We took my FC's engine apart today and to clean it up after it suffered an apex seal fail (though somehow it didnt damage the housings at all! ), so got to look at how it was ported.
I know a lot of people are secretive about their port size and shape, but I dont give a damn, so if this helps anyone, and if anyone can help me, thats great

The car is a Jap import with a 'side ported' FC engine by ERC (Elite Racing Corporation) www.erc-rotary.com

Its clearly a street port, with enlarged exhaust ports too, but what do people think? Is this big? Ive not seen enough RXs in bits to know, and we only had stock ones to compare it to.
The ports are amazingly well done, like glass to the touch.

Ive heard a few times that FD ports are much bigger than FCs, but, well, they are, but not as much as people say. The 'Large ported FCs are only as big as stock port FDs' rumour ive heard a few times is ****, thats for sure...

In the centre iron, the FD inlet ports are MUCH taller than even my ported FC ones, and about as wide as the stock FC ones, but neither are as wide as my ported FC ones...


Very similar situation on the side ports...


The reason being is the FC lower inlet manifold isnt tall enough to have any bigger TBH. But whats probably more important is how big the ports are as the reach the rotor...

On the centre iron, the stock FD is a fair bit bigger than the stock FC, but my ported FC one is miles bigger than both of them...


On the side irons the FC and FD ones are actually very similar, but again my ported FC ones are bigger than both as expected...


On to the exhaust side, FC and FD ports are totally identical. But the difference between my ported ones and stock ones are pretty big...

From the outside...


From the inside...


With a ruler to see the difference easier...


And finally all 3 to show FC and FD ones are the same...

 

exhaust ports get the thumbs up from me. The inlet ports look good. They could do with some changes. The primary and secondary ports COuld open MUCH EARLIER and primaries could close later.

Those type of ports will give you a good peak hp figure but not much for power over 8500rpm.

 

Agreed, they are pretty conservative, but would be good for street use. My FC primaries are as big as FC secondary ports, actually slightly bigger.

What is your use for the car?

 

Thanks for the responses, much appreciated.

It was a competition drift car in Japan competing in D1, and only had a little T04E on it (though I managed a 119.5mph quarter mile terminal, which isnt bad for a little T04E).

I do want a lot lot more power though, feels slow to me still, im pretty immune to speed.

My current rev limit was only 8k but felt like it wanted to go further.

It will be going back together with a much bigger turbo etc, thats for sure. Think I need a good 500bhp to keep me entertained to be honest.

Interesting about the inlet ports- Im fully up for enlarging them if anyone here (ie UK) can well enough.

Shame your in Oz RX72C as with your results I certainly trust your judgments on ports etc!

 

I would just do it yourself. If you pm me ill give you all the specs you need.

 

The closing side of your intakes should be shaped by the side seals tracks. A little more pointed like this.

Barry

 

quick FYI... the s4 and s5 turbo irons are different. The port runners are smaller on the s4 and that's part of the reason why the LIM gaskets are different between series.

How many people actually enlarge the runner section of the ports anyway? I thought about it on my s5 irons, but then they would be bigger than the s5 LIM runners... for air velocity it seemed best to just leave them how they were. I could have enlarged the runners on the motor, then port matched the LIM, but that still leaves me with an intake system that really isn't designed for it. I think I'd rather just install 13B-RE Cosmo irons and manifolds. At least they are designed as a system to have big runners.

For the exhaust ports, at one point mine were like yours, matched to the sleeve basically. When I built the current motor in the car I went with the Pineapple racing template, which goes a little bigger than the sleeve:



I noticed that reduced the amount of vacuum the engine could pull (about 300-325 mmHg vs. 350-375 mmHg with the smaller ports). It probably helped top end power but I don't have good testing to be able to tell, as I changed a lot of stuff on the engine.

 

RX72C- I tried to PM you but it says your inbox is full

Everyone- Thanks for the responses, all interesting info

 

Here is the primary port on my S4 T2. I have more pictures on another computer I can upload.

When the primary ports get this big the vaccum is lowered at idle by quite a bit. This port w/ my secondaries continues to make power over 9K. The bad thing is my rev limiter is set at 8K. I don't see a need to run it over 8 on the streets. It doesn't make much power at 2500 but at 5500 it really comes alive.

It all depends on where you want the power. I would not say that the porting on that motor is a restriction for 500 Hp. Remember the bigger the ports the higher the powerband is in the RPM range. Select how you want the motor to perform and build it accordingly. Bigger isn't always best.

Keep us posted.

 

just cleared my inbox. send us another pm.


Also the comment about bigger the ports the higher the power band. THat is GARBAGE if done correctly.
My street ports make power right down from 3000rpm all the way to 10 000rpm all turbo depending.

But one of my customers had his car tuned elsewere and his power was with in 5% of peak hp from 3500rpm to 9000rpm and it only had a 35r on it.

 

There's more to a powerband than the shape of the ports.

 

I am not going to turn this into a pissing match, but if you think a stock primary and a primary that is bigger than a stock secondary are going to make power in the same rpm range go for it. I have seen what I have seen, and could care less what you say.

I agree it is the entire set up.

My whole point was that the porting he has was not a restriction.

Have a nice day.