High flow / sports particulate filters

garethdj

garethdj

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So I know a lot of folks will just decat and remove the OPFs but it’s not something I’d ever do given the legalities, always like to remain above board.

Whilst sitting googling some exhaust stuff I came across a high flow DPF so I emailed the supplier to ask if they could also produce the same for petrol engines (maybes it’s just the same part regardless), they said yes and that they’d just need to know dimensions.

I know there’ll be a load of debate, what’s the point, will it make any extra performance gain, sound difference etc.

Wondering if many aftermarket manufacturers will go this route with Downpipes, offering both sports cats and opf. I was speaking to someone on insta a while back who said milltek where looking at something like this.

Once the car can be mapped it’s something I’ll personally explore, even if there’s nothing off the shelf, I’ll look at the custom fab route.

It may well be a grey area legally as the existing emissions stuff has been replaced but it would no doubt pass both visual and emissions checks in an mot.


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garethdj said:
So I know a lot of folks will just decat and remove the OPFs but it’s not something I’d ever do given the legalities, always like to remain above board.

Whilst sitting googling some exhaust stuff I came across a high flow DPF so I emailed the supplier to ask if they could also produce the same for petrol engines (maybes it’s just the same part regardless), they said yes and that they’d just need to know dimensions.

I know there’ll be a load of debate, what’s the point, will it make any extra performance gain, sound difference etc.

Wondering if many aftermarket manufacturers will go this route with Downpipes, offering both sports cats and opf. I was speaking to someone on insta a while back who said milltek where looking at something like this.

Once the car can be mapped it’s something I’ll personally explore, even if there’s nothing off the shelf, I’ll look at the custom fab route.

It may well be a grey area legally as the existing emissions stuff has been replaced but it would no doubt pass both visual and emissions checks in an mot.


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Removal of opf on a pcp car or that matter any new car is just asking for trouble
 
jassyo06 said:
Removal of opf on a pcp car or that matter any new car is just asking for trouble
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I’m talking about replacing not removing altogether, granted that might be by the by as the original won’t be there. The same goes for any modification generally though but all depends on the terms of your PCP too…


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garethdj said:
I’m talking about replacing not removing altogether, granted that might be by the by as the original won’t be there. The same goes for any modification generally though but all depends on the terms of your PCP too…


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I was in agreement with you.. as for pcp terms and conditions replacement of the opf l aint familiar with .....but if its fine by Audi service technicians ..ergo
 
jassyo06 said:
I was in agreement with you.. as for pcp terms and conditions replacement of the opf l aint familiar with .....but if its fine by Audi service technicians ..ergo
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Ah right got it.

I’m going to map mine regardless so happy to take the warranty risk. I don’t think it’s more of a concern with those on Audi finance.

I’d imagine most PCPs say no mods but I do also know some generally have the approach that as long as it can easily be put back to stock and is so if returned then no issues, of course that’s subjective when mapping and what not.


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garethdj said:
Ah right got it.

I’m going to map mine regardless so happy to take the warranty risk. I don’t think it’s more of a concern with those on Audi finance.

I’d imagine most PCPs say no mods but I do also know some generally have the approach that as long as it can easily be put back to stock and is so if returned then no issues, of course that’s subjective when mapping and what not.


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The minute you make those cuts to get rid of OPF / put in sports one / put in straight pipes the engine warranty is kaput……

Even if you bolted them back in Audi would notice extra exhaust clamps, the whole turbo / OPF is one single piece.


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8YARWY said:
The minute you make those cuts to get rid of OPF / put in sports one / put in straight pipes the engine warranty is kaput……

Even if you bolted them back in Audi would notice extra exhaust clamps, the whole turbo / OPF is one single piece.


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I’m going to map it anyway so warranty will go.

I thought the opfs were in the Downpipe, post cat? Or is it different on the 8Y?


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garethdj said:
I’m going to map it anyway so warranty will go.

I thought the opfs were in the Downpipe, post cat? Or is it different on the 8Y?


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Yes after the primary cat, it’s all one piece so if just removing the OPF you’ll need to make a cut in the pipes.


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8YARWY said:
Yes after the primary cat, it’s all one piece so if just removing the OPF you’ll need to make a cut in the pipes.


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Separate for the turbo though right? If I was to do it I’d get a full replacement Downpipe fabricated rather than chopped and swapped.

Chances of me actually doing it and going beyond stage 1 are pretty slim just interesting to explore!


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garethdj said:
Separate for the turbo though right? If I was to do it I’d get a full replacement Downpipe fabricated rather than chopped and swapped.

Chances of me actually doing it and going beyond stage 1 are pretty slim just interesting to explore!


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Yes.

If you aren’t going beyond stage 1 though I don’t see the point of removing the primary cat on the turbo, stage 2 upward yes to get rid of thermal load.

So in theory you could just cut out the OPFs like a Golf R res delete and put in straight pipes / map out / module delete the pressure sensors.


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8YARWY said:
Yes.

If you aren’t going beyond stage 1 though I don’t see the point of removing the primary cat on the turbo, stage 2 upward yes to get rid of thermal load.

So in theory you could just cut out the OPFs like a Golf R res delete and put in straight pipes / map out / module delete the pressure sensors.


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Yeah that’s what I’m saying I’ll likely just go stage 1 and not do anything with OPFs, was just interesting to know high flows are a thing.


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garethdj said:
Yeah that’s what I’m saying I’ll likely just go stage 1 and not do anything with OPFs, was just interesting to know high flows are a thing.


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Your Op was regarding the OPF’s though no ?

My point is if you are looking at spending money on sports OPF’s, why bother ?

Just cut the OPF’s out and replace with straight.

You can always clamp the OPF’s back in should you need too.


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8YARWY said:
Your Op was regarding the OPF’s though no ?

My point is if you are looking at spending money on sports OPF’s, why bother ?

Just cut the OPF’s out and replace with straight.

You can always clamp the OPF’s back in should you need too.


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I'd assume it's the same reason some people do sports cats instead of a decat. It just means that you don't have to take the whole downpipe out when it comes to an MOT (which appears to be a pain in the ****) and if you get pulled they won't be able to do you for removing the emission control system.
 
Daggerit said:
I'd assume it's the same reason some people do sports cats instead of a decat. It just means that you don't have to take the whole downpipe out when it comes to an MOT (which appears to be a pain in the ****) and if you get pulled they won't be able to do you for removing the emission control system.
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Yes if you want a ‘belt & braces’ approach, however most would be happy to have clamp in / out straight through pipes ala 2nd decats.

Chances of a roadside inspection to see if OPFs are in place, very minimal I’d say.


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Daggerit said:
I'd assume it's the same reason some people do sports cats instead of a decat. It just means that you don't have to take the whole downpipe out when it comes to an MOT (which appears to be a pain in the ****) and if you get pulled they won't be able to do you for removing the emission control system.
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This is essentially my thinking.


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8YARWY said:
Yes if you want a ‘belt & braces’ approach, however most would be happy to have clamp in / out straight through pipes ala 2nd decats.

Chances of a roadside inspection to see if OPFs are in place, very minimal I’d say.


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I agree chances are minimal and probably still complaint with a cat in place as far as the emissions level go but I’m thinking worst case, you’re involved in an accident, police look at the car, declare it’s not road legal, insurance void, even if it’s listed down with the insurer, I’m sure they’ll look to get out wherever the can.

Anyway just hypothetical out of interest at this point as I say.


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Anyone know if the US version has the filters and where it might be located? My car is super quiet and its driving me nuts, everything else about the car is amazing, especially the suspension, that was a nice surprise. Since its not my daily I'm contemplating a temporary custom straight pipe until AWE comes out with an affordable exhaust system (just spoke with them, its in the works, 4-6 months tops).
 
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Economist said:
Anyone know if the US version has the filters and where it might be located? My car is super quiet and its driving me nuts, everything else about the car is amazing, especially the suspension, that was a nice surprise. Since its not my daily I'm contemplating a temporary custom straight pipe until AWE comes out with an affordable exhaust system (just spoke with them, its in the works, 4-6 months tops).
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ASR valve controller helps with more ‘noise’.


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There's a set of resonators just before the back box, I'm curious to see what the sound would be like without these in place.
 
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8YARWY said:
Yes if you want a ‘belt & braces’ approach, however most would be happy to have clamp in / out straight through pipes ala 2nd decats.

Chances of a roadside inspection to see if OPFs are in place, very minimal I’d say.


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Pretty sure that's not possible given that the cat is directly behind the turbo. Likely why you don't see any 'clamp in and out' options for these cars.
 
Economist said:
So to remove those, that would be the downpipes correct?
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Correct. Don't quote me on it, but I believe that the 8V downpipe options fit on our cars so there's plenty options if so. The issue you'll have is that once the filters are removed you'll end up with the engine light coming on and maybe pulling power / not running right since there's no mapping options yet to map them out.
 
HulkRS3 said:
There's a set of resonators just before the back box, I'm curious to see what the sound would be like without these in place.
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Worth a try! On the B9 S4 I had, people took out the resonators and it did make the sound louder but also caused drone in the cabin. I really think the ideal setup (for my taste) would be a sports cat downpipe with OPFs removed and the standard Audi sports exhaust from there back.
 
Daggerit said:
Pretty sure that's not possible given that the cat is directly behind the turbo. Likely why you don't see any 'clamp in and out' options for these cars.
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I’m on about the OPFs.


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Daggerit said:
Pretty sure that's not possible given that the cat is directly behind the turbo. Likely why you don't see any 'clamp in and out' options for these cars.
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Also Scorpion did a clamp in / out sports cat option for the FL 8V, again for the primary cat, not the OPF's which is what I've been discussing above.

OPF's are accessible from under the car in the same position as the 2nd Cats used to be in........
 
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8YARWY said:
Also Scorpion did a clamp in / out sports cat option for the FL 8V, again for the primary cat, not the OPF's which is what I've been discussing above.

OPF's are accessible from under the car in the same position as the 2nd Cats used to be in........
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I stand corrected! Surely that can't be worthwhile given how stuffed down in the engine bay the cat is?

EDIT: I've had a look and see what you mean now. The clamp in and out cat section is in a completely different place than the standard primary cat, my only concern would be the O2 sensors actually reaching it.
 
Daggerit said:
I stand corrected! Surely that can't be worthwhile given how stuffed down in the engine bay the cat is?

EDIT: I've had a look and see what you mean now. The clamp in and out cat section is in a completely different place than the standard primary cat, my only concern would be the O2 sensors actually reaching it.
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Scorpion moved the clamp in section further down so it was easily accessible to owners.......

Below is the 8Y layout
 

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8YARWY said:
Scorpion moved the clamp in section further down so it was easily accessible to owners.......

Below is the 8Y layout
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It would work for removable OPFs then, not sure if you'd be able to combine it with a removable cat though, just given the space constraints and stuff.

All this being said, you'd have to get the car mapped to need removable OPFs and cats anyway which defeats the point for me. If you're trying to keep it legal and have a high flow cat and OPF then you're not going to need them removable anyway I wouldn't have thought.
 
Daggerit said:
It would work for removable OPFs then, not sure if you'd be able to combine it with a removable cat though, just given the space constraints and stuff.

All this being said, you'd have to get the car mapped to need removable OPFs and cats anyway which defeats the point for me. If you're trying to keep it legal and have a high flow cat and OPF then you're not going to need them removable anyway I wouldn't have thought.
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Not on OPF removal though, as there are pressure sensor module deletes available soon..........

The key thing is whether someone can come up with a solution for removing OPF's that doesn't involve removing the whole downpipe to achieve it, which is a big old job......

Although i bet someone will probably have a go at gutting them 'in situ' at some point lol
 
Daggerit said:
Correct. Don't quote me on it, but I believe that the 8V downpipe options fit on our cars so there's plenty options if so. The issue you'll have is that once the filters are removed you'll end up with the engine light coming on and maybe pulling power / not running right since there's no mapping options yet to map them out.
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Im hoping on the American model its a little different. But im so desperate for some sound that im willing to try and let yall know haha
 
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Economist said:
Im hoping on the American model its a little different. But im so desperate for some sound that im willing to try and let yall know haha
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If you lie down level with drivers door you should be able to see them.


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