Okay I've had my RX-7 for about 7 months now and I still don't know what this is. It is a deep, low exhaust note that sounds like a sub pounding at 60hz. It comes when my foot isn't on the gas or off it, like in the middle keeping the rmps steady. It sounds best at 2700-3300 rpms. Is it a rotary thing, turbo thing, or my exhaust. I have stock turbo, with 2.5" downpipe and midpipe, with Borla Cat-Back. Tenzo intake and Greddy BOV are also installed but I don't think that has anything to do w/ it. I have a cat on the midpipe right now, before that it was REALLY loud. Now it sounds a little muffled. My airpump belt is cut, I only had the airpump on for one day for emissions so I don't remeber if it was still there when it was on. Past 3400 it kind of fades out b/c it starts to get higher pitched. Am I just that big of a newbie or is this something different?

 

your a newbie dude..... rotarys are loud with no cats.... i call that loud noise... the drone zone

 

Sounds like the 3000 RPM resonance. It’s more common on systems with exhaust mods.

 

Ya, it's VERY intimidating, I love doing it to ricers, i thought it was common but too scared to ask, didn't want to be called a newbie, oh well. I mean what other cars can do such a thing?? Like I like to do this rise to 3000 slowly let is blow for about 2-3 seconds, then punch it to 4500 chirp second hard and let off, all without boosting. The ricers run scared...ahhh that chevy corsica with that gay *** wing!!!

 

augh ricified cosica... only thing that gets worse than riceified rice is riceified domestic cars. If you want your domestic car to look like an import, buy an import.

glad i have a rare car

 

Ever have anyone ask why it sounds like your car isn't running right. Then you tell them it's a Rotory and they don't know what to say.

 

Mine does the same thing in between on and off throttle. Sometimes on a full throttle upshift I get a loud backfire too. The neighbors love it!

 

I love making my car backfire right next to other cars.

waaaaaaah!!! POP!

It's even more cool when you're in a tunnel and the top is down.

 

I baked a newer MR2 turbo at night back about a year ago, when my car was hardcore N/A, with almost straight through exhaust.
I was behind him on a single lane road (very dark) and we were both racing, I passed him in the opposite lane, and just as I pulled back into his lane, I was redlined in 4rth and shifted to 5th. I got a fantastic backfire and I saw the front of his car light up in my mirrors!! The flames must have looked fantastic and intimidating... I know if a jet black car that should be slower than mine rocked me, then blew flames in my face as he passed, I would be in awe!!!!

 

Hey everyone, I'm new on the boards. JAPSPECGTUs
, I've been reading a little bit on car parts off of MazdaTrix's web site ( http://www.mazdatrix.com/c-5.htm ) , and they have a description for a symptom with the shutter valve on 81-85 cars with that deep exhaust noise you're having. I don't know for sure if our cars have that valve but it may be something you might want to look into.

Also, for your backfire skyypilot and mykl, that website url I listed above states your air control valve may need to be cleaned or replaced.

Hope all this helps. Hope our cars don't bring us too much trouble

-Ryan

 

Later this year I will be installing full flamethrower exhaust on my car. Liquid Propane. I hope to get big blue flames out of my tailpipes. I already have the first parts rounded up......

 

It says this is indicative of a problem for 79-80 models. Mine is '91. It doesn't seem to happen all the time either.....

 

Well I have an 89 and they are talking about carbed 1st gens so I'm guessing that problem is related to my exhaust noise. I happen to love this noise, makes people turn their heads and my cars pulls very hard and has no problems other than the check engine light coming on(sensor problem) when I accidently boost, seriously I try not to boost but sometimes it happens when I am not paying attention, i.e going up a big hill at 60mph in 5th=no power if my foot is barely on the gas, tends to want to boost so.........anyhow.