Syonyk

New 1988 NA RX-7, 117k miles.



A few questions I had:



Is the exhaust supposed to stink? I was driving around with the hatch up today (bike in the back), and my exhaust *stinks*. I suspect this is related to the fact that my air pump is disconnected (no belt to it) and is in fact seized up (I can't turn it by hand).



The catalytic converter probably isn't terribly happy with this state of affairs. Suggestions? I'm in a state without emissions testing.



Also, there is a "groaning/squeaking" coming from the back of the car under braking with it in neutral (probably with it in gear as well, I just can't hear it). It seems to be tied to wheel rotation speed, so I suspect it's a rough disc or such. Anyone ever have this?



Thanks!



-=Russ=-

1gendreemer

Sounds like the catalytic converter is done, if there's one there. The stink could also mean engine problems (coolant burning?). I'd have the compression checked.



Groaning in the back could be lots of things. Wheel bearings, brake rotors/pads, suspension issues, rear end problems. I'd see if you can lift up the back of the car and make it do it..that should check suspension. To check the bearing, just jack the car up and spin the wheel (ebrake off). If the bearing is so bad that it makes noise, it'll be stiff and probably make noise then too. Brakes and the diff should be checked by a mechanic if it's over your head.

Syonyk

Yea, I thought the converter might be toast. I'm pretty sure one is there, I'll confirm next time I have a chance.



What are options for it if it is toast? Replace, remove - what would I replace it with if I removed it?



Later this week I'll try to find time to jack the car up and see if I can figure out what's groaning.



-=Russ=-

1gendreemer

If you don't have emissions testing in your state this is a no brainer. Rip that thing off! You can get "test pipes" or "downpipes" that replace the cat with a straight pipe and works with the existing exhaust manifold, but I think you're best bet would be to get a header and presilencer from Racing Beat. There's all kinds of writeups out there on how to take off the air pump and do away with lots of the emissions garbage too. Since your air pump is already fukd, I'd start doing that stuff too. Iluvmyrx7.com

ambassador_josh

An added sidenote: Be prepared for a louder exhaust when you gank your cats...I didnt anticipate such an increase in mine, but going stock (albeit fecked up stock) to straight pipe WILL make it louder. I found the increase in pep to outweigh the negatives, though.

Syonyk

I actually was looking at the Racing Beat set. $300 though... I'm pushing it to afford the car.



One other related question: How much can I free up the airflow (intake/exhaust) before I need to start worrying about the stock fuel system not getting enough fuel in? As I understand it, the quickest way to kill a rotary is to add lots of airflow and not enough fuel. Would replacing the cat with one of the less restricted pipes still be OK with stock fuel settings?



-=Russ=-

ambassador_josh

I dont see why not, just don't bypass the afm (duh.) With NA you probably won't lean out the engine with just bolt ons. I haven't yet...

SoniX

I got the Bonez presilencer/downpipe for my 90 GTU, it was nice, not a big difference in sound or performance, but it will probably help you a lot more than me, since your cat is already messed up. Also, the creaking/groaning noise from the rear end is normal, most of the time anyway, there are joints there (can't remember the name) that need to be greased to make the sound stop, though it doesn't do anything other than that, my fix was much easier, just turn up the stereo till you can't hear it, just to be on the safe side though, replace your pads anyway, front and back, it is cheap, and is a good idea whenever getting a car you aren't totally sure about.

1gendreemer

Yeah I wouldn't worry about going too lean...you need boost to do that. I've got all my gear off and running just a muffler and it still likes to run a little rich! I can vouch for the Bonez DP...I had one on and liked it a lot for the $.

gazellis

In an 88 N/A are the 5th and 6th ports actuated by back pressure from the exhaust? If they are then you may need to worry about that if you go to a straight pipe, no cats, and a free flowing catback. You may not have the back pressure to open the ports. I understand it is only 2 psi that is needed which is very little.



There is a way to open them using the air pump but you said that is toast also.



You could wire them open but then I have heard you lose power in the low end.