6-Port NA Street Porting Thread
 

I'm looking to street port my motor when I pull it apart do to a rather lame mistake I made, and I figure it's time to make a thread about the latest and greatest NA street porting information.

I think we all know about Kahren's 200-HP class street ports, but I can't seem to find any sort of information on actually doing those ports (templates, etc).

Also, does anyone have any information on port matching, polishing, etc.


And, I found these carbide rotary files on eBay that are about half the price shipped as one from RB is not shipped:

http://cgi.ebay.com/ws/eBayISAPI.dll...ayphotohosting

I wonder if they're any good?

Also, you can get die grinders from Harbor Freight for 9.99 a piece, and they apparently work very well for the price (just oil them and they'll keep working from what I've heard at work).

Also, who makes the best templates? Mazdatrix or RB?

Also, what about street ports with and without the rotary sleeves? I'm pretty sure all the 190+ NAs have them removed, usually with modified intake manifolds.

Also, what about exhaust porting? Should the diffusers be removed or not? Are there gains? And what about noise?

Mazdatrix says not to port them and to use turbo rotor housings if you're going to port it.


...TBC...

please do continue. :D

I can only type so much before the bosses get suspicious...lol

The die grinder kits are only 2 dollars more and come with cases, grinding stones, and IIRC sand paper on mandrels, for rough polishing the ports. If you've got a turbo, you don't need to make it all that shiny (from what I've heard), but for NAs you ideally want to see your face in it...lol

Also, I had the idea of forming "ramps" in the rotary valves to smooth out the air flow like the Pineapple Racing inserts or like the ones in the 8, but using JB weld instead of paying a lot and having to wait for parts. But I wondered if there was a danger of it coming lose or disintegrating and then damaging the engine... which means maybe the epoxy they use to fill side ports for p-ports would be better.

And, I wonder if anyone makes a heat insulated intake gasket for the 13B, like they do for the Miata and Honda engnes. You can apparently get 5% more HP from this. Or, where can you get the plastic material to make your own (that are also port matched)?

I'm also thinking that maybe installing some heat shielding between the block and the UIM might be a good idea.

..except this has apparently turned into an NA engine building thread...lol

https://www.rx7club.com/rotary-car-performance-77/throttle-body-mod-thread-airflow-data-702539/page2/

Very useful thread for an NA build up. I think I'm going to do this when I pull my motor apart. One, because I think I broke my thermowax assembly, and two, because 180-degree coolant in the intake system = bad.

https://www.rx7club.com/showthread.p...=port+matching

I can't seem to find many threads on port matching with much info, but this picture basically shows how different the gasket and ports are.

Pineapple racing also makes porting templates.

The nopistons forum has a good engine section and there's lots of good info there, even about some fairly advanced racing stuff. Definetely worth a look.

Hmm, they're cheaper AND already cut out... very nice.

They look like they're bigger than the Mazdatrix ones, although at some point, you don't make any gains as long as you still have the rotary valves in the engine. If you don't, then there's not much reason to even still have separated ports.

(that is, unless you have a different type of valve that opens up the aux ports that lets you open them up bigger and keep the low end torque)

http://www.pineappleracing.com/index...PROD&ProdID=98




http://www.racingbeat.com/FRmazda2.htm

Hmm, I don't think my lower hose has a spring...thing in it. I guess I should get one.

I've decided to get an oil baffle plate for autocross, so the oil buzzer doesn't go off in corners.

Use the pineapple template and then make sure you cut the insert open to match the port size. Adam did this to a friends s5 along with rx8 rotors and it had good torque and what seemed like an endless powerband. Here is what the template looks like over a stock port.

Danger, pineapple "makes these already", why chance having anything fall into the motor? But with the enlarged opening due to the streetport i wouldn't even try them. The ramp or radius you speak of would make a bigger difference with forced induction than n/a.

The ramps would be different from the Pineapple ones... made to work better with a street port.

And they're almost as likely to fall into the motor, according to some.

If Devcon is strong enough for P-ports, its probably strong enough to form some ramps for the rotary valves.

Also, cutting the valves means they'll be open before they need to be, so I have to wonder if that would cause any driveability issues.

I've got one, and even with overfilling the oil slightly, the buzzer still goes off in hard cornering at the track (I use R comp tires), however the oil pressure gauge stays rock steady, so it's not a problem. I'm sure it helps, but there's only so much that it can do. If you really want to keep the oil in place, then maybe a Pineapple oil pan is in order, but you'll loose the oil level sensor.

FWIW, I knew a guy who drilled and put a screw on the end of the auxiliary valve so that the epoxy had something to grab.

I've used epoxy in the aux sleeves for years and on several different motors, inclusing ones I've done for a few others. I have never ever had the epoxy come lose in one. It's pretty much impossible for it to enter into the motor if it does comes lose anyways as the diameter of the sleeve is larger than the port opening. I have seen evidence of a Pineapple sleeve coming lose and migrating down the runner and knocking the pin lose that rotates the sleeve. This can get ingested. However that wasn't the fault of the sleeve but rather the person who installed it. I also use epoxy in almost all of the ported motors I've built. Right inside the port opening. Never had issues. This is common practice with piston engines too. If you are thorough and take your time, there's no reason why it has to be any less reliable than any other engine part.

Turns out someone does make an insulating intake gasket for the NA FC... and it comes with a UIM gasket that's reusable. How convenient.

I already ordered one...

http://cgi.ebay.com/89-90-91-Mazda-R...QQcmdZViewItem

Chris Ludwig does some the best porting i've ever seen.

http://www.ludwigmotorsports.com/

I also suggest getting rid of the stock manifold if you want to make more power.

I don't have *that* much cash and I want to keep the 6PI system, so no custom manifolds.

I'd get a turbo engine before I spent $1000 on new NA induction stuff.

I think 250 hp. is the goal. Whats the rx-8? 238 hp or something. I have a secret plan.... muh-huh-huh!!!! 250 hp NA on a 13b with no turbo or supercharger. No nitrous either.

Ramses666

Not going to happen unless you spend about $5,000, and that's doing all the work yourself (including tuning). And that's assuming you know how to build a 9,000 RPM motor (and don't have to pass emissions or care about longevity...).

I'd be happy if I gained 15 HP from the stuff I'm going to do... I'm going to need headers and a new exhaust to really make a difference after I'm done though (I'm probably going to leave the diffusers alone, but gasket matching seems like a waste if you don't have a decent exhaust system at least). I'm also going to have to make a heat shield for the intake, and a few other mods aimed at cutting down the intake charge temperatures.

250 Flywheel or Rear Wheel horsepower?

I now have a short block sitting in my garage...

I took off the front cover and low and behold, my thrust bearings were SMOKED for some reason. Last time I took the pulley off, I had the clutch pedal in like you're supposed to... One was just pinched, the other was literally evaporated, like the wreckage of nuked skyscrapers you see in post-apocalyptic movies. One of the washers looked ok, with some minor denting, but I guess I'll need to replace it anyway. The thrust plate is heat-scarred nearly black on one side, and ruined on the other side from grinding (damage looks identical to the damage one of my bike's spare clutches had). The spacer seemed to be OK.

I've got some major cleaning to do before I get to porting... but the tards at Harbor Freight couldn't find me a parts washer before they closed.

Anyone know of a way to mark seals and rotors that won't come off when you clean them? Whiteout, maybe?

This work goes really slow when you do it a weekend at a time... (minus 10 hours from driving back/forth from Georgia).

Ridiculous.

cheap + engine => expensive

I ordered my engine parts and Mazdatrix templates... I didn't really like the looks of the center ports on the pineapple version.

My credit limit is not so happy...

I'm not one to tell someone what to do but I would steer clear of spending money you don't have.

I have the money... theoretically. I just have to wait another two weeks for my next paycheck (which is more than enough to cover what I've spent).

Plus, I've bought basically everything I need for the project, besides a few more tools (namely a parts washer, although I could probably borrow one).

Has anyone else noticed that the stock intake tube a sharp angle near where it meets the throttle body. It seems thick enough where you could smooth out the angle. But I wonder if it's worth the effort.

Also, the plastic TB to expansion chamber manifold seem to be slightly bottlenecked two spots with the secondaries, but I wonder if you make any gains from matching the gasket and expansion chamber to the throttle body (or visa versa, not sure).


I also had to do some minor grinding on the throttle linkage because it wasn't opening to 90 degrees at WOT, which can rob you of power (for obvious reasons).