Here are some pictures of my port job I just did on my S5 TII engine. Can you give me an estimate of how much power increase I should expect with these ports. I ported the side plates, intermediate housing, exhaust ports as big as sleeve, runners. How do the ports look? I didnt go over to the sides too much did I?

Intermediate housing:


Side Plates:




Exhuast:

 

I see a couple of mistakes with your ports. I'll start with your intake ports. In your ports you changed the port opening and closing timing a bit, but you didn't port the runners. The runners are very important in creating a better air/fuel flow. You want to make a port that has little to no restrictions vs the factory ports. Besides changing your port timing you need to create a better flowing port.

Your exhaust port is fine, but you need to pay close attention to the closing part of the exhaust port. That is the upper edge of the port. If that edge is too sharp the apex seals will crash into that sharp edge and start to wear and eventually break. All you need to do is look at a factory exhaust port. Mazda finished the port with an angle to the outer edge of the port to protect the apex seal when it closes the port. This way the apex seal will not crash into the sharp edge of the port. Just create the same type of port finishing job that Mazda has done and your exhaust port will be fine.

Power increase is all relative to how well you assemble the engine, how much compression you extract from the the engine and how well you tune and time the engine.

I congratulate you for porting your own engine and giving a try. Many people would like to port, but few actually try.

 

So the ports themselves look good.. like the shape and size of them right? Well, I did port the runners... I took it down to where it comes out straight without that lip. I dont know exactly how much I have to take off to port them, so I didnt take off a lot. Here is a picture how do they look?

 

here

 

I concur with rotortiller that you could improve the port by smoothing down the bowl of the port and blending it into the runner below. There is a lot of metal there standing in the path of flow. You can also aim the airflow in a certain direction by shaping the lower bowl.

 

Net Seven, very nice job in doing this on your own.

What Judge Ito is talking about is the work that's done on the port tunnels themselves. There's more to porting than just modifying port opening and closing timing, although that can be beneficial in and of itself. A significant increase in port efficiency can occur when you do three things:

) Remove material from the walls of the port tunnels to conservatively increase port volume as well as reduce the boundary layer
) Transition the port tunnel into the port outlet's short and long radii (perform work to contour
) Match and flatten the iron plate's nitrided facing with the cast iron portion below it.

Here's a couple of photos that illustrate what we're talking about:







As you can see from the above, more focus (in my opinion; some can argue against this but this seems to work best) is placed on retaining the velocity of the wind that's moving through it. Look closely at the transition point from the port tunnel
The other benefit of grinding and sanding away the cast iron roughness on the intale port tunnel and port outlet is reduction of the boundary layer, helping to sustain charge velocity.

Good luck! Let us know how they turn out.

B

 

BDC, that port work looks great, who did it?

 

He did... of corse. How else do you get to be known by only 3 letters?

 

 

Yeah, I'm "so lucky" to have my initials also mean "Bottom Dead Center". Yay, what a great selling point that is.

Yes, I did those. Those are actually pictures from two different customers' engines.

B

 

What kind of attachments did you have to use to do those turns?

 

I'm interested in knowing this also. Please share!

 

Very nice ports BDC. Any new info on the half bridge FC? Any pics of those ports?

 

Sure, I'll link a few.

I'll have my first half-BP FD motor on the street running here hopefully tomorrow or Thursday. I've already got one half-BP Cosmo 13BRE motor out running from since about May time and all is going well so far.

Here's a couple quick pics:





B

 

I do mainly sanding. I've never once used a grinding stone on a port although I know a number of people use those. It takes longer to sand but the finish has a greater chance, in my opinion, of having a more uniform and fine finish.

B

 

Where do you get your sanding bits from? and which ones?!?!

 

Very nice BDC. Let us know how the REW 1/2 bridge does. I'm impatiently waiting

 

I've been waiting myself for quite awhile. The fella who has the car started it yesterday afternoon but he said it was smoking oil from the front chamber. I'm not sure if he's positive on it or not and I have no idea what else was done on the engine (my only involvement was porting the intake ports and matching up the lower intake manifold). I hope everything is alright with it; the FD core he's using came from another car so there's no known, immediate history with it.

I neglected to ask him how it sounded when he started it or how it ran.. it seemed a little inappropriate given the fact that it was smoking like a James Bond car.

B

 

but back to our (kinda desperate ) question.....

...you ONLY sand it? No grinders? no rasps?

Christ that must take you ages! (and go through a hell of a lot of rolls of paper!)

any particular grade? or just the general boggo sizes for a rotary tool?

 

when i was porting the runners of my intake i liked doing my ports with a die grinder first....taking some metal off and then i liked using the sanding roll for a bit....got most of the irregularities off....then i used a dark greyish almost black kind of stone which looks like a little disk and i ran that stuff over....and what io noticed was that the runners were getting pretty smooth and the stone had left a lot of powder behind....once i was done that it was pretty much good to go....but then i took the polishing attachment and went at it too....i did all this with a rotary tool....for porting i think it's better to use a die grinder to cut the ports out roghly and then smooth and polish the ports with the rotary tool!

 

Yep, only sanding. I may change to some light grinding for getting some of the cast iron off more quickly in the port tunnels (on the irons), but otherwise it's all sanding. I use 36 grit to cut and shape and then 120 to cleanup on the irons. On the rotor housings, I use a different technique. The 36 grit seems to last a very long time; it's quite rugged.

B

 

Hand sand or sand drums in a diegrinder/dremel?

 

I won't be polishing the ports though (except on the port outlet), since having a perfectly smooth port is detrimental to the fuel/air mixture.


The fuel tends to stick to the walls, and can cause the engine to "bog-down" when you come off the acclerator after a hard run.

 

But under boost, given the pressure would it really matter. It had been brought to my attention that a complete glass-like finish was only on N/A applications.

 

Looks nice, Brian.