Porting...I don't get it
 

So I don't really understand all these different "ports" you can get done to your car. I went to wikipedia and looked it up, and well it really didn't help. Bridge Port, Half Bridge Port, Street Port. Whats that all mean? Whats the point? What are my HP/Torque Gains? Is this for overall engine life good/bad?

It's a simple idea: for intake, you port to allow more total air in (more air w/more fuel = more hp...well, in theory :D). For exhaust, you port to allow the exhaust gases to escape more easily.

In sizes (change in size from stock, anyways), from smallest to largest: street port, half-bridge, bridge, peripheral port.

As for HP, it's also about what you have hooked to the engine to get you HP #'s, as a ported motor w/stock exhaust might not see as much of a difference as a stock motor w/new exhaust (of course, I could be wrong, but I'm just trying to say that it's not just engine dependent)

j0rd4n is right. It is basically opening up the air/fuel intake port so more can flow to the engine and gain more power.

Honestly I'm trying to push 300-350HP nothing higher really I was wondering if Porting an engine (maybe a street port then??) would be a good thing to do in terms of engine performance. In contrast to say running high boost with a turbo, yeah you get decent amount of HP gain but it kills the engine (if not properly set up)

Be careful about about saying that turbos kill an engine quickly here...

A well-done street ported 4-port, with the stock turbo and good exhaust (with a fuel cut defensor, and R-tec) can put out 300 Whp and still be a daily driver.

To do that NA, you will need basically no mufflers, cats or anything restricting your exhaust and a very big peripheral port. This will need hardened planetary gears, lightened rotors, High flow/pressure oil pump and a standalone ECU. (Plus many other mods like a high-RPM clutch.)

This is why the turbo seems to be the better option. For low horsepower aplications, the NA may be more reliable, but the turbo is more reliable and less expensive for large power goals.

If you simply meant low boost and porting vs high boost and not porting, the issue rests on the current condition of your engine, is it in running condition or does it need a rebuild? If it needs the rebuild anyway, you might as well port it (streetport).

With a street port on an na, you are looking at a maximum of 200hp.

Yes. Porting is definately a must if you are after those figures. I have not heard of any (13b?) pulling numbers like that without some sort of port. Basically as the other two have stated, it just makes the flow larger = more air/fuel = higher figures.
If you google 'rotary porting' or something, there will be a tonne of info on mild street ports to j-ports.

If your car is tuned right you shouldnt have a problem with running high boost. But beware of detonation.. rotaries tend to go pop.

I forgot to mention I'm doing a S5 TII Swap into an 87' GXL. Chances are I'm going to upgrade the turbo but I'm going to run it under 10psi. If and when I do this, I'll rebuild the engine and try for lighter rotors/better apex seals. I'm not going to do a port job on an N/A, I want a dual exhaust system thats somewhat mild or quiet sounding.

I know this sounds bad but Rotary car's in general...or just cars in general I'm new too, but I'm trying to learn! I don't really understand everything about everything yet and I'm more then likely going to ask a question thats been asked a billion times before (I'll try searching the forum first though!)

Read Mr J-Rat on this thread: https://www.rx7club.com/forum/showth...hlight=PORTING

Stock porting.

Is the S5 a JSpec from eBay? If it is, it may be ok (do a compression test and see).

Yeah, good-sized street port, decently quiet, but good flowing exhaust, Front-Mounted InterCooler (FMIC), R-tec and fuel-cut defensor (FCD) should get you most of the way to 300WHP.

On a Turbo, the lightened rotors are pointless, they allow you to turn faster which you have no need to do with forced induction. The stock Apex seals should be ok to 10 psi.

Under 10 psi, you should be safe without a standalone (aftermarket Engine Control Unit (ECU)).

You are doing the right thing, drive (or at least own) the car fora while, read posts here, ask question when you need to, and eventually you will know enough to start your build.

If the car runs now, I would suggest driving it some NA, you will get to understand how the suspension will react and how the car feels when it is going to lose traction, etc.

After people go turbo, they tend to start taking their car to the dragstrip instead of the autoX.

First, learn about intake timing...
Learn about:
* intake opening timing
* duration
* intake closing timing
* overlap

Once you understand those terms, we can apply them to porting on rotary engines.
Read up on cam profiles for piston engines as a reference.


-Ted

Yeah I'm trying to get as much info as possible before I do anything at all.

I'm getting a new suspension also after the swap. This is the first car I've had thats RWD and I can really feel oversteer and figure out when it's going to break loose and snap. I had to go to Massachusetts where theres ice everywhere right now and I apparently have 15-20% tire tread on the back tires (NOT FUN)

I'm not doing Drag at all with this car (Not a big fan of straight line "racing"). I'll be doing Auto X and MAYBE light drifting (for fun) next year, this year is strictly to build up the car.

I'm one of the few 'kids' under 21 that isn't huge when it comes to drifting and would rather do some track racing.

Thanks for the help everyone!

Youre gonne run under 10psi? I dont think you will need to change your turbo!

There are stock highflowed turbos pushing 340+wrhp with a e-port.

What figures are you looking at?!

keep in mind that the more aggressive the porting, the farther the powerband shifts to the right in some cases. and since you say your going turbo, its more dependent on the turbo's size and wether or not its Ball-bearing or journal(ceramic) bearing.

a street port has the broadest power curve as a simple mild job will spool the turbo faster than stock and flow more air for the top-end.

stock port turbo cars usually start to run out of steam after 6000 or so. and a street port with a modified stock turbo can take that to 7000 with some good tuning.

Rtek's already come with the FCD built in, in their latest version.

Meh, Im getting 340 rwhp from a stock unported block. Just put a decent turbo on it. I wouldnt stuff about with porting for low HP's