I removed the catalytic converters from my 87 N/A Friday and ran up to the muffler shop and had him put in a straight pipe and weld in O2 bung. The sound went from a good medium note to Ricer, sounds like a bumble bee. What exhaust out there will give a deep tone, but not loud, with no cats?

One thing I notice while under the car was that the O2 sensor was not hooked up, when I went to connect; I couldn’t find any wire to connect too. I’ve had this car for two years and it has run flawlessly. Do all rotaries run this good with out no O2 sensor? I get 18 -20 mi./gal average and like I said it runs smooth at all rpm’s.

 

as far as have no O2 sensor. that seems kind of funny...bcuz the engine wouldnt be giving the correct info to the ECU...

 

my apexi n1's have a deep sound, no matter where in the powerband, and they dont sound "ricer" and i have no cats. but then again, i've set off car alarms with this setup 3 or 4 times...lol

 

You would think so, as far as I can tell every thing looks stock, but I know it has to have been into, it has over 200k mi.

 

I know it’s hard to reduce the exhaust note on rotaries, but I was hoping some one had come across a remedy.

 

your engine will run fine without the o2 sensor hooked up. It just wont run as efficient. The ECU uses the o2 sensor while you are in closed loop mode with is very light throttle down to idle.

The connector for the O2 sensor should be on the END of the emmisions wire harness which raps around from the passenger side of the engine to the drivers side near the rear of the engine. It should have little square connector on a shielded wire.

What ype of muffs you have on now? Stockers?

I would reccomend you getting the muffs of your choice but go buy some resonators and of the mufflers shop install them before the muffs near the rear of the exhaust. If the resonators are fiberglass packed, they will help make the exhaust note a little deeper and much quieter.

 

Are you serious? I had the hardest time getting the local muffler shop to weld in my 50 mile used hi-flow cat. I had to pay in cash under the table it was so "illegal". ******* California.

I'm running with no O2 sensor ATM because I just put in my header yesterday and havn't figured out how to wire it up with the extension racing beat sent me with the header. It's running just fine. The thing I noticed was after about 15 minutes of engine running the Check Engine light comes on, but i'm sure that's just due to the O2 sensor not being plugged in.

I have a RB header to bonez hi-flow cat to Apexi N1. The N1 is deep bellow 4K RPM but my only complaint is it drones like a bitch from 3-3,500 RPM, it sucks. I'm going to try a silencer soon and see if it quites that drone down.

 

run an extra long high-flow resonator with magnaflow muffs...will give you that throaty deep tone...sounds oh so sweet...

 

Whatever mufflers you get, Id say run a Dynomax bullet muffler in the system somewhere. They help to deepen and quieten the note a good bit. Wouldnt hurt to run 2 really, they are only like $50 a piece. IMO the only way you will get a clean deep tone and not too loud is going RacingBeat system. Most every home build system Ive heard I havent liked.

 

I'll give the resonator or the Dynomax a try and yes i am running stockers.

I looked all over the harness; I think the O2 plug may be under the intake.

I had the pipe put in so to get the O2 bung away from the heat, so to install my wideband LC-1 O2 and Megasquirt plug-n-play from Zeal Engineering .

We have no emissions check in my county! Muffler shops don't mind as long as you remove it before you come to the shop.

 

yeah get a full racing beat exhaust. when my car is idleing i cant even tell its on but when i rev it up it sounds great. really u cant go wrong with racing beat. u bolt it on and never have to worry about exhaust again

 

The check engine light doesn't come on like I would expect it to. The light, lights up when you turn on the switch, like it should, then goes off after start.
It's hard to find the perfect exhaust on an rx7, is for me anyway. I've never had any problem find the sound I was looking for with piston engines.

 

I had a rb header no cats no presilencer just 2in from header, then went to 2in a quarter to my magnaflows. Not the cheap ones they were 400 bills each.. Oh yea it was all manderal bends too.
I have never heard a fc like mine ever!

 

Yea, I really didn't want to put that much into a setup.
Thanks to all for their input.