. Not sure on the M90 (yet) but it takes a bunch of power to turn these little bastards. Maybe hook one up directly to your transaxle :p.
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Rotor timing is part of the reason why I don't suggest opening the outlet.

Ideal rotor timing also changes based on the speed at which you spin the rotors.

Would take some serious R&D.

Working with gen III blowers wouldn't be worth it considering gen V's are pretty reasonably priced, inlet flows much better and the coating is much better.

Gen V also pushes the rotors further into the case so the end of the rotors are open to the outlet instead of being shrouded like the gen III.
 
alkygto said:
I don't think you understand what I said. At all.
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The "timing" being what?

The rotors have to be "timed" to leave proper clearance between the rotors at all times.

So playing with "timing" of the rotors relative to each other is impossible.

Perhaps you're referring to playing with changing the "overlap" between when a rotor is open to the inlet and to when it seals against the side of the case. Like-wise with the outlet.
 
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people are mad. So should i just clean up the arrow or make it a v also im still confused about the inlet of the sc where the tb goes
 
matt5112 said:
The "timing" being what?

The rotors have to be "timed" to leave proper clearance between the rotors at all times.

So playing with "timing" of the rotors relative to each other is impossible.

Perhaps you're referring to playing with changing the "overlap" between when a rotor is open to the inlet and to when it seals against the side of the case. Like-wise with the outlet.
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Thanks for editing your post ;).

What I was talking about was the lead ins to the rotor. At the "rear" of the case you can start filling the rotor valve earlier by altering the lead ins.
images
that is the part on the outside of the bearings leading into the rotor opening
 
Ha, not a problem. Frustrating being told you're wrong with no rebuttal as to why.

Issue with our blowers is we have the PCV passage right under there. There is only so much we can remove before that would become an issue.

However, how far you can go, I am not sure.

Have a junk case I can play with though.
 
It took three tries to get my current setup. Fine balance between making more HP up top and losing TQ down low. All dyno tested of course. As I've said before I'll help anyone I can, if they're willing to listen. I don't know everything there is to about these cars but I know enough about superchargers that I can be a part of the discussion.
 
See where my logic gets you?

Somewhere.

Both of you whiners are welcome :D

BTW, where were the pics of the port you did on your cam setup?
 


alkygto said:
BTW my dyno has about 100 hp to spin the M112 to 18000 rpm. Not sure on the M90 (yet) but it takes a bunch of power to turn these little bastards. Maybe hook one up directly to your transaxle :p.
Click to expand...



I have to check the.

I'm looking for large.

What did my sentences have in common with your post? Unfinished.

I.E.: What pressure ratio was the 18000 RPM, 100HP blower operating at? What was the specific gravity of the air you were using?
 
Doug 97 gtp said:
people are mad. So should i just clean up the arrow or make it a v also im still confused about the inlet of the sc where the tb goes
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Make it a v how i posted mainly all you have to do is cut the two little bumps on the bottom of the V were the bolts go throuh on the s/c case and just smooth out the whole V outlet you can make it just a bit larger the whole V itself even a bit higher but very little just to smooth it all out. look at the pics i have posted. What are you confused about on the inlet side of the s/c case/TB side?
here is another pic

photo-1.jpg
 
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