i love my exhaust, it sounds very throtty but im an exhaust guy when it comes to V8's. I love the deep growl of the V8's. I kno a Lexus shouldnt sound like a ****stang, and it sure in hell doesnt but it sounds mean. I like my car to be noticed... and a way i like to be noticed is by sound.. either by my system or my exhaust/intake. I want my exhaust to be as loud as possible, but also to sound good. I heard an SC4 on here on the forums video/sound clip of the same setup but on a newer year SC4, and it sounded incredible so i decided to go with the same set-up. I love it and i recommend it to anyone who is looking to throw on an exhaust. I want to change the front cat's because my car makes a funny noise that seems to be coming from under my feet where my cats are. I can feel it. I think it might be my front 2 cats opening up into a 2.25" instead of the stock pipes. Plus i want more flow and sound!!!! Im just throwing it out there, im no exhaust expert, so if someone knows why its making this odd noise/feeling then feel free to let me know! But back to the question at hand...... i know atleast one person had to have changed out there front cats, i just want to know what brand and part number they used, and if they got the cat's with or without the O2 sensor built in

 

yes, at least one person did.

If you bothered to search, his user name is Mrjohntan (and many more). I've done the search for catalytic converters before so I am 100% sure it exists.

I hope you get a little something out of this and use what the forum provides you.

 

Yeah, I did too. https://www.clublexus.com/forums/sho...d.php?t=170220.

I played around with 3 different exhaust set up's. To get the sound that you are talking about you will need to go to a 2 1/2 pipe system. The stock CATS do quite the system down, but I would not buy aftermarket Cats. There are only 2 CATS that flow better than the stock CATS.. One is Metal Cat, and the other is Random Technology.
The stock Cats are 2 1/2 inch in and out. You did not describe what you have done so far or what Model / year your car is. For sound you can save money and leave the stock cats. Run a X pipe instead of the center double Y pipes, delete the dual rear resonators and run some 2 1/2 mufflers.

The noise you hear maybe a mistake you made when you altered your system. Bolted to the bottom of the CATS going to you exhaust system was a real nice bowl shaped, Mandrel bent funnel into your exhaust. If you deleted this and used non mandrel bent pipe you are most likely hearing the exhaust running into a wall as is reduces the flow .

I'm still playing around with my system a little actually making it quiter while producing even more horsepower. See Page 2 / Fig # 10. It's called a Zero Loss system. http://www.popularhotrodding.com/eng...re/0505em_exh/

 

This is type of setup I will doing to mine - running 2.5 (or 2.25) pipes from the first set of cats to an X-pipe and then straight to the mufflers (deleting both resonators and 3 rd cat that currently exisit)
Hey thanks for posting your feedback regarding your exhaust.

It's interesting that you note that it is better to use a 2.5 inch pipe instead of 2.25 inches. From what I have read on here posted by other guys with some experience with this stuff - such as JBrady - he recommends a 2.25 inch pipe instead otherwise you may end up with some loss of power on the low end.

Did you dyno your car after you put on your 2.5 inch pipe to see what kind of power your car was making?

 

I would think that you would want the sensors in, that way you would not get the dash lights coming on....you can't go wrong that way.

 

Ok first I did not say that 2 1/2 pipe was better. J Brady is most likley correct abut the choice being 2 1/4 unles you are running F/I. I am running Nitrious. MikeSC400 was asking about noise, and I am sure about that producing the Mustang type noise. Also be aware that most Mustangs you here are Iron Block, 16 Valve Motors, that will give a different tone.

Be aware when you are talking about 2 1/2 or 2 1/4 pipe that Non Mandel bends make a big difference. I read somewhere that crush bent 2 1/2 goes down to something like 1.8 inches or lower. my current system uses J Brady/SS headers, No cats Stock piping to cent section, a X pipe ( all 2 1/2 ) into X pipe then 2 1/4 back still using the Factory pipe, Resonators and stock straight flow mufflers. The bends under the drive shaft are gone replaced with Mandrel bent 2 1/4 pipe.

My orginal dynos were in the 230 range only moving up and down about 7 HP w/o Nitrious. But I have alot of other Mods if you look below my Sig. My objective was quite HP. You got to figure what CFM you want to flow based on your HP. Unless you are just after sound.

http://www.broaderperformance.com/mu...flow_tests.htm



My next step may be running those Borla's at the bottom. They flow well and are very quite. I'm trying to flow 350 CFM.