Performance claims are totally anecdotal . Unless the engine has had racing cams, larger injectors/fuel pump and racing ecu, de-catting is just polluting for no reason. There is literally zero gain. I can smell a de-cat bike or car a mile away, fortunately they are easy to pass. Unpopular facts but there it is.
De-cat Headers 1250 vs 1300
- Thread starter gateway77
- Start date
Agree.
That's why I made clear it was about ' feel and character' not numbers.
All of these bikes have more than enough power out the crate for any old / young idiot to ride stupidly fast.
But that's not the objective.
That's why I made clear it was about ' feel and character' not numbers.
All of these bikes have more than enough power out the crate for any old / young idiot to ride stupidly fast.
But that's not the objective.
CATS are restrictive and detrimental to power output. However, simply removing them isn’t enough, you have to increase the fuel to air ratio (AFR) as well.
I'd normally agree that a decat header will make a good gain over stock.
in the gs1300 case it seems bmw did a great job in its design. BHP uk said their system is only 2hp more over stock (both flashed) which really surprised me. the decat headers obviously lighter which is always nice.
in the gs1300 case it seems bmw did a great job in its design. BHP uk said their system is only 2hp more over stock (both flashed) which really surprised me. the decat headers obviously lighter which is always nice.
Modern properly sized cats have almost no restriction or back pressure. Virtually zero effect on engine performance.
Yeah, I’m starting to learn this. I don’t own a 1300, but after speaking to people that own them and Motorrad mechanics, it would seem the latest closed - loop management system works very well with the Euro 5 suffocation and simply doesn’t want you fucking with it. For this reason, if I ever bought a 13 I’d be tempted to leave well alone
All interesting feedback - much appreciated.
Ironically and opposed to most of our beliefs (mine included lol) you actually go faster with less noise!
Clearly illustrated with earplugs - as they increase your concentration and awareness.
Just saying
Clearly illustrated with earplugs - as they increase your concentration and awareness.
Just saying
………having said that, I do enjoy a ‘blip’ between downshifts and the occasional loud backfire 
Absolute rubbish, a properly set up engine with a decat & correct fueling helps the bike run cooler, protects the upper cylinder, reduces valve wear into valve seats and doesn't smell either.
Just to give an update on this subject.
I fitted the DNA stage 2 filter package - that's made a really HUGE difference in the sound and character!
Not that noticeable when you start up or around town or so good for the neighbours etc.
Also fine at cruising speeds without any constant drone in the background.
But once you give it the beans it's got a great induction growl, very rorty - also sounds good coming down through the box.
Much more prominent than I expected and personally I wouldn't want it any louder, so no need now to consider the de-cat headers.
As said this wasn't about increasing 'performance' but giving it more character. The bike was already faster than my ability.
The Akra slip on and the Healtech servo switch I had already and they helped a bit - but it was still lacking something.
With the DNA filters fitted it sounds fantastic especially in Dynamic Pro - (but can't see how that makes any difference).
One last point for anyone doing this - it's an easy job in itself but very fiddly to get the filter cover bolts back in place when re-assembling.
None of the YouTube videos show this in practise and I can see that it wouldn't film very well. You just have to take your time and be patient.
NB. I've no doubt the service dept at BMW will not like this addition so assume I'll should replace the originals before getting anything done? ( to not void any warranty ).
Thanks for the feedback to my original question - much appreciated.
I fitted the DNA stage 2 filter package - that's made a really HUGE difference in the sound and character!
Not that noticeable when you start up or around town or so good for the neighbours etc.
Also fine at cruising speeds without any constant drone in the background.
But once you give it the beans it's got a great induction growl, very rorty - also sounds good coming down through the box.
Much more prominent than I expected and personally I wouldn't want it any louder, so no need now to consider the de-cat headers.
As said this wasn't about increasing 'performance' but giving it more character. The bike was already faster than my ability.
The Akra slip on and the Healtech servo switch I had already and they helped a bit - but it was still lacking something.
With the DNA filters fitted it sounds fantastic especially in Dynamic Pro - (but can't see how that makes any difference).
One last point for anyone doing this - it's an easy job in itself but very fiddly to get the filter cover bolts back in place when re-assembling.
None of the YouTube videos show this in practise and I can see that it wouldn't film very well. You just have to take your time and be patient.
NB. I've no doubt the service dept at BMW will not like this addition so assume I'll should replace the originals before getting anything done? ( to not void any warranty ).
Thanks for the feedback to my original question - much appreciated.
Good to hear. I've ordered the DNA stage 2 a few weeks back but haven't received it yet. Something went wrong with the delivery. But this sounds promising.
The warranty is also something that crossed my mind. I might be tempted to go back to stock before going in for service, although it depends on how fiddly the assembling process is
The warranty is also something that crossed my mind. I might be tempted to go back to stock before going in for service, although it depends on how fiddly the assembling process is
If you just replaced the original covers no one would know what air filter is underneath.Good to hear. I've ordered the DNA stage 2 a few weeks back but haven't received it yet. Something went wrong with the delivery. But this sounds promising.
The warranty is also something that crossed my mind. I might be tempted to go back to stock before going in for service, although it depends on how fiddly the assembling process is
I can't imagine it's a problem to use different air filters providing they are compliant - but BMW are definitely getting more picky.
The stage two covers are easily identified as different as they have massive cut outs to allow more air to flow.
This might be a problem if spotted a they clearly state - Race Use Only.
As I mentioned it's not hard to take the covers off - that's a just two minute job.
But lining up the bolts to put a cover back on was a bit of a pain.
Having said that now I know I'd just be prepared to take more time over it - so not really an issue.
I'm due a 12k service in a few weeks which I believe includes air filters - if I tell them not to bother changing them I would expect that potentially would cause a warranty issue.
Presumably they would need to check the current filters are fit for purpose and in good condition. So in that case it would make sense for me to replace with the originals.
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