My N/A S4 engine with almost 190,xxx miles is about ready to be torn down. I've been thinking of streetporting. So, as this will be my first rebuild/porting, I have some questions...

Where can I find alot more information on streetporting?
Whats bad about porting the 6-port iron's exhaust port?
What should I do with the exhaust "splitter"?
Should I worry about oil pressure?
Will heat be the same as stock temperatures?
Is there anything I should upgrade to keep my engine safer.

FWIW:
I will be running my 5th and 6th ports using my airpump.
My power goal is whatever.
I'm not into the carb setups(for now).
I plan to use rtek
Daily Drive/ Drift/ Autocross
No emissions in my state.

Thanks for taking the time to read my thread and help me out a little bit!

 

we just talked about the oil! https://www.rx7club.com/naturally-aspirated-performance-forum-220/oil-pressure-vs-volume-891788/

obviously on a full race car you want the higher PSI, street car seems like its fine with just the bigger oil pump.

 

Oh! I didn't know if that thread was pertaining to my needs.

So by switching to a turbo pump and using a more viscious oil, I can have cooler oil temperatures, thus keeping my engine safe.

Also, I will add that I should as well use an oil baffle plate to keep my oil from sloshing around in the oil pan. Scratch that one off the list...

 

yep, more oil volume + baffle plate (less foam) = better oiling. the higher pressure is more to keep the rotors cool, when the engine is used @ full throttle 90% of the time its running, so not a street car....

the exhaust port splitter; i've seen people cut em out, none of the tools i have would make a dent though... and it does help slightly with noise, on a mild engine (i don't know what you're looking for) its not really hurting power.

plan A is just to swap to t2 sleeves.

i'm happy with my na's once you get the exhaust to flow, and then tune it. i teed in a boost gauge into the exhaust.

 

what "more" information are you seeking?
not sure what you're asking with this one.
leave it in place. you could try doing some finish work on the surfaces, but that's about it. as j9fd3s said, you could try to locate a turbo sleeve for use, but as a street car, every bit of noise reduction helps keep attention to a minimum - especially since you'll need to run a less restrictive exhaust (if you don't already have one).
i like to increase pressure with my engines, but the truth is that the volume increase is fine for a street car. however, with your reference to possible drifting, you may want to consider upping the pressure, too.
i can't speak for exact numbers, but what i can say for sure i've never seen any streetport show signs of taxing a well-maintained stock cooling system.
safer in what respect? you will have addressed lubrication and temperature control and at that point, it's simply a matter of tuning and maintenance.

 

Why are streetports different? Which side should I extend, what will it increase and why? I didn't want to ask,"what is the best streetport template? But it may come to that.
When I was reading on Mazdatrix's website about their templates, they said do not port a 6-port iron's exhaust port sleeve. I don't know why; because, on this site in a thread about porting, a member said that one would see a big increase in hp by porting the exhaust bigger than the intake.
I plan to have a full straight pipe, as stated earlier, my 5th and 6th ports will open via the air-pump. So I will try to work around them.

-Thanks diabolical1

 

that first one is the $64,000 question! have you looked at kahrens port? or what mazda did with the rx8? especially in regards to the intake/exhaust sizing relationship? i don't know the answers either, BTW, but that's the direction i'd be heading in

the reason mazdatrix doesnt port the sleeve is that a turbo housing is the same $$ as the NA housing, so you don't have to if you're building a good engine. plus the sleeve is SO HARD, that the amount of shop time it would take to actually grind it out, well you could buy a new rotor housing i bet. i've seen people do it, and hey if you have the time, and some sort of insane cutting tool, keep in mind mine hardly made a scratch, then go for it

 

I don't know how I didn't think of that in the first place. So I could try to switch sleeves(I have no idea how to), or I should get some turbo housings.
- Thanks j9fd3s again.

I have another question...

I was curious about if it was possible to re-chrome the housings. So I came across JHB performance. They offered service, but there is only one review I found that acually came from that individuals experience. So I thought, would it be worth it? But alot of people, herd from some other person, who herd from another person, who herd from some other person, etc... that the new chrome will scrap off.

Would it be worth to test, or will I be wasting money?

 

the sleeves are held in with a roll pin, so they arent too hard to swap, or you could run turbo rotor housings, or just keep the NA sleeves, they arent that big of a restriction.

the JHB people gave us candy at sevenstock, they are very nice. i prefer NEW mazda housings, we know those won't have problems, new housing motors actually DO seem to run better (new irons/rotor/rotor housing, really runs nice)

if i had an engine where new housings were not available, like my P port, then the JHB looks really attractive.

 

the easiest way I found out to how to swap the turbo inserts in the exhaust housing is just do take a die grinder and grind away with a carbide bit in the NA insert where the pins are until you grind all the way through, then you can take a punch and knock the roll pin out without the risk of breaking taps off in the housing or damaging the aluminum.

there is no need to save your NA inserts because nobody wants them and they are just gonna become trash anyways. I did this after breaking 2 taps in the stupid roll pin.....

 

for what it's worth, i haven't read or heard anything disparaging about JHB housings, but in the same breath, my sample size wasn't a great number of reviews either. i've perhaps read two or three, but no more. the only thing i remember was that someone said the new coating was so hard that it made porting very difficult, so if he were to have done it again, he'd port the housing first and then send it to get re-coated. actually, i plan to use them on one or two of my future projects.

as far as the exhaust sleeve goes, i'd say unless you plan to get another set of housings, in which case you can just get Turbo housings, then don't sweat it. as was said, it's not that big of a restriction.

 

Yeah, I found a thread on how to remove the sleeves, but I'm gonna keep them to help lower noise. If my housings look bad, I'll get a quote from JHB, or get some low mileage housings.

I bet there Okay, because before my grounds shorted out, my engine still has full compression. Also, I don't have any oil leaks. But, my rear iron has a crack, I don't know how deep, but nothing is coming out of it, so I'm fine until this summer. As until then, I'm trying to get everyting ready, so I'm getting another low mileage block to take apart and take what I need, and sell whats left.

Also, do any of you think its a rip off that the salvage yard closest to me is selling a 90,xxx S4 and a 100,xxx S5 block for $800 Firm? Come on! This is why I'm glad to be apart of this forum, I can get one of each for half that!

Thanks for the help!

 

think of it like this. when changing the shape of the intake and exhaust ports, it's kinda like the lift and duration of a cam in a piston engine.

 

How do I determine how much to port on the intake runners?

 

For the intake runners after a streetport, they need to be bigger. So how would I go about that?

 

IMO the runner is big enough stock. we just clean the big casting boogers out, and run em as is. if it was a drag race motor only, then yeah hog it out, but for anything else you want the velocity than comes with the stock sized port.

the port is not the thing that makes or breaks you, its the port+ intake + exhaust + ecu tuning.

mild port + excellent exhaust + good tune = big broad power band.

crazy port with huge runners + stock exhaust +stock ecu = slow turkey

its my opinion of course

 

...and my opinion is that the primary ports should be made huge, and the secondary ports should be made so huge that you need to leave a strip of metal to hold the rotor seals in. You could think of it as a bridge for the seals to cross. Hmm, that'd be a sweet name for that kind of port.

(Yes, I am absolutely lovin' my half-bridge. Drivable and more torque at about 3000rpm than the streetport made at peak)

 

Thanks, I was doing a lot of reading on the nopistons forum, I've been looking for an ITO template, but I'm going to settle for a pineapple racing streetport template. You guys are a lot of help.

 

thats right you could call it the strip of metal to hold the seal port!

 

^

 

...and somehow it's slower than the old engine. I just turned a 14.06 at 96.5 or something like that. My only clean run that didn't involve blowing the meter fuse when I touched the clutch.

And serious ignition break-up issues.

So, uh, I guess it's better, if I could solve the ignition problems, oh and find out why I'm going through 15 amp fuses at an alarming rate.

 

its not really all that much more louder, it sounds better and I don't care what anyone says but a small restriction is still a restriction and the less of those the better.