Could anyone answer me this? Whats the advantage to 3mm apex seals...and street porting. Does Street porting make MPG worse? this is my 1st night on this Forum...Holy! is it ever great have any questions answered here within minutes it's rad.


Thanks, RX-7 fellas

 

welcome. ask questions away. just be sure not to say you're going to put a v8 in your car and you'll be a.o.k!

I don't know the complete answers to your questions but I'll see what I can do.

to street port your engine would be to make the intake ports larger. a lot of the time this requires larger fuel injectors, but either way its going to take more fuel causing lower MPG. and 3mm seals would be sort of a safety precaution. I'm guessing they seal a bit better and are stronger. but I don't think they give that much of a performance gain by themselves. hope I could be of some help

 

A street won't increase your fuel consumption if you drive exactly the way you did before, and don't use any of your newly found power. Like that's going to happen!
You'll open a can of worms asking about 2mm vs. 3mm seals. There are people here who'll argue both sides hard! Here's what I think:
Late model 2mm seals actually seal better than the old 3mm ones, that's why Mazda use them! But 3mm is obviously stronger and may survive a bit longer under detonation. But others argue that if you detonate hard and your 3mm seals don't break something else probably will instead. The obvious solution is NO detonation, but your tuning has to be spot on all the time. I've heard of 600hp 13B drag cars in Australia with 2mm seals so it can be done!

 

well ive got both the obove mentioned items so i'll take a shot at it
what year is your 7?
mine is an 89 so the streetport dosnt do too much b/c its got the 6 intake ports and i couldnt cut that much out. many shops will tell you that it is not possible, but it will make a little difference
3mm-dont worry about them if your car isnt a turbo, the only reason i have them in my NA is b/c when the motor went the apex seal damaged the rotor tips so i had them enlarged and fit the 3mms in them

 

Thanks! you have answered all my Quesions. My car is an 87

 

I had mine ported at MAZDATRIX and they claim that you will not feel a very big difference unless you are going big turbo if you have a TURBO 7. What they did to my new housings was port and polish the existing intake and exaust ports. They did a good job i must say...

About 2mm vs 3mm seals..Mazda used 3mm seals on the 84-85 GSL-SE.
That was good but if you try to convert your 2mm seal groove to a 3mm be very carefull to who you are taking the rotors to because alot of shops cant do it perfectly. When they mill the grooves they dont do it precisely and you will end up with compression blow bys... Not too many shops i heard dont do it right!!!..UNLESS you want to be a mean drag racer i would stay away from 3mm seals...2mm seals seal better!!!..

 

Yeah, what he said about the 3mm apex seals. I've seen some discussion on that, basically 3mm is used in non-stock aps. only when you've had a seal "roll" and the groove no longer holds its, so you have to go bigger. I would recommend against it just based on my limited knowledge.

 

...Not too many shops do it right..rather

 

Anyone know how much HP you can get with a street port on a 6 port motor? I would want to have a good idle still. Thanks.

 

That is a hard question to answer because it really depends on the other mods that you have and how healthy yourt motor is.