RX7Club.com - Mazda RX7 Forum - NOOB'S GUIDE TO PORTING (56K Beware)

RX7Club.com - Mazda RX7 Forum (https://www.rx7club.com/)

- Rotary Car Performance (https://www.rx7club.com/rotary-car-performance-77/)

- - NOOB'S GUIDE TO PORTING (56K Beware) (https://www.rx7club.com/rotary-car-performance-77/noobs-guide-porting-56k-beware-619991/)

if you have the patients you can do it with a dremmel tool. in fact i use both air and dremmel.

you could do it with about 8-10 gallon but it will be running 24/7 and you may still have to wait for it to build back up.

Try a Electric Dermal

Quote:

Originally Posted by arghx (Post 8630939)

thread revival time, I have a question. I am going to start some porting soon for the first time and I have read through all this thread, but of course there are different perspectives on a lot of issues that I need to sort through.

I have Series 5 Turbo II irons (wanted the stronger casting)Good thinking for over 350hp with my old series 4 Turbo II LIM. The runner portion of the intake port, where it mates with the intake manifold. Is it common to enlarge the actual runners in the iron to match the LIM gasket? Yes and No, if you are not going to port the LIM then you only want to port match to the LIM, if you make the Iron larger than the intake port then there will be a HUGE drop in air velocity when the air leaves the LIM and enters the Iron, Port match it to the LIM only this will keep the air at a constant velocity and keep the turbulence low. I have not ported the LIM and I wasn't planning to.Unless you are going for major hp

Also, for the final finish on the intake ports, what grit sandpaper should it be? 200-300ish Some people are saying mirror finish, many others are saying it should be slightly textured. Is that for all three areas of the port (aperture, bowl, runner)?The entire port should have some texture but not much, Look up why a Golf Ball has Dents in it and it will explain everything

For the exhaust ports, people keep talking about beveled edges and whether they are needed or not. Depends on how good your port is Could somebody explain that a little better? The bevel is there just in case the apex seal is bowed, it will allow a smoother transition back onto the rotor housing surface Is that on the top side of the port? YesGot any pics illustrating what it actually looks like? Look at the exhaust ports very close, you don't need much 1/16-1/8 bevel I have the Pineapple Racing EP3A exhaust porting template which is their largest template for non-bridge engines. Am I supposed to do anything to the sleeve like polish it or something?You don't really have to, but if you make them like a mirror then carbon cant stick to the metal and it will cut down any build up, make sure you port the sleeve to the port in the housing, basically make the opening the same as the port

Thanks, this is a good thread, but it leaves a lot of unanswered questions for someone with 0 experience porting. I'm going to be messing around with my junk irons and housings first.

That is why you ask questions, so everyone can learn

Quote:

Originally Posted by antnicuk (Post 6800426)

Hi
thanks for your reply,

I am currently building a new engine for my Series 5 TII, I had done the exhaust ports already and made them square as i thought it would get the largest area so i'm glad about that. I did go a little wider each side, i'm about 12mm in from each side although i am using new Mazda 2 piece seals, do you think this would be ok?

Some have said i shouldnt go down because it shortens the power stroke and others have said dont go up due to overlap. I live in the UK and this was advice from 2 specialists i have known for a long time! Due to the doubt, i ported about 2mm down and 4 mm up. I retained the exhaust sleeve but took it out, heated it and splayed the opening so it matches the port in the housing, this way i managed to retain the sleeve but dont have a step between the sleeve and the port opening. The inlet ports are quite a large streetport as are the runners and the Lower inlet manifold.

What do you think? do you keep the sleeve

I currently run a S4 engine with Low comp rotors and a GT35/40 with a 0.96 hot side, the engine was dynoed at 380 RWhp with little lag, i am aiming for 400 RW hp at 1 bar with the new one so i have done a lot more porting and got a 1.15 exhaust housing, hopefully it wont be too laggy. This one will use S 5 rotors and FD e shaft, s gears and oil pressure regs as i want to reve it to 8 k rpm safely

regards
tony

while i may be a bit late with a reply ( ima newcomer here )
i personally use a very similar exhaust profile to what you describe
( mine in fact go to 11mm from edge )
i also follow much of the principles of what blake described lately above
trialling both the square ( shovel ) , and slightly oval versions of same basic timings
- with both turbo 6 port and extend port plates , and 8.5 and 9.0 and 9.4 comp rotors
i havent had any issues with bowing, up to approx power level you describe
( and with OEM seals only, for same suspicions as what blake had )

http://img517.imageshack.us/img517/7...1007618vl8.jpg
http://img517.imageshack.us/img517/p...jpg/1/w640.png
a recent set , slightly "ovalled" edges
i always run no insert at all, and usually left a 1 mm bottom reversion lip
- ATM pictured above housings are trialling no lip
and same ex and in ports and timings as you describe above
( s4 rotors, OEM hard seals , s5 housings , s5 plates, no dowelling, street )

http://img291.imageshack.us/img291/7...0917546vb2.jpg
http://img291.imageshack.us/img291/p...jpg/1/w640.png
a stack of retired housings showing some progression in shape
( and a stocky in there )

very nice diy to make ;)

I post in this thread only after reading the title and realizing something... There are people reading this forum that have no clue what "56k beware" means....that is all.