Apex944

iTrader: (10)

I've been searching around for days now trying to figure out the ACV and EGR setups between the S4 n/a rotor housings and the S4 turbo rotor housings.

I am ready to put my engine back together, except I have S4 n/a rotor housings instead of S4 turbo rotor housings. I got a good deal on them and was told there were only 2 differences. I sort of ran out of money and would like to finally get my engine back together ASAP.

I learned about the ACV having something to do with pumping air into the exhaust port for emissions purposes.
Does it only pump air into the rear rotor housing?
Or does it pump air into the front rotor housing?

I only see one hole in my exhaust manifold gasket so it's either one or the other....

I also learned that the passageways for the n/a and turbo rotor housings are different as well. I dont have any turbo housings to compare to so i'm sort of stuck.
Is there anyway I can re-drill holes to make the S4 n/a housing passageways work like S4 turbo housing passageways?


Also, does the EGR get the exhaust gases from the housing passageway's as well?

I know I have to drill out the water jacket for my turbo water line and o-ring it for an o-ring as well as swapping the exhaust sleeves.



My main concern is passing california emissions, which includes an EGR test, charcoal canister test, visual, and of course the readings from the sniffer.

I dont care if it will destroy my cat converter or anything like that. I will be replacing it with a dummy cat after I pass emissions.

Thanks for any help

HAILERS

The single hole in the exhaust gasket feeds exhaust gas back into the engine for the EGR. (EDIT: and if you mixed na rotor housings with a Turbo intermediate housing, that won't work because of the internal passages in the rotor housings).

TURBO, series four, feed the air from the ACV, past the round spoked checkvalve, into the intermediate housing, straight down that intermediate housing thru a cast air passage, and that air exits the intermediate housing at the very bottom at two somewhat triangular openings, one in the front of the housing, one at the rear of the housing. Those two triangular passages mate with two similar passages on the Rotor houisngs.

That somewhat triangular passage in the Rotor housings has a drilled passage that leads directly to the sleeves in the exhaust PORTS.

The non turo is different. The ACV air goes past the round spoked checkvalve, to passages inside the intake manifold. One passage goes to the rear side housing, the other to the front side housing. It enters those side housings thru a somewhat triangular hole below the intake ports on those side housings. Then the air goes straight down in a cast passage in the side housing to the very bottom of each side housing. There it exits at a somewhat triangular hole in the side housings and enters a similar hole in the adjacent Rotor housing. In that triangular hole in the Rotor housings, it enters a hole of approx 1/2" size that leads to the exhaust port sleeves.

Tell you what. Pick up in your hands one of your old ROTOR housings. Look at them. Look at them as if looking fwd at the housing, and with the exhaust side to your right. Look at the bottom right on the housing. There is a passage there somewhat triangular in appearrance. With a light source, look in that passage and you'll see a hole slanting upwards toward the exhaust port. That half inch hole leads to the exhaust port/sleeves and mixes ACV air with exhaust gasses.

The KEY here, is that if you have a REAR TURBO ROTOR housing in your hand, the half inch hole will be in the fwd side of that trangular hole. If you have a non turbo REAR ROTOR HOUSING, that half inch hole will be in the aft side of the rotor housing.

Bottom line, this means if you have a TURBO intermediate housing mated witha non turbo ROTOR housing, there is no passage to the exhaust ports. The hole is in the other side of the rotor housing.

Non of the above makes sense just trying to figure out what the hell I just wrote, but if you hold one in your hand and look, it makes sense. The half inch hole that leads to the exhaust ports will be on the wrong side of the rotor housing if you mix Turbo intermediate housings with non turbo ROTOR housings.

I think I just wasted ten minutes of pecking on the keyboard. Gone. (I'll take a picute someday)

HAILERS

If you picked up a FRONT ROTOR housing, and you looked either fwd or aft at it, at the very bottom on the exhaust port side of the housing, you would see the triangular passage shown in the attached jpg.

On a TURBO engine, this hole has a upwards half inch hole that leads to the exhaust port. On the FRONT rotor housing of a turbo engine, this half inch passage is on the aft side of the rotor housing. On the REAR rotor housing of a turbo engine, this half inch hole inside the triangular passage, is on the FWD side of the rotor housing.

Now there is a triangular hole on each side of the two rotor housings. What is different is that only one of those triangular passages on a rotor housing will have the half inch hole inside it, leading to the exhaust port.

ON a NON TURBO engine, the half inch hole in the triangular passage is on the opposite side of the rotor housing. So on a non turo engine using a Turbo intermediate housing, things won't work because the half inch hole leading to the exhaust port is.........on the other side of that given housing. The intermediate housings outlet passage for the ACV air, will be dead ended in the rotor housing.

I suppose you could just put the F rotor housing in the A positon and vice versa and things would then work out.

But then you need to think about the hole for the EGR gas. I forget if things would work out for that or not. Later maybe.

Apex944

iTrader: (10)

That actually makes alot of sense.
I've been studying and trying to figure these things out for a while.

I see now how it all works.



Thank you very much HAILERS

Apex944

iTrader: (10)

OK, I am comparing my S5 turbo rotor housings that I have laying here to my S4 n/a rotor housings.
They are identical.
The holes are in the same spots on the same sides of the housings.

Are the S5 turbo rotor housings different from the S4 turbo rotor housings other than the spark plug locations and knock sensor holes?

Pics...

Front of Front rotor housing


Rear of Front rotor housing


Front of Rear rotor housing


Rear of Rear rotor housing


Thanks again

HAILERS

On a Turbo engine, the path of the ACV air, from the intake manifold, follows the path I outlined in this jpg attached. Enters the rectangular hole.....then travels straight down a passage internal to the Intermediate housing......exits at the triangular hole shown in my post before this post, and goes up inside that trangular passage in the Rotor houising to the exhaust ports.

ON a non turbo, it ain't like this. There is NO triangular passage on a series four non turbo engine in the intermediate housing (series five is different) for the ACV air. There is a round freeze plug in that location instead.

HAILERS

On a non turbo engine, the ACV air enters the two holes shown in the attached jpg. Goes straight down in the rear and front side housings to a trangular shaped hole at the bottom, then enters a like triangular hole in the ROTOR housings, then travels up a half inch hole into the exhaust ports.

HAILERS

I think just swapping the front rotor housing to the rear and rear to the front would solve the triangular ACV passage issue.

I've still to think about the EGR thing. The EGR gets fed from one of the two half inch holes below the exhaust ports. I can't remember enough to say whether swapping the front rotor housing to the rear would make this work or not. Depends a bit on where that hole is in the exhaust Gasket.

Apex944

iTrader: (10)

This is very helpful information, thanks again

Also, I forgot to mention that the engine I am building is a 4 port S4 turbo engine.
Which means S4 turbo intake manifolds, side housings/irons, 8.5:1 rotors, etc...

HAILERS

The gasket in the picture in this above post is from a non turbo six port engine. And the holes I pointed to are for a non turo acv passage. I do realize your building a turbo engine up but using non turbo ROTOR housings. I think everything else is turbo in your rebuilt engine. Only the rotor housings are different. Right?????????? You used non turbo housings .....probably because you had them handy and the turbo rotor housings were trash.

Apex944

iTrader: (10)

Yep, everything im using is turbo other than the rotor housings.
Paid 3/4 of the price for new S4 n/a housings and figured they were the same other than exhaust sleeves and the water port for the turbo.

I just did a mock up with the side housings/irons and both pairs of rotor housings.
Everything lines/matches up perfectly.

What I dont understand is how the EGR port on the rear rotor housing gets exhaust gas. I put the gasket on and had the hole on the rear rotor housing but when I go to match up the exhaust manifold the hole is covered by the exhaust manifold.

slo

iTrader: (1)

You don't actually need EGR functional to pass the sniffer test, the car will still have low enough NOX to pass.

My question is how do they test the EGR valve?

Do they actually test it?

Never seen them test it before on any car I had that actually had the valve, they just inspect to see that its present if its visible.

You also don't actually need the port air injection to be functional.

I have passed several times without that.

Apex944

iTrader: (10)

They dont test it because they are not allowed to disconnect/disassemble anything on the car.
They can only do a visual and put the sniffer in the tail pipe.
The only thing they can touch is the EVAP/charcoal canister to test it.

I can't beleive I wasnt thinking about that until now...

Thanks for all the help guys

HAILERS

What I dont understand is how the EGR port on the rear rotor housing gets exhaust gas. I put the gasket on and had the hole on the rear rotor housing but when I go to match up the exhaust manifold the hole is covered by the exhaust manifold.
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Let's beat this horse to death.

It sounds like you don't have a TURBO exhaust gasket, but instead a NON turbo exhaust gasket.

The turbo exhaust gasket should match the exhaust manifold, where the *HOLE* for the EGR in the gasket, will match the EGR hole in the manifold. In turn, that *hole* should match the REAR of the two half inch holes below the exhaust port in the Rear Rotor housing.

If the EGR hole in the gasket matches the FWD EGR hole in the rear Rotor housing, then the gasket is a NON TURBO exhaust gasket. On the non turbo engines, it's the fwd hole, of the two holes below the rear exhaust port, that feeds the EGR, on a seies four engine.

Like I said earlier, the path for the EGR and Port air is different on Turbo vs Non Turbo series four engines.

On a series four Turbo, rear side housing, if you blow thru the REAR half inch hole below the exhaust port, the air you blow will exit up above just below the intake port. It'll exit a small irregular hole below the intake port. That irregular hole matches a similar hole on the intake manifold and leads to the EGR which is mounted on the aft end of the intake manifold.

That said, a EGR has little use on a RX-7. I've Turbo and non turbo engines with a sheet of metal b/t the EGR and the manifold (blocked off EGR) and pass emissions each year and the nox is almost zip, or at least a mere percentage of what is allowed.

Now that that is said, there is a guy called RXTASY who has a post on the other forum (Team FC3S, non turbo forum) who I believe said the emissons tester said his EGR wasn't working and he had tried three or so other EGR and none worked. I asked how the *tester guy* knew they did not work and didn't get an answer. I'm still wondering how a *test guy*would know if it worked or not.

By the way, when you matched things up, was that with the front rotor housing in the rear and the rear housing in the front or?????

HAILERS

Look at the gaskets at this site. Look at the Non Turbo then the Turbo exhaust gaskets. You have to flip the TURBO gasket in your mind because it's shown at this site as if looking towards the exhaust MANIFOLD instead of looking towards the engine.

See how the non turbo EGR hole would mate with the fwd of the two holes below the exhaust port, while the TURBO gaskets EGR hole will mate with the rear of the two holes below the exhaust port.

http://www.mazdatrix.com/e6.htm

Attached two jpg. The first is the TURBO gasket, but it needs to be flipped around in your mind so the EGR hole is on the left as you look towards the engine.

Second jpg is NON TURBO gasket viewed looking towards the engine.

Apex944

iTrader: (10)

I matched up the rear half of the engine.
Rear iron + rear rotor housing + middle iron

Everything matched up just like you said it should if they were turbo rotor housings.

It was quite weird, because the housings were both S4 n/a and both had the coolant passages blocked off. But the triangular holes on the sides of the rotor housings were designed like a S4 turbo rotor housings.

Meaning that the EGR passage only had the 1 rear hole for the exhaust gas to be sucked in though on the rear rotor housing. The triangle shape on the front of the rear rotor housing had 2 holes, the top for the ACV and the bottom to exit the passage into the exhaust stream.

The front rotor housing was the same way, except setup like a S4 turbo rotor housings should be. The front triangle side peice had only 1 hole and the rear side of the rotor housing had 2 holes, 1 on top for the ACV feed and 1 to exit the passage into the exhaust stream.


What I meant by my EGR not ligning up is that when the gasket is on the rear rotor housing, it lines up with the correct rear hole.
But when I go to put the exhaust manifold on, the exhaust manifold covers up that hole. The exhaust manifold only has the 2 large holes for the exhaust from the rotor housings. No other holes are on the manifold.


So yeah, the 2 rotor housings I have work just like you said a S4 turbo rotor housing should. I just need to drill out the hole for the coolant passage on the rear rotor housing and o-ring it for the rubber o-ring and then swap the exhaust sleeves and im ready to go.


Thanks again for all of the help

HAILERS

What I meant by my EGR not ligning up is that when the gasket is on the rear rotor housing, it lines up with the correct rear hole.
But when I go to put the exhaust manifold on, the exhaust manifold covers up that hole. The exhaust manifold only has the 2 large holes for the exhaust from the rotor housings. No other holes are on the manifold.
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It sounds like you have a series five trubo/exhaust manufold on your series four car. If you have no twin scroll actuator on the exhaust maniflod, then that is what is happening.

If you do have the twin scroll acutator..........then look to see if someone has welded up that EGR hole. That's the only explanation I can come up with.

Then again, like was mentioned in another post, the engine will pass the nox without a EGR valve easily, so the lack of a passage to the EGR is moot.

HAILERS

Here's a jpg stolen off this site showing the series four EGR manifold hole.

Apex944

iTrader: (10)

Yep, my S4 twin scroll exhaust manifold does not have that hole in it.
It does'nt look like it was welded shut either, it's like it was cast without a hole.


Thanks again

pfsantos

iTrader: (1)

To test the EGR system, one would generally apply vacuum to the valve directly. Since on our cars the EGR valve is not too accessible (on NA's anyway), one would have to apply vacuum to the pipe that leads to the valve near the EGR solenoid. I doubt a lot of emmissions testers would know where to apply vacuum in our case.

Edit: The engine should run rough or stall at idle with the EGR under vacuum.

HAILERS

Answer me this, does your turbo have the twin scroll Actuator???? And if you have the turbo off the exhaust manifold, do both the exhaust openings in that exhaust Manifold (where the turbo mounts to the exhaust manifold) have the same shape/size?????? They should be oval in shape. The series four has one opening not as long as the other opening. On a series five the oval openings are the same size/height/length.

It's still a moot point in a sense, since the engine will pass NOX easily without a EGR. As you know, the series five had no EGR at all.

I'm just curious why yours has no hole in the exhaust manifold where it mates with the rear rotor housing. As I said, if it's a series five manifold, it will have no EGR hole but it also won't have a twin scroll Switching actuator and linkage on the manifold.

The signal to the EGR can be checked using a common LED attached to the EGR soleniods input wire from the ECU and watching it while driving. It will NOT function (unless you trick it with a vacuum hose) in the driveway at all or the inspection station unless on rollers and in gear.

Here's a series five exhaust manifold. Pay no attention to the numbers etc. You can faintly see where the EGR hole impression was left on this manifold when it was attached to the series four engine at one time.


T-34 with German Markings attached as a distraction from the subject. Kite surfer thrown if for fun.

HAILERS

I made some errors in what I wrote above. Here is a series four manifold in the jpgs.

Apex944

iTrader: (10)

Yeah, I know the difference between the S4 and S5 turbochargers and the other major differences.

Here are the pictures of my S4 exhaust manifold.....





And yes, I removed the twin scroll setup because I did not want to deal with its issues and it is only temporary until I order my Stage 2 BNR turbocharger in a few months.

HAILERS

Darn if I know why it's not there. I was just curious, like they say, it isn't needed anyway (EGR functional).

Howru

iTrader: (25)

I've got a similar problem. I need to replace an S4 TII rear rotor housing and got a few N/A housings leftover. Coolant passage and sleeves will be swapped, as needed.

Is it as simple as swapping the positions of the N/A housings for use in the TII (N/A front->TII rear) or am I just reading this wrong?