I took off my stock exhaust manifold and the cats. I noticed my header+presilencer is shorter than the stock stuff (previously had been used in a custom application). Also, the presilencer bolts were closer together than stock.



Anyway, exhaust guy cuts header off where it connects to presilencer, tells me to go ahead and put that on my car, and drive back there with just the header on. Then he'll rig up the presilencer to fit.



Additionally, he says he will need to eliminate the tube that went to the main cat. Do I need this to activate the 2ndary ports? Or does the backpressure activate the ports some other way?



I would really like to keep my secondary ports functional.

also, what's with that little hole by the lower-left mounting bolt where the exhaust meets the engine? the racing beat header just blocks it off

Sorry, I'm no help with this.. but, why'd the guy cut off a piece of the header?

so he could create a sleeve (?) to affix it to the presilencer (?)



he does a lot of [illegal] exhaust stuff, so he seems to know what he's doing, I just can't understand all the words that come out of his mouth

Oh ok.. Tell him to speak english..

you need that tube, it's what provides the little tube on the lower intake manifold with exhaust for actuating the aux ports.



sounds like you found a hillbilly with a torch.

try contacting the manufacture if nothing else it will be reliable info!!!!!

Yea, really.. beware who you take your car to. Never know what they [illegally] did to it..

you can use your air pump to actuate the 6 ports. what is the header from? racing beat?



mike

i want headers. I called a shop and they said that if i want to o2 sensor i have to pay $220 instead of 187 cause they got to make a hole in it for the o2 sensor is that true.

?

I thought with an s4 the aux. ports are activated by back pressure? or are you talking about rigging it some other way?



yes it's from racing beat, but the previous owner of it fit it to a 13b on a 1st gen, so it came up a little short...that's what I get for saving a buck https://www.nopistons.com/forums/pub...#>/biggrin.png

I thought with an s4 the aux. ports are activated by back pressure? or are you talking about rigging it some other way?



yes it's from racing beat, but the previous owner of it fit it to a 13b on a 1st gen, so it came up a little short...that's what I get for saving a buck https://www.nopistons.com/forums/pub...#>/biggrin.png [/quote]

you can hook up your siz ports to the air pump, basically making like an 89



mike

I thought with an s4 the aux. ports are activated by back pressure? or are you talking about rigging it some other way?



yes it's from racing beat, but the previous owner of it fit it to a 13b on a 1st gen, so it came up a little short...that's what I get for saving a buck https://www.nopistons.com/forums/pub...#>/biggrin.png [/quote]

you can hook up your siz ports to the air pump, basically making like an 89



mike [/quote]

ok, I'll let him ditch the pump pipe, but you're going to have to help me out with this later



edit: make that as soon as possible, I'd like to be done with this by Monday, if possible....like, how do you get them to open only at a certain rpm? and what exactly do I do to get the air pump hooked up to the 6 port actuators?



it pretty much ran like crap when I took it for a loud spin around the block, I don't know where the low end power went (secondaries should have been closed)

http://www.teamfc3s.org/forum/showthread.p...p?threadid=3712



just read the first post, after that it gets confusing fast



mike

Why don't you just buy the RB header and presilencer?

I think he was trying to be frugal.

yes, I was trying to be frugal



update: I went to get the job done, and let me say, the drive there was very loud (header only)



the guy who cut it off on Friday wasn't there, it was a different guy



new guy, let's call him tim, welds the the flange that connected the presilencer to the header back on (where other guy cut it off), along with the presilencer bolted on



the presilencer came up short to the y-pipe, so he welded a length of pipe between the y-pipe and the presilencer



he cut the nozzle off of the old main cat that the air pump leads to, and welded it to the length of pipe behind the presilencer...if I want to use this, all I'll have to do is get a slightly longer hose that connects the air pipe to the engine



from what I've read before, the stock catback would have enough pressure to activate the secondary ports, correct? (assuming everything moves smoothly)



so I can re-attach the air pipe to activate secondary ports, lose the air pump and get dual alt pulley, and do I keep the acv for this application?



the reason I have to go through all this is the seller didn't tell me it would come up short until after I received it in the mail, and I didn't feel like returning it

on the rx7.com website they use a peice of rubber hose between the bonez cats and the stock air pipe. so you could cut the stock air pipe and put a piece of hose in there, its one option.



and yes you can ditch the acv



mike

So how do you like the header now that it's installed?

Why don't you just buy the RB header and presilencer? [/quote]

I was going to get the RB header/presilencer pack but the RX7store had a back order from hell on them.. so, I just told them to forget about it.

It sounds great compared to all stock, but I have yet to reattach the air tube this weekend, so I'm sure that has an effect (in addition to not opening secondaries).



I'm not sure if I notice the power difference, but I have yet to go all out with it installed. And I'm sure the stock catback has an effect on the power. I will get the rest of the RB system later, hopefully.

that little hole where the header meets the engine is what activates the aux ports. Reconnecting that pipe that runs to the cat won't do **** for the ports, it's there to pump air into the cats. Why does everyone think it's for the aux's?

what?

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (rotary>piston @ Mar 17 2003, 03:02 AM)</td></tr><tr><td id='QUOTE'> that little hole where the header meets the engine is what activates the aux ports. Reconnecting that pipe that runs to the cat won't do **** for the ports, it's there to pump air into the cats. Why does everyone think it's for the aux's? [/quote]

https://www.nopistons.com/forums/pub...1047683561.gif



well, you obviously don't have any idea what you're talking about.





see the tube running along the bottom of the LIM here, it's on the top of the LIM in the pic due to it being oriented upside down. Note this thread is in the context of S4 NA, and so are these pictures:



http://pengaru.com/~swivel/cars/rx-7...2/IMG_1485.JPG



that tube, goes to both sides of the LIM, with banjo fittings connecting them to passages that lead to the auxillary port actuators.



Now, that tube also has a inlet tube, which branches out from it here:



http://pengaru.com/~swivel/cars/rx-7...2/IMG_1487.JPG



See the inlet sticking out toward the lower left of the picture? Thats part of the same system, and that inlet connects to the rubber hose that forks off from the split air pipe. Thats the same pipe you claim is only there for injecting air into the catalytic converter. Bzzt, wrong.



And here you can sortof see the banjo fitting (at least the bolt that screws it into the LIM stickign out the side) and the rest of the tube...



http://pengaru.com/~swivel/cars/rx-7...2/IMG_1489.JPG



There is also a check valve in the split air tube, it is after the fork for the rubber hose that provides the exhaust gases to this litle tube under the LIM... so this tube sees exhaust gas/pressure. The check valve prevents the exhaust gas from going to the AC&CV though only permitting air to be pumped into it when the AC&CV wants the air pump air to go into the catalytic converter.



so, as you can see, that hole you refer to has nothing to do with aux port actuation.

cool...thanks for that thorough explanation, it puts things in perspective, and puts some of my questions to rest about the airpump/acv/secondary intake issue

no problem, the emissions related stuff on this thing can get confusing. There are alot of passages integrated into the LIM and engine housings that many people misunderstand.



If you inspect your LIM while it's off the car and try blowing through various ports with the AC&CV removed it will likely help clear some things up... some things to note that arent entirely obvious are:

There are holes in the exhaust port sleeves inside the rotor housings, those holes provide an exhaust interface to passages *inside* the rotor housings, from the rotor housings the passages continue into the intermediate and side housings. The details vary depending on the series, S5 has no EGR valve on the intermediate but does have an exhaust port under the primary intake ports where S4 does have the EGR valve (utilizing this exhaust interface) but does not have the additional port under the primary intake ports. Both S4 and S5 have exhaust ports under the secondary intake ports. If you look at your LIM on the face that mates with the engine there are weird shaped ports under the secondary intake runner ports. Those holse match up with exhaust ports on the end housings... they provide an interface into the exhaust via the aforementioned passages, into the exhaust port sleeves. The hole mentioned before by rotary>piston is also an interface into the same system that normally goes into the stock manifold... you have it blocked with a header. But the holes in the sleeves still remain.



The purpose of these ports interfacing with the exhaust system on the LIM is for the AC&CV... if you blow in the holes you will find the pressure escaping from where the AC&CV was, provided you have it removed and not blocked.. if it's blocked off you won't be able to blow if you plug up the other holes that would meet up with the engine for the experiment.



You can also observe where the tube exiting the rear of the LIM (where the split air pipe connects after the check valve) ends up leading to internally, by blowing in it with no AC&CV installed and no blockoff plate. The AC&CV controls a handful of junk, but once you have blocked it off with a plate these passages are all meaningless.... because they all meet at the AC&CV.



The above was typed from memory so some of the details may be off slightly, you can confirm this stuff for yourself easily though by just blowing in various holes in a LIM while plugging other various holes... it can be quite fun actually and helps get a clear picture of what all goes on inside that piece of cast aluminum... defininitely a recommended activity for those curious. You might want to find a way to do it without using your mouth though https://www.nopistons.com/forums/pub...R#>/tongue.png



fortunately for you, the aux ports are completely independant of this mess...

good to know...I recently had the LIM off, hopefully I won't have it off again for a long time, but I'll take your word for it



I just try to do everything right the first time, so I want to be sure I'm not blocking something that needs to be opened, or leaving something that should be removed, or open something that should remain shut...you get the idea. I think I'm doing good so far.

get that split air pipe connected back up so you can tell us how she feels up top with the header https://www.nopistons.com/forums/pub...#>/biggrin.png , it should be noticably quicker at least in the upper rpm... with aux ports functioning though.

I was going to get the old rubber hose off that connects the air pipe, so I could get the correct replacement pipe size. I couldn't get it off yesterday, as pathetic as that sounds, but hopefully I'll get it today.

ok, it took some clever bending to get the split air pipe to fit in again, but it's in. I attached the vacuum hose, but the larger rubber hose (I used heater hose) kept kinking and flattening...but I don't really need that, do I? I mean, judging by other info, now I only need the small hose leading to the LIM, right?



and it never opened my aux ports...I think the air pipe isn't sitting flush and is leaking air, but I'll figure something out this week

oh, and I never saw flames...at night, with Edna revving it to hell... https://www.nopistons.com/forums/pub..._DIR#>/sad.png

no flames? that sucks richen the fuel mixture a little

um...how?