JAPSPECGTUs

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?

ra ra rotory

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

Icemark

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

JAPSPECGTUs

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!!!

Kenteth

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

G2 Racer

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.

skyypilot

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!

Mykl

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.

Bambam7

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!!!!

predikt

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

skyypilot

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......

skyypilot

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.....

JAPSPECGTUs

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.