I am thinking of having a local exhaust shop make me a custom exhaust. I don't like rear mounted muffler systems. They just sound raspy with no cats to me. I have had many different systems on my past cars and particularly didn't like how my Shelby sounded. It had longtubes, offroad mid pipe and a 3" catback with rear mufflers. Very raspy. The best sounding car I had was my 04 Cobra. It had long tubes, offroad x-pipe and a magnaflow catback with mufflers before the rear axle. Nice, clean and crisp v8 sound. I am hoping to get my IS-F to sound similar or better than my 04 Cobra sounded.

The shop I would use is the only exhaust shop in my state that mendrel bends up to 3" exhaust piping. They have done many turbo systems and custom exhaust systems. The guy is a killer welder and does really good work.

My plan is to come off the manifolds and run 2.5" mendrel SS pipe back to a Y about where the current resonator is located. It would Y from 2.5" to 3". I would run a 3" SS polished magnapack muffler thats 18" long and 7" round. After the muffler, it would Y back to 2.5" and be dual to the tail pipes. At the tail pipes, I will probably have both sides Y to have 4 tips and run the stock tips . I might run it on out and remove the stock tips. it would all be SS and mendrel bent. In the future, I would add headers and highflow cats.

What do you guys think? Has anyone run a system like this? The closest thing to this I have found would be the guys that remove the dummy cats and rear mufflers and have pipe welded in its place. I like the way they sound and I think my exhaust would give me similar but better sound and very good exhaust flow.

 

Interesting...IMO removing just secondary cats doesn't make it sound too raspy, I've heard some F's with this mod. Just gives it a deeper tone.

I'm contemplating removing my muffler & 2nd cats... many owners have said that there is minimal to no drone at highway speeds... I just have to check with my friend who works at the shop to see if I will pass inspection, since I'm not willing to have it re-welded just for that. I plan on keeping the muffler and cat so that I can have it welded back on when selling the F years down the line.

Here is the thread with my questions: https://www.clublexus.com/forums/is-...-question.html

 

I figured running the 3 inch section with the single muffler wouldn't be restrictive unless I made over 550rwhp. I searched and most people think at 550 rwhp a single 3" exhaust would start to become a slight restriction. I also thought about running 2.5" to 4" back to 2.5" But this would prob cost me even more. So far I am looking at around $1,500 doing it the way I said in my first post.

 

If you get 550rwhp on this car be sure to let everyone know how you did it.

On topic though, I think your idea sounds very interesting, especially if you have an exhaust shop guy that you trust to do the quality work. I suppose coming from the Mustangs you used to have the Lexus sounds pretty darn quiet, huh?

 

I'm @ 534WHP. :-). NOS

Many people have done custom exhaust and end up happy. Just try and dyno it before and after the exhaust to see the performance value of it.

Regards,

 

^^ Discussing any exhaust sound as a result of NOS sounds anticlimactic. You only get to hear it at WOTs with NOS? How often is that? It seems far in between...lol

 

When I mentioned the NOS I was just replying to vbb on the hp topic that he brought up. On the next paragraph I was talking about the different ways ISF have gone on their exhausts. But yeahh when the NOS is activated it sounds muuuuch better!!

 

something like this???



I have magnaflows on my cars... and I think it sounds amazing.... I dyno'd at 343 tho' (ALL cats retained)

 

The ISS forged system uses Magnaflow mufflers and X over piping.





Digger08

 

Kinda... I just don't like rear mounted mufflers. Instead of 4 mufflers at the rear my kit would have one larger magnapack. I wouldn't have a x pipe. Well I would but it would join together at the single larger muffler and back a part after.

 

I understand your theory, but you will have some serious clearance issues, unlike the Mustang. Lexuswtf's picture seems to be closer to what you are trying to achieve.

Digger08

 

wouldn't it just be easier to replace you resonator with the magnapack and remove the rear section all together?..... your concept.. (although a great idea) sounds like just the stock setup minus the muffler section and bigger pipes

(you're talking about something like this set up right?)


....on my setup I have dual 2 1/2 pipes going into FOUR magnapacks.. my car is pretty loud but not raspy at all.... I'll try to upload a sound clip for you when i get some free time and you can hear it....

 

It would be easier and the example above is what I plan on doing. But running all mandrel exhaust, larger SS tubing and better turn and Y transitions. Also I should save some weight by losing the rear cats and rear mufflers. I also think the magnapack will weigh less then the resonator. It really is copying the factory exhaust but making it better. Haha.

 

I'm thinking about getting random technology hi flow cats and doing something similiar to what your describing and using magnaflow muffler.
My buddy is an excellent welder.

 

scratch the random tech cats I meant the magna flow high flow cats.. or should I just get PPE headers instead.
anybody have used PPE headers for sale?
I'm a baller on a budget