befarrer

iTrader: (1)

This might be a dumb question, but I am wondering if I can make more power running a S4 turbo motor non-turbo, or a S4 6-port motor.

The S4 turbo motor is modified, it has S4 rotors with 3MM apex seals and S4 irons and S5 housings, however it has a street port of unknown size. I assume it has the Turbo rotors due to it having a stock S4 turbo flywheel/counterweight.

The S4 6-port is stock ported with Atkins port sleeves, no port actuators, wired open.

I plan to run ITB's on this motor, but I am wondering if I can make more power running ITB's on the ported Turbo motor, which I think I can get a better manifold for, which will compensate for the lower compression.

Ideally, I would like to put the NA rotors in the turbo engine, but I don't want to do this right now.

peejay

Here's the problem. The rotors in the turbo engone are now garbage because someone put 3mm seals in it. Now they can not rev over 8000 without risking blowing the engine.

Other than that, the turbo block is a far superior engine to start from, ports-wise. You can make more power at lower speed than any 6 port engine. I used to run deturboed turbo engines and 6 port engines are disappointing afterward, no matter how they are ported.

Lower compression is actually a benefit at super high RPM, but you won't be seeing that without pulling the enigne apart and changing rotors or installing carbon-aluminum seals.

BLUE TII

iTrader: (9)

3mm rotors with stock 3mm apex seals (not aftermarket steel) will be fine running up to 8,000rpm though.

I have done this many years without problems on my turbo car (though perhaps higher turbo combustion pressure helps it seal better than NA which helps mitigate the heavier apex seals skipping at high rpm).

I wouldn't trust an unopened motor rotating assembly to over 8,000rpm anyways- since I learned my lesson on that with my FD. Rotors could be letters off/out of balance and stuff themselves into the side housings.

Lower compression is actually a benefit at super high RPM, but you won't be seeing that without pulling the enigne apart and changing rotors or installing carbon-aluminum seals.

Right, most people don't realize the higher comp is for tip in throttle response and gas mileage.

Mazda factory race NA rotors were 9.4CR until they employed their fuel saving strategies to win Lemans with the 787B.


I would definitely go 4 port.

I have seen 230rwhp out of small steetport S5 TII motors on stock intake, have only seen 210rwhp out of ITB 6 ports.

Use cheap 4150 TB and 4150 style intake manifold for ITBs and later when you take it apart you can bridge it, and make even more power.

If you do want to make a high rpm rotary (8,000rpm+) with that rotating assembly later- you will need 3mm Carbon or Ceramic apex seals as stated as well as rotor side machining/balancing.

SpeedAddict62

Why?

BLUE TII

iTrader: (9)

Pumping loss.

The entire intake charge has to pass through the rotor slot to get from one side of the rotor housing minor axis (the pinch) to the other side.

When you restrict flow through the rotor slot with less volume from higher CR the pumping losses increase greatly at high RPM.

lastphaseofthis

iTrader: (8)

what about a 6 port bridge with the turbo 4 port intake port mached?
someone has the setup and im trying to convince them it's garbage.
the 6 port manifold flows more right?

BLUE TII

iTrader: (9)

That set-up is garbage because of the bridged 6 ports in the motor, not the intake manifold.

The runners of the 6 port irons are too small diameter and have more surface area so they become a source of frictional drag that limits total CFM flow into the motor compared to the larger and lower surface area 4 ports.

This happens at around 210rwhp.

If you siamese the 6 port aux and 2ndary ports into 1 large port (to a 4 port motor) you overcome this disadvantage, but now have the disadvantage that the ports runners are so large and the ports are so late closing that they only work well in the very high RPM (Mazdatrix said they had trouble tuning the intake/exhaust lengths to get the motor to peak torque below 10,000rpm in their EP car).

peejay

I saw huge gains on a half bridged Turbo engine when I switched to a 6 port manifold.

I would really like to find a stockport TII engine so I could run a 6port intake on it to see what it does.

My experiences were shocking enough that I have no idea why Mazda bothered with the 6 port engine. The TII block, as some longforgotten forum member posted 10-15 years back, shat all over the 6 port.

My power experiences are, in power order not chronological order, stockport 4 port 12A, stockport 6 port 13B, 1/3rd bridge port 6 port 13B, street port 6 port 13B, 2/3rd bridge port 6 port 13B, street port 13BT, (small) half bridge port 13BT, (small) half bridge port 13BT with NA intake, fullbridge 4-port 13B on ITBs. Those are the engines I have played with not counting the peripheral port 12A, if it's not there then I haven't built one!

A 4 port 13B has much smaller ports than a 13BT does. You would meet water most of the way around if you tried to make 4 port runners the same size as 13BT runners.

lastphaseofthis

iTrader: (8)

thanks guys, we got into on facebook local group, and to make matters worse 3 miss informed ******* think that 6 port bridges are the ****, and 4 port manifold flow better then 6 ports... im gonna let them find this thread on there own, until there are ready to look for the light they won't be able to handle the truth in this thread.

i though about using rx8 irons, with peri exhuast, and side exhaust.. the port runners are much bigger on the rx8..

Kenku

Any good testing to show actual power gain with the 9.4 rotors vs the 9.7 ones? And for that matter I'd like to see a 230whp streetport dyno graph. I'm not calling BS on either, I'm just trying to decide whether to use the pile of ex-EProd parts I have or to move on to T2/FD irons.

lastphaseofthis

iTrader: (8)

the 230rwhp street port is logans from defined auto works.. it was a 13b-re block with huge 4 ports.. and a really nice header, with more work i think that setup had 250 in it.

careful grouping turbo2 (13BT) irons with FD irons, they are not the same, completely different engines mainly the port angle.

Kenku

I was referring to BLUE TII's "I have seen 230rwhp out of small steetport S5 TII motors on stock intake" - I'm aware of Logan's engine, which wasn't a small streetport nor a TII, which is why I was curious if there was more evidence out there.

And what I meant was more, whichever of T2 or FD irons works better on the flowbench rather than mixing and matching necessarily, though unless I see anything weird in doing so I'm probably looking at 12A center iron. I'm DIYing an intake manifold no matter what so I'm not worried about the angle issue.

lastphaseofthis

iTrader: (8)

sweet, im making my own manifolds as well, starting with a 6 port shorty..
i hadn't seen the one blue is talking about so i look forward to seeing that...

BLUE TII

iTrader: (9)

I was referring to BLUE TII's "I have seen 230rwhp out of small steetport S5 TII motors on stock intake"

Was a Yawpower budget project if I remember correctly (so, some 10 years ago or more).

But I have seen a dyno of stock 13B-REW with turbos removed for header and tuning make over 200 as well.

So in this case I would start with the 13B-REW ports as a base.

Why stuck with 12A center? Or will you use 12A tall port center?

BLUE TII

iTrader: (9)

The Yawpower site is long gone (motor was in a September 2004 post apparently), but I found my earlier references to the motor from 9 years ago.

The motor only made 210rwhp not 230rwhp.

Cmon, I only added 20hp over 10 years of memory recall so it wasn't that bad of an exaggeration

Kenku

Oh, that one! I remember that.

Idea was the tall port center, yeah. Plus, at least for the irons I've seen, you can close a lot later on the 12A center irons than the EFI irons.

Suppose I'll have to come up with an adapter for work's flowbench, put together a pile of irons and test some stuff. Wish I had an engine dyno that would handle these sorts of tests - wouldn't it be awesome to do A/B testing?

BLUE TII

iTrader: (9)

I was surprised how many hits on NA 13B-REW I got on Yahoo.jp.co
I guess it is pretty popular.

This site alone has more NA 4 port dynos than you can shake a stick at!

Look at all em!

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BLUE TII

iTrader: (9)

Suppose I'll have to come up with an adapter for work's flowbench, put together a pile of irons and test some stuff. Wish I had an engine dyno that would handle these sorts of tests - wouldn't it be awesome to do A/B testing?

I would think flow bench and measure port exit velocity as well because the port has to punch hard for good chamber filling especially on late closing ports.

peejay

Anniversary Racing Factory are my heroes

I saved a bunch of their old videos, then they took the site down, now someone going by "ARFtaka" or something put a lot of them back up.

Kenku

Thank you, that is actually a pretty cool site. I never think of hitting the .co.jp sites for things like this. My ultimate idea for a flowbench would be to come up with a computer controlled touch probe / pitot and map velocity *everywhere* in the port to see where there's dead areas or places that need help, but that requires making some hardware from scratch. A handheld pitot really should be a given though, at least IMO.

Dak

Man, it's threads like this make me wish I could've used a TII or RE block when I did my rebuild.

BLUE TII

iTrader: (9)

I saved a bunch of their old videos, then they took the site down, now someone going by "ARFtaka" or something put a lot of them back up.

Takayuki Kato perhaps

Anniversary Racing Factory

A-RF HomePage

befarrer

iTrader: (1)

Wow, lots of information, so I guess I will look at swapping in my TII block in, I was mostly worried about the lower compression rotors, but I guess the better ports will make up for it, when the engine gets opened up, I can swap in higher compression rotors with 2mm seals at that time.

j9fd3s

iTrader: (3)

something changed, they used to sell a ton of cool stuff, but now they just resell Racing beat

j9fd3s

iTrader: (3)

me too, ive been really close to doing it too.