I'm new to this whole rotary engine thing ( but I have a pretty good amount of expierence in dealing with V8's), I was wondering if i could Run headers/straight pipes, AND PUT A NEW INTAKE MANIFOLD on my 88 Rx-7 convertible (non turbo) with out having to change the ecu, also i was wondering what emissions related things i could remove from the engine and still run it safely (i would like to take out the a.c. for sure), because i believe i have read something about the exhaust needing back pressure to operate some actuators or something like that, also i live in a county in Wisconsin where i don't have to have emissions checked, so i can pretty much do whatever i want with the exhaust

Thanks for any help!
Tom H.

 

You would be scared to rev up your engine let alone drive it much if you did that.. you need at least a stainless steal muffler or presilencer.

 

Im not very worried about it being loud, i just want to know if it will mess up anything on the engine (throw sensors out of whack and that kind of thing), i have a 87 camaro with a "decently" built 350, (about 340hp) and the exhaust consists of the headers, and thats it, nothing else, i drive it everywhere, and ive only ever gotten one warning for it, i said my exhaust fell off on the freeway, but i am still wondering about what all emissions things i can remove and still have a totally drivable car

 

You will have to remove the ACV(air control valve) and the air pump. Once removing the air pump you will have to either buy a "yohoo" belt or a double pully for the alternator (so the waterpump wont slip). Also you will have to buy a block off plate for the ACV.

 

the search button is your best friend!

you dont *need* a dual pulley for your alt. i run without one and have no problems yet.

just go to the 2nd gen tech and search around. you will find your awnsers!

 

You need a muffler. You don't understand how loud it is going to be.

 

When your asked to leave the raceway park cause your exaust is makeing peoples ears bleed then there might be a prob. You may not have emmisions, but i am willing to bet that you still have a sound ordinance law, Much like we do in Idaho. But sence your new to rotary you dont know just how loud they can be.

 

hehehehe yeah i remember my first 7 and the strait pipe accident............ the pain oh it hurrt sooooo bad! lol

 

You don't understand that the rotary engine rapidly expels 1700F hot gasses directly out of the exhaust ports, similar to a turbine engine. Even racing RX-7's need a sound suppression device to stay within the 113 dB IMSA sound limit. I have a magazine article about one of the La Carrera Classic rally events in which the other drivers were warned that the RX-7's exhaust noise could crack their windshields.

Anyway, the optimal header pipe inside diameter is 1.7-1.8" collected at 22-27" or uncollected if you want dual exhaust. Do not use a balance pipe. You can keep the same exhaust diameter, or gradually increase the diameter. Make sure you use 1/2" plate for the one-piece header flange. Thick pipe will last longer and also help reduce the noise level. You will need a quality muffler rated for rotary engines (Racing Beat, Apexi, HKS, etc.) as the cheapie non-rotary engine stuff with the spot-welded baffles (Flowmaster) will blow out in as little as a week.

FC emissions removal thread:
https://www.rx7club.com/forum/showth...hreadid=112251

Why would you replace the decent stock intake manifold but not replace the horrid stock ECU? Anyhow, the stock ECU will continue to act like its awful self even with a modified exhaust system, but the intake manifold may affect things depending on the design. You do realize that you need to keep the stock AFM when using the stock ECU, right?

 

Alright, if i need a muffler, what kind of muffeler should i buy (i just want the muffler's not the exhaust), i have a guy who is going to do me some stainless straight pipes, from what i have read must mufflers wont hold up, i could reuse my stock mufflers, but they are pretty bad shape, also is it true if i put straight pipes on my car that it will have no low end power, and will idle horribly, also i was reading in another post that when you remove your stock exhaust manifold, and acv valve, you have to rig up something for the acv valve, what does one need to rig up to have it work properly? As far as modifying the ecu, i have no expiernce programming ecu's, or dealing with them, the most i have ever done with a cars ecu was adding a ecu programmer, that had 4 levels of performance options, (if there was one that was pretty simple to use i could probably do it, something that had the stock ecu settings pre programmed and i could just modify the settings from there), otherwise any other car that i have built up has been a 5.0, or 5.7 chevy, so i dont have much expierence with japenese cars