I'd like to buy a decent pipe but its got to be quiet enought to pass noise regs at a track day. Ive heard certain exhausts have 'bungs' to help on the noise front but surely that defeats the point of having a free flowing exhaust in the first place?

Cheers

Andy

 

Have a chat with Pat about one of his systems. They work extremely well and noise levels are remarkably low. IIRC he had the system flow tested and it didn't even register on the backpressure gauge. I have one on my car and it is definitely more quiet than the scoobysport + magnex system I had beforehand.

 

I have one of those too, but mine is deafening Moray! Gotta get a new mid made up with another silencer......

Tim

 

Speaking as a Moray, I have to say that yours is not actually deafening Moray!

Mine has a mid section silencer in it. Its almost too quiet. Will be changing to unsilenced sometime... I remember that Pat had to add fuel in the midrange when he changed to his straight through mid section.

Must say, this system is louder with standard headers than with tubular headers.

 

Go to H+S tomorrow and you'll be able to hear how loud it is....then I WILL be able to deafen Moray!

Tim

 

Not heard Pat's system, but I can heartily recommend the APS full system. Less than 90dB at .5m behind the pipe, 5000rpm. Can come with or without sports cat (I have the cat). 3" the whole way, except the backbox, but 3" backbox is coming soon for a little more noise & power.

Tubular headers - or even ported OEM headers - will generally result in a quieter exhaust note (and often more power). I would seriously recommend porting your existing headers in this case - drops the noise a bit, gives better spool up and more power.

 

A fairly important point is - what sort of power are you playing with? Restrictive to one is free flowing to another... also, are you after 'quiet', or 'quiet enough to get through db tests at a track'? Quite a difference!
Must say that Pat's 'this is noisy' on his Legacy wasn't very noisy Or, at least, is quiet enough for a track...
(and I also think that the APS is good - have no idea what the noise meter thingy says, but it's quiet & the flow seems to be a smidgen under the Hiper sort of level - that's without the cat, though.)

 

The only restriction are track day noise limits, I dont need it to be quiet for any other reason. I believe a common level is 98 dBA at 50cm and 45 deg from the exhaust exit and axis?

Other than that, I'd just like a very unrestrictive system, one that doesnt break the bank would also help. Im a bit worried that running a full decat might affect the fuelling as I dont really want the expense of a full remap. The car is currently running 263 bhp with a PE ECU, filter and current exhaust which is knackered but retains the cat in the downpipe.

 

nom,

In case you were wondering... I can state that the Pat spec exhaust worked extremely well with the MRT headers you run now.

Moray

 

Ooo, ta.
Done the rounds, these headers, it seems!

 

If you have a PE ecu then why not have a word with PE about their own exhaust system. They do one with a sports cat gas flow rated to 400hp. It is more expensive than most systems but then the quality is higher also. PE have a WRX with the system fitted and will take you out in it so that you can judge the noise levels.

Alan

 

I doubt that even a 2.5" Magnex would pose any power reducing restricition to anything with under 300bhp, and they are one of the quieter systems.

 

According to a spreadsheet I made from some tests I did, and some results from NASIOC, a Magnex with a "godspeed" decat (inc up-pipe) and non resonated centre gave 98dB at 20" in a straight line at 5000rpm. The 45º reading will almost certainly be a couple of dBs less. Prodrive BB with similar setup gave 93dB. Blitz 104dB with OEM up and downpipes would probably fail to get on track.

For some reason, all US measurements appear to be 20" back in a straight line . . . probably so that 98 USA dBs is 93 UK dBs, as they seem to exagerate everything

 

mongoosse, 3" comes with de catted down pipe as well and 2 silencers plus your back box, must be the 3" pipe absolutley briliant, increased torque loads more and revs free,r and its not at all boy racer loud it souds the bollox makes the care sound very powerfull, well worth the money, well i got mine for £380, RECOMENDED.

 

Based on the PE system I once owned: The PE exhaust system claims to be 3", but actually drops down to 2.5" at each section join, which is not good in terms of gasflow.

The T75 centre pipe with sports cat is more restrictive than the Magnex 2.5" centre pipe with resonator. I know this as I had to add fuel into the map after changing from the PE T75 down to the Magnex 2.5" unit.

I still have the T75 catted centre section lying around in my garage. I guess i ought to consider selling it on sometime.

Moray

 

Well well, how about that - I have a PE catted centre lying in the garage too, waiting for me to get the energy up to sell it...

Maybe if they were somehow connected together in parallel they would flow better