Nathan Kwok

Hey all,
When I am lugging around town and I shift at low rpms, lets say from 2nd-3rd or 3rd-4th at 3k rpms, after shifting, when I step on the gas I get a strange rattling noise that sounds like its coming from the tranny or maybe the rear end (sounds further forward than the rear though). It never happens if I shift at high rpms, only at low. The sound isn't very loud, but definitely noticeable (I have a pretty quiet car, stock exhuast), and the sound is similar to something rolling on noisy and very large ball bearings. Any ideas?

EugeneChoe

as i remember from reading old reports, it says that the early rx7 (early 93s) have a low rpm rattling. its from the heat sheild. i guess itll be gone if you go with aftermarket exhaust peices because they dont even have heat sheilds to rattle

Nathan Kwok

Eugene,
Thanks for the suggestion, but I don't think its the heat shield because it only happens after I shift, and it is also dependant on throttle position, ie if I step on the gas, it will happen for a few seconds, otherwise if i let off it won't. Upon getting back on the gas, it then happens again. It isn't totally consistant either, which is weird. It could be somehow the tranny shakes at low rpms when I accelerate from them, causing the heat shield to rattle, or something to that effect, but its not purely a function of resonance. Anyone else want to take a shot?

Rix7

My FD does the exact same thing ('93 touring) and my car has an aftermarket exhaust. So, it can't be anything related to the heat shield. I can't think of any other cause at the moment.

Nathan Kwok

Ok, that makes 2 then, anyone else? Anyone? *bump*

EugeneChoe

im still pretty siur thats your prob... i know where to find one of the many resources i read. ill cut and paste it and give the web address as soon as i get my lazy butt moving.. if its not i wonder what it is.. oh well rx-7 gezzz.. peace

DefBringer

I hear that same sound when I shift at too-low RPMS and I'm postive that is coming from the transmission. I think it puts a lot of stress on the transmission to accelerate while in a high gear at low speeds. I don't know enough about transmission but I would bet my butt that's where the sound is coming from.

I have a late 94 car so it isn't a problem specific to early 93s.

Nathan Kwok

Yeah, I was thinking the tranny too, just due to the nature and location of the sound. Eugene, if you can find the post about the heat shield, I'd still like to see that. If its the tranny, I wonder if shifting at low rpms hurts it, or is it just something that will annoy me?

EugeneChoe

http://www.rotarypowered.com/3rdgenfaq.html


i have a couple more pagegs that look like this i just have to look through my million bookmarks.. im in a rush but this is just one when i have time ill look again for the others.. maybe its in here

G 's 3rd gen

Both of mine did it..Maybe it has something to do with the torque at such low end. Its almost like the car bogs down for a split second. It definately is not a problem. I think just the nature low rpms. The engine does not like to run under 3000 rpms!!Keep em high!HAHAHA!!

whitet777

I think I know what you are talking about. I have always heard that noise from my 94 FD when driving between garages (where I can hear the sounds better from the echo) when I step on it at low RPM's. I hear the same thing from my 99 Tiburon, so I am not concerned. I think it is just something from the transmission.