Deffinetly nice thread. really gives inspiration for diy. im going to use this when i start my porting
STICKY!!!!!

Haha, I meant 13btnos's port picture. :)

I'm definetly going to try this later on this yeah. STICKY!!

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sticky

Thank you here's a shot of the inside runner. This is a good thread with some nice shots of the port work in progress but I'm going to have to agree with Judge Ito that there is still alot to do with porting than just early opening and late closing. Porting is kind of a black art and that a lot of those that are good at it don't reveal what they do. Judge Ito reveals alot to the rotary community when it comes to porting the rotary engine. Rx7_Nut13B keep porting engines the more you do it the better you will get.

Why do you smooth the runners out so much?

Flow, flow,flow it's all about the flow! You will gain more porting the runners and in the bowl area than you will in just increasing the port timing.

I agree with Ito and 13btnos. You have a good begining to a decient port, but theres tons more finishing work and grinding that needs to be done. Much MUCH back cutting of the opening edges of both the bridge port and the stock opening port. The bowl needs smoothing as does actually opening up the runner to delet the venturi all things mentioned by already. Theres TONS of info on porting here on this forum and at nopistons (A lot from Ito himself). I strongly suggest you guys read up on porting techniques and what works from masters before you go cutting up your engine bits. Its obvious theres a lot of inexperiance here (more so readers/posters then the original poster), praising newbs (no offence but I'd give it a C-, like I said a good start to a decient port) for there work. Kudos for starting this thread and A+++ for effort. This could be a great start to how to port effectively.

~Mike..............

I agree with that to a point. It's not only about flow but I know what you are getting at for simplicity sake. The biggest mistake people make is that they just try to go larger and larger. Flow is important but if your intake ports can flow more than your manifold can (or vice versa), it's worthless. You've now just gotten to a point where your velocity slows down. If your engine setup flows so much that you shift while your power curve is still going up, you have too much flow. More is not always better. I know what you mean as it was a generic response but it's not all about the flow. It's about flow consistency throughout the entire system and having only as much flow as you need and no more. That's what makes the most power.

VELOCITY VELOCITY VELOCITY!!!!! up until it holds flow back..... THATS what makes power.

~Mike....................

I was really just saying that they are really really smooth and thus you will not be able to flow as much air. Ruffness is somewhat good.

That's not necessarily true. Some parts of the port should be mirror polished (laminar flow areas) and others should be slightly rough (boundary layer areas). You can read about some of this in my porting article in MazdaSport, which is available in Barnes and Noble now. I am hitting my business partner Rob hard to do a porting DVD and really show people how to do it, step by step.

Blake is totally correct! The picture of the port shows it to be very smooth but in reality it is "flapped" sanded with 220 grit. It does have texture and as Blake said there are areas that are polished and areas that are rough "boundary layer areas". But surface finish also depends on what the motor will be used for whether it is going to be N/A or boosted. But that's a whole other can of worms to open.

Blake I just finished porting an engine using your mild streetport template. When I get a chance I'll post the picture on your thread.

Hey what up mac I've seen those blue plate's those are manny's old plates right? The polishing work this guy does is off the chain good job mac your work and what you show is where i hope to be some day man

guys you are always talking about the importance of the "bowl"! what exactly do you mean? 'cause if i bowl the port too much on the closing side, i'm afraid to fall into the water jacket!! does nobody have any pics about this "bowl"??!!

The port has three parts: the aperture, bowl and runner. The aperture is just the 2-dimentional outline of the port opening to the chamber. The runner is the straight "pipe" from the manifold. The bowl is between the runner and aperture; the curved transitional space. We generally mean the outside portion, or bowl shaped area, but it can also refer to the inside radius of the transition as well as the "roof" and "floor". It just depends on the context.

Here is a photo of the early roughing-out of the bowl, if that helps.

https://www.rx7club.com/forum/attach...d=226760&stc=1

Here is a more finished bowl for comparrison. This is a scondary port and the other a primary port, but the principle is the same.

https://www.rx7club.com/forum/attach...d=226764&stc=1

EXACTLY! I'm glad you have more patience to type than I do.

thanks Blake, now that was clear! :)

but still i'm worried, 'cause i can't exactly tell how thick the wall behind the bowl is... i'm afraid of breaking through...

You have to feel the thickness with your fingers or instruments. It is usually not too hard to do on the closing side (top) of the port, feeling from the water jacket side. The tail of the port is harder, but (1) you generally don't go too far there and (2) if needed, you can cut away material to get a pinky in there.

Here is the motors first startup after the porting

http://www.youtube.com/watch?v=ZY1NuGmDm5Y

No Exhuast and the turbo had some thick lube in it when i first started now it turns really easy

Next http://www.youtube.com/watch?v=Ogud8O_PzsU

good job. adjust ignition timing and idle and start driving it.. always keep in mind that a bridgeport has a tendency to foul up plugs and sometimes the engine will not kick over..