RixRotary7

I have a 1985 rx-7 gs and I was wondering what it would take to port my engine. Is it difficult, expensive, worth it? Now, when I put on my Racing Beat Exhaust System, it took me about a day and a half. How long would it take me to remove the entire engine? Like I said before, my car has 90,000 miles on it and I don't want to dammage it beyond repair. Thanks guys.

RixRotary7

Also, what is the difference between porting the intake and the exhaust? When I say difference, I mean in power, ease, ect. Thanks for your time.

coldy13

If you port just the intake, then your exhaust port will be the main restriction for you making power. If you just port the exhaust, your intake port will be the main restriction for making power. If you want to get a good gain in power, you have to port them both. Also, the stock carb will only flow enough for 145hp, the stock ports will flow enough for 155hp. So, if you port, then you need a beter flowing carb. With a good exhaust and carb, a streetport will give you about 170-200hp. People have gotten more than that out of a streetport, but unless you really know what your doing with the port, then dont expect over 200hp. Power will probably die off near 8000rpm, so it's fine to keep the stock seals and engine internals.

A bridgeport will give you about 200-280, depending on how big you make it. It will also not idle below 1500 since there is too much port overlap. It is a harder port to make, and depending on how big you make the port, it can require you to notch the rotor housings. It's a good idea to use carbon apex seals, hardend stationary gears, and race clearance the rotors with a bridgeport, since it's power will probably die off around 9000rpm. If you use stock seals in a bridgeport, you will not be able to get the full power out of it, stock seals should never be taken over 8500rpm, they will chatter, possibly snap the seal, and make nasty marks on the rotor housing and then you need to replace the housings.

I would defiantly say porting is worth it, it will give you MUCH more power than a stock ported engine. Porting can be very expensive, at the least you need a full rebuild kit, and two porting templates(intake and exhaust), probably cost about $900 including shipping for a streetport. For a bridge, add hardened stationary gears and race clearance the rotors, and you'll probably be looking at around $1500. This is if you do all the work your self, and not including the other costs, new carb, fuel pump, pressure regulator.

Oops, I just noticed you only have 5 posts, so I probably just completely confused the f*ck out of you. If you have any more questions go ahead and ask them.