I’ve had my headers on for a while now and it has increased the volume and changed the tone of my exhaust to a point where I didn’t like it that much. Too much of the engine sound was passing straight out the tail pipe via my Nismo cattack system. . I had a pretty good drone and I didn’t care for the exhaust tone either. It was almost too high pitched too rapid. I’ve tried on a couple of occasions to take some video clips but the weird part is that unless the car is under a load it so sounded fine, not as loud and no drone.

My initial exhaust mods:

1. The combination of the Cattman Y-pipe and Nismo catback sounded really good on the car. I liked it a lot. Got plenty of compliments on that set up. Deeper sound very 350ish

2. When I added a catalytic converter to the Y-pipe it changed the tone and volume level of the exhaust and it was fine, not quite as nice but still good.

3. When I added the headers to that combination it wasn’t what I had anticipated

Initial solution was to try and add a second resonator to the system:



But that is basically identical to the Nismo resonator, would two them be enough to do the job?

 

So I decided to do something different. I went to the local (not Midas type chain) Lakewood Performance Muffler& Brake talked to the owner and decided to go with a 26in glass pack. It looks like this on the inside.



It’s the same diameter on the inside as the rest of the exhaust but the nice thing about this one is that it can be turned around either direction

Ridges going with the flow of the exhaust: Louder


Ridges going against the flow of the exhaust: Quieter.

 

I went with the direction of ridges going with the exhaust with agreement that he would switch it around, no charge if it was still too loud.

It wasn’t been on there for just a day now and I’m really feelin it. Sounds like my Nismo setup when I first put it on. Those ridge slots seem to be absorbing that higher pitched sounds and I’m back to sounding deeper under load. If I can figure out a way to gets some video of it from the outside while I’m driving I’ll get some. Probably just need to have someone take it for me.

Hope this helps anyone with headers and volume/tone issues.

And I will be putting up both the Magnapak and Nismo resonators for sale in the classifieds
Anyway, some random pics

He had one up on the wall for display:





After Nismo removed took a couple of random pics

 

Id did something similar when I had my custom mandrel bent exhaust built and installed. I had two 14" Magnaflow resonators welded together which is larger than the cattman resonator. I also have a single output exhaust. The combination of single output and larger resonators makes for a better sounding exhaust and no drone.

 

Nice! You will have to try and get a video eventually!

 

I can't wait to hear it. Thanks for the info.

 

Nice, have you posted the vid with the sound yet?

 

Thx for posting this, I will keep this in mind when my headers are installed.

 

I still haven't got a decent vid on it yet, been so pre-occupied with getting rid of my CEL lights. Here is a weak vid that I tried to get after we replace my AFR sensor. Garage was pretty loud so it interfered with the sound a bit. You can see my backup lights are nice and bright after I upgraded them.

I'll try to get something better. Keep in mind I've got that new resonator in facing so the ridges go with the flow, I can quiet it down even more if I turn it around.
(See vid in next post.....)

 

Sounds nice and deep! I'll have to keep something like this in mind when I decide to actually change things around myself...

 

Okay got my dyno tune today. My A/F was off. Found something interesting. The AF sensor in Bank2 which I had replaced last week was showing a correction factor of 1%. The AF sensor in Bank1 which is original to the car was correcting 18-21%. We suspect this one is bad as well and I'll be getting it replaced soon. Both of those sensors should be correcting around the 1% range.

I didn't get my 02 simulators in last night. We will get those in when I put the new AF sensor.

Finally got a decent vid while it was on the dyno. I like it but I may have him turn that resonator around anyway to quiet it down. I don't know yet.

You have to scroll forward about half way to hear it pull.


Same thing on this one, about half way thru.

 

If you can, take some pics of the o2 sim installation... I know a lot of people will be so glad to see something more than the instructions (incomplete IMO) that come with them.

So bank 1 is really that much off? That's pretty crazy! Hopefully just replacing it will help!

 

Yeah it better help. At the street tuner Mayhem I pulled off a 15.377ET Last night I dropped a half second down to 15.8. Not good, hopefully it's that other AF sensor.

I know it can be the sensors too, because the tech put in two from a 350z (they fit) that turned out to be bad, the car was much slower before he just extended my OEMs and put them back. Interesting that AF sensor go bad after headers go in. Just a coincidence?

 

How many miles on the car?

 

I'm at 88,000 right now. The Bosch replacement I bought says it's good for 100,000mil so it may just be time to replace it.

 

I may be swapping out the Greddy resonator for a glass pack by the end of the week... Going to give the 28" Thrush a shot...

 

I might go ahead and get one of these because sound is a concern for me, anything to tone it down a little I can dig as long as power isn't being noticeably affected.

 

I'm fine with volume/grunt... it's just the bees I need to get rid of. lol

 

Ok, looks like Flowtech and Jones/IMCO (Same as far as I can tell) both have the louvered cores... Thrush only has perforated, which would be craaaazy loud, and probably even raspier.

Flowtech:

http://www.holley.com/types/Red Hots.asp

Nothing over 24" that I could find.

Jones:

http://www.summitracing.com/parts/JEX-A4540S

They have a 40"... I'll do some thinking... this may be the one I need.

 

Louvered cores like that decrease the effective size of your exhaust, and increase backpressure. It's like taking two steps forward, and one step back, running something like that with headers. You should run at least a 1/2" larger core if you are going to use louvered, so if your exhaust is 2 1/2" diameter, you would want to run a 3" louvered muffler.

 

Ahh... didn't think about that...

http://www.summitracing.com/parts/JEX-A4330S/

 

Also try welding two smaller resonators together to get a long length. I have two 14" Maganflow resonators for total of 28" of resonator.

 

Yeah thought about that too. I'm actually going to pass on the glasspack, and try some mufflers... the last few weeks, the Greddy SP2s have gotten significantly louder... or at least I've noticed the damn buzzing...

I was actually considering the Vibrant 1148s:

http://vibrantperformance.com/catalo...products_id=51

or the 1040s:

http://vibrantperformance.com/catalo...oducts_id=1153

Just have to decide if I want the more stealthy look like you have Deus. Plus, the flat blacks are cheaper too...

 

As posted at the "other" site... Rasp is totally gone now:

Ok, so Nick at THMotorsports.com (shameless plug) finally got all my stuff in today... they had the Vibrants since Friday but I wanted to pick up everything together.

On my way home I stopped by a local muffler shop and got everything installed. It's PERFECT now!

Forgot to take a pic of the Magnaflow resonator, but everyone has seen those. lol It's huge, but fits, and works great!

I'll get a video sometime soon.

Too lazy to resize, but you all have broadband, so

Vibrant 1148:



Out comes the Greddy resonator... so tiny! You can see the Magnaflow on the ground:



Muffler going on:



Here it is, at home in the garage:



I should have done this years ago. I absolutely love it. lol

Looks hot, and there's no more rasp! The Vibrants give a very deep rich tone coming out the back.

------------------------------------------

I'll get better pics of the car with an actual camera, and when it's not so overcast out.

 

I love my single 3" Vibrant muffler. Its black too so its more stealth and has a great sound. Nice job!!!

 

Yeah these Vibrants are great! Not very expensive either!

 

nice!

 

Thx man very nice!!! My cattman headers should be arriving next week, now all I have to do is install them when I do my manual swap...

 

pretty sure it will sound good.

 

While you are doing that, get the front and rear motor mount inserts from Racingline!

 

Ok here's the new vid:

http://www.youtube.com/watch?v=VE-Xa8tpLc0