Chaotic_FC

I am going to be meeting with my machinist in around a week or two.

i am wondering what would be a good size for my intake port, and intake tubes?



i was thinking a 2.25 ID tube that changes shape slightly, so it is squared off at the bottom a bit inside the rotor housing.



the reason why i ask, is i wont be revving past 9k, and if that size port will support 11k, i'd like to make it smaller, just so i can see some better low end power.



anybody who has any experience with this, feel free to chime in. I would appreciate it greatly.

j9fd3s

2.25 is HUGE, mine is a 12a, but at MFR specs its like 1 7/8"



plus you have a turbo, so you could get away with a much more conservative intake port than an NA could

Maxt

2.25 OD tube is about where you want to be, that would give you 2" Id assuming 1/8th wall thickness, but that might be oddball.. I turned mine out of out 2" sched 40 6061 pipe to get a the OD and a tapered ID that finishes a hair over 2".

I could have done a lot more with the port on my n/a car, originally it was just an experiment to see if it would run, so I left it just round with no real shaping, I know there is more power in shaping the port end area. This motor was supposed to be dead 2 years ago, no real reason to take it apart yet.

My friend in Japan runs a Cosmo 110 turbo P-port car, exhaust turbine and the ECU choice really affects the power and driveability.

Chaotic_FC

Well I'm going with a S475 with a 1.32 a/r, and am thinking of using the autronic sm4.

Maxt

Thats sounds good, you need generous turbine sizing, I think the autronic should work well, you need alot of map area for good control, also I am not sure of the autronic loading, but an ecu that can do AlphaN in conjunction with speed density is the ecu to use.

Even on an n/a p-port on the street I see sometimes see the need for map sensor correction over and above that of Alpha N, at certain speeds at given TPs position, you just cant tune that map for more than one load situation, the map sensor would really help with that, but the e6k I use with it is not capable of it.

j9fd3s

no? the 6.34 firmware has and input and map you can use, i wanna say its the "gas compensation" map, but it lets you take an input from and change the fueling



on the 7? firmware, it has a tps map added to the menu, so its backwards, but essentially its got the normal map, and then one for a tps too

Maxt

The aux in is a global adjustment on the k, I remember the X having the gas compensation map. I once set it up with zero and full throttle map and tried a 1 bar map, but it didn't work , A p-port makes basically nil for vacuum so on a map sensor it uses about 5 cells, but the fueling needed for 2000 rpm at 15% throttle in 2nd gear is different from 15% throttle at 2000 rpm in 4th. Thats where the second map would come into play. For a turbo p-port, life would be alot easier if in vacuum it referenced Tps, but boost it went to map.

Chaotic_FC

thanks guys

i just ordered my 2.25 OD mandrel bends, so it looks like thats what im goin with.

j9fd3s

you're gonna make my fire up my laptop huh? there IS a way to do it with the e6k, you have to cheat though



i tuned a 56 chevy, with a big throttle body, and its tricky on the MAP sensor too, because its an automatic for idle and cruise it only uses like 3-4 different cells.

Maxt

I know the way people were using pressure correction, it was pretty coarse , just a percentage correction of the main map. I think the low speed reversion of the p-port would make that an interesting tune.

Whats funny is I did a 56 chevy with a throttle body system as well, holley commander 950 pro, it was setup for speed density by another tuner as per holley instruction, changed to alpha n, 65 rwhp gain. . The holley has the option of alpha n below x rpm.. nice option.