Home M90 port and rebuild, pics !!!

Shockwave

Registered User
I had bought a used early blower last year to use for porting and rebuilding. I installed all new front snout bearings and new rear case needle bearings from Tbird88.

Click on pics for full size pictures.

I did a conservative port on the rear inlet. I was looking to move the opening up into the rotor centerline. I took about .200 out of the top of the opening, but I ported in an angle to match the case floor.
<a href="http://www.jerrytbirdsc.com/m90/full/Dscn0004.jpg"><img src="http://www.jerrytbirdsc.com/m90/Dscn0004.jpg" width="240" height="180" border="0"></a>
There is a lot of material available to work with on the inside unlike the rear where you need a sealing surface. This should increase the volume of air available to the rotors.
<a href="http://www.jerrytbirdsc.com/m90/full/Dscn0002.jpg"><img src="http://www.jerrytbirdsc.com/m90/Dscn0002.jpg" width="240" height="180" border="0"></a>

I didn't go crazy on the outlet side either. The triangle outlet is about a half an inch wider than stock and a little longer. It looks about right to me.
<a href="http://www.jerrytbirdsc.com/m90/full/Dscn0008.jpg"><img src="http://www.jerrytbirdsc.com/m90/Dscn0008.jpg" width="240" height="180" border="0"></a>
Here are a couple of side-by-side shots of a stock blower and my ported one.
<a href="http://www.jerrytbirdsc.com/m90/full/Dscn0006.jpg"><img src="http://www.jerrytbirdsc.com/m90/Dscn0006.jpg" width="240" height="180" border="0"></a>

<a href="http://www.jerrytbirdsc.com/m90/full/Dscn0007.jpg"><img src="http://www.jerrytbirdsc.com/m90/Dscn0007.jpg" width="240" height="180" border="0"></a>

I also port matched the inlet plenum to match. The factory original was smaller than the blower opening to start with, so this should really be beneficial.
<a href="http://www.jerrytbirdsc.com/m90/full/Dscn0009.jpg"><img src="http://www.jerrytbirdsc.com/m90/Dscn0009.jpg" width="240" height="180" border="0"></a>
 
Im going to try and be nice. The rotors are timed with the case. When you port the intake to the sides or the outlet sides you screw up the timing. The porting you did will probably result in little or negative results. Not that it cant be easly fixed you just need to know how to port it.
 
yah you need to make sure you retained the v in the outlet of the blower..Very inportant....Also you can cut down those bolt bosses a bit. If you are unsure on your porting compare it to others on teh site..There have been many pictures posted
 
I wasn't expecting such a negative response. I'm sure that my blower isn't as good as a MPII or even a 94-95 blower for that matter. I would be shocked if it's worse than stock though. :confused:

The motor is 100% stock.

With the folowing mods:

95 Mustang manifolds
2.5-3-2.5 exhaust with Borla straight throughs
76mm C&L MAF
MAC CAI
10% pulley

car made 13 psi and put down 217 HP and 327 TQ

I know these numbers are low compared to some, but on the same dyno a 93 SC auto with 5%, flowmaster catback and K&N cone made 203 HP and 300 TQ, and a 89 5 speed made 199 HP and 291 TQ with 70mm TB, 70mm MAF, K&N panel, flowmaster catback and underdrive pulleys.


When I added the 75mm TB and the car made 14 psi.
When I added a Fast Freddie top the boost dropped to 13 psi.
My best time is a 15 flat @ 91 Mph. The 10% pulley feels really good on the street due to the torque gain, but When I was making 14 psi the tach was pretty lazy after 3500 rpms.
I feel that the 10% pulley is causing the IC to get heat soaked by the end of the 1/4, as the car just doesn't pull well at the big end of the track. So I wanted to try and go back to the stock pulley and trade some TQ for HP. I have a 10% jackshaft pulley to go on there to compare with.

Right before winter I reinstalled the stock top and stock pulley and the boost dropped to 11 psi. Now I installed the ported blower, stock pulley, and raised top and the car is making 12 psi. To me that's seems pretty good for an open exhaust car on stock pulley. Even more so with the raised top, as it has dropped the boost by one point whenever it's been on the car.

In response to
BKB said:
Im going to try and be nice. The rotors are timed with the case. When you port the intake to the sides or the outlet sides you screw up the timing. The porting you did will probably result in little or negative results. Not that it cant be easly fixed you just need to know how to port it.

I tried not to touch the sides of the inlet on the rear case as that looked to be where the rotors start to seal air into the side of the case. Also, I tried to maintain the exact angle of the triangle outlet so that the rotors would seal until they hit the outlet.


DamonSlowpokeBaumann said:
yah you need to make sure you retained the v in the outlet of the blower..Very inportant....Also you can cut down those bolt bosses a bit. If you are unsure on your porting compare it to others on teh site..There have been many pictures posted

I did round the bosses some although MP does knock them down quite a bit more. I don't think you can maintain the V angle any better than I did. The outlet is the same angle just wider and taller.

I welcome any response even if negative. I guess the track will determine if the port was any good.

Jerry
 
What i was trying to explain is that you dont widen the V if you didn't do major work to the intake side. It all depends how much you opened it up, if its 1/2 on each side timing will be way off, if its only 1/4 on each side then you are OK but little to no improvment in power. I have been porting these for awhile if you want a good port job e-mail me.
 
I think that there is a question here that hasn't been asked, but needs to in order to determine your port job in comparison to your goals. That question is this: Are you looking for maximum performance or simply a gain over the stock design?

I think that all too often people tend to assume that others are going for maximum gain and efficiency. If the max is your goal, then you have a long way to go.

I believe, though, based upon your comments, that you are simply trying to get a little more out of your SC without going extreme. If that is your goal, then you have nothing to worry about. You didn't do anything too extreme to the blower, so you will see a little gain. I don't think that you will see a lot, because you did stay conservative. You opened up the inlet and outlet slightly, but more importantly, it appears that you have port matched the inlet plenum to the case. This is where you will see your gain in performance. I think that you may pick up 1/2 to 1 lb of boost, (maybe). I'm not sure that the outlet was ported enough for you to see some significant temperature decreases in the air, but the dyno will tell.

I will say that I ported my blower myself and have not seen any performance fall off at all. In fact, I've got quite a bit done to my SC, and even with my exhaust mods, I'm still seeing 15 lbs of boost with nothing more than a 5% pulley on my supercharger. I've got a dyno tune in about 2 weeks, so I will see what my mods have done to my SC. I certainly don't predict that I'll have less power and torque than when the car was new. My goals are like yours, nothing too extreme, but an improvement over stock. I'm not trying to get every CFM possible, so I can make a few mistakes...and learn from them. It's all part of the process. The important thing is that you are not afraid to try like a lot of people on this board.
 
Thanks for the support 007_SuperCoupe, yeah I'm just trying to get a little more out of the early style blower. The car is my daily driver and I put up with the marbles in a can from the snout bearing all winter. The port job was to see if I could improve the early style blower while I did my rebuild.


Jerry
 
heres what my home port looked like, but sold it cause i got this to install. 94 blower that i rebuilt and port matched the plenum to the sc opening, and ported for the 75mm tb
 
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How much on the intake side do you have to do in order to get a gain or need to port the outlet "V"? I just got the new style today and I was looking at it in kind of a dissappointment. I thought it would be larger.

Chris
 
Shockwave said:
I tried not to touch the sides of the inlet on the rear case as that looked to be where the rotors start to seal air into the side of the case. Also, I tried to maintain the exact angle of the triangle outlet so that the rotors would seal until they hit the outlet.
Jerry
Nice work Shockwave, you're headed in the right direction but you've just scratched the surface, by all means go ahead and touch 'em some more! Heck, you can gouge on the sides of the inlet a lot more than some would have you believe before you even come close to the so-called "danger zone" where timing is concerned.

'bird
 
More positive response....

Shockwave,
Just wanted to give you some more reinforcement....

I just got my SC dyno tuned Friday night. With stock heads, cam and injectors I ran 248.8 rwhp and 340.1 rwtq on my "home ported" blower. My hp rating is actually higher but my tranny was shifting like clockwork at 4200 rpm, so I couldn't make any pulls higher than that. And the hp level was still going up at that point.

So just to make you feel better, home porting can work wonders. :D Keep it up and let us know how it turns out.
 
Soo...if we take the port jobs shown above...how do they compare to a stock (non ported) 94-95 m90? Which one would flow better?
 
CaifanSC said:
Soo...if we take the port jobs shown above...how do they compare to a stock (non ported) 94-95 m90? Which one would flow better?

The 94-95 would flow better.
 
Looks like a nice job for an upgrade over stock.But then I don't
know much.

Anyone have info for porting a A/R blower?

THANKS RANDY
 
AlanEdwards said:
Am I to understand that I don't need to port my '94 blower? Is it already done right from factory?

Alan

No, a stock 94-95 blower would make more power then the 89-93 blower that was home ported in the first pic. 94-95 blower respond very well to mild porting more so then the old ones IMO.
 
94-95 Blower

The 94-95 blowers are 4% more effecient than the early style.It has less rotor contact as well as coated rotors,along with that it has the square inlet port with a piece casted under the rotors for improved flow. A 4% improvement does not sound like much but it accounts for a 15-20HP gain on a stock block.If you make the alterations to a early blower you can achieve good results. :)
 
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