Snapper Posted July 28, 2017 Share Posted July 28, 2017 Please forgive my laziness and lack of research, but I have a simple question for those who understand what a 'cat' does ... If I remove the entire stock exhaust system from my 2001 (pre-VTEC) VFR800 and replace it with this complete Delkovic system ... Link ... ... then how will it affect the running of the bike (given that the sensors previously attached to the Catalytic convertor will now not be attached to anything)? Thanks, in advance, for your replies. Andy Link to comment Share on other sites More sharing options...
Member Contributer VFROZ Posted July 29, 2017 Member Contributer Share Posted July 29, 2017 You will need to make some O2 eliminators with some 330ohm resistors from memory. It got rid of the closed loop to open loop hesitation in the fuel injection when cruising on my bike, which used to annoy me. Link to comment Share on other sites More sharing options...
Member Contributer slowbird Posted July 29, 2017 Member Contributer Share Posted July 29, 2017 12 hours ago, VFROZ said: You will need to make some O2 eliminators with some 330ohm resistors from memory. It got rid of the closed loop to open loop hesitation in the fuel injection when cruising on my bike, which used to annoy me. The O2 Elimination can be done while still running a cat. Link to comment Share on other sites More sharing options...
Member Contributer swas Posted July 30, 2017 Member Contributer Share Posted July 30, 2017 I've been researching the same conversion and assumed the two plugs shown on the right angled mixer in the parts explosion pic were for O2 sensors? Link to comment Share on other sites More sharing options...
Snapper Posted August 1, 2017 Author Share Posted August 1, 2017 On 7/30/2017 at 9:09 AM, swas said: I've been researching the same conversion and assumed the two plugs shown on the right angled mixer in the parts explosion pic were for O2 sensors? I think you're right - I didn't spot that when I was looking at the exhaust system pics on ebay. Thanks! Link to comment Share on other sites More sharing options...
Member Contributer Mohawk Posted August 2, 2017 Member Contributer Share Posted August 2, 2017 The cat does 2 things, 1. it changes some burnt gas hydrocarbons to CO2, this being its primary function. 2. restricts exhaust exit velocity, this is a parasitic loss, the design of the cat usually reduces this as much as possible, but it still obstructs gass flow. If you add the Delkevic system & I assume it was tuned for no O2 sensors, the you don't have to worry about the bike running lean, as without the O2 sensors the ECU defaults to a richer map, so all good there. You only need one of the O2 sensor circuits to have a resistor fitted to turn the Fi light out, or buy a Powercommander O2 eliminator, which just plugs in. You should get a better mid range, a nicer noise & about 5hp increase in peak output. Disable the pair system & do the flapper mod then fit a powercommander & have it mapped & your bike will feel much fitter & should have a much reduced snatch from on/off throttle opening. YMMV Link to comment Share on other sites More sharing options...
ciprinakos Posted August 6, 2017 Share Posted August 6, 2017 The gain from removing the convertor is not great comparing with the fact that you, and your passanger mostly, will get choked with the exhaust gases when stopped or going very slow on traffic. Due to an accident I have replaced my headers with one without catalytic convertor but I intend to put one back. Cheers! Link to comment Share on other sites More sharing options...
Member Contributer thtanner Posted August 6, 2017 Member Contributer Share Posted August 6, 2017 18 minutes ago, ciprinakos said: The gain from removing the convertor is not great comparing with the fact that you, and your passanger mostly, will get choked with the exhaust gases when stopped or going very slow on traffic. Due to an accident I have replaced my headers with one without catalytic convertor but I intend to put one back. Cheers! How ever did we survive riding VFRs before 2000 when they added the cat? I think you are overstating the fume situation just a tad... Link to comment Share on other sites More sharing options...
ciprinakos Posted August 13, 2017 Share Posted August 13, 2017 My intention was not to make it seem that the riding is impossible but the well being on a cat exhaust is better. The difference can be observed while standing behind a car with and one without cat (running on gasoline). Not to mention that, when I am at red lights, the nearby drivers are cursing me or the bike for the fumes. On a track and outside city it may not make a difference though... except if you are stopped by a in traffic mobile laboratory control - usually they do random checks on the vehicle safety and pollution abiding rules :) Link to comment Share on other sites More sharing options...
Member Contributer JZH Posted August 13, 2017 Member Contributer Share Posted August 13, 2017 Bizarre theory you've created there... Personally, I find the noticeable egg-smell associated with catalyst-equipped petrol engines much more noxious than that associated with older gasoline-powered internal-combustion engines. But then again, I have a very planet-unfriendly attraction to the unmistakably intoxicating aroma of a two-stroke burning Castrol R... Ciao, Link to comment Share on other sites More sharing options...
Member Contributer Lorne Posted August 13, 2017 Member Contributer Share Posted August 13, 2017 7 hours ago, JZH said: I have a very planet-unfriendly attraction to the unmistakably intoxicating aroma of a two-stroke burning Castrol R... I've heard that adding just a little Castrol R to your VFR's tank offers that old race-bike scent to the exhaust. Don't add too much - you don't want too lean a mixture Link to comment Share on other sites More sharing options...
Member Contributer MaxSwell Posted August 14, 2017 Member Contributer Share Posted August 14, 2017 I've noticed an unwelcome smell when idling in traffic and my 2001 fifth has oem engine and exhaust. I feely a little guilty for those nearby. But I'm a tree hugger from way back. A former fifth came with aftermarket exhause and a Power Commander. Fuel mileage improved by ~10% when I removed them. However the off-idle snatch was back. It was nice how smooth all across the rpm spectrum the throttle was with the PC. Link to comment Share on other sites More sharing options...
Member Contributer MaxSwell Posted August 14, 2017 Member Contributer Share Posted August 14, 2017 7 hours ago, Lorne said: I've heard that adding just a little Castrol R to your VFR's tank offers that old race-bike scent to the exhaust. Don't add too much - you don't want too lean a mixture And I just love the smell of napalm in the morning. Link to comment Share on other sites More sharing options...
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