Experiences VFR 1200 riders with disabled PAIR

[vfrflanders]

Some say that it would not be wise to disable the PAIR on the VFR 1200. That's why I would  like some feedback from those who have done it anyway.

Explanation:

When the PAIR opens fresh oxygen comes through the exhaust valves in the exhaust pipe and the O2 sensors ( also called lambda sensors) will measure other air / fuel ratios. With an open PAIR, presumably the ECU receives from the O2 sensors a richer mix. The question is: what does the ECU with this changing value and HOW is it compensated?

If the compensation is done by the ECU on the actual values sent by the O2 sensors, we have a problem with a disabled PAIR.  If the ECU is programmed that the mix is richer with an open PAIR and the ECU adjusts the A/F ratio to the combustion chambers this will result in a wrong (too lean) mixture.

We just do not know what the ECU does just at the moment when the PAIR opens and that is the big problem. In short, many questions but no real answers.

Hence the question: what are your experiences after the PAIR was eliminated?

[luvtoleanit]

Excellent.  It's not needed for anything other than emissions.  If you disable the PAIR  you will have to tune the bike via piggyback ECU module.  I use a powercommander for this.

[crakerjac]

I blocked the PAIR valve and I don't have a PCV or tuning module.  Bike seems to run the same as before and I haven't any problems with the bike flooding while taking off like I did before the PAIR removal.. but that might be coincidence.

[Volfy]

IMO there is no need to block the PAIR unless you are planning on altering your fueling via PCV or reflashed ECU.  Just because it is used for emission control doesn't automatically mean it negatively affects performance.  First, decide whether you want/need to modify fueling, then block the PAIR accordingly.  Not the other way around.

If your bike is not running well, it would be better to troubleshoot the actual problem than fussing with the PAIR in hopes that it would get better.

[crazybrother]

For those of you that have had Don Guhl flash your ECU it works great with the PAIR system removed/disabled. He corrects that in his tuning.

[BiKenG]

This is a good question that I've pondered before. If there are lambda sensors downstream of the PAIR injection point, then they will see a different mixture. But, this air injection only occurs on the overrun as far as I know (correct me if I'm wrong) at which time it's possible the ECU isn't checking the lambda sensors' output. The PAIR system cannot be very precise and for the ECU to mess with mixture while the PAIR system is operating, letting in imprecise amounts of fresh air would not seem very reliable to me when the ECU normally needs to control the mixture with great precision.

 

I've removed and blocked it off completely on my bike. I have a PCV, with a map for an Akrapovic. But my can is not the std. one for the VFR and it runs a bit rough low down. In fact, it's better at low revs with the PCV 'disengaged', i.e. not modifying the fuelling. Hard to tell what effect PAIR removal has had. None I suspect.

 

One thing's for sure, PAIR removal does not increase power as it's not a power related function. It's emissions only and I can't stand the garbage it puts on top of the engine under the airbox. It's bad enough working on modern bikes without all that additional shit in the way, so I remove it all as a matter of course on all my bikes.

 

As for its actual operation, well they try to tell us that it helps burn off nasties in the exhaust gas, while in the pipe, which has always sounded very suspect to me. Actual combustion continuing inside the pipe? Doesn't sound like a good idea to me. What it IS doing is adding more clean air into the overall output. This quite obviously will reduce the emissions figures which are calculated as the quantity of unwanted gasses etc (which hasn't changed) compared to the overall quantity of gas, which has been increased. So in my considered opinion the PAIR system is nothing more than a new fangled modern version of the 'air pump' that many US cars used to have to have in order to pass emissions tests. Simply pumping fresh air into the exhaust reduces the emissions figures. Does it actually reduce the quantity of noxious substances being emitted? Nope. But passing those tests was all that was required.

 

Surely vehicle manufacturers can't be that sneaky and underhand, can they?

 

VW

 

I rest my case.

[Marsman99]

2 hours ago, BiKenG said:

Does it actually reduce the quantity of noxious substances being emitted? Nope. But passing those tests was all that was required.

 

Surely vehicle manufacturers can't be that sneaky and underhand, can they?

 

VW

 

I rest my case.

 

Not very sneaky really.  VW at least tried to hide it in code, a PAIR system is a bit obvious.  Surely the EPA or EEA wouldn't be so easily duped if it were simply a volumetric deception...but then again.  

[Volfy]

The amount of fresh air injected into the exhaust is nowhere near enough to "dilute" the emissions test readings.  The catalytic converter does a good job of catalyzing the reaction that reduces NOx and CO to less harmful NO2 and CO2, but it is only a catalyst.  The reaction requires oxygen.  This is where the fresh air injection comes into play.  It injects just enough air to provide the O2 necessary for the reaction, which is exothermic.  That's why the cat gets hot and can melt if the engine is wayyy out of tune and makes the cat work overtime.  This rarely happens these day with ECU and feedback controls.

 

PAIR isn't a cheat.  It actually does work to reduce harmful emissions.  Yanking it out in the name of performance, if you so choose, but you are not doing the EPA any favors.