Porting Your Supercharger
- Thread starter kfish
- Start date
blueguy
The Blue One
Then the rotors have nothing there to push against...so you wouldn't make any boost at all...and you'd have a 50 pound metal air intake instead.
twol8uluz
New member
Sooooo, does doing this make a considerable amount of difference? I haven't heard anybody on this thread sounding all excited to have more power with a newly ported sc. Of course I understand it all depends on what other mods are done to each vehicle. But on a broad spectrum, stock to heavily modded, who's feeling the power?
TheOtherNick
The mod from over yonder
not much of a diff in power, the whine is nice tho
SMazza
New member
The main difficulty with M90 blowers is getting the air in so the rotor cavity is filled. These particular blowers (GM Gen 3 and Gev 5) have pretty generous inlet ports to begin with, so the main problem is out of the way already.
If you compare the inlet ports on these blowers to the early M90s as used on the Thunderbird SC, you will see how much the inlet has grown over the years. Aftermarket products like the Magnum Powers MPX case have gone even bigger on the inlet that these blowers ... but those are designed to be spun very fast and give major high-RPM boost. There is a trade-off between minimizing boost leakage at low RPMs and maximizing airflow at high RPMs, and the MPX is skewed toward maximum performance.
Here is how to tell how far is too far. At the point where the leading rotor opens to the outlet port, the trailing rotor had better not be open to the inlet port. Otherwise, the pressurized air in the LIM will force air back out the inlet port. So that is the key thing to check.
Don't worry about the two small silencer ports ... they might let a small amount of air bleed back from the LIM, but it is by design, to keep the blower less whiny. Old people buy Regals, you know.
As for beveling the outlet port: Don't bother beveling the edge facing you. What would it do, help the air make the turn out of the outlet and shoot to the sides of the case? That doesn't make sense. Beveling (or filleting) the edge on the inside of the case is a good idea. It will help the air make the turn out of the case. Removing the bolt bosses (or not) is up to you. At a minimum, remove a little material to smooth out the airflow from the backside of the bosses out of the case.
The other problem that the early M90 had was control of the rotor clearances. The coated rotors in the second generation helped that issue, and the Gen 3 and Gen5 benefit from it.
If you compare the inlet ports on these blowers to the early M90s as used on the Thunderbird SC, you will see how much the inlet has grown over the years. Aftermarket products like the Magnum Powers MPX case have gone even bigger on the inlet that these blowers ... but those are designed to be spun very fast and give major high-RPM boost. There is a trade-off between minimizing boost leakage at low RPMs and maximizing airflow at high RPMs, and the MPX is skewed toward maximum performance.
Here is how to tell how far is too far. At the point where the leading rotor opens to the outlet port, the trailing rotor had better not be open to the inlet port. Otherwise, the pressurized air in the LIM will force air back out the inlet port. So that is the key thing to check.
Don't worry about the two small silencer ports ... they might let a small amount of air bleed back from the LIM, but it is by design, to keep the blower less whiny. Old people buy Regals, you know.
As for beveling the outlet port: Don't bother beveling the edge facing you. What would it do, help the air make the turn out of the outlet and shoot to the sides of the case? That doesn't make sense. Beveling (or filleting) the edge on the inside of the case is a good idea. It will help the air make the turn out of the case. Removing the bolt bosses (or not) is up to you. At a minimum, remove a little material to smooth out the airflow from the backside of the bosses out of the case.
The other problem that the early M90 had was control of the rotor clearances. The coated rotors in the second generation helped that issue, and the Gen 3 and Gen5 benefit from it.
GTPmonster0501
New member
I am looking at porting do you have to tune it?
cmal37
New member
How did you do it on a CNC lathe? i was going to do it on a full CNC machine, but a lathe sounds much easier
Thanks
SuperchargedFiero
New member
One other thing is it true that when closing the two small squares or how u spell it
The charger will whistle more
And second how do they close it beqouse when using a welding machine al the heat in the
Aluminum will bent the charger
Am I wrong ,
The charger will whistle more
And second how do they close it beqouse when using a welding machine al the heat in the
Aluminum will bent the charger
Am I wrong ,
87IROCZOWNER69
New member
Some people have talked about blocking those "silencer holes" in previous threads, however no one has come to conclusion on the best way to do so really. All I have heard is to not use JB Weld or anything else that could break up. Those who have said it is very noticeable sound difference and you can even hear the supercharger whistling on idle.