Can the inlet of a m90 be over ported?

90tbirdsc

90tbirdsc

Registered User
Here soon I will start porting my late model m90 since the one on my car now is a logan butler screw up. I plan to just knife edge the outlet and remove the bolt bosses. but I planned to open up the inlet more than the s-ports ive seen. is there a disadvantage to doing this? from what I understand the lest restrictive the inlet is on our cars/superchargers the more power we can easily gain.

or should I just contour some on the sides of the inlet?
 
I know Jacob Royer had a butcher of an inlet on his SC before he welded and fixed it. And his still made 15+psi. Id imagine there is a fine line, as with anything, between good and overdone. I'm just not exactly sure where that line is for you. However an S-port blower is capable of over 315rwhp with the correct supporting mods, so just be aware they do make good power with free flowing heads and a cam
 
On porting an M90. There is a balance to the port work you do. The inlet is probably causing performance loss if the lobe of a rotor at the inlet side isn't sealed at the inlet before the preceding lobes following edge reaches the silencer port. It takes 120° of case to seal.

This being said, the porting should almost always improve performance.

Maintain enough lip at the inlet to seal the inlet plenum to the s.c. case. Where you get major gains from porting are smoothing the sharp steps in the corner of the "smile" and making the "smile" inside the case larger and more smooth.

As long as there is no way for the pressurized air from the outlet side of the blower to flow back into the inlet side, you are fine.

Also this thread http://sccoa.com/forums/showthread.php?t=94951 has a ton of information. The best advice I have seen is to imitate the MP2 as much as possible when porting a late model case.

That's what I got from lots of research here and at other sites.
 
Last edited:
This is the best way to port a m90 for maximum performance................:eek:

z6zh.jpg
 
heres mine

This is how I ported mine

Made ~16.5psi on 10% steel pulley

Will see how much it makes now
At first I thought I had overported but it turned out quite good most gains are from the inlet towards the top
 
Last edited:
Non ported will work just fine I liked how mine worked over the early model when non ported

But then again its a great improvement and he will probably do it anyways. ..

outlet stays same size on an s port
Inlet I copied mine from an s port its identical to
90mn12 s port and dirtysouthbird MP s ported blower

Just copy someone's u cant go wrong that way my outlet I copied somewhat the mpx look it just bumps up the efficiency band of the blower to more of a top end
 
Also consider sending it to Charles at Magnum Powers for an S-port and rebuild. This way you know it's done right and it's rebuilt at the same time....one less thing to worry about
 
LIVipers said:
Also consider sending it to Charles at Magnum Powers for an S-port and rebuild. This way you know it's done right and it's rebuilt at the same time....one less thing to worry about
Click to expand...

+10
If u got the $$$ its a great option and ull know u start with a fresh ported blower
 
Quite honestly,

Doing the work and research myself probably cost me more then just sending to Charles in the first place. I'm certain my port work will not flow as well as his and, if you factor in time, cost me more.

The only real bonus I get is the "I did this" factor.:D
 
SDCoupe said:
Quite honestly,

Doing the work and research myself probably cost me more then just sending to Charles in the first place. I'm certain my port work will not flow as well as his and, if you factor in time, cost me more.

The only real bonus I get is the "I did this" factor.:D
Click to expand...

The "I did this!" Factor is great till something goes wrong lol. Then it becomes the "oh crap, I did this....." Factor hahah. In all honesty, blowers are one thing that shouldn't be messed with without knowing exactly what you're doing. One wrong cut and you're out $300+ for a case
 
SDCoupe said:
Quite honestly,

Doing the work and research myself probably cost me more then just sending to Charles in the first place. I'm certain my port work will not flow as well as his and, if you factor in time, cost me more.

The only real bonus I get is the "I did this" factor.:D
Click to expand...

If u got a Few tools its very inexpensive to do I think I spent 20 bucks at the most
If u have a die grinder
Air compressor etc

Reaseach isnt bad either with the internet its fairly simple and self explanatory

But u risk messing up :p I thought I did before I ran it :p
Its not a great feeling before u start the car again
 
Miguel,
the tooling to do the porting is very inexpensive. I was talking about taking the time to do it right. Now it would probably take me just a few hours. Figuring out exactly what to do and how to port and then doing the work took some time. I had to work up from having zero working knowledge.

To help the OP. Yes, you can screw things up. You can also leave porting alone or send your case off to be ported. It is a great learning experience and if your patient quite rewarding.
 
SDCoupe said:
To help the OP. Yes, you can screw things up. You can also leave porting alone or send your case off to be ported. It is a great learning experience and if your patient quite rewarding.
Click to expand...

Very well said ! It is a great learning experience I agree

It is a patience job as well, idk how well mine is, and im by no means an expert or experienced in the porting
but I want to compare it to an s port from my friend and another late model case I have that has a different port job and outlet style see differences

I worked on mine on small periods of time throughout a couple days
But before any grinding I did measurements to it to know exactly what to remove :b on outlet and inlet
I also had no working experience whatsoever

Key is not to get carried away with the carbide bits ! Lol

And one recommendation is leave the silencer ports
alone
Outlet dont go past 1/4" opening on the sides
And keep it in a symmetrical or better said parallel line use the silencer ports as guideline to be parallel with
 
Last edited:
You must log in or register to reply here.
Back
Top