Getting rid of the 4 cyl buzz? 4AGZE...

[TERRA Operative]

Ok, so i picked up a 2.5" straight through exhaust cheap and stuck it on my AE101 4AGZE in place of the old system (stock system with the rear mufflers replaced with another brand).

Thing is, it buzzes something chronic, to the point it's embarrassing to drive.. I sound like a Honda.

What is the best way people have found to get rid of the typical 4 cyl buzz? I'm planning on using a high flow metal cat of some description (suggestions?) and twin outlets at the rear (as was stock on the AE101 Levins)
For the outlets, I'm thinking of two small diameter cannons (only a 2.5" or 3" outlet to look somewhat respectable...) or two 2.5" stainless tips. I just need help with the middle bits.

Should I just stick a heap of big 2.5" resonators in? How do I determine the correct size for the exhaust note and natural resonance of the exhaust?


Any help would be awesome. I want to get this done in the next week or so, before I have to start reclining my seat and wearing my hat backwards.....

[Duk]

When I built the 2.5" system after the cat. on my 4AGZE AW11, I just put a Genie Super Turbo muffler in there. The end result of that was 1 of those lovely yellow stickers that special people attach to the inside of your windscreen .
I then added a 'Gonzo' resonator. Basically a straight thru resonator but it has an internal cork screw (also a small diameter straight pipe right thru the center).
The end result was 4 dB knocked off the total racket. And 1 dB over legal.
There was no noticable seat of the pants differance to performance, but that's hardly scientific.
The same post cat system is still there with the turbo and it's bloody quiet for an aftermarket exhaust with very little room.
I have had no addition interactions with special people since that fateful day, 'cept for that 1 time when 1 of them had special 'velocity measuring device'.........

[TERRA Operative]

Here's the exhaust in question:

[pandaah]

hotdog might help this situation...?

[mattysshop]

you could put an 'aussie boomer' in place of that resonator up front..

or ditch the drift cannon and put a nice polished offset centre Magnaflow stainless muffler (or two) up the back..

if you want the full twin system look, can do like a reverse merge cone so it actually flows well, and looks the part, not just a press cone rightprice job that will sorta get it knocked together..

only one place to go hahahaha extreme custom engineering 3274 3700

[old_mr2]

Yep, i think the fart can on the end is causing your problems! A quality muffler will do a world of good.

My gze aw11 used to sound horrid. I had 2.5, gutted cat, hollowed truck muffler etc. The raspiness was shocking.

Now running a extractors, new cat, 2.25 cat back, , lukey muffler. Still fairly loud but no raspiness...

[takai]

That is what you need, no rasp no more.

Seriously though, 2.25" with a 3" cat, 2.25" hotdog, and a Lukey SuperTurbo shut my AE92 GZE up quite nicely.

[MRMOPARMAN]

in my limited experiences ive found mufflers right at the tailpipe tend to not work aswell as they should. i reckon piss off the fart can at the rear, and put a proper muffler a bit behind the resonator.

[TERRA Operative]

Yea, I've booked it in for tomorrow.

I'm getting a high flow metal cat, 2.5" mandrel pipe with a BIG straight through center resonator/muffler then the pipe is splitting at the back with a proper 'reverse merge' to two straight through mufflers with 2.5" or so tips.

Basically replicating the layout of the stock system, but with straight through mufflers and 2.5" pipe.


Takai, I was actually thinking of doing a similar setup, just so I could measure the frequency response to allow me to custom build the required mufflers and resonators to suit the resonance.
And for some nice drivebys down the street for youtube....

I got another Levin to play with, so I'll probably do it when that needs an exhaust.

[takai]

That setup i have there is my permanent exhaust....

Does help that its a race car though.

[Shifty]

straight through

cheap

I think you answered your question mate

[feral4mr2]

terra, do you have to stay 2 1/2"?? go down to a 2 1/4" good quality luckey muffler.

i know the aw11 is a different exhaust layout, but i have all 2 1/2" pipe, cat to a 2 1/2" straight through muffler followed by a 2 1/4" straight though muffler. both luckey stainless ultraflo. good deep tone with no horrid rasp.

[Julz01]

ditch the cannon and get a high flow muffler instead, Ive done this on my 4age with a 2 1/4 system and it doesn't buzzy and is not loud either

[TERRA Operative]

Yep, it's staying 2 1/2 all the way through. Any smaller restricts the rest of the pipe. Although, I am splitting to two....

It'll be done this afternoon, we'll see how it sounds.

[feral4mr2]

by the time the gasses get to the end of the exhaust, a smaller diameter muffler would not hamper performance.

hope it sounds good.