Pro's and Con's small street port?
 

My 93 rx-7 has been down for a while now. Going to get in back on the road soon. Thinking of going with small street port or just sticking with stock rebuild. Is the sound, reliability and gas consumption worth the output?

Mods: intake, downpipe, pulleys and catback.

In my opinion, you've already spent the money on the mods to make it flow better, why not spend a few hundred to help those mods do their job even better? Especially since the engine will already be apart.

I have the opposite opinion. When/if the engine blows, it's a pain to get matching irons/housing which are ported (or you have to get the replacement ones port matched with your existing ones). Unless you are going for all out performance, stick with the stock ports. Much easier to deal with should anything happen with your motor.

i'm at a point right now where i simply will not put a non-ported engine into my cars, but i also do my own porting, so i understand it might not be practical for some.

that said, unless something else is terribly wrong, fuel consumption increase should be minimal and there should be no difference in reliability. i strongly advise against porting any engine for sound. if sound is a major factor, i find many people usually regret it - whether they admit it or not.

a mild streetport should give a modest bump in the middle and upper ranges. drawbacks would include possible emissions issues.

With a stock ecu I wouldnt do much porting. Idle with a street port and stock ecu/pettit/m2 or whatever other remapped ecus are out there is pretty terrible. If you plan to go PFC and get the car tuned I see no harm in porting. Gas mileage is horrific either way, but I wouldnt expect much real gain with porting and keeping the stock twins. ;)

I can attest to this i really wish i would have kept the stock ports, with my pettit ecu. Some times you have to learn the hard way though:( Sounds like a v8 with a lopy cam until it warms up fully. I really didnt feel much of a power gain either.

Thanks for the info, staying stock.

is there a certain mileage when doing the rebuild that porting is ill advised? im at 80k and found out my motor was done for today, was thinking about street porting but now double guessing it, if its less reliable i dont think i will, is it though?

A good port job should not have any ill effect on your engines reliability. 80k miles on one engine isn't that bad either.

You could have probably started your own thread, but I suppose the revival wasn't *too* terrible =P

Well, if you are doing a rebuild, I'm guessing you will be looking for new housings since your motor is toast from the mileage right? I would NOT reuse parts from an 80k motor at all.

The porting itself shouldn't lend a motor to a shorter life. I think the boost you run through it might! If your configuration can be helped by a small streetport, I'd do it. You don't lose that much on a conservative port job like that.

80k pretty low. Lower than mine