aftermarket pipe + cat, stock muffler?

[lucky03602]

ok first off i own a 1990 240sx. i plan on keeping the sohc in it and therefore im considering what to get for it first. i like trying to keep the car looking stock, not so much for a sleeper effect but more so tha cops stay off my tail (more then if i had a 5" tip and a 4' high wing) so i was considering this for an exhaust:high flow cat (probibly monza or something, i dont have emissions issues in nh) to a 2 1/2" piping to a stock or stock looking muffler.

yes i know it would work but would it be worth the money putting it together in hp gain? i plan on getting a hotshot header for it also and ill probibly get it first so that its a complete exhaust, but would it still be worth it with the stock muffer?

obviously im trying to avoid noise issues so that another concern...

let me know what you think and plz give any suggestions (including hi flo cat)

thank you.

[naed240sx]

sounds like a good idea, but the stock muffler is very restrictive, and will not alow as high gains as a more free flowing one. I personally have a custom system with a canister muffler, but if you want to make it look nearly stock, I would go with something like brm.(there is a sticky at the top of general). They have a dual tip catback that looks pretty close to stock. Just do some searching around, there are quite a few options. Ive never heard any bad feedback about brm though, so u might just go for that if you dont feel like looking around. Defineitly dont go for the stock muffler though. he piping wont even be the same size, causing a bad backup and turbulence in the exhaust stream before the muffler. good luck

[lucky03602]

ok so 2 1/2" piping is good but no stock muffler, got it. ill check out brm. how about sound though? like i said i dont want anything that will be "loud" i know no matter what itll b louder then stock but, well i think you understand what i mean.

any input on monza cats

[574-240sx]

I don't use a cat but I hear Catco cats are decent for the money. Check summit for cats their catolog has a variety to choose from.

[Florida240sx]

Yea if you don't have emissions then forget the cat.

[naed240sx]

Yeah, loudness all depends on the muffler, use of resonator, size of pipes, cat, too many variables. If you want it to be quite, be sure to use a resonator (like a secondary muffler) and the catalytic converter, as they both cut down on noise. Also, removing cat may help a little at top end (or alot if car is heavily modified), but will kill low end torque(which is bad). 2.5 piping is a pretty good size, but i would go for 2.25 if you are not planning on doing much more than exhaust, intake, basic stuff. As far as noise, I would go with a good high flow cat, resonator, and some kind of muffler that is made by a well known company(flowmaster, magnaflow, brm, ect.), and stay away from straight-though canister style if noise is a huge concern. I run a custom 2.25 inch system, no resonator(it cuts down on flow slightly), magnaflow cat, and a universal canister style muffler. It sounds good, but is so low that it sometimes bothers me. Kinda wish i hadda gotten a resonator or gone with a quieter muffler. Yeah this post is long enough so im out.

http://www.cardomain.com/id/naed240sx

[TheOne]

get BRM 3" dual tipped exhaust with resonator and hotshot header:), and a hi-flow cat.

[naed240sx]

3" exhaust is massive for a NA car. 2.5 would be max for a lightly tuned sohc 2.4. 3" would not only be heavier and louder, but would cause huge torque losses and little if any gains. Remember,its exhaust velocity, not backpressure that has a direct effect upon effieciency. A NA 240 does not produce enough exhaust flow to account for using 3 inch.

[masticatingcow]

3" exhaust is massive for a NA car. 2.5 would be max for a lightly tuned sohc 2.4. 3" would not only be heavier and louder, but would cause huge torque losses and little if any gains. Remember,its exhaust velocity, not backpressure that has a direct effect upon effieciency. A NA 240 does not produce enough exhaust flow to account for using 3 inch.

This has been hashed out over and over. Apparently the backpressure brigade doesn't like hard facts. The KA responds well to large diameter exhaust piping. There are dyno charts out there to prove it. Old souls cling to the backpressure physics, but have yet been unable to produce ANY proof that a 3" exhaust is as bad as they make it out to be.

Check it for yourself. zerothread?id=112978

Still, I would say that a 3" exhaust is definately NOT the way to go if you're paranoid about teh po-po hunting you down. The KA is a LOUD NA motor, and a 3" exhaust only makes it louder. I'll put it to you this way: with my A'pexi N1 duals (2.5" collector from cat, split into two 2" mini "catbacks"), sans silencers, it set car alarms off ON DIFFERENT FLOORS in a parking structure. It used to be funny, but now it sucks... I have to tip-toe everywhere unless I want EVERYONE to know I'm showing up.

My $0.02.

[lucky03602]

ok so im still gonna stick with 2.5" piping. definetly going to use a resonator. possible catco hi flo cat. and hotshot headers.

honestly, do you think this setup will be semi loud or?? or because of the headers should i put a full cat on the car?

i would go without a cat but i seriously dont want it that loud. stupid cops lol (well not all of them actually)

oh yea and ill find a decent muffler (not stock) to go with the package.

[skydragoness]

get BRM 3" dual tipped exhaust with resonator and hotshot header:), and a hi-flow cat.

Indeed, now just paint it a special high-temp black paint, and it won't be noticeable at all.

[naed240sx]

sounds great, loudness shouldnt be bad at all. good luck

[lucky03602]

ok so here is the complete exhaust system i will be doing...hotshot headers (with the o2 sensor bung moved lower)2 1/2" pipingcatco hi flo catresonatormagnaflow performance 2 1/2" inlet, dual 2 1/2" outlets.

ill be buying it piece by piece and ill posts as soon as its done.

thanks for all the help seriously!!!! awsome ppl on this forum!!