2ZZ Exhaust too loud

[GazMav]

Hi All,
Finished the 2ZZ conversion, all went very well,hits lift, no codes, happy with power.

The exhaust is far too loud, Measured 121db @ 6k revs!
I modified the 2ZZ manifold to come out above the sub frame and then bend to 200 cel cat, another 180 bend to a 420mm Jetex back-box then out the back of the car.

I'm a bit stuck for space and worried about making a track day, My only idea is to swap out the cat for another back box (its clamped on so easy) but do you think this will quieten it down enough, (just for the track day).

How have others managed to fit a bigger back-box, i think i made the mistake of going about the sub-frame rather than below.

[GazMav]

Here's a photo part way through showing the setup..

Sent from my SM-G950F using Tapatalk

[1979scotte]

Pretty small back box.
It should quieten down as you use it a bit.

[shnazzle]

Isn't it the length of the pipe?
Think didgeridoo... Long, very loud.

Surely there's a more efficient route?

[GazMav]

Good point, I always thought it was best to get max length but makes sense what you are saying.

Sent from my SM-G950F using Tapatalk

[shnazzle]

https://www.google.co.uk/search?q=2zz+exhaust+mr2&client=ms-unknown&prmd=sivn&source=lnms&tbm=isch&sa=X&ved=0ahUKEwid3-WG87_bAhVsK8AKHeXdCogQ_AUIEigC&biw=455&bih=729#imgrc=1CuQWDA6w062BM:

Same concept but shorter. I would use a flexi at the joint but that's me

[GazMav]

I'd have to take it down under the subframe. Think I might have to redo it.

Sent from my SM-G950F using Tapatalk

[dan944]

I think if you have a reverse flow box it can quieten it. Or a box that has a U bend inside like the stock but much lighter lol.
Doesn't really help with what you've got though I know sorry.

[GazMav]

Thanks all, will try replacing Cat for a small silencer first, if that doesn't help then I'll redo.

Sent from my SM-G950F using Tapatalk

[shnazzle]

Personally I would do manifold, left 90deg into removable cat/resonator, up to flexi and joint, 90deg right into a long, good, well-packed silencer, then down with a tip on the right.
Or inverse for left tip.

That way you can add a 400cell cat for street use (which also dampens the noise a fair bit) and a resonator for track use to get less noise but a lot less flow restriction.

Copied the above from the SP240 turbo exhaust design but with single tip