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VJZ

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I have been thinking of gutting the cats and removing the resonators, but leaving the stock muffler. Or maybe gutting the cats and leaving the resonator.

Either way I'll leave the stock mufflers.

Will gutting the cats set off the check engine light, make the car run weird, or get worse mileage?

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I have been thinking of gutting the cats and removing the resonators, but leaving the stock muffler. Or maybe gutting the cats and leaving the resonator.

Either way I'll leave the stock mufflers.

Will gutting the cats set off the check engine light, make the car run weird, or get worse mileage?

Remove the rear resonators and stock mufflers and add high flow Magnaflows with high flow tips. You need to keep yteh sensors just aft of the forward cats or your light will come on...I'm pretty sure that's what your ECU uses to analyze the engine and its output.

Kill the resonators fist and foremost and I recommend replacing those stock mufflers for sure. Those stock mufflers are heavy as crap and WAY too restrictive.

I replaced everything aft of the center-rear cat (more of a junction than a cat). I added 2.25" pipes, straightened as much as possible without blocking the drivetrain, added oval, high-flow, polished stainless steel Magnaflow mufflers that fit PERFECTLY and use the stock mounts and added oval high-flow tips. The mufflers are smaller and MUCH lighter than the stock ones (full of water), but they look like they belong. It has a very smooth, deep, but quiet, purr when idle and when I accelerate I get a nice smooth, assertive rumble. A European sound versus the burble of an American V-8...its sounds sweet as hell. I plan to replace the 2 forward cats eventually with high-flowers as well. I'm keeping the pipes no bigger or smaller than 2.25" to keep the backflow where it should be. My car hauls now, but I still need to replace/recalibrate the torque converter for a bit more instantaneous launches....but it moves when you hit that sweet spot.

Just my 2 cents.

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The stock mufflers and the stock headers are the most restrictive part of the SC400 exhaust system... If your looking for performance start with the mufflers first... If you don't mind sound get on Ebay and get some stainless steel straight thru mufflers for cheap..If you want to keep the noise down get some high flowing oval mufflers like the Magnaflows such as GDawg suggests...

I changed out my exhaust out one portion at a time..Also tried different combinations .The most noticeable differences is when I changed out the stock mufflers to the straight thru's.. Clearly gains were made on the topend.. I also noticed gains when I changed out the Center main cat to a magnaflow 2 into 1 high flowing cat to my suprise..... The biggest difference was noticed when is when I changed out headers and deleted the two small cats.....Big gains noticed on the topend but lost a just little lowend power...

Changing the stock piping out to larger sizes I didn't notice much over stock...

The mufflers are big though.....

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The stock mufflers and the stock headers are the most restrictive part of the SC400 exhaust system... If your looking for performance start with the mufflers first... If you don't mind sound get on Ebay and get some stainless steel straight thru mufflers for cheap..If you want to keep the noise down get some high flowing oval mufflers like the Magnaflows such as GDawg suggests...

I changed out my exhaust out one portion at a time..Also tried different combinations .The most noticeable differences is when I changed out the stock mufflers to the straight thru's.. Clearly gains were made on the topend.. I also noticed gains when I changed out the Center main cat to a magnaflow 2 into 1 high flowing cat to my suprise..... The biggest difference was noticed when is when I changed out headers and deleted the two small cats.....Big gains noticed on the topend but lost a just little lowend power...

Changing the stock piping out to larger sizes I didn't notice much over stock...

The mufflers are big though.....

And the Jedi Master has spoken...again...Nuff Said! Since I based my plan of attack on Jibbby's experimentation/experience...I default to him. You have two guys that have done most of the same mods (exhaust-wise) and the results are identical and truly amazing. Listen, learn, and love the results!

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I cut it of right before the mufflers on each side..... I know it was a stupid mistake but I did it and regret it now... But I love the sound but the problem is if ur sitting in the back seat you cannot hear what anyone is saying in the front and while ur doing any highway driving it gets to be old.. But I mean I was 16 and rushed it didnt help I had 3 other friends telling me to do it... But I wont Lie the sound is great, it sounds like a 350z or G35 I love it and no lights came on in the car because of it. I mean only problem is people always ask me why I dont have exhaust gets to be annoying, and I got pulled over one time and cop asked me where my exhaust was I just told him I was doing work on them and he didnt seem to mind with it ... Not sure if having no mufflers is legal or not so always though I got lucky.... But yeah forgot to say what mine is ... Its a 95 SC300 But yeah I Will try and get some sound clips tomorrow of it but I cant remember if my camera does sounds also. Ohh miss read the last post Idk about taking it of at the cats didnt try that but cutting it at the mufflers didnt cause and problems

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Gutting the cats will not flash the engine light, but you can kiss smog checks goodbye forever. The problem with gutting the cats is that for one you create a hollow area inside the cat and that creates the sound...Flow will increase some but is will not be a smooth flow such as piping...The hollow area you created in the cat will disrupt the natural flow some... Your reallly better off going to a smog shop and asking them to remove the cats and install piping in place for maybe $50... That will result in the best flow and gains...

Just my two cents...

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My problem is that most places won't remove a cat. Here in Indiana, we do not have emissions testing and since the car is registered and titled in Indiana, there cannot be a citation issued in another state for lack of emissions equipment. I only want a slightly louder tone than stock, which is why I am keeping the stock mufflers. I'd like to gut the cats, remove the resonator, and then leave the mufflers alone. Tone should increase a bit. Would fuel economy increase at all or decrease? I'm getting just under 20 MPG, but I still need to do a tune up and put my OEM rims back on for the winter/school year (Commuting).

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So, Dawg, I'm getting ready to do some simple exhaust modifications. I wanted to start by getting rid of the resonators but wasn't sure if that would screw anything up. Does removing them help anything at all? Sound? Power? Also, what is the model of MagnaFlows that you put your SC? Is the sound obnoxious? You could reply to my e-mail, chances are I'll have more questions. Thanks a lot!

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Ok, I have an update on my exhaust situations. I went in and had the 3rd resonator/cat removed as well as the two resonators, and used 2.25" pipe like EVERYBODY suggested. So it's a REAL dual exhaust at this point, but left the stock mufflers on....IT SOUNDS LIKE HELL. I'm not kidding, I was freaking out when I heard the car turn on for the first time. It sound like a truck and it's nasty. Now I'm missing the beautiful sound I had before, a nice low hum...and now that I'm thinking about it, it was just right.

DON'T MAKE THIS SAME MISTAKE. YOU WILL HATE YOURSELF FOR DOING IT. I'm going in tomorrow to have him throw back on that 3rd resonator, I'm hoping that will do that trick, otherwise it will be back to the original and $200 down the drain. What a freaking shame.

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It still sounded like hell with your stock mufflers on? Wow, I would think it would still be very quiet even with all the deleted cats and resonators with the stock oval mufflers still intact ...Interesting...

So the exhaust sound is nasty or the volume is too loud? I am not comprehending your last post...

2.25 mandrel piping is good call, if it's bent piping you should go with the 2.50" piping...

So in India they don't allow you to remove or alter the exhaust a certain way...WOW, that sounds a bit communistic to me.. I hear India is a bit over populated but schooling and education is the main focus for most...Is that true?... I see alot of Doctors here in the States that are from India.. Am I right in my assessments?

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Yeah, like hell. It seems those stock mufflers aren't exactly "stock." The guy that did the work for me, who does a fabulous meticulous job by the way, said that he's never heard that kind of sound come out of "stock" mufflers, he was SUPER surprised. Anyway, it's not quiet at all, it would blow your mind. Maybe I'll get a sound clip or something, my gosh.

Let's put it this way, I sound like a truck....no joke. Because it's true dual exhaust now, I'm getting that pitter patter sound, yeah, just like those big trucks, have you heard what I'm talking about? So, the guy suggested that we could put a cross pipe in between the two where the 3rd cat was and see if we can get the sound to mellow out and be in sync, rather than pitter patter. If that doesn't do the trick, I'll probably just have him throw the 3rd cat back on, I seriously miss the old sound now, regardless of the flow. I feel like I've ruined my baby, 1995 with 27,500 miles on it...yeah.

I've lost a bit of my bottom end as expected, but the top end feels a bit snappier. I can't image putting on magna's at this point, would be even louder...yikes. I wish you could test things with out committing to buy into them, you know? Anyway...

I also can't imagine putting on 2.5", I'd loose even more of my bottom end and end up spending another $1k to get a torque converter put on there.

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Oh, I see what you did...making it a true dual exhaust is causing the noise and also probably making you lose power... The cross exhaust is what you need to get everything back in order..

DON'T GO DUAL EXHAUST ON THE 1UZ-FE MOTORS... That's a big no no...Got to keep the X intact at the center main cat... These motors are designed to have the X cross in the exhaust systems..It's a pulse thing that is hard to explain.. That's what is giving you that loud tractor sound...

The crappy thing about turning your stock exhaust into high flow is that you will lose lowend power but get bigger gains at the topend... Unfortunately, the stall rate on the stock torque converter is set to accomidate old people holding coffee in their hands while driving at takeoffs... So what you will get by up exhaust mods is crappier take off power.. However, once the car eventually does gets moving your high rpm power will be noticeably increased...

If your going for the full exhaust mods overall you almost have to consider a torque converter stall rate change as well...

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I see, I wish I would have known that before I started. So you're positive the X pipe will do the trick? Do you think it will tone it down a bit as well?

Yes, I do.... The X evens out the exhaust tone and flow for sure... Definetely restore the cross section..

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GREAT NEWS!!! I had my exhaust guy throw the 3rd res back on and keep the 2.25" pipe all the way back. So, the final setup is 2.25" pipe from the 3rd res back, minus the two resonators to each muffler. I kept the stock mufflers. DUDE, my car sounds soooo incredible. When we started it up it was so freakin sweet, Jim said he thought it sounded like a Ferrari, and this guy has been doing this for 21 years.

So, if you want more sound, but want to keep it simple and low budget, follow the above. It cost my $255 after all was said and done, but that's because we had a screw up [read above]. So, it shouldn't cost you more than $200. There is a noticeable power increase, my take off is actually the same if not quicker, and top end is sweet.

Jibbby, thanks for your input, I really appreciate it. I had a heart attack after the first round, and the 2nd round was my defibrillator, it brought me and my car back to life.

Good luck ya'll!

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