Sixth Generation PAIR valve & flapper valve disabling

Please indicate your actual experience with the two modifications in the poll.
Only actual experiences please. There's already a whole lot of posts stating why they will or won't do anything.
Not interested in theory, only interested in actual experience.

I have done both mods individually and together.
I have removed them both individually and together for comparison rides..
I have had the tank up so many times I may need a new hinge or at least new bolts.

[image: View Post]CharlesW, on 07 April 2011 - 09:05 AM, said:

Please indicate your actual experience with the two modifications in the poll.
Only actual experiences please. There's already a whole lot of posts stating why they will or won't do anything.
Not interested in theory, only interested in actual experience.

I have done both mods individually and together.
I have removed them both individually and together for comparison rides..
I have had the tank up so many times I may need a new hinge or at least new bolts.

5th Gen here, so I didn't enter anything on the poll.

No performance effect on either.  Removed PAIR for PC-V autotune.  Flapper removed, snorkel in place.  Engine bay area is much easier to maintain without the hoses/solenoids for either.

I've had the PAIR disabled (by blocking off the rubber hose), the flapper undone, and the snorkel removed. Didn't really notice THAT much smoother of a ride or any noticeable performance gains. Snorkel made things louder, but that's it. Ended up putting it back to stock. Seemed like it was running rich with the PAIR disabled because the bike always left me reaking of exhaust (which is a common complaint of any bike with undertail exhaust, but this was really bad). What was probably happening, though, is the lack of extra air normally added by the PAIR made for cooler temps in the cat, causing it to take forever to light off (if at all). Just my theory.

Mike

I had removed my PAIR only because Dynojet had told me that I needed to for the Autotune to work correctly.  Later I decided to test it's function.  I connected a light to the PAIR electrical plug and went for a ride. I found the PAIR circuit was only active when the throttle was closed and when the temp was below 168(ish)F. Once the bike hit 169(ish), I never saw the light come on again. Since the bike doesn't go into close loop until it's up to temp, that would make since. The PAIR would never effect close loop operation. With further research, I found the PAIR is only to help reduce emissions during warm up. At the same time it helps generate heat in the CAT and also heats up the O2 sensor to help them both operate correctly. So what does removing it do? Well after the bike is at operating temp....nothing.   However, it my take the bike it's self a little longer to get to that temp. The reason I left mine off? One less thing to malfunction.

While the snorkel and flapper are there to lower intake noise, their main purpose is maintain intake viscosity at small throttle openings. The flap doesn't open until the bike can use the 'extra air'. Disabling the flap doesn't increase the overall volume for max power, at full throttle, and a RPM at which it's needed, the flap opens anyway. Disabling it and removing the snorkel can only hurt low speed torque.  

The fact that the intake sounds louder, mentally tricks our 'butt dyno' into thinking we're making more power.

Think about it, even if you could find a way to get more air in, because the bike has no air flow metering, you would only make the bike run leaner than it already is.  You would need to dynotune or Autotune to see any results.

Personally, I feel the only way to increase airflow without affecting low end torque is at the air filter, but that too would require some type of re-tuning.  I'm guessing after a little dust buildup on the stock filter, (with its screen and metal mesh) at full throttle the two 'intakes' will flow more air then the filter itself.

My 2cents.

[image: View Post]MadScientist, on 07 April 2011 - 10:29 AM, said:

5th Gen here, so I didn't enter anything on the poll.

No performance effect on either.  Removed PAIR for PC-V autotune.  Flapper removed, snorkel in place.  Engine bay area is much easier to maintain without the hoses/solenoids for either. No disrespect toward the 5th Gen, but one thing often commented on is the effect the PAIR mod sometimes has on V-Tech transition. Not likely to happen with the 5th Gen.   :biggrin:
Good to have your input though.

[image: View Post]CharlesW, on 07 April 2011 - 07:38 PM, said:

[image: View Post]MadScientist, on 07 April 2011 - 10:29 AM, said:

5th Gen here, so I didn't enter anything on the poll.

No performance effect on either.  Removed PAIR for PC-V autotune.  Flapper removed, snorkel in place.  Engine bay area is much easier to maintain without the hoses/solenoids for either. No disrespect toward the 5th Gen, but one thing often commented on is the effect the PAIR mod sometimes has on V-Tech transition. Not likely to happen withthe 5th Gen.   :biggrin:
Good to have your input though.
Disrespect? Sounds like a complement to me! :cheerleader:

[image: View Post]whiteboyslo, on 07 April 2011 - 10:55 AM, said:

I've had the PAIR disabled (by blocking off the rubber hose), the flapper undone, and the snorkel removed. Didn't really notice THAT much smoother of a ride or any noticeable performance gains. Snorkel made things louder, but that's it. Ended up putting it back to stock. Seemed like it was running rich with the PAIR disabled because the bike always left me reaking of exhaust (which is a common complaint of any bike with undertail exhaust, but this was really bad). What was probably happening, though, is the lack of extra air normally added by the PAIR made for cooler temps in the cat, causing it to take forever to light off (if at all). Just my theory.

Mike
Interesting about the exhaust odor. I didn't notice that at all.

[image: View Post]coderighter, on 07 April 2011 - 12:33 PM, said:

I had removed my PAIR only because Dynojet had told me that I needed to for the Autotune to work correctly.  Later I decided to test it's function.  I connected a light to the PAIR electrical plug and went for a ride. I found the PAIR circuit was only active when the throttle was closed and when the temp was below 168(ish)F. Once the bike hit 169(ish), I never saw the light come on again. Since the bike doesn't go into close loop until it's up to temp, that would make sense. The PAIR would never affect close loop operation. With further research, I found the PAIR is only to help reduce emissions during warm up. At the same time it helps generate heat in the CAT and also heats up the O2 sensor to help them both operate correctly. So what does removing it do? Well after the bike is at operating temp....nothing.   However, it may take the bike it's self a little longer to get to that temp. The reason I left mine off? One less thing to malfunction.

While the snorkel and flapper are there to lower intake noise, their main purpose is maintain intake viscosity at small throttle openings. The flap doesn't open until the bike can use the 'extra air'. Disabling the flap doesn't increase the overall volume for max power, at full throttle, and a RPM at which it's needed, the flap opens anyway. Disabling it and removing the snorkel can only hurt low speed torque.  

The fact that the intake sounds louder, mentally tricks our 'butt dyno' into thinking we're making more power.

Think about it, even if you could find a way to get more air in, because the bike has no air flow metering, you would only make the bike run leaner than it already is.  You would need to dynotune or Autotune to see any results.

Personally, I feel the only way to increase airflow without affecting low end torque is at the air filter, but that too would require some type of re-tuning.  I'm guessing after a little dust buildup on the stock filter, (with its screen and metal mesh) at full throttle the two 'intakes' will flow more air then the filter itself.

My 2cents.
So based on your findings the exhaust reek experienced by whiteboyslo would only be happening while at idle or when the throttle is closed and prior to reaching operating temperature.
It seems like you would have to spend a lot of time idling with the throttle closed and the engine at less than operating temperature to cause one to reek of exhaust fumes.
I don't do much riding in traffic and very seldom idle the engine. That might be why I have never noticed any exhaust odor.
The fact that you didn't mention any exhaust odor either makes me think that the results are somewhat varied.

Interesting discussion even if I don't understand much of it.   :mellow:

well, don't get me wrong. i didn't get off the bike EVERYTIME smelling of exhaust. it was a cumulative thing. my jacket would smell of exhaust and need washed every few weeks. i still have to wash it now, but much less frequently. as to whether i ride before operating temp, yes. my general rule is to warm the bike until the temp gauge reads a value (95�?), then take it easy until over 150 or so (because you don't get VTEC until then anyway). past that, i ride it like i would any other time.

Mike

'whiteboyslo' Mike:
Another thing that seems a little strange to me is your bike running rich with the exhaust modifications and the K&N filter.
Based on the information provided by 'coderighter' it should be running lean, shouldn't it?

The fact that the ECU doesn't compensate for changes in air flow was a surprise to me.
Don't most automotive ECUs do that?
Do most motorcycle ECUs not do that?

As I said earlier, lots of good information that I certainly don't understand.
The only thing I am sure of is the fact that I do enjoy the bike.

Well, again, I'm not doing a good job of explaining myself. Sorry. My first post was a bit hasty. What i meant by 'running rich' was that the exhaust smell was as though the bike were running rich (in that the exhaust smelled more). But like I said, I think what's REALLY happening is the whole deal with the cat that I wrote before.

And yes, you're absolutely right that, if anything, my bike is probably running lean due to the mods I've done. As to why the ECU doesn't compensate, I'm going to take a stab at it but certainly someone can come along and tell me I'm dead wrong. With automobiles, there are basically two ways FI systems handle the amount of air coming into an engine. A mass-air system has an inline sensor upstream of the throttle body that actively measures the volume of air coming into the engine and adjusts accordingly. However, prior to this system, most FI vehicles ran a system known as speed density, which doesn't so much 'know' how much air is coming in so much as it 'guesses'. These systems use feedback from various other sensors (O2, MAP, etc) to get a rough idea of what's going on, but ultimately they're just using a bunch of tables that were calculated based on what the engineers thought the original air volume was going to be. While many (most) cars run Mass Air systems at this point, bikes are a bit behind the curve and mostly use speed density systems.

Mike

The fuel injection system on your average bike don't  have air flow meters like cars do.  The main reason for this is because the meter has to be after the air filter but in the 'path' of all cylinders.  There's just not room on you average bike for all this plumbing.  Think of it, on the 6th gen VFR you would still have to have the cover over the throttle body but you'd have to add  a 3 inch (or so)  tube off it  that would  house an air flow meter of some type on it.  The tube would also have to be a minimum of 8 inches long to get a good reading.  Then on the other end of the tube you would still need a filter housing large enough to hold an enough filter to feed the engine.  Just not enough room.  The other reason.........bean counters!

If you look at the K&N filter for 6th (and 5th) gen VFR you'll notice that the actual filter size is much smaller than the factory filter.  The K&N has about half the surface area of the factory filter.  K&N knows the bike has no way of accounting for any extra air so they make the filter flow the same as stock so as not to disturb (further) the air/fuel ratio.  Since K&N's filter medium flows more than the factory paper filter, they simply made the filter area smaller to even things out.  Which means, by design, the K&N filter buys you no performance gain, zip, zero, nota.  However, it's the last filter you have to buy because you can wash and re-oil it.

The fuel smell could very well be you EVAP canister.  If you try to cram the tank full for a long ride, you can actually back fill the canister with fuel through the vacuum lines.  Once you stop the bike the hot pipes will heat up the canister, expanding the contents forcing vapor out the vent port on the canister.  Run 'light' fuel fills for awhile and it should eventually go away.

[image: View Post]coderighter, on 08 April 2011 - 09:09 AM, said:

The fuel smell could very well be you EVAP canister.  If you try to cram the tank full for a long ride, you can actually back fill the canister with fuel through the vacuum lines.  Once you stop the bike the hot pipes will heat up the canister, expanding the contents forcing vapor out the vent port on the canister.  Run 'light' fuel fills for awhile and it should eventually go away.

Uhmmmm........ could that vapor overflow out of the vent pipe be dangerous? Maybe that's why one should get rid of the canister all together to prevent that build up and let the vapor just go out freely. Your description makes it sound like there could be a gas bomb building up under the bike next to the hot headers......

Beck
95 VFR

[image: View Post]Beck, on 08 April 2011 - 11:52 AM, said:

[image: View Post]coderighter, on 08 April 2011 - 09:09 AM, said:

The fuel smell could very well be you EVAP canister.  If you try to cram the tank full for a long ride, you can actually back fill the canister with fuel through the vacuum lines.  Once you stop the bike the hot pipes will heat up the canister, expanding the contents forcing vapor out the vent port on the canister.  Run 'light' fuel fills for awhile and it should eventually go away.

Uhmmmm........ could that vapor overflow out of the vent pipe be dangerous? Maybe that's why one should get rid of the canister all together to prevent that build up and let the vapor just go out freely. Your description makes it sound like there could be a gas bomb building up under the bike next to the hot headers......

Beck
95 VFR


The pipes are not really not enough to ignite the vapors.  You pretty much would need a spark or open flame, or a least pipes that were glowing red (white) hot.  However, if you have a gas water heater with a pilot light in your garage, I wouldn't park right next to it

When you see on the gas pump where it says 'Don't top off', back filling the Evap canister is the main reason.  Not only can it be dangerous, but it can turn the charcoal in the canister into mud ruining it.   Besides, the mud inside adds weight to the bike and we don't want that now do we.

[image: View Post]CharlesW, on 07 April 2011 - 07:44 PM, said:

[image: View Post]whiteboyslo, on 07 April 2011 - 10:55 AM, said:

I've had the PAIR disabled (by blocking off the rubber hose), the flapper undone, and the snorkel removed. Didn't really notice THAT much smoother of a ride or any noticeable performance gains. Snorkel made things louder, but that's it. Ended up putting it back to stock. Seemed like it was running rich with the PAIR disabled because the bike always left me reaking of exhaust (which is a common complaint of any bike with undertail exhaust, but this was really bad). What was probably happening, though, is the lack of extra air normally added by the PAIR made for cooler temps in the cat, causing it to take forever to light off (if at all). Just my theory.

Mike
Interesting about the exhaust odor. I didn't notice that at all.

I have a very sensitive nose, the VFR is a VERY VERY stinky Bike, it has a rotten egg smeel via the cat, everyone who rides a catted vfr smells like this. It is true if you ride the bike under operating temp, it will run rich , especially, below 140 degrees, you might even smell raw fuel.  This is total stock no mods

I have done both, the pair valve has no affect but the flapper un done for me made the VTEC smothers   !!!!!!!!!!!!

I have been running without the PAIR and flapper for a couple of years now, and to get a good idle my PC3 is set to -5% at 0% throttle and 1200-1500 RPM which indicates that with the PAIR disabled, the engine goes slightly rich at idle
(why you may ask?)  which could account for the rich smell.
Interestingly, the map then goes +5% and +10% at 2% throttle to get good transition off idle.
I dont think there is much point in doing the PAIR disable unless you have a powercommander to compenste for any changes in fuelling that may result.

Edi:t Yeah I forgot, you need to increase the idle speed and I also had to adjust the wax unit to get a fast idle on cold starts after disabling PAIR

Asking for just a little more information.
For those that voted "No noticeable effect".
Did you not see any difference at all in the operation/running of the engine?
I'm referring in particular to the 200 to 300 rpm drop in idle speed. (Never understood what caused that.)

FWIW, it's easy to see why this topic creates so much conversation.

2/3 of the PAIR voters see "No noticeable effect". Quite a signifcant percentage.
But, 1/3 of the PAIR voters see "A positive effect". Too large of a percentage to completely ignore.

The flapper valve voting is equally inconsistent.
"Positve effect" votes equal "No noticeable effect" votes and there are even a couple of "Negative effect" voters.

[image: View Post]CharlesW, on 09 April 2011 - 10:02 AM, said:

Asking for just a little more information.
For those that voted "No noticeable effect".
Did you not see any difference at all in the operation/running of the engine?
I'm referring in particular to the 200 to 300 rpm drop in idle speed. (Never understood what caused that.)

FWIW, it's easy to see why this topic creates so much conversation.

2/3 of the PAIR voters see "No noticeable effect". Quite a signifcant percentage.
But, 1/3 of the PAIR voters see "A positive effect". Too large of a percentage to completely ignore.

The flapper valve voting is equally inconsistent.
"Positve effect" votes equal "No noticeable effect" votes and there are even a couple of "Negative effect" voters.

Isnt the purpose of disabling the pair valve is so you dont get false air/fuel ratio feedback data when you tune a PC3 on a dyno?

[image: View Post]mello dude, on 09 April 2011 - 11:13 AM, said:

Isnt the purpose of disabling the pair valve is so you dont get false air/fuel ratio feedback data when you tune a PC3 on a dyno? Possibly, but that isn't covered in this poll.

[image: View Post]CharlesW, on 07 April 2011 - 09:05 AM, said:

Please indicate your actual experience with the two modifications in the poll.
Only actual experiences please. There's already a whole lot of posts stating why they will or won't do anything.
Not interested in theory, only interested in actual experience.

I have done both mods individually and together.
I have removed them both individually and together for comparison rides..
I have had the tank up so many times I may need a new hinge or at least new bolts.

I have just done the Pair Valve and flapper valve disabling together with removing the snorkel and I can say that at 5k rpm the bike accelerates better...am on stock pipes and K&N airfilters.

Waiting for then next fuel up to know the exact mileage if there is a decrease or increase.....