554 replies to this topic

[JimmyJamJerusalem]

the bigger the diameter piper the louder though...

Not necessarily.....

The bigger the bore, the slower the flow of gas, so the easier to silence!

[Muncher]

Just got in, it's certainly louder! At idle it's got a pretty purposeful burble, under load and sub 3,500rpm it can be pretty loud (well, in my mind I've been driving a diesel golf for the past 3 weeks!) but on a constant throttle, at 4,000rpm for example it is pretty quiet. At certain points under load, part throttle and on the overrun in can be pretty loud so Chris is increasing the length of the silencer to 30/31 inches. More details and pics to follow

[NickB787]

Just got in, it's certainly louder!

At idle it's got a pretty purposeful burble, under load and sub 3,500rpm it can be pretty loud (well, in my mind I've been driving a diesel golf for the past 3 weeks!) but on a constant throttle, at 4,000rpm for example it is pretty quiet. At certain points under load, part throttle and on the overrun in can be pretty loud so Chris is increasing the length of the silencer to 30/31 inches.


More details and pics to follow

Are you going to do a db check

[MAXR]

Just got in, it's certainly louder!

At idle it's got a pretty purposeful burble, under load and sub 3,500rpm it can be pretty loud (well, in my mind I've been driving a diesel golf for the past 3 weeks!) but on a constant throttle, at 4,000rpm for example it is pretty quiet. At certain points under load, part throttle and on the overrun in can be pretty loud so Chris is increasing the length of the silencer to 30/31 inches.


More details and pics to follow

Paul, a static test will be taken at above 4500rpm...I had two silencers on my 2ubular system!

My average static test is around 99db, God knows what a Harrop will do to that! I do have space to greatly increase the size of my secondary silencer & I'm having a downward pointing single tip added.

Also, Jim has made my 2-11 rear silencer with a new internal design with a perforated internal cylindrical baffler??? he says that tests he has done reduce the sound noticably...mmmm...We'll see!

Max

P.S. what gauge s/steel is he using for the silencer?

[NickB787]

Just got in, it's certainly louder!

At idle it's got a pretty purposeful burble, under load and sub 3,500rpm it can be pretty loud (well, in my mind I've been driving a diesel golf for the past 3 weeks!) but on a constant throttle, at 4,000rpm for example it is pretty quiet. At certain points under load, part throttle and on the overrun in can be pretty loud so Chris is increasing the length of the silencer to 30/31 inches.


More details and pics to follow

Paul, a static test will be taken at above 4500rpm...I had two silencers on my 2ubular system!

My average static test is around 99db, God knows what a Harrop will do to that! I do have space to greatly increase the size of my secondary silencer & I'm having a downward pointing single tip added.

Also, Jim has made my 2-11 rear silencer with a new internal design with a perforated internal cylindrical baffler??? he says that tests he has done reduce the sound noticably...mmmm...We'll see!

Max

P.S. what gauge s/steel is he using for the silencer?

I think the Harrop with Jims system is doing about 101-102db at 4500 just sounds slightly louder than the Miltek which had no stuffing in at all. Will check ASAP

I think I might ask for a slightly longer back box and maybe a replacement cat/silencer similar to yours Max

[Muncher]

Nick, yes I will do a DB check as soon as I find/buy a meter. Max, at 4,500 rpm I still don't think it's very loud... It's 304 grade stainless, not sure on the gauge but I will ask. Off the top of my head the silencer was 1.5kg lighter than the piper 2.5" one and it was less than half the weight of the standard one. (The Scorpion was even heavier than standard!) Now uploading a video to youtube, not sure how much you will be able to tell from that though.

Edited by Muncher, 28 March 2009 - 05:56 PM.

[Baron Von Scubadaddy]

That looks like a beautiful bit of work there Muncher Hats off to you fella

[Muncher]

Loads of pics here showing various bits of development, including the jigs which I thought were quite interesting.

http://www.muncher.org.uk/exhaust

[Jameshs]

Link to video please

[Muncher]

Link to video please

^^^

[Jameshs]

Personally i dont think your gonna get on a track with that

[Muncher]

Personally i dont think your gonna get on a track with that

I don't really think you can tell the volume of it from that vid as even the slightest breeze is picked up and sounds boomy by the camera.

[alanoo]

Hum, I don't like this mate :
http://www.muncher.o...st/full/008.jpg

this is an aluminium pipe, and you'll be running a very rich supercharged bomb with very high EGT's ...

[Muncher]

I just checked on the car as best I could and I'd say there's 5-7mm of gap there, could possible fit some nimbus in there too, but I will check with Chris. At what temperature would that aluminium melt?

[alanoo]

Yep, fit some heat shield there, I did I am almost sure this stupid thing is done this way on stock config to get the engine on temperature quicker, an emission stuff as always, but bad for the cooling performance, really bad

[mandarinvx]

According to Wiki, Aluminium will melt at 660 degrees C The video on CMS's website shows that the manifold will glow red The temp this happens to stainless according to Wiki is 580 for visible in daylight, and dark red is >700 degrees C

[Muncher]

I don't think there's much danger of melting it, I've got a laser thermometer so I will check out the temperatures tomorrow.

[alanoo]

I know for sure the supercharged conversions run in high 900's °C EGTs

[Muncher]

But it's going to radiate considerably less over an air gap. On the drive home coolant temperatures were as normal.

[alanoo]

Yep, it will never be a problem on trips to home, but an a hot track day or a long dyno session... You can take the risk, but one thing I learnt with our long N/A build, is that each risk, if not taken care of, will always break someday (fuel pipes, oil pump, electric circuit....)

Edited by alanoo, 28 March 2009 - 09:20 PM.