71plymouth

I am new to the rotary world and I wonder how much does it cost to get each port job done? What power increase can you expect? What different port jobs are there? What other mods must be done to run the car ported?

Hades12

Have you seached for the topic yet? and checked the FAQ?


The most common ports are Street and Bridge.

Street will up the power a good bit and goes well with a Header and a worked for aftermarket carb.

Bridge gives even more power but makes the idle very lumpy.

Hades12

From the FAQ.


http://www.mazdatrix.com/faq/porting.htm

71plymouth

Okay I am a little more knowledgable now. But what are the gains from all this? Also is there only street and bridge porting techniques?

Kentetsu

Head over to www.nopistons.com and go through their "engine rebuilding/porting" section. You will walk away an expert on the subject...

Latin270

^^^^ an expert.....I think not,^^^^lol.... but a solid foundation of info (yes) Read up and soon you too will be able to open up your motor and port her up yourself!

trochoid

iTrader: (6)

There are 4 basic intake porting techniques. Street, bridge, extended and peripheral. Each one has variations and can vary greatly from one porter to another.

Then you can get into exhaust porting.

71plymouth

wow thats cool. Does anyone have these on their cars. What horsepower and torque increases are there?

rxtory

tourque in these engines will allways be low compaired to piston engines

Hades12

I have a street port in my 79, has some good grunt.

71plymouth

Okay, let me spell it for ya'll. Dyno numbers on HP and/or Torque? If you do not have any than don't waste my time. Its no wonder nothing can get answered around here.

FIBREMAZ

What do you want from the car? How often will it be driven? Do you care about noise levels? if you want something streetable then mild/street port is the way to go. if you want more power and aren't fussed about noise go for a bridge or PP.

peejay

Dynos are for numbers-hungry weenies. Many a 300hp engine has been laid to waste on the track by a 250hp engine that makes more useful power.

That said, you can reasonably expect 150-160hp from a street port, 200-240hp from a bridge port, 260-280hp from a full house peripheral port, with reasonably decent tuning. Torque is always dictated first displacement and compression ratio, so it doesn't change much.

If you *really* have your **** together, you can get 150-160hp from a stock engine, 200-220hp from a street port, 260-320hp from a bridge port, and 280-320 from a peripheral port. It all depends on how much you can afford to spend on custom manifolds, headers, and exhaust (the last 10-15% comes at great expense in pipe tuning, lots of R&D on your part), time spent tuning, and deciding if it's *really* important to get a high HP number if it means you only see gains in a 1000rpm band (racing transmission?).

13 BEEF, how loud the engine is has pretty much nothing to do with the porting. My peripheral port was as quiet as my stockport, with the same exhaust system. Yes, peripheral ports *require* a straight through exhaust, as they do not tolerate any exhaust or intake restriction. On the other hand, with some intelligent choices, this can be quiet enough for street use, and a stockport engine responds quite well to this kind of exhaust as well...

FIBREMAZ

Were you running a Primaflow muffler? The way i see it what's the point of having a fat port if it's no louder than stock port. Anyway 99% of the time flow=noise=more power with ported motors, maybe you are the exception to the rule. A good mate of mine has a GURU PP in race trim,52mm or bigger port size with 60mm throttle bodies....no muffler can shut that thing up

peejay

What's a Primaflow?

I didn't say it was quiet as stock, the RX-7 was the "Silent Sports Car" as you may remember. I just said it was quiet enough to drive on the street.

71plymouth

BADASS!! Thats the info I needed. I appreciate all your help. Thanks again and keep on keepin on.