car is 88 gxn na

6 port motor with functional sleeves

will these ports change idle in any way, higher or lower?

images:

before


still before



and after



and the primaries i dont have a before pic

after

 

You could bring the primaries down much further. Your's looks similar to mine and my idle is around 1,000. Any lower and it struggles...

Brian

 

They look fine to me. The aux ports might close a touch late. Have you tossed a rotor on it to see if the chamber decreases in size before the port is closed? Might shove air back out the intake... There's a small amount its allowed to decrease before closing completely as the air's momentum will still be charging the chamber... but after that, its just a waste.

 

Should have little if any effect on idle.

Also, no real reason to port the primary down. Does basically nothing to improve flow and just increases port volume...not really a good thing on the primaries in most cases.

 

Are you saying bringing the primaries down is not a good thing for an N/A or a turbo as well? I thought a turbo's primary was elongated at the bottom.

I extended my primary (N/A) based on a mazdatrix template.

 

It's the top, inner edge and outer edge of the port that sets port timing. The bottom is really only open for a fraction of the time the port flows, so porting down really doesn't do much.

Mine are ported down as well a little, and most templates do move the port down somewhat.

To see what I mean, grab a rotor and iron and then bring the rotor through it's orbit.

 

It will slightly affect it but it's not very aggressive. You could stand to open the primaries earlier (opening edge; not short radius edge). Don't expand the 5th and 6th ports on the outer irons; bad joojoo.

B

 

well i have already ported the motor as show and it is running in my car.
i do believe i extended the aux port a bit to far up, the sleeves try to jump in and out when the car is idling.
i haven’t taken the motor over 3k rpm because i want to break it in and it only has 20 miles on it,
i have noticed a slight hesitation when revving the motor from 1k to 3k slowly in neutral.

it kinda sucks, i thought i did alot of research and i saw other people extend their aux ports up even higher than mine. i only went up .2" and that was mainly just rolling the edge.

who knows, it may perform better at higher rpms with higher air velocities, but i wont know for a while.
As of right now I don’t even have the backpressure vac line attached to the actuators for the aux port sleeves, so they wont even open anyways.

Reason why i didnt go big on the primaries and ported the aux's instead was because i still have to pass CA emissions.

Question: on the aux port actuators, can you adjust how far the sleeves rotate closed?

 

just because i want to share some info,
instead of using a dremel tool which takes forever and a day, i used this to port

 

well that could be that it hasn't built much compression yet, as it wears in it should quicken up, mine was doing about the same with a street port when i first go it running, seems to have went away now and mine has ~650 miles on it

 

The design of thows ports is alright but I think the aux design is going to hurt it masking the gains of the main porting. As stated no they are not agresive at all but we all understand emissions passing. It looks to me most of the port work was just beveling the edges out. I don't count my timing much on the bevel I stop the timing mark just befor my bevel start and the bevel depends on how far I advanced the port.

I would not bring thee aux port up at all but slightly out towrds the spark plugs is ok but just a tad. You can close the P tad bit latter if you want it will shift your band further up about 1k if you close it late as you can but I do not recoment bringing them up far on the S and use the ledge for a bevel if needed. How are the runners ported? Casting grounded down is all or did you shape them?

 

the average compression # before even running the motor the front rotor was 95 and the rear was 100psi, im pretty sure they are a bit higher now when checking the first pump i got on the gauge went up to 60psi, which i think is pretty good., they where both 90 ish before

i dont have any good pictures of the runners, but here are some.
basically i just used a sand drum to polish them up to a smooth finish

 

some guess work but this is what i have come up with.
i think my port is on the very edge of compression