4.5 exhaust system and decat

[Tang Soo Tim]

Ok my exhaust is pretty worse for wear and cats looking old and feel like they are strangling car performance.

So what systems are the most popular on here ? Top one I can find seems to be the ACT big bore system with 6 silencers on it ! I want to allow the car to breath without being too noisy.

Already running sport tails but think it will be to noisy if I just decat it

Any other systems out there ?

[Gazzab]

Plenty of options... Including:-
- bespoke system (mine is from Raceproved with 3 inch tails)
- standard (arguably the best with decat)
- act
- Silverstone performance. Not sure who sells these now.

All can be catted, decatted, linked decats etc

[jackwibble]

As Gazza said, i also have a bespoke stainless system by Raceproved which gives good power with re-map but is de-catted and noisy i like it others may think too loud it depends what you are trying to achieve.

[gruffalo]

I have the full ACT system with decat and yes it is loud, nice deep rumble at low revs biulding in intensity as the revs rise. It delovered a noticable increase in torque through the mid range.

Here is what mine now delivers, only work done is short induction with a TVR power safe map chip that I fitted and the ACT exhaust.





You can see from the AFR how rich she is running so no danger of burning a piston or any thing and still good HP and torques.

[Tang Soo Tim]

Cheers all

Gruffalo is yours the system with 6 silencer's ? It's advertised as not being that loud ? But buy the sounds of it it is !

Might wait till after a couple of meetings and have a listen to a few before parting with my cash ...

[Byker28i]

I've got the ACT quiet system on my 4.2. It's not the full bore 4.5 system, has additional silencing in the long centre pipes and tail pipes and runs at 106db decatted. When I put the cats back in (mot time) it's 96-98db.

This one in fact


The added thing I'll say about buying from ACT is that if ever you have any issues Tim bends over backwards to help. I had a weld that cracked and broke twice. First time was returned and welded, second time the pipe was completely replaced with a bend rather than weld.

[Rufus Roughcut]

The blue car in this vid http://www.youtube.com/watch?v=QTwvhr783ac has standard headers, ACT 6 silencer system (as per bikers post) and decatted. I ended up fitting some cats as it was too loud for me.

[Tang Soo Tim]

Rufus Roughcut said:

The blue car in this vid http://www.youtube.com/watch?v=QTwvhr783ac has standard headers, ACT 6 silencer system (as per bikers post) and decatted. I ended up fitting some cats as it was too loud for me.

Blue car sounds nice ! Is it me or was the silver one much louder ?

I have a very friendly mot station so don't need to worry about cats but just want to pick the right system ...... But always a gamble I guess !

Decat with std back box is something I would like to hear I think !

[robsco]

I tried standard with decats on my 4.2, and it felt no louder to be honest. Now on a sports backbox with decats, and it STILL sounds nigh on the same as it did. I'm thinking of going for a full sports system, I'm sure mine is one of the quietest Cerberas out there.

[Gray_101]

robsco said:

I tried standard with decats on my 4.2, and it felt no louder to be honest. Now on a sports backbox with decats, and it STILL sounds nigh on the same as it did. I'm thinking of going for a full sports system, I'm sure mine is one of the quietest Cerberas out there.

You should hang on till chatsworth, there will be loads of differant systems to sample,, I've tryed a few combinations over the last couple of years,, but my currant RP system is stupidly loud,,,,, but I love it

[Gazzab]

My iPhone decibel meter was 92 db when driving through Sheffield on sat night from within the car (peak reading).

[Bigadz]

My silenced ACT decats arrive this week and I already have sports tails. I'm hoping it will remain at a similar volume but with even more pops and bangs and keep the cabin cooler in summer. Mine is a 4.2 and will be hooked up for Chatsworth.

[Tang Soo Tim]

just been chatting to the boys at Haywood and Scott who handmake systems to fit ( they have done 2 now for my brother on his Noble ) quality is very good and they are recommending decat with std large rear box configuration but much better quality than std box obviously ! and should keep sound levels below 100db so track day use would be perfect.

Anybody had any dealings with them ?

[FarmyardPants]

I would go with a single rear box (like oem) as it tends to sound better and the sports tails can be a pain to keep aligned. Also slightly phatter tail pipes suit the car's macho look/stance IMO. The bespoke option sounds like a good idea.

I have the SP system which I love but not sure if you can still get it...

[PoleDriver]

I've found that the easiest option in terms of price and alignment is:-
Decat
Linked
Large bore
Shiny tail trims.


Silencers??? They just add a bigger price tag, more weight and make it more difficult to line up!

[Gazzab]

We ought to have a chatsworth noise test (but not on the estate).

[gruffalo]

Tang Soo Tim said:

Cheers all

Gruffalo is yours the system with 6 silencer's ? It's advertised as not being that loud ? But buy the sounds of it it is !

Might wait till after a couple of meetings and have a listen to a few before parting with my cash ...

Mine is the full large bore sports system with the balanced headers, very few silencers, 1 each side from memory and around 120dB when giving it beans.

Bloody marvelous noise.

[Tang Soo Tim]

Gazzab said:

We ought to have a chatsworth noise test (but not on the estate).

I have a db meter

[Gazzab]

Points for static and fly by plus objective points for quality of sound. Maybe points for number of pops n crackles? Flames scoring max points.

[scotty_d]

I will have my new custom system with cats still in at Chatsworth. Looks much like the ACT one.

My old system was far to loud but i want a couple of silencers to swap out the cats if it is OTT.