Exhausts Single Or Twin

[Boganspeed]

I have manta 4" to twin 3", I don't have any droning issues but overall it is louder than other systems.

At cruise on the highway, I can hear it but it's okay.

I wouldn't want to live in the hills with it though.

I had a few issues with it touching the body but is now all good after a bit of lovin'.

I went with this system as XFT reckon it's about the best system around.

Which, of course, is subjective.

Edited 24/09/13 04:54 AM by Boganspeed

[sr71]

Can you go bigger, with power gains, but go quiter than stock ( F6 ) ? Similar to some of the Euro Rockets?

There's a business in Vic: Exhaust Control Technologies who do big silencers for industry. Apparently they have done Cats for HSV. The more that gets thrown into the system, the more restricting, but.... surely there is a way.

J pipes for a start?

[BRK]

You would need some r and d to test this. When you think about it, some ( a lot) of the cars on this forum are at the 450+KW at the engine mark. There are very few factory cars making that sort of power and passing drive-by noise requirements and customer-acceptable drone/cabin boom levels.

You can certainly get close to stock noise and a lot more power but the bucks required to build and test the mufflers you would need is beyond most people's ability. Once you get into this and start to cut open some of the late model factory mufflers to see how they do it, you soon know just what lengths they go to in order to get this stuff to work. EG, some ( BMW) use tapered, angled and perforated reducer cones inside the flow paths within the mufflers to deflect gas sideways and create noise buffers within expansion chambers within the mufflers. The factory N/A falcon 6 mufflers are a maze of pipes and chambers - the ford 6 is a noisy thing it seems. The turbo version is not and the exhaust dynamics change a lot with the snail in the way - and the reasonning ( not myth and B/S) in that is not something I fully understand. Muffler/resonator size is a part of the noise reduction formula but position in the system along with dump pipe size and design is another etc. Most of the aftermarket seems to have this sorted out and we get good flow and exhaust note that suits most of us.

When you look at the FG F6 system which is actually quite small, and the power it supports once you fiddle with the boost, air box, and "adjust" the cat converter, the results are actuallty good. To get more power with less noise......... maybe a bigger job. An F6 makes about 310 at the engine. FG F6 owners help me here but IMO you can go pretty close to 340+??? with just a cat change, air box mod, tune and stuff all difference in noise. After that - well......... have a look at the build ups on the forum.

[Panda Eyes]

im a fan of twin 2.5- but id go twin cats too to avoid a choke point.

my mild steel has no drone at all.

its a redback system.

[Sambo87]

My bf manual is only making 394rwkw so I don't ow if this is even relevant...

I've got a 4 inch dump into 3.5" single system by xforce and I've had HUGE issues with the fitment.

Cost me an extra couple hours labour with the tuners trying in vain to get it to fit and an extra trip to a performance exhaust shop.

The exhaust guy said he spent 3.5hrs on it (only charged for two). Had to heat the dump pipe to bend it up, elongate holes in the cat as it was rotationally out of step. And cut the muffler, re-weld it to get it to sit level, move the mounting brackets, bend the transitional pipes to clear the transmission tunnel... Etc etc.

So not great for something that should really bolt straight on.

[Sambo87]

But it does sound good, not too loud, doesn't drone.

[Ralph Wiggum]

IMHO two single systems merged into a single unit is the only way to go.

[Bomber]

I'll be running the new Venom s/s 4" dump and cat combo with my 2.5" twin s/s xforce in a couple of weeks. Might be wishful thinking but I'm actually hoping the less restrictive front end of the exhaust will decrease noise. The xforce 2.5" twin in s/s is a little raspy in the mid range. Little drone up hills under load. Love it at WOT and idle.

Edited 05/07/14 10:53 PM by Bomber