Pete Denzer
New member
Just finished installation of Evoluzione O2 eliminator in an effort to cure low-end and light throttle spittiness experienced with Hindle muffler and Evoluzione air filter in unmodified OEM airbox.
Installation was not difficult as directions were clear. Disconnected battery as per instructions to allow ECU to reset.
Of course, it started to rain just as I was buttoning things up in garage so I am unable to report performance results. Needless to say, I will be driving on a closed course for competition purposes only.
But I will say this: Revving it in garage sounded a lot less spitty, even when not fully warmed up. Idle was steadier, rock solid at 1350-1400 rpms, same as stock air filter and muffler. Without the O2 eliminator idle was not as steady and went as high as 1450 and as low as 1300.
I think I'm on the right track, thanks to Ken's patient explanation of how the eliminator works when I phoned in my order. Aparently the O2 sensor leans out the mixture but only works at lower rpms and light throttle openings. The stock muffler has enough back pressure to not be affected that much by it, and it is so quiet that any spits and pops are muted.
But put on a louder, freer-breathing muffler and the low-speed mixture is not only leaned out, but the spits and pops are much more evident. Eliminating the O2 sensor is akin to unplugging the mixture screw on a Keihn CV carburetor and running it out a little bit, and maybe raising the needle a notch.
At larger throttle openings and higher rpm the mixture is rich enough that the Hindle pulls like gangbusters. Makes me wonder if it's actually too rich for the stock muffler,
I am encouraged by the results so far, will offer complete track test when weather conditions allow.
I can hardly wait.
Installation was not difficult as directions were clear. Disconnected battery as per instructions to allow ECU to reset.
Of course, it started to rain just as I was buttoning things up in garage so I am unable to report performance results. Needless to say, I will be driving on a closed course for competition purposes only.
But I will say this: Revving it in garage sounded a lot less spitty, even when not fully warmed up. Idle was steadier, rock solid at 1350-1400 rpms, same as stock air filter and muffler. Without the O2 eliminator idle was not as steady and went as high as 1450 and as low as 1300.
I think I'm on the right track, thanks to Ken's patient explanation of how the eliminator works when I phoned in my order. Aparently the O2 sensor leans out the mixture but only works at lower rpms and light throttle openings. The stock muffler has enough back pressure to not be affected that much by it, and it is so quiet that any spits and pops are muted.
But put on a louder, freer-breathing muffler and the low-speed mixture is not only leaned out, but the spits and pops are much more evident. Eliminating the O2 sensor is akin to unplugging the mixture screw on a Keihn CV carburetor and running it out a little bit, and maybe raising the needle a notch.
At larger throttle openings and higher rpm the mixture is rich enough that the Hindle pulls like gangbusters. Makes me wonder if it's actually too rich for the stock muffler,
I am encouraged by the results so far, will offer complete track test when weather conditions allow.
I can hardly wait.