96 replies to this topic

[2-20]

[color=rgb(40,40,40);font-family:helvetica, arial, sans-serif;]I have a 2.5" system on my 2.2 N/A. The fit was fine [/color]

[Graeme Lambert]

Watching this one... Sent from my SM-G930F using Tapatalk

[vocky]

anything is possible if you try hard enough

 

This system gives 20 ft lb more torque than an 'aftermarket' full 2.5" system

 

[Nev]

What's the noise level coming out of your home made exhaust Vocky?

 

[vocky]

What's the noise level coming out of your home made exhaust Vocky?

 

 

it is quiet on tickover and cannot be heard over the throttle bodies at full throttle

 

I have tried an empty Piper backbox and that was very LOUD    

 

 

 

ps: My first Piper backbox was replaced FOC by Piper with the repackable version, this is still using the original packing.  

[vocky]

and it all fits under the OEM heatshield, with a few small mods

 

[siztenboots]

whilst manifolds are nice to admire, ideally I wanted this thread to focus on the packaging of the rear silencer in to the space available and the noise levels / repacking issues.

 

personally I do not run a main cat, but I know many do and have problems with the options versus cost for longevity.

 

I would want a 3" U section on the left , but retaining the boot heatshield could be replaced with nimbus and have a clam cutout

[vocky]

turbo engines do seem to prefer a high flowing exhaust system.

 

If you want big power and a quiet exhaust it might be worth fitting an even bigger turbo (to keep the power levels similar) and a more restrictive backbox to reduce the noise and still get good power. But that creates extra heat and thus power will reduce.

 

A standard vx220 is simply not a great car for high power turbo'd engines due to the rear engined layout and lack of decent air flow.

 

Buy a NA and fit a Harrop sc

[CHILL Gone DUTCH]

There one of them for sale

[fezzasus]

whilst manifolds are nice to admire, ideally I wanted this thread to focus on the packaging of the rear silencer in to the space available and the noise levels / repacking issues.

 

personally I do not run a main cat, but I know many do and have problems with the options versus cost for longevity.

 

I would want a 3" U section on the left , but retaining the boot heatshield could be replaced with nimbus and have a clam cutout

 

 I feel those are fairly arbitrary requirements that have been created without studying the constraints of the current system. 

 

For example, consider the tailpipe position. A central tail pipe requires that the pipe has to turn 180 degrees on exiting the silencer to return to the central point. This adds weight, cost, and limits the size of the silencer as the maximum volume occupied by the silencer is now a function of silencer diameter + separation between silencer and tailpipe return + tailpipe diameter.

 

This would direct me to asking the following questions:

 

1. is the current pipe routing within the engine bay the best solution. What are the compromises of changing the routing?

2. Is the current tailpipe routing the optimal solution, what are the compromises of changing it (for example, cutting an exit into the rear diffuser).

 

If both of the above answers are that there is too much compromise, I direct you towards the Posche 911 silencer approach, which essentially uses a silencer in each bumper corner to maintain a central tail pipe. Would using two small silencers enable more optimisation of available space?

[vocky]

focus on the packaging of the rear silencer in to the space available and the noise levels / repacking issues.

 

if you look again you will realise it is 'thinking outside of the box', unlike pretty much every other vx220 backbox system  

 

the Posche 911 silencer approach, which essentially uses a silencer in each bumper corner to maintain a central tail pipe.

 

now that would be worth looking into

[Nev]

 

What's the noise level coming out of your home made exhaust Vocky?

 

 

it is quiet on tickover and cannot be heard over the throttle bodies at full throttle

 

I have tried an empty Piper backbox and that was very LOUD  

 

 

 

ps: My first Piper backbox was replaced FOC by Piper with the repackable version, this is still using the original packing.  

 

 

Presumably it's a straight through perforated pipe in the middle - do you remember what diameter and length the perf. pipe was please?  

Edited by Nev, 17 November 2016 - 02:06 PM.

[siztenboots]

 

focus on the packaging of the rear silencer in to the space available and the noise levels / repacking issues.

 

if you look again you will realise it is 'thinking outside of the box', unlike pretty much every other vx220 backbox system  

 

the Posche 911 silencer approach, which essentially uses a silencer in each bumper corner to maintain a central tail pipe.

 

now that would be worth looking into

 

 

sorry, clearly a lot of thought has gone into having the optimal n/a layout with the primaries and merge collector positioning , can't see but guess its s 4-2-1, it was not my intention to criticise you.

 

my porsche is also mid engine, being the boxster variant and has a central exit, so yes in some ways similar, but having the two banks of three exhausts quite different from our I4. You could split the flow and perhaps have a valve controlling that.

[fezzasus]

 

my porsche is also mid engine, being the boxster variant and has a central exit, so yes in some ways similar, but having the two banks of three exhausts quite different from our I4. You could split the flow and perhaps have a valve controlling that.

 

 

You don't need to split the flow, you can flow from one silencer to the other.

[siztenboots]

 

 

my porsche is also mid engine, being the boxster variant and has a central exit, so yes in some ways similar, but having the two banks of three exhausts quite different from our I4. You could split the flow and perhaps have a valve controlling that.

 

 

You don't need to split the flow, you can flow from one silencer to the other.

 

here is the boxster backbox , opened up, two input flows and one common tailpipe, but two distinct output flows.

 

for a flat boxer 6, its quite a heavy thing with all the manifolds , iirc 4 or maybe 2 cats.

 

the green line is a mod, to drill the tailpipes , into the central section and bypass some chambers

 

[fezzasus]

 

 

 

my porsche is also mid engine, being the boxster variant and has a central exit, so yes in some ways similar, but having the two banks of three exhausts quite different from our I4. You could split the flow and perhaps have a valve controlling that.

 

 

You don't need to split the flow, you can flow from one silencer to the other.

 

here is the boxster backbox , opened up, two input flows and one common tailpipe, but two distinct output flows.

 

for a flat boxer 6, its quite a heavy thing with all the manifolds , iirc 4 or maybe 2 cats.

 

the green line is a mod, to drill the tailpipes , into the central section and bypass some chambers

 

 

 

Not the point. I'm not describing the flow within the silencer. I'm describing a route to get a more effective layout of the exhaust system

Edited by fezzasus, 17 November 2016 - 03:24 PM.

[vocky]

 

 

my porsche is also mid engine, being the boxster variant and has a central exit, so yes in some ways similar, but having the two banks of three exhausts quite different from our I4. You could split the flow and perhaps have a valve controlling that.

 

 

You don't need to split the flow, you can flow from one silencer to the other.

 

 

that was how I imagined it to be, go from turbo to a silencer mounted behind the wheel, then across to another silencer and then out the back. The silencers would have to be bespoke to fit in the vx220 clam, but quite a good idea  

[vocky]

 

 

clearly a lot of thought has gone into having the optimal n/a layout with the primaries and merge collector positioning , can't see but guess its s 4-2-1

 

 

I was trying to point out the fact that it comes out of the 4-2-1, then a U bend, then cat and a straight section, another U bend and into the Piper backbox, out of that and via another U bend out the back.

This creates a longer exhaust, a so called 'looped' system.

 

I had to remove the Piper backbox mounting brackets, spin the backbox 180 degrees, move the silencer up and back as far as possible, then reweld the backbox brackets in the new position. Took two weeks and plenty of headaches to get it to fit inside the heatshield

 

Works great on a NA and gives you an idea other than the 'norm'

[vocky]

 

Presumably it's a straight through perforated pipe in the middle - do you remember what diameter and length the perf. pipe was please?  

 

 

It is a perfed straight through silencer, and only has 2.5" pipework.

 

You should have a think about Fezz's idea, twin custom silencers - might work well with your power levels. I would suggest the inlet and outlets should be next to each other, rather than a straight through box.

[Exmantaa]

Turbo silencing should not be a huge problem due to the extra centrifugal silencer, but a high power SC is where most have huge noise problems.

(The 3" straight through Tullett SC noise is a joke on full chat...)

Clearly some out of the box thinking is required here and we also thought of removing the back loop to create more volume.

 

My feeling is that we simply need more absorbtion length for a decent straight through system (2 silencer cans), or we will need to make some kind of combined reflective/absorbtiontype muffler... 

(Vocky's loop creates a nice length in the system, probably evening-out the pulses and keeping his wadding in...)