greensix

my car is 86 NA rx7..
i want to replace the heat exchanger with a straight pipe....
and there is a small pipe connected to the intake manifold is on the heat exhanger.......but there is no place for the small pipe to connect to the new straight pipe.....if i don't connect them...what will happen??...and will the 6PSI work???

myfc3s

iTrader: (2)

Well, you can get a block off plate. Or you can do a garage hook- up and plug a spark plug at the rubber end.

greensix

thx......
if i block the small pipe...any bad effect on the car????

myfc3s

iTrader: (2)

No, but if you have a TII and putting a straight pipe. You will need a FCD.

greensix

thx...and the length of the straight pipe of Turbo is different from that of NA??
or just the same.....coz i buy the straight pipe from a website of Japan...
and the RX-7s of japan are turbocharged...but mine is NA.......will it fit????

HAILERS

Your aux ports will not, cannot work without that *Relief air pipe* being connected to the *Heat exchanger* (catalytic converter). Or some OTHER source of pressurized air feeding it.

scrappyfc

below is a pic of my original cat (heat exchanger) next to a straight pipe/ decat i got from ebay, it was described as suitable for n/a or turbo but as you can see it won't fit the n/a, so be careful when buying, i'm going to measure before i buy in future.


the new pipe is 445mm(17.5in), maybe a turbo owner can tell us if it fits the turbo model.
i've decided to replace the original cat with the baffle removed, in the hope that i'll have more flow and still have aux port activation, it's also better for the visual part of emissions testing.
i won't really know how this will affect performance until i have it all put back together but i'll let you know when i do.

HAILERS

A 17.5" cat is the same size as one that fits a turbo car.

I'm kinda wondering if that is really a heatexchanger instead of a catalytic converter. I look at the jpg in the first post and it seems to be out of a factory manual, so I wonder why they would call a catalytic converter a heatexchanger.

Atually, if memory serves, I think 17.5" is the same for a non turbo main catalytic converter. I might go measure later. USA model anyway.

I also see they have the relief air pipe going to the rear of the car, whereas on a USA/Aus model it goes to a silencer in the right front fender.

misterstyx69

iTrader: (142)

If the "heat exchanger" is still in Good shape,what you can do Is HOLLOW IT out..and that would give you the Pipes you need to activate your aux ports.you could Also do this: get the flanges and make a Pipe that is BIGGER,but smaller at both ends,.so 2inch Flange(?..maybe 2 and 1/4 or 1/2..not sure,please measure) to 4 inch pipe to 2 inch flange..Drill a hole in the side of the 4 inch pipe and put the Small flange on for your "split air pipe"(that pipe that activates your Aux ports)..sort of what the catalytic converter used to look like but NOW it is a pipe!...What will happen is your Exhaust will be creating Back pressure in that pipe and therefore activate your Aux ports...I hope you get what I am trying to say..STYX....ah CRAP!.EDIT:it looks like that piece of Shiny pipe in the picture!..ahha!

HAILERS

Sorry, I made a bad reply in my threads above. Seemingly ALL wrong.

The place on the heat exchanger where you have HERE written in RED. That pipe is what supplys pressurized exhaust air to the aux port actuators to make them work (on a series four) .....USA VERSION.

Some other versions do not use that pipe for aux activation. They use VACUUM and a shutter valve. See the third jpg attached.

The Relief Air on a USA version, leaves the ACV and goes to a silencer in the right front fender, not to the rear of the car like shown in your picture. We have USA version cars and are not familiar with that setup.

It's the placement of that Relief Air Pipe that confused me. In fact still confuses me a bit.

Soooooo, if your car uses VACUUM and the Shutter type valves, then the exhaust does not effect 6PI operation.

HAILERS

.

greensix

thank you so much...
but i am still confused...
if i cannot connect the new straight to the intake manifold..,,
what will happen???
and i wanna know the reason that the heat exchanger is connected to the intake manifold..???

HAILERS

thank you so much...
but i am still confused...
if i cannot connect the new straight to the intake manifold..,,
what will happen???
and i wanna know the reason that the heat exchanger is connected to the intake manifold..???************************************* ************************************************** *******************************************

Ah. On a series four non turbo USA car, that small tube that connects to the heat exchanger(it's a Catalytic Converter in USA), is called a Split Air Pipe and carrys air from the ACV to the middle of the catalytic converter to mix with exhaust gas prior to part of the converter that neuters bad gas (best way for me to describe it).

On a USA car with a straight pipe in lieu of a catalytic converter, that small pipe can be left wide open. It effects nothing at all. NOT a vacuum leak of any sort.

Tell you what. I need to read that manual and find out if that is indeed a heat exchanger or catalytic converter on YOUR car. Most of us are not familiar with your set up. I'd be curious if you have the vacuum operated 6PI actuators or not. Look at the jpgs above and see if your car is like that i.e. with the shutter valve type actuators.

In case you missed it, it seems the straight pipes sold in the USA won't fit your car. That's what Scrappy FC indicates. The turbo and non turbo both use a 17.5 inch long straight pipe to replace the catalytic converter. YOUR heat exchanger seems to be a different length.

I should have looked up/read about the heat exchanger prior to posting. Gut tells me if you left that small pipe open to the atmosphere, nothing bad will happen. Later, maybe.

I've a feeling you do have a heat exchanger instead of a catalytic converter.

HAILERS

Tell you what. I read that Emisisons part of that manual for cars other than Austraila, and there's not any real information about that heat exchanger.

About that small pipe that connects to the heat exchanger...........I'd just get under the car and disconnect it and tie it out of the way with a piece of wire etc. Then drive the car for say fifty miles. See if you note a difference or not. I doubt you'll notice a thing. Leave it open. Don't plug the small pipe. Hmmm, might have to cap the small fitting coming off the heat exchanger though.

If I has that car, I would not put a straight pipe on it. I'd remvove the heat exchanger along with everything from it to the exhaust manifold (Includes the Recator). Then I"d install a header and exhaust pipe from RacingBeat or Mazdatrix. Unfortunaltley I think you'c come up with a slightly wrong length. You'd have to work around that.

greensix

thx for your detailed reply..really thank you so much..
yes...my car is "except Austraila" version..
i put the 'Y' pipe and mufflers of MAZDASPEED to my car....the 'Y' pipe is shorter than the original one and the buckles of the 'Y' pipe is different...but finally, i could install it with adjustment.....and as the 'Y' pipe is shorter...so the straight pipe does not fit...i have to process it to make it longer to fit....the length of the straight pipe is 14.5"......and i want to buy another new straight pipe with the small pipe that can connect to the intake manifold...for some reason, the new straight pipe will be sent to me about two months later...and i think i have to process it too.....the pics are the one i wanna buy.....and
why there are two small pipes beside the straight pipe??
i think that the bended smal pipe is used for connecting to the intake manifold..
and i have no idea about the small short pipe....

Turbonut

iTrader: (1)

Random Technology makes a converter with 2 "air pipes", but when installed the one not used is to be plugged.
Maybe this co. supplies the same pipe for various applications, so the one not used is to be plugged, same as above.

l4nc3r

Yes, in a S4 car, you need that red circled thing in your OP connected to operate your Aux Ports. In S5 cars, it is no longer needed as the Air Pump gives the pressure to open them. If you do get rid of that pipe, and not connect it, you will need to tie them open. You will lose lower end power, but you will keep the same upper end power.

So all in all, yes, you must keep that connected unless you plan on wiring open your aux ports.

ericgrau

iTrader: (1)

The "heat exchanger" is the catalytic converter. The 1986-1988 is the s4, the 1989-1992 is the s5. The auxillary ports close at low rpms for better low rpm power and fuel economy while they open at high rpms for better high rpm power. The s4 uses the exhaust to open the ports, the s5 uses the air pump. www.aaroncake.net has a guide to test if your auxillary ports are opening properly.

IMO do it right and make sure the ports are opening and closing. I wouldn't even wire them open, because then the low rpms suffer. If they won't open then the high rpm power you lose will be more than what you gain from removing the catalytic converter. So don't remove the catalytic converter without making sure the aux ports still work. What's the point? Besides using the exhaust, you could hook them up to the air pump or another electronically controlled method of activation. Search forums for more info.

One last thing: the auxillary ports are only for performance. They will not cause any problems whatsoever if they are stuck closed or stuck open or have trouble opening or w/e. So you can still drive while figuring everything out.

HAILERS

Uh. Some of you REALLY can't read.

He DOES NOT NEED THE PIPES IN THE DWG to operate HIS CARS aux actuators (6PI).

I posted the WORDS out of the Training Manual and also posted PICTURES/DWGS of HIS cars method of operating the 6PI.

What is it about SHUTTER VALVE that is not understood? The SHUTTER VALVE is VACUUM OPERATED. The SHUTTER VALVE operated HIS verison of the 86 RX-7's 6PI. See pictures above. Post number 11.

And I doubt very much that the HEAT EXCHANGER is a catalytic converter.

greensix

i think you really understand the model of my car...
i find out something strange in the manual, the EGR system which is to inject the some exhaust gas to the intake manifold to reduce CO and NOx....the manual shows no EGR system is in my RX-7(except for Austraila)...but why there is still a connection between the intake manifold and heat exchanger?? i think it is a
"Simple" EGR system of my Rx-7.....For Austraila model..ECU controls the amount of exhaust gas that is injected to the intake manifold...For my Rx-7, maybe ECU does not control that...the amount of exhaust gas injected to the intake manifold is regulated by Relief Air Pipe(the pipe beside the main silencer)...i think thats why no Relief Air Pipe is in Australia model....am i right??

If no exhaust gas is injected to the intake manifold??what will happen on rotary engine??

HAILERS

No EGR or a non working EGR has no effect that I know of. The series five does NOT have a EGR at all. Mines been removed on my series four and I pass state required emissions easily. To be specific, the NOX is waaaaaay down there and not even close to not passing.

Ah! I just looked at your chart. That confirms that you have no catalytic converter and do have a Heat Exchanger. Plus it makes honorable mention your car has no aux port valve but has the shutter valve.

And you have the distributor instead of the CAS arrangement

You also have no pressure sensor (boost sensor in Mazda jargon).

Seeing as how you have a Air Control Valve, It makes me believe that the pipe connected to the heat exchanger apes what the USA versions do, it dumps air out that pipe when the ACV selects that passage. On a USA version, the air from the airpump goes to the ACV. That air is then sent to the exhaust PORTS. The exhaust ports being where the mulitport inserts are located. About two inches from where the engine and exhaust manifold meet eachother. It mixes that fresh airpump air with the exhaust gasses coming out the engine. It does that so the afr will be closer to 14.7 prior to getting to the catalytic converter. There's honoraboe mention in that Training Manual that the catalytic converter works best when the gases going into it are in the 14.7 afr range.

Anyway, once driving, the ACV at times deslects the air going to the exhaust ports and selects the split air pipe instead. Like on a USA version, when you go to fifth gear, the Split air solenoid on the ACV, opens a passage to the split air pipe. The again, when driving for something like 120 seconds or so, the ACV dumps the air into a *silencer* (USA) in the right front fender. On your car it SEEMS to dump it using a pipe that runs on the left side of the exaust system.

Anyway, the pipe that is connected to the heat exchanger, I would wager, could be vented to atmosphere and you'd never know it while driving.

I doubt any USA or Aus exhaust parts will fit your car without some modification.

greensix

do i need to block the pipe connecting to the heat exchanger????