cat removal... does it work?

beaver

beaver

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Have a spare set of headers and was thinking about removing the cat, anyone done this at all?... its wider where the cat sits so does this give pressure waves for flow... so may be best to fabricate a pipe inside to take its place?... any thoughts :) obviously the valve will go aswell
 
Yes, I have on a 2017 GSA mainly to get rid of excessive heat on the right side. Seems to pick up and go better although the fuelling might need sorting out. Slight improvement in fuel economy as well.
 
I have a catlless akro, if you want to remove the heat and improve throttle response yes it works, but if you are looking for more peak power and torque then ignore the hype, it doesn’t work. Mine produces exactly the same peak power and torque as my mates which has a stock system. Both have hilltop remaps both on the same dyno. I was on knobby tyres so I may have lost a couple of ponies through them. But the throttle response is better, no more heat at the feet and sounds awesome without being intrusive.
 
From what I know that stupid cat is only good for emissions controls, some swear you loose power, I removed cat on my fatbob, stuck a set of streetbob headers on without cat, engine ran cooler, no loss of power, so why would BMW be any different.
 
Amazingly the MoT revisions in May didn't bring in any significant changes, so emissions still not tested/measured. noise is largely at the testers discretion too, as long as the pipe isn't marked as being 'for race/track use only'.

However, if you plan to tour on the bike, just be aware that some countries have anti-tampering laws when it comes to exhaust systems. Whilst the chance of getting spotted is low, the implications for the trip, if pulled, can become a right PITA.
 
squibb34 said:
Amazingly the MoT revisions in May didn't bring in any significant changes, so emissions still not tested/measured. noise is largely at the testers discretion too, as long as the pipe isn't marked as being 'for race/track use only'.

However, if you plan to tour on the bike, just be aware that some countries have anti-tampering laws when it comes to exhaust systems. Whilst the chance of getting spotted is low, the implications for the trip, if pulled, can become a right PITA.
Click to expand...

Any legal issue in a foreign country is a PITA but I don't know anyone who has been pulled for a noisy pipe in Europe, listen to what the HD crowd rides. The tone of the pipe changes when going catless, it was a bit tinny and harsh but changed for the better after a re-map, I don't find it intrusive over longer trips, even 600milers.
 
GB. said:
Any legal issue in a foreign country is a PITA but I don't know anyone who has been pulled for a noisy pipe in Europe, listen to what the HD crowd rides. The tone of the pipe changes when going catless, it was a bit tinny and harsh but changed for the better after a re-map, I don't find it intrusive over longer trips, even 600milers.
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Although you are correct about the tinny noise and sometimes a remap, in Germany, they get the bloody noise meter out now, and if bike is to loud at the Police stop, bike goes away on a trailer.
 
Not wanting to argue but I go to Germany every year and never heard this before and still don’t know of anyone myself That I know in the last forty years of riding being pulled for a noisy pipe in Europe but I’m sure someone has.
 
I met a guy down in the W.Tyrol, with an R1. Full race system, a tiny 'show' plate & tail tidy. He got pulled in Germany, in an Umwelt zone, where stop checks often crop up in my experience. Apparently the Polizei spotted both issues but seemed more interested in the fact that cameras would not be able to read his dodgy plate & hence the authorities would be unable to send on any speeding violations. He managed to talk his way out, without a fine or confiscation - I think they took pity on his discomfort, riding that bloody noisy thing for a few thousand miles.

However Switzerland is an entirely different ball game. Cross the line of legality there & little/no sympathy will be shown. Your bike, your trip, your decision - just don't come bleating on here if you get nicked please.
 
No, I'm thinking more of taking the cat out of the std set,, either down the pipe if you can smash it up (as ive done before) or having to open the pipe and remove it... but should I put a pipe in its place to help the flow as it goes into a can type area?...
 
squibb34 said:
I met a guy down in the W.Tyrol, with an R1. Full race system, a tiny 'show' plate & tail tidy. He got pulled in Germany, in an Umwelt zone, where stop checks often crop up in my experience. Apparently the Polizei spotted both issues but seemed more interested in the fact that cameras would not be able to read his dodgy plate & hence the authorities would be unable to send on any speeding violations. He managed to talk his way out, without a fine or confiscation - I think they took pity on his discomfort, riding that bloody noisy thing for a few thousand miles.

However Switzerland is an entirely different ball game. Cross the line of legality there & little/no sympathy will be shown. Your bike, your trip, your decision - just don't come bleating on here if you get nicked please.
Click to expand...

Same old story really, you run a small plate and an obnoxiously loud exhaust you are asking for trouble really, small plates are like a red flag to a bull. No bleating from me bud, it’s a bit like speeding in the towns on the IOM, behave like a twat get treated like a twat.
 
GB. said:
Not wanting to argue but I go to Germany every year and never heard this before and still don’t know of anyone myself That I know in the last forty years of riding being pulled for a noisy pipe in Europe but I’m sure someone has.
Click to expand...

Does not happen all the time, but they have their crackdown moments, I have had one already, but bike was all standard so OK, on Harley taken away on a trailer, many more videoa around.

 
beaver said:
No, I'm thinking more of taking the cat out of the std set,, either down the pipe if you can smash it up (as ive done before) or having to open the pipe and remove it... but should I put a pipe in its place to help the flow as it goes into a can type area?...
Click to expand...

If you are smashing the cat out of the standard headers, their is no way they can see anything at all, but I can tell you one thing having decatted an silencer on a Harley, that metal is bloody hard to get out.
 
As I said in my first post the only benefit is the reduction of the heat and a slight improvement in throttle response. And it is as hard as hell like you say, a mate just did his triumph and took him forever
 
GB. said:
As I said in my first post the only benefit is the reduction of the heat and a slight improvement in throttle response. And it is as hard as hell like you say, a mate just did his triumph and took him forever
Click to expand...

Yep the bugger comes out in bits, and cuts like a stanley knife, stole the wifes steel meshed gloves from the kitchen to do the job, but got caught.................:D
 
Did it on the pre-cats on my TVR (both sides)... as you say, took ages and its sharp... if it does not change things much then maybe it can stay?... will just take out the flap so it sounds better on the bottom end ;)
 
beaver said:
No, I'm thinking more of taking the cat out of the std set,, either down the pipe if you can smash it up (as ive done before) or having to open the pipe and remove it... but should I put a pipe in its place to help the flow as it goes into a can type area?...
Click to expand...
Just mark and cut at one end of the cat and drill/smash it out before welding back up, jobs a good 'un


Sent from my SM-A320FL using Tapatalk
 
that was plan B if you can't get to it :)
 
not sure they would go back... on first start up they would be blown into the silencer, but agree, cut the can and re-weld... but as posted above, if the flow is not restricted that much why bother?... May be just a flap job to make it sound nicer :)
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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