Porting & Polishing Gen III Blower

I want to port & polish a Gen III supercharger. I also have a stock LIM and TB that could use some help. Has anyone ever done this, or know of someone that could be of assistance? I'm not looking to experiment. I want to get it right the first time.

I know what ZZP says:

" Outlet porting reduces blower outlet temps and increases blower efficiency. Tests show that CFM gains begin at 10,000 rpm blower speed. We recommend porting your lower intake or running our lower intake to maximize performance gains.



For our inlet porting we open the inlet to 78mm, remove the divot in the airpath, revamp the bypass hole angle and taper the bore."


I know what INTENSE says:

"Our entry level ported blower housing (INT-PSC-671) features a ported outlet area. This removes all the rough casting points, which eliminates heat spots, and produces a cooler charge.



In addition to the outlet area, the inlet/outlet ported blower housing (INT-PSC-672) increases the inlet size to 75mm which will work with stock L67, ported L67, aftermarket LS1, or aftermarket Northstar throttle bodies. The EGR "divot" is also blended out to help with airflow into the rotors.



The inlet/outlet/intercooler ported blower housing (INT-PSC-673) has all the above and features a longer smoother outlet area to take full advantage of an intercooler core."



And I know what W-Body Store says:

"A stock M90 with a smaller pulley can see outlet temperatures of 300 - 350 degrees! We can reduce these temperatures by using an intercooler. We can also reduce the temperatures by improving the efficiency of the stock blower.

By modifying the supercharger's outlet and porting/ polishing the inlet we can slightly increase boost and significantly lower output temperatures. All W Body Store blowers feature re-packed bearings, full intercooler compatibility, and are media blasted for a like new finish!




W Body Store VS1 Supercharger - This is our basic supercharger upgrade. The supercharger's outlet is reworked and beveled. This is a major contributor to dropping outlet temperatures. Milling each piece ensures a high quality finish far beyond what the home porter could achieve. This increases velocity and also improves adiabatic efficiency by reducing the amount of energy required to spin the rotors.

W Body Store VS3 Supercharger - Our deluxe supercharger. As well as modifying the outlet of the supercharger we open up the inlet from 72mm to 75.5mm in diameter, polish and blend it. This further improves adiabatic efficiency and is ideal for setups where a larger throttle body will be used in the future.

Optional Intercooler Outlet - Add an intercooler outlet if you're running an intercooler or plan on running one in the future. The intercooler outlets allows you to take full advantage of your intercooler's core.

The Eaton M90 is a relatively efficient blower when compared to older Detroit Diesel roots blowers. The advantage to a positive displacement blower like the M90 is that it's constantly pushing out 90 cubic inches of air for every revolution resulting in a torque advantage off the line. This advantage also turns into a limitation as we can not increase the displacement of the blower. We are left to improve on adiabatic efficiency, which lowers heat, thus reducing knock and resulting in a denser air charge (more air passed). We do this 2 ways:

1. Porting & polishing the inlet - Porting and polishing the inlet increases velocity (the speed at which the air moves through it) which reduces the amount of energy required to move that 90 cubic inches of air. This requires less work from the motor to turn the supercharger and since the supercharger now doesn't require as much energy to spin it runs cooler, resulting in cooler outlet temperatures.
2. Modifying & polishing the outlet - This is the most effective way of reducing outlet temperatures and when combined with our ported and polished inlet results in significantly cooler outlet temperatures than an equivilent M90 with a stock case. We have worked with several outlet designs and have used what we feel is the most efficient."

So what I want to do is make the blower more efficient (lower KR), but not necessarily take in more air. I'm thinking bevel and polish the outlet, match the LIM if necessary, and maybe polish out the intake and TB, keeping them matched, but not making them huge.

Anyone car to share additional knowledge and/or experience before I get started? If successful, I'll make a write-up out of this should anyone else care to take the DIY route.

I don't think I've seen all those pictures before.
I'd like to know what you find out also as I have a professional porting bench available to me.
Maybe there is some inlet and outlet work that can be done to the GEN V as well.
Rick

Do you mean you can check flow volume/efficiency before and after porting? Does it work with superchargers?

I've heard that a properly ported/polished Gen III is roughly equivalent to a Gen V, which is pretty much optimum, imo.

you can talk to "goat6919" thats his AIM screen name... he ports blowers his name is Chris Kemp... Very nice guy

There's a porting and polishing bench/cabinet with blower and 2 flow benches.
Unfortunately the flow benches are set up for high performance Harley heads and intakes.
I need to see if I can get adapters made for the supercharger and if they will let me. But with TWO flow benches there is a possibility.

AA wrote:

So what I want to do is make the blower more efficient (lower KR), but not necessarily take in more air. I'm thinking bevel and polish the outlet, match the LIM if necessary, and maybe polish out the intake and TB, keeping them matched, but not making them huge.

Anyone car to share additional knowledge and/or experience before I get started? If successful, I'll make a write-up out of this should anyone else care to take the DIY route.

I will say that you need to get the LIM machined if you ever want to go intercooled. Im not sure, but I do believe that is your goal one day. It will save you some work in the future.

I would machine the intake, because it wont really move more air than stock because the throttle body will be what is restrictive at that point. But if you want to upgrade later (like after an IC), then the supercharger inlet porting will already be done and you wont have to send it off again.

i wouldnt bother self porting the TB, you will only get minimal gains because the butterfly valve is the same size.
HOWEVER, zzp's stage 1 TB has a larger butterfly installed so that the porting could actually make a difference.
if i were you (and this is my plan), get a zzp stage 1 TB, WBS vs3 blower, and a LIM from a gen V car. (i believe the lim on the 04+ motors is already enlarged making it "factory ported".)

Aaron, with those mods added to your sig i'd hope for mid 13's on a good tune.

ok.. where to start.

-A ported Gen 3 is not as efficent as a Gen V. A gen v makes a cooler boost charge and more efficent charge. A 3.4 on a Gen V similar to a 3.2 on a Gen 3 but with a cooler charge.

-Mr.Riviera the LIM from a Gen V is only opened 7/8 of a inch towards the nose drive to accomidate the opening on the Gen V blower. You shouldn't use a gen 3 SC on a Gen V LIM as you may get a severe vaccum leak.

-Aaron it may be easier to pickup a used ported blower from clubgp. The first time I ported and polished my SC casing it cost me about $170 thats including Tools, bits and gaskets to port my old SC. Later I discovered I could have bought a used ported casing that one of the vendors ported for less and not need to do all the work..


I am doing one again but this was a unfinished project by billboost and all I am doing is finishing it.

I will post up pics of it tomarrow if you'd like

Though it may sound like it I am not trying to discourage you from porting the SC just giving you some other options.

If you decide to do it yourself . I will give you two tips to safe you lots of agony. Use a dremel and but 80 grit flapper wheel bits. This wil make taking the rough casting out alot easier.

After looking closely at my stock blower vs the one I got from chris kemp vs the products from the big three, I'm really not liking how WBS and Intense both leave out the edges of the outlet alltogether with their porting, which sucks.

If you really want to, you could produce a better case than you can buy from them, IMO

Travis, thanks for the info. I may talk with Mr. Kemp.

RickW wrote:

I need to see if I can get adapters made for the supercharger and if they will let me. But with TWO flow benches there is a possibility.

Thanks for the offer, but now I'm thinking the shipping cost and time it would take to optimize my blower for flow - it might be more than I want to invest in the project. Thank you, though.

dreww wrote:

I will say that you need to get the LIM machined if you ever want to go intercooled. Im not sure, but I do believe that is your goal one day. It will save you some work in the future.

I would machine the intake, because it wont really move more air than stock because the throttle body will be what is restrictive at that point. But if you want to upgrade later (like after an IC), then the supercharger inlet porting will already be done and you wont have to send it off again.

I've decided not to IC. It's too much investment for me. I like the idea of porting because I picked up a Gen II core for cheap and I have the tools to do this. Now I just need a little knowledge.

Again, I'm not interested in moving any more air. I only want to make the blower more efficient at moving the air I already have. I have enough air, I want less KR without the need to drown it with fuel.

Wouldn't machining the intake and LIM for IC create irregular surfaces and steps that would cause erratic air flow? I would think you'd want all surfaces to meet up nice and smooth.

Mr.Riviera wrote:

i wouldnt bother self porting the TB, you will only get minimal gains because the butterfly valve is the same size.

This is a good point. I'm not planning to modify the butterfly, nor change the TB. So let's say it stays stock - maybe with some minor polishing.

oldsman105 wrote:

A ported Gen 3 is not as efficent as a Gen V. A gen v makes a cooler boost charge and more efficent charge. A 3.4 on a Gen V similar to a 3.2 on a Gen 3 but with a cooler charge.

Okay, maybe ported Gen III isn't quite a Gen V, but it's closer to one. How close is depending on how well the job is done. Since I don't have a Gen V, I want to try & make my Gen III as efficient as possible.

oldsman105 wrote:

Aaron it may be easier to pickup a used ported blower from clubgp.

I already have the Gen II core. It wouldn't make sense for me to buy a 3rd supercharger at this point. Plus, I want to do the work myself. They say an average Joe can't do a good job, but with some research, a steady hand, and a pair of calipers - I intend to do it right. If I have to, I'll design the opening in CAD, mount the housing to a CNC machine, and do it like the professionals do - but it doesn't seem like it needs to get that complicated.

oldsman105 wrote:

I will post up pics of it tomarrow if you'd like

Please do! I'm only researching at this point. This may not happen for a couple months.

oldsman105 wrote:

If you decide to do it yourself . I will give you two tips to safe you lots of agony. Use a dremel and but 80 grit flapper wheel bits. This wil make taking the rough casting out alot easier.

Thanks for the tips!

turtleman wrote:

After looking closely at my stock blower vs the one I got from chris kemp vs the products from the big three, I'm really not liking how WBS and Intense both leave out the edges of the outlet alltogether with their porting, which sucks.

Why does this suck? Do you like how ZZP does theirs? What does Mr. Kemp's port job look like?

I'll post some pics of the outlet soon so you can see. ZZP's outlet looks a lot like Kemps except Kemp fills in the silencing vents so they are not there. If we say the outlet is shaped like an arrowhead, I'm talking about the base of the arrowhead. WBS and Intenses base is left cut basically the same way. They clean it up but they don't enlarge it because two of the screws that hold the snout to the case go through the area that Kemp and ZZP removes. If you look at any other blower whether its an MP112, whipple, differently configured M90's, etc. it's pretty clear that that arrowhead wants to be as wide as possible at it's base. As I see it, that is the no-brainer issue to correct from the factory cast design. Obviously get a couple shorter bolts for those bottom ones so they don't protrude through the outlet area.

I had my blower ported by WBS. Or should I say I ordered one and sent back my core at a later time.

I believe I got the vs3 porting. They did the outlet, inlet and the IC outlet but didn't charge me for the IC outlet.

This mod alone dropped my IPW's from a max of about 20 to 18-17, and I also lost some boost in the process but that was only due to less restriction.

Less boost after porting the blower? I don't think that's something I want.

Decrease resistance = decreased boost / pressure = decreased temps = less KR.
Decrease pulley size after porting and will bring boost back up yet still have overall reduced intake manifold air temp's.

RickW wrote:

Decrease resistance = decreased boost / pressure = decreased temps = less KR.

Please substantiate this logic with more info. I don't understand how decreased resistance = decreased boost. Imo, decreased resistance = less friction = less heat = less knock. I've got a stock roots blower moving 90 cu in of air with each revolution. Now, port & polish to make it easier for that air to exit the blower - now I have less heat, but why less boost? Same amount of air entering the manifold, right? I'd think if you make the blower more efficient, you'd have slightly more boost, not less.

I do understand how decreased pressure = decreased temps, but if I wanted decreased boost, I'd just increase SC pulley size. That's not what I'm after here.

Is it common to drop SC pulley size after only a blower port/polish? Anyone with personal experience?

no personal experience per say for the m90 here, however, when I ported my LIM I ended up with better air flow and velocity through the engine. The result of this was less boost and more power. To make up for the roughly 1-2 psi drop in boost, I dropped back to my 2.5" pulley to take boost back up and then some(as i had no issues with heat and knock). TO me it makes sense that porting of the LIM, exaust work, and valvetrain work would all do their bit to increase air-flow through the engine and result in more power and less boost.


The resulting lower boost that some people have observed with ported m90 blower housings; I have my own opinions here.
I've spent countless hours looking up info on these eaton blowers and the various opinions of how to (and not to) port them and my opinion falls to the side of those who feel that too aggressive porting in various areas of the blower housing makes it less efficent.(however the lowering in heat buildup leaves the person using it to feel that it increased power) Specific areas that I feel are trouble areas for lowering efficency are the two silencer slits, any cleaning/polishing of the outside circumfrence of the bores where the two rotor lobes turn, and too much deformation to the shape of the V outlet.

my own thoughts are that if boost has gone down from a ported blower, and nothing else on the engine has changed, you have just sacrificed some efficency in exchange for less heat buildup. For some people this is a good thing as it allows through the lowering in heat to run full strength with no KR and the engine preforming better. A smaller pulley could be then be added depending on case, but its really to bring the boost back and the resulting heat that will bring must be taken into effect.

as always, we end up with the same story with these engines where we want to process as much air through it as efficently as possible, but keep temp down.

anyway thats my 2c....

Thanks, Karma. Your cents make sense. I agree that there is a wrong way to port/polish a blower that lowers efficiency, and boost. I want to steer clear of making such a mistake. From the photos on page 1, do you see any that look correct? I'm leaning towards ZZP's approach, but not sure.

the first photo on page one looks the best IMO. It keeps the lines and angles for the V while opening it out a bit more. Maybe could use a little more agressive rounding and smoothing on all edges on the BOTTOM facing side of the housing. I like how the silencer slits are largely unchanged, a slight rounding of the edge can be done there as long as it does not change the original hole size, but making NO changes other than a slight break of the corner from the inside edge where the rotor lobes will pass by. Also a good hard polishing at the inlet end when the air comes from the TB(near where the EGR lets in) will reap the most benifits in regards to heat, as flow testing on these eaton blowers shows that is where the greatest buildup of heat is due to friction.
anyway, thats how I would do it.

If you realy want to increase the efficency and maybe remove a little fricional heat you could look at plugging the scilencer ports themselves, but that is its own bag of worms as to how to properly do it.
here is a link on porting these things with various points of view, also discusses the plugging of scilencer holes..:
http://www.eatoninside.com/showthread.php?t=156

Kemps

Thanks, Codith!

Codith what did u use to fill in the silencing ports

palermocorey90 wrote:

Codith what did u use to fill in the silencing ports

Kemp closes them with a mystery filler....

looks like old fashoned JB, or maybe perma-steel, or magnum steel, or cold-weld or all that good stuff... as long as the sides of the ports are scuffed up to be nice and rough it should hold no problems.

-still best porting of m90 IMO that i've seen ever...

Karma wrote:

looks like old fashoned JB, or maybe perma-steel, or magnum steel, or cold-weld or all that good stuff... as long as the sides of the ports are scuffed up to be nice and rough it should hold no problems.

-still best porting of m90 IMO that i've seen ever...

JB weld NO.... that can come undone and screw junk up!

AA wrote:

RickW wrote:

Decrease resistance = decreased boost / pressure = decreased temps = less KR.

Please substantiate this logic with more info. I don't understand how decreased resistance = decreased boost. Imo, decreased resistance = less friction = less heat = less knock. I've got a stock roots blower moving 90 cu in of air with each revolution. Now, port & polish to make it easier for that air to exit the blower - now I have less heat, but why less boost? Same amount of air entering the manifold, right? I'd think if you make the blower more efficient, you'd have slightly more boost, not less.

I do understand how decreased pressure = decreased temps, but if I wanted decreased boost, I'd just increase SC pulley size. That's not what I'm after here.

Is it common to drop SC pulley size after only a blower port/polish? Anyone with personal experience?

the decreased boost is proof of increased efficiency. You make more power with less boost. You will notice less power "off the line" but have more power on the top end. The engine is also struggling less to produce the power, which is why my IPW's went down.
You could probably drop pulley size .1" with a full porting job.

I only gained maybe 1lb of boost with my IC install, despite my pulley going from 3.25" to a 2.76". With all the extra restriction due to the IC core, thats what I ended up with. But you thing Im not making tons more power with that boost than I was before? IC increases efficiency, just like a ported blower does.