I just got finished transforming my cat into a sound deadening test pipe. Im sure many have thought of or done this but Id thought Id share anyway as its easy and a good alternative to the annoyingly loud cabin noise of a gutted cat and keeps stock look (as test pipe doesnt). Basically all ya gotta do is gut out your cat pack the inside with sound deadening material (guy at auto store told me packed steel wool, so I used it and it sounds great) and weld in a piece of pipe straight through the cat. The only problem was the pipe to go through. You need to get a 2" Inside diameter pipe from autozone that has the stupid openings on the one side and cut that off (for some reason 1 7/8 ID was too big...but 2" fit, doesnt make sense). Then shove it through and measure how much you will need (use a 2x4 and a hammer to get it through). Pull out a bit and cut. Push back in properly, weld, and sand down the welds. Sounds like alot of work but not at all and pipe is tight enough that JB weld or some other welding sealant would do the job just fine. You end up with a finished product that flows exactly as a test pipe would, is surrounding in deadening material (forms a resonator of sorts to kill sound and rattle), and looks exactly like a stock cat when installed.
I dont know if this is stupid or some may think its pointless, but to keep down the sound and up the velocity this seemed the only way to go for me. Also, cabin noise is FAR less than it was before. It seriously sounds like a different car and sounds cleaner than the gutted cat did. Also stopped messin with the airflow like gutted cat does. Total investment = 7$ and change for a cleaner sounding and feeling car. Dont pay 50$ for a test pipe, do this instead. That is all. If you need anymore help for anyone wanting to do this just Email me at JMRacing2002@hotmail.com or AIM at JMRacing2002
#40598, "RE: Alternative to test pipe" In response to Reply # 1
why didnt you just keep the stock cat on the car as is instead of gutting it and then stuffing it full of sound deadener?
1997 Eclipse GS AEM CAI Apex'i N1 Catback Greddy Header 5% window tint Front-Rear-Lower Rear STB's Yellow Painted Calipers 1st gen altezzas with original painted center piece Soon-Tokico Illum's or Blues
#40599, "RE: Alternative to test pipe" In response to Reply # 2
Read it again Brian. There's a pipe through the middle, just like a test pipe. The sound deadening material works just like it would in a resonator. He's actually created a straight through glass pack - which flows just like a test pipe would....except it looks like a catalytic converter. Take a look into a catalytic converter - it's nothing but a big block of shit in your exhaust path.
Good work man. Nice and legal looking.
ride__________95 Eclipse RS : 5 speed power________Field SFC Hyper-R : Gude cams : Jeep TB : AFX UDP : ram air : test pipe : GST catback suspention___Hurricane F/R lower strut ties : BOMZ F/R upper strut bars : ES inserts sound________Kenwood KDC 5000 : Audiovox 8" sub toob - no sub amp(damnit!) shizzle_______AutoCommand remote start : dual air horns : Caspers o2 simulator(rear) incomming___Bosal header(maybe), 14b turbosystem(eventually), Xplod 222w amp(soon) Jeep TB writeup - http://www.dimensia.com:81/jimbo/JeepTBfor2gnt.html
#40602, "RE: Alternative to test pipe" In response to Reply # 5
only thing is....i dont know how it is with your state but in NY, having something that looks like a cat doesnt really mean anything cuz they toss the car on a chassis dyno and test the emissions at 60mph.... I was just wondering cuz you might as well have just tossed a test pipe on the car.
1997 Eclipse GS AEM CAI Apex'i N1 Catback Greddy Header 5% window tint Front-Rear-Lower Rear STB's Yellow Painted Calipers 1st gen altezzas with original painted center piece Soon-Tokico Illum's or Blues
#40603, "RE: Alternative to test pipe" In response to Reply # 6
JZA, I more did it for 2 reasons. A) Every bit as effective as a test pipe for under 10$ B) Doubles as a straight through resonator in addition. No emissions here in FL, so its all good.
#40604, "RE: Alternative to test pipe" In response to Reply # 7
Yeah no emissions testing here either....Just a visual..
Well I test drove my car today and it definitely got rid of the whistle but the rattle I had in my exhaust got worse so now I think I am gonna get a new muffler.
#40605, "RE: Alternative to test pipe" In response to Reply # 6
>only thing is....i dont know how it is with your state but >in NY, having something that looks like a cat doesnt really >mean anything cuz they toss the car on a chassis dyno and >test the emissions at 60mph.... I was just wondering cuz >you might as well have just tossed a test pipe on the car.
i've been told that any modern fuel injected car that is in good running order can pass a tail pipe test with no cat as long as the ingition system is in good order (plugs, wires and what not). I have yet to try this out.. but it wouldn't supprise me.
#40606, "RE: Alternative to test pipe" In response to Reply # 9
nope...i know cuz i tried it...without the cat on my car it failed the emissions test misearably...the emissions werent even close to the required levels. Of course, if you just got a visual then your custom made unit works well.
1997 Eclipse GS AEM CAI Apex'i N1 Catback Greddy Header 5% window tint Front-Rear-Lower Rear STB's Yellow Painted Calipers 1st gen altezzas with original painted center piece Soon-Tokico Illum's or Blues
#40607, "RE: Alternative to test pipe" In response to Reply # 10
OZ GS... did the same thing to me only its quiter in cab so it doesnt bother me at all. But PLEASE keep me informed on whether the muffler you get changes it and if it does the exact one you got because I would kill to get rid of that rattle, but I think thats just the sound of a straight through muffler with a straight through cat. I hope not tho. Please keep me informed dude, JMRacing2002 on AIM...
#40608, "RE: Alternative to test pipe" In response to Reply # 11
mine has that same prb when I rev it up at high rpm I'm thinking it might be the heat sheld around the cat . now that the cat is guted more goes out so might make it do that duno I'm going to take all mine off just to see if it helps some I know after I got a after market muffler it help some but not all
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