8 port runner - JDM

Power was not increased

If the flow was improved why not the power....quite contradictory my dear Holmes

Ps. I am searching the net for some "facts"

Draco wrote:

If the flow was improved why not the power....quite contradictory my dear Holmes

Emissions and MOT my dear Watson.... This is Europe we're talking about...

Draco wrote:

Ps. I am searching the net for some "facts"

Now thats a contradiction!!!! 😛

If the flow was improved why not the power....quite contradictory my dear Holmes

Maybe they changed the timing to restrict the power output??

Sokar wrote:

Draco wrote:

Ps. I am searching the net for some "facts"

Now thats a contradiction!!!! 😛

My point exactly 🙄

Another tidbit for the imagination.

The CA is essentially a baby RB....

Nissan NEVER put the 2 port butterfly design on an RB (The do have ITB's though, but its a single ITB Per cylinder ) and there are no after market kits for it, why do you think that is?

Look, I'm not knocking the 8 port. I'm sure the power difference is minimal. If you have an 8 port, keep it, if you have a 4 port, congrats.

If you're at a point like VC where you can choose either for free, FFS take the 4 port!!! Less hassles, more flow...

PS, make sure your 8 ports are working correctly or you get the buildup in the photo's that VC posted....

make sure your 8 ports are working correctly or you get the buildup in the photo's that VC posted....

Thats presicely why I say disconnect it, it does not work if the whole thing isn't done right eg vacumm tanks and all sorts, if it stays open I don't see why the flow will be worse...if you mathematically go and messure the 8 ports when butterflies is out and 4 ports....how much diffs will it make?

aah i see. you have both then VC? and it will cost 0 (or practically zero) to choose whichever. Then take the 4 port man...now what was all the fuss about?

I have both, cant say i ever noticed a difference...hence dont care which one im running

Draco wrote:

make sure your 8 ports are working correctly or you get the buildup in the photo's that VC posted....

Thats presicely why I say disconnect it, it does not work if the whole thing isn't done right eg vacumm tanks and all sorts, if it stays open I don't see why the flow will be worse...if you mathematically go and messure the 8 ports when butterflies is out and 4 ports....how much diffs will it make?

*sigh* OK here goes, it all boils down to fluid dynamics.

Basically if you look at the air moving through the ports, the air "touching" the sides is "rubbing" and moving slower than the air in the middle of the port. Because the 2 port design has more "sides" it has more "rubbing" and less flow, while this isnt a problem at low RPM as the speed increases, the friction does aswell, also the air is under pressure so its getting forced against the sides aswell.

Also the single port is "bigger" in total, so there's alot more potential for flow. The 2 port has a chunk of metal in the middle.

I'd say stock for stock this wont be a big diff, but I think a 4 port gas flowed head vs an 8 port gas flowed head would make a huuuuuge difference.

I didnt know the RB has ITB, cool. I wonder what size they are and what difference they would make over a single TB??

As you say sokar, I am not dissing the 4 port either, to me it's the same thing if the buttelflies are disengadged, again, there are no scientific proof of the flow....no facts, I wouldn't base the link to a scientific fact.

At the end VC, as I said in the beginning, just because of the headgasget sets that come in 8 ports, I would rather buy a made up set rather than a cut myself job, it is up to you and the owner.

Just a side note, if your car was N/A the 8 port might be the better option, its also been shown that smaller ports will "accellerate" the air and it will enter the cylinders at a higher velocity "they call it high velocity ports"

But on a turbo'd car, you wanna get as much in as you can!

Gary57 wrote:

I didnt know the RB has ITB, cool. I wonder what size they are and what difference they would make over a single TB??

Only the RB26DETT's, the normal RB25DET and the like have a single throttle.

you guys make me laugh.

its all about the FLOWWWWWWW!!!!!!

anyway - because the head is also 8 port, a change would require a headgasket. not an option at the moment.

currently i think the butterfly system is just linked to a vacuum/boost reference - like a T-piece in the vacuum hose for the FPR.

@gary - there are only butterflies on 4 of the 8 ports. so each of the 4 intake tracts are divided into two, and one of the two on each has a butterfly which closes the port and therefore in essence alters the "length" of the manifold - leading to higher velocity FLOWWWWW at lower boost levels and lower RPM. but at higher RPM and boost, the butterflies open again changing the manifold length and therefore the amount of FLOWWWWWWW!!!

my problem was that i wasnt sure how to connect it up without all the correct equipment - e.g. vacuum tanks, one way valves, delay valves, solenoids vacuum hoses and a vacuum actuator.

but now that i know the ecu was also altered to accomodate this 8 port story, i think i will just keep the butterflies open.

one more thing - from some pics on the net, it looks (and i stress looks like, as in "by da eye darren" like the total area across both ports in an 8 port is larger than the total area across the single port of a 4 port design.

but we're talking a single mm - maybe 1.5mm.

hey monkeybooi - dont forget to bring the angle grinder!!!

Tadaaaaaa!!!

hey...

you found a picture of widowmakers mama!!!

awesome.

LOOK EVERYONE... WIDOW'S MOM!!! 😂 😂 😂

What the hell is she doing with my angle grinder!!!!

Sokar wrote:

What the hell is she doing with my angle grinder!!!!

she looks just like him hey, the resemblance is phenomenal!!!

Look shes got man tits 😂

Draco wrote:

Look shes got man tits 😂

hehehe - like yours or widows???

Like mine.....you got a pair too 😉

Yip it's true...and I am proud of it 😂

Iv'e got a man-gina aswell 😀