Possible clogged exhaust affecting performance? Replacement?

[RickBlaine]

Hello NICO!

I have a rust-free 1991 240sx with 103,000 miles, 100% stock black beauty, with an automatic transmission.

Lately, the car takes 15-16 seconds to go from 0-60 mph. It does not stall, the idle does not fluctuate (stays at 750 rpm), but it sounds rough. At idle, it will shake. It can hit 90 mph easily, and seems to do fine ABOVE 60 mph. But getting to 60 mph takes 16 seconds.

I used this site to figure out how to access my ECU- and received a code 55 (all is well). Next, I checked maintenance records for spark plugs and wires, and they were done 8 years (and just 5,000 miles) ago, so that seems OK. I listened to fuel injectors and changed the fuel filter- no change.

Then I looked at my exhaust system- THAT is rusted. I banged on the muffler and it sounded like a lot of sand was in there- I even blocked the tail pipe with a rag for a minute and there was no change in sound or idle speed or anything. In fact, that muffler was warm, not hot. I could safely touch it with my bare hand! The exhaust coming out of the tail pipe was not under much pressure. It was like a "gentle breeze", not a blast of air. I ran my hand a couple of inches away from the rest of the exhaust system and detected a leak just where the rear of the catalytic converter joins exhaust piping. Seems the gasket failed.

A) Can you please tell me if you think the condition of the exhaust is causing my poor performance?

B) If my exhaust is stock, is that a 2.25 inch, a 2.5 inch, or a 3 inch exhaust? It seems as though all the replacements are 3 inches. Which size should I stick with?

C) No emission testing on my vehicle...is it OK to get a replacement exhaust system without a catalytic converter? Is that simply called a test pipe? I drive it 2-3,000 miles a year in the summer.

4) The current exhaust system seems to have two mufflers- or is the "other muffler" between the catalytic converter and the rear muffler in fact a resonator?

I am not going to boost this car, nor track it, nor drift it. I don't want tuning issues, a huge "coffee can" exhaust, or to make my wonderful neighbors angry with loud exhaust. I don't want to attract the attention of law enforcement either. Just want to get back my 0-60 mph times and stop the weird idle blips.

What are your thoughts, advice, or comments please? Thank you. I will respond to one and all....

[2_Liter_Turbo]

Sounds like you may have a clogged exhaust, I would definitely look into getting an aftermarket exhaust setup. If you have zero intention on doing further upgrades, BRM has a nice 2.25" diameter exhaust system that will bolt up and sound awesome (make sure to get a resonator) and not too loud at all. Get the dual tip muffler for a close to stock oval muffler look (I believe the single tip version is a round muffler). I had this exhaust back in the day on my first 240SX, and it was solid! Good luck!

Here's a link for the exhaust

http://www.brmexhaust.com/1989-1994-Nis ... -240sx.htm

[Rosenbjudy]

What I found was similar.

[RickBlaine]

Thank you, Gents!