Fake exhaust pipes
Re: Fake exhaust pipes
It’s just a conclusion based on the fact that I’ve followed many BMWs crawling in traffic in London and in such instances the valve opens and closes irrelevant of how much throttle is used. They’re usually opening and closing every 10 seconds crawling at 5 mph so it must be doing something to reduce emissions.
How about not having a sig at all?
Re: Fake exhaust pipes
It isn't. Mito is an idiot. None of this is news.
Re: Fake exhaust pipes
When we run our gas engines through big urea filters we control the back pressure with a big butterfly valve. This is downstream of the cat and filter arrangement. It’s to make the filters more effective but I’m not sure at what point the back
Reassure affects it, ours is load dependant but I’ve not commissioned one yet.
It may be similar in that you need a certain gas flow through the cat to be as effecient as possible.
Dave!
Reassure affects it, ours is load dependant but I’ve not commissioned one yet.
It may be similar in that you need a certain gas flow through the cat to be as effecient as possible.
Dave!
Re: Fake exhaust pipes
How about not having a sig at all?
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NotoriousREV
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Re: Fake exhaust pipes
Noisy start is probably just the delay in accumulating enough vaccum to close the exhaust valve flap. I think some cars have started fitting small vacuum tanks to enable a "quiet start" mode. That or electric exhaust valves but they're far more expensive and heat sensitive.
As for the valves being used for controlling back pressure that's been happening for a while on dieseasels so it's now affecting petrol too. Higher back pressure gives you more EGR as a guess?
Re: Fake exhaust pipes
It's different to the pre-WLTP cars. They open and close constantly to increase back-pressure and heat the cats up more. It looks ridiculous.McSwede wrote: ↑Sat Apr 27, 2019 7:49 pmHow can it be anything to do with emissions? All the valve is doing is altering the route the gasses take as they have already been through the cat and PPF.Mito Man wrote: ↑Sat Apr 27, 2019 6:52 pm The valve opens and closes randomly when crawling through traffic from what I’ve seen, of course it opens fully under harder acceleration to also give more noise but it is definitely being used for emissions purposes too as every dual exhaust BMW seems to have it now regardless of being a sporty model or not.
Re: Fake exhaust pipes
Ok. I'm glad mine is out of site. I may just unplug it.ste wrote: ↑Sun Apr 28, 2019 11:04 amIt's different to the pre-WLTP cars. They open and close constantly to increase back-pressure and heat the cats up more. It looks ridiculous.McSwede wrote: ↑Sat Apr 27, 2019 7:49 pmHow can it be anything to do with emissions? All the valve is doing is altering the route the gasses take as they have already been through the cat and PPF.Mito Man wrote: ↑Sat Apr 27, 2019 6:52 pm The valve opens and closes randomly when crawling through traffic from what I’ve seen, of course it opens fully under harder acceleration to also give more noise but it is definitely being used for emissions purposes too as every dual exhaust BMW seems to have it now regardless of being a sporty model or not.