Exhaust system help

[vxsr33]

Hi all,

 

I'm making around 250rwkw in my r33 gtst with a hypergear op6 highflow.

 

My exhaust of right (3 inch system) now is a bellmouth dump pipe, to venom 100cell cat, then straight to a jasma cannon. However the jasma cannon reduces to around 2.5 inch.

 

This setup is fairly loud but not too bad when cruising and light throttle.

 

I want to replace the cannon with a piece of 4 inch straight pipe. Mainly because i want to remove the 2.5 inch restriction, i like the look and i can do it fairly cheap. I don't want the exhaust to be insanely loud or drone heaps. A little louder than now is ok.

 

If i install a hot dog resonator after the cat, will this be enough to reduce noise a bit and keep drone down? Or will i have to install a different type of muffler?

 

 

[GTSBoy]

Nope.  No chance.  You will need a decent mid muffler at the very least.  Hotdog resonators are about as useful as the South Australian Liberal party.

[vxsr33]

Ok so hot dog resonator will do stuff all. What kind of mid muffler would be best? Would a straight through mid muffler work?

[niZmO_Man]

A big, fat muffler.

[GTSBoy]

'zactly.  There is a logical limit to how big a muffler under the floor can be.  You obviously need 3" in and out, and it is quite likely that you will need it to be centre-centre because it will be going in in place of a piece of straight pipe.  So your typical oval mid muffle will only be so tall and so-so wide.  Your main degree of freedom is the length, and there will only be so much freedom there.  Get the longest one in the catalogue.

[vxsr33]

I just checked my exhaust and the way its the piping goes doesnt allow space for a mid muffler.

I also drove the car with a straight pipe (was doing hicas delete so had to drop rear exhaust) just to see how loud it was. Needless to say its unbearingly loud, i got about 20 angry looks even though i drove around at low rpms.

Can anyone recommend me a rear muffler ( preferably dual tip ) that flows well but is quiet?

[Piggaz]

5 minutes ago, vxsr33 said:

I just checked my exhaust and the way its the piping goes doesnt allow space for a mid muffler.

I also drove the car with a straight pipe (was doing hicas delete so had to drop rear exhaust) just to see how loud it was. Needless to say its unbearingly loud, i got about 20 angry looks even though i drove around at low rpms.

Can anyone recommend me a rear muffler ( preferably dual tip ) that flows well but is quiet?

http://www.smb.net.au/ovalmufflers.htm

They will do a twin tip if you ask

I added a photo of a single tip, 4 inch offset in, centre out for reference. Can be made I any length you want. 

[vxsr33]

Thanks for the link mate but honestly a bit too steep for my budget. I'm looking to spend around $200-300.

[Piggaz]

... they work and they're quiet? An extra $100 is nothing. 

[vxsr33]

... they work and they're quiet? An extra $100 is nothing. 

$100 is a fair bit when your a uni student with limited workshifts. And most of the prices i am seeing are around $450.

But i guess you get what you pay for. Ill give them a ring next week.

[Piggaz]

You own a skyline... $100 is a drop in the ocean. A decent exhaust worth a mint.

[KiwiRS4T]

Or leave it as is. At 250KW you are not going to gain a lot from going to 3in. Save up til you can afford a good muffler.

[vxsr33]

Or leave it as is. At 250KW you are not going to gain a lot from going to 3in. Save up til you can afford a good muffler.

The main reason i want to change is the drop to 2.5 inch really bugs me and I'm over the look of the cannon.

Not expecting any noticeable performance increase.

[Kinks]

Don't cheap out on exhausts.

I spent $450 on a catback once that was f**king awful.  It was so bad I chopped it up with an angle grinder rather than attempting to sell it again.

 

 

 

[AngryRB]

Has anyone experimented with using a helmholtz resonance chamber? I read a pipe somewhere between 38-40inch will help cancel drone.

[AngryRB]

I added a helmholtz chamber to my HKS system and it super quiet now so you can keep a loud ass cannon still, expensive big mufflers not needed.?

Edited June 11, 2017 by AngryRB

[chiksluvit]

Got a photo of the setup?

[AngryRB]

It's pretty amateur but it works, I'm gonna clean it up alot more and paint black.. just wanted to see if it worked first..

Edited June 11, 2017 by AngryRB

[chiksluvit]

And the pipework looks 3 inch while the his exhaust is 3.5 if I'm right?

 

Was looking at this before but had another idea, joining the end of the chamber the end where it's capped to the actual exhaust (without actually drilling through. Just not sure if it'll still be effective that's all)

 

Saves the hassle of having to find a way to mount the chamber

[Steve85]

I have a cheap, second hand exhaust system that came off my car if you interested, let me know and I'll try to find some pictures.