de cat what extra can i expect

fizzer

fizzer

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hi folks,i have a r1200gs twin cam ,i had it remapped at hilltop last year and it goes great ,but i have a mate who is giving me some std headers untouched,i am going to cut them open at the weld and have the cat removed then re tig welded back together.what power increase if any can i expect .or am i just wasting my time and effort :bow
has anyone done this
 
You would be better get a set of used no cat headers. The gas flow is significantly improved and you have the old cat header to put back if you ever need to. The OEM headers do not flow very well and removing the cat core (while removing the bung) wont solve the poor gas flow.
 
Probably not much after it's been hill topped.

De catting normally helps smooth out the power dip at 4500rpm ish, makes it rev a wee bit better and gives you a few bhp.
 
Bendy toy said:
You would be better get a set of used no cat headers. The gas flow is significantly improved and you have the old cat header to put back if you ever need to. The OEM headers do not flow very well and removing the cat core (while removing the bung) wont solve the poor gas flow.
Click to expand...

Why not? the Keihans are identical size to the OEM and improve things no end.
 
I done both, one after the other and (in my experience) the decat headers perform much better then the standard ones with cat removed. Much better sound as well.
 
thanks guys for the imput,BENDY ,yeh i hear what you say mate ,but spending money at the moment is a no no ,we have just moved house.and i have spent a fortune.:thumb
 
fizzer said:
thanks guys for the imput,BENDY ,yeh i hear what you say mate ,but spending money at the moment is a no no ,we have just moved house.and i have spent a fortune.:thumb
Click to expand...

Keep watching the For Sale section. Meantime, put up with what you have and hope a bargain doesn't arrive while you're still broke.
 
Bendy toy said:
The OEM headers do not flow very well....
Click to expand...
I'm curious as to the evidence for this sweeping statement. Why do they not flow very well? Or rather, how does the not flowing very well manifest itself?
Alan R
 
fizzer said:
thanks guys for the imput,BENDY ,yeh i hear what you say mate ,but spending money at the moment is a no no ,we have just moved house.and i have spent a fortune.:thumb
Click to expand...

Bad news Fizzer, about to put my Keihan headers on the for sale section....in great condition....they really do add some extra punch...but also noise that Mrs Oldnfat couldn't put up will (we tour....a lot).



Happy to send up to you if you pay postage (about £15) and will sell for £160. Happy to hold on to them for a couple of months if that helps....no probs if you then decide you don't want them as long as you can commit to a response by end of say...January.
 
mate,they look gorgious ,but i am going to go down the route of cutting up an original set ,but thanks for the offer.
i rang geoff at hilltop this morning,he said if i do this when i start the bike ,let it tick over for about four mins for the remap to read the fact that there is no cat in place .:thumb
 
A pal of mine had a full Arrow decat system and can on his twincam,also Hilltop mapped.
MWhile it defo had more top end ,it introduced a horrible little vibration through the foot pegs.

I put the standard headers and can back on minus flappy valve and it is now the smoothest twincam I have ridden.
I guess it depends on wether you want noise or smoothness.
 
fizzer said:
mate,they look gorgious ,but i am going to go down the route of cutting up an original set ,but thanks for the offer.
i rang geoff at hilltop this morning,he said if i do this when i start the bike ,let it tick over for about four mins for the remap to read the fact that there is no cat in place .:thumb
Click to expand...

No problem...good luck with the decatectomy.
 
I had my TC Hilltopped then fitted decat headers (Keihans). I hesitate to disagree with a man of Bilko's experience but the improvement with the headers was quite marked on my bike. It's also quite a bit noisier, but not, for me, in a bad way. I discussed retrofitting decat headers with Geoff when I was at Hilltop and he said the map would self-adjust and I haven't had any problems at all.
 
The BMW ECU can adapt to decat headers and free flow silencer or the plain OEM system with no problems. The standard can with free flow headers is a bit noisy but I wear ear plugs and it's not offensive to other road users so I enjoy the extra zip available.
 
I agree that the noise is increased...but in a good way. If I wasn't so pussy whipped I'd still have them on.
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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