Air Induction system removal?

[Fred]

There's multiple components to the system.
There's the reeds, which are one way valves, and are necessary because the pressure in the exhaust system varies in pulses.

Then there's the main valve, which is computer controlled. This is a simple on/off valve.

So, if the computer has turned the main valve on, then the reeds come into play and will allow the low pressure pulses in the exhaust to suck fresh air into the exhaust system.

The main valve is only on when the throttles are closed, or when the bike is still warming up. I should not have said "idle" as that is confusing to some. During decel, the throttles are at idle position, even though the engine is at high revs.

I'll recap now and hope that there's no more confusion.

The AIS only operates when the bike is in one or more of the following conditions.

1. Warming up.

2. Idling.

3. Decelerating with a closed throttle.

Given that none of these are situations where you are trying to make power, the AIS is totally irrellevent to your dyno tuning.

The AIS is not linked to the cat, either. Many bikes have an AIS without a cat.

As for the popping of the exhaust, that's what AIS does. The sound is unburned fuel getting burned off in the pipe. The reason you can hear it with your aftermarket pipe is quite simple. You have an aftermarket pipe, and it doesn't muffle the bike as well as the stock pipe. So you're hearing the popping that was already happening.


On another tack, I really enjoy breathing. Can we please leave the emissions stuff in place so that the next generation can also experience the pleasure that we refer to as "air"?

Fred

 

[gt89stang393]

About 10+ years ago European Car magazine took a VW GTI and put on a CAT by pass pipe and then dynoed it. It made LESS HP and less torque with the by pass pipe, that is how good the VW CATs are, really any CAT sold today.

I have to disagree, I will bet money that the ONLY reason it would lose power is a lean condition caused from removing the cat and the engine cutting timing instead of dumping in more fuel. You cannot tell me a properly tuned engine will make more power with a cat than without. Not going to happen or you would see racecars and race bikes with cats on them. Also, I will bet that GTI was a normally aspirated engine on regular fuel and not the turbo engine on premium.

 

[Hellgate]

I have to disagree, I will bet money that the ONLY reason it would lose power is a lean condition caused from removing the cat and the engine cutting timing instead of dumping in more fuel. You cannot tell me a properly tuned engine will make more power with a cat than without. Not going to happen or you would see racecars and race bikes with cats on them. Also, I will bet that GTI was a normally aspirated engine on regular fuel and not the turbo engine on premium.

You may disagree but the fact of the matter is that in this case the car made less power, period. Yes this particular car was an NA car. GTi series motors have typically run on Super.

Also a lean condition does not necessarily reduce power, usually it increases power depending on the throttle setting and the rpm of the motor.

Racers don't run them because the are exempt for emissions and because CATs can build up with stuff over extended periods of very high rpms so race cars don't use them. But for street use there is no issue at all in modern vehicles.

The whole point of this post was to state that will a CAT may not add power, it does not kill power.

For all of the people on this forum who have installed a CAT by pass pipe please post before an after dyno sheets, I've not see one yet.

 

[ddg]

This is what I like about this forum so much. With my first post yesterday morning I knew pretty much nothing about this part of the bike. It seems to get a bit more discussion on FZ1 and R1/R6 forums. 24 hours later I've spent 4 hours or so researching and discussing here and now I know a lot more about it. Everyone will make their own decisions and have their own opinions but more knowledge is never a bad thing.

 

[gt89stang393]

I still feel there is some information missing from the outcome in that article. I have had every imaginable exhaust combination on my mustangs. Stock, high-flow cats, no cats, and back when I first put an off road H-pipe onto my first mustang it went two full tenths quicker in the 1/4 mile. I broke that car into the 13's by putting the off road H-pipe on it. My second mustang is my GT I have now, when I removed the cats on that I put an off road X-pipe on it acted like a new car.

A lean condition COULD make more power if you have the fuel/timing to support it. Go lean in a turbo/blower motor at WOT and watch what happens. I run my car lean actually, close to 1400* EGT's, only possible with 110 octane.

 

[coursonap]

Yes, and after you turn the reed valves around, the bike's exhaust will be flowing into the airbox during closed throttle and warmup.

Fred

It wil not be going into the airbox if you Remove the hoses and selonoid. Then cap off the tubes on the head and in the air box.

 

[Wildcard]

I just did this mod in about 2 hours (which included going to the store to get caps). Fairly easy and straight-forward. Just take off the air box and the battery box and move the rubber heat shield around to get to everything. At first I took the reeds out and flipped them around and tried to do the other side, but the screws were so tight that I started to round them. Therefore I just ended up capping off the tubes on the head (with 5/8" vacuum caps) and the air box got capped (3/8" cap). The AIS itself comes off with just one 8mm screw. Piece of cake.

As for riding now, there is much less pop on deaccel, and my idle has smoothed out significantly (deleted cat + two bros +bmc).

 

[ddg]

I ordered a set of these, Graves Motorsports - Graves Motorsports Smog Block Off Plates Yamaha R1 (04-09) R6 (03-09) R6S (06-09) FZ1 (All) Kawasaki ZX6RR (03-08) ZX10R, ZX14R (ALL). They don't specify that they fit a FZ6 however an '04 R6 and FZ6 have identical part numbers for the cap. I'll let everyone know how it goes once I get them in the mail. Shouldn't be any different then turning the reeds upside down and capping off the tubes, however I'm a sucker for add-ons.

 

[gt89stang393]

I will be doing the complete removal tomorrow afternoon. I cannot think of a way to vent the crankcase into the exhaust without custom work being done so I will do the complete removal.

 

[4drfocus]

The setup on the FZ6 looks like whats on my Ford Focus.A one way valve hooked up to the valve cover thats connected to the intake via a rubber hose,when the throttle opens it pulls the crankcase blow-by gases thru the intake to be burned with the air/fuel mixture,by doing so you relieve pressure in the upper portion of the engine,resulting in 1.a stable idle 2.a smoother and more responsive engine.I looked over the FZ6 and didn't find anything that connected the AIS to the exhuast?. I have raced my Focus with both setups, and it runs alot better with the crankcase ventilation system hooked up.just food for thought.

 

[SovietRobot]

The AIS isn't connected to the exhaust.

It "injects" air into the cylinders during the exhaust stroke, which makes it come out through the exhaust system superheated. Then it combusts with the unburnt fuel when it comes in contact with the hot catylitic converter.

 

[Fred]

The AIS isn't connected to the exhaust.

It "injects" air into the cylinders during the exhaust stroke, which makes it come out through the exhaust system superheated. Then it combusts with the unburnt fuel when it comes in contact with the hot catylitic converter.

Sorry, but that's incorrect.

The air is injected into the exhaust, not the combustion chamber.

The air comes in via the two ports in the valve cover, and then goes down into the cylinder head and comes out in the exhaust ports on the cylinder heads, downstream of the exhaust valves.

Also, don't confuse the air injection system with the crankcase breather. That's a separate system.

Fred

 

[SovietRobot]

Sorry, but that's incorrect.

The air is injected into the exhaust, not the combustion chamber.

The air comes in via the two ports in the valve cover, and then goes down into the cylinder head and comes out in the exhaust ports on the cylinder heads, downstream of the exhaust valves.

Also, don't confuse the air injection system with the crankcase breather. That's a separate system.

Fred

That's exactly what I said...

Sorry, I said "cylinders" instead of "cylinder head", but you know what I mean.

 

[gt89stang393]

What I am thinking about is how to do a setup like I have on my Mustang, I have breathers that have hoses that run down into the rear of the header collectors and connect to one way check valves which connect to angled tubes welded to the collector. As the exhaust flows through it pulls the crankcase gasses into the exhaust stream and helps with ring seal. This has been confirmed that an air pump sucking the pressure from the engine does show a huge increase is power. The system I have gives you quite a bit less though.

 

[SovietRobot]

What I am thinking about is how to do a setup like I have on my Mustang, I have breathers that have hoses that run down into the rear of the header collectors and connect to one way check valves which connect to angled tubes welded to the collector. As the exhaust flows through it pulls the crankcase gasses into the exhaust stream and helps with ring seal. This has been confirmed that an air pump sucking the pressure from the engine does show a huge increase is power. The system I have gives you quite a bit less though.

I'm not sure what that system would be.
If it pulls fresh air from the intake, then it would be a variant of the AIS system.
But you say it pulls it from the crankcase? I've never heard of that.

A crankcase breather system usually goes back into the air intake(like on my jeep)

Is your mustang a fox body? They used all sorts of weird smog control devices back then, so who knows

 

[gt89stang393]

The car is very far from stock and yes it is a fox body. Its a strip/street car, I say it that way since it is street legal but I cannot drive it on the street due to fuel being close to $8 a gallon for 110 octane. In PA you are emissions exempt if you put less than 5000 miles a year on the cars. Anyway, I completed the AIS removal along with BD's dual headlight mod today. The bike is a little smoother in decel, but still was surging at idle. I turned the idle down a little bit and it smoothed out. I gotta get the TB's synced.

 

[urbanj]

lets reexamine the manual for a second. everything in bold i'll touch on.

"Air injection
The air induction system burns unburned
exhaust gases by injecting fresh air (secondary
air) into the exhaust port, reducing the
emission of hydrocarbons. When there is negative
pressure at the exhaust port, the reed
valve opens, allowing secondary air to flow into
the exhaust port. The required temperature for
burning the unburned exhaust gases is
approximately 600 to 700°C.
Air cut-off valve
The air cut-off valve is controlled by the signals
from the ECU in accordance with the combustion
conditions. Ordinarily, the air cut-off valve
opens to allow the air to flow during idle and
closes to cut-off the flow when the vehicle is
being driven. However, if the coolant temperature
is below the specified value, the air cut-off
valve remains open and allows the air to flow
into the exhaust pipe until the temperature
becomes higher than the specified value."

All vehicles have catalytic converters for one reason only - emissions.

all vehicles have precats and maincats. the precats are placed as close to the cylinder head as possible so they heat up and light off faster which reduces the cold start emissions. cold start emissions are the number one worry for manufacturers. you'll see a lot of modern technology will have the precats built into the exhasust manifold right at the head.

the fz6 has precats in the header tubes and a main cat in the middle of the exhaust. the manual clearly states the ais only injects air at idle OR when the vehicle is cold until the coolant temp is at a specified value. That is so the unburned fuel can be burnt off in the precat during cold start. the ecu is waiting for when the magic 600-700 deg. C exhaust gas temp is achieved and the gases can burn themselves. this all reduces cold start emissions.

when you snap the throttle shut there is a brief rich period that happens. the more throttle leading up to snapping thr throttle shut, the more fuel out the exhaust. adding air into the exhaust gives air for the fuel to burn with thus reducing emissions further.

none of this has anything to do with being on the throttle and making power. thats why race cars will backfire huge flames out the exhaust when coming into a corner under these certain conditions.

so getting rid of the ais will only make the bike run dirtier. it will not smooth out a pull on the dyno or make it more accurate in regards to AF ratio.

 

[SovietRobot]

It also activates during closed to partially opened throttle. This is what gives you "decel popping", because you let off the throttle and the AIS valves open up.

If you already removed the cat, there's no reason you shouldn't remove the AIS system, as it'll make it run smoother(only if you've removed the cat)

These systems are put in to appease governments with regards to smog polutants. Sure if you're an eco nut you can talk about how removing it is "bad for the environment", but whatever. To each his own.

 

[Fred]

The point that just about everybody is missing is this.

There is NO PROOF WHATSOEVER that removing these components will make any more power. And until somebody does consecutive dyno runs with their bike stock, and then with their bike modified, there will be no proof.

There is, however, plenty of proof that they will make more pollution. But I guess I'm an "eco nut" for wanting clean air.

But go ahead, **** up your bike all you want and try to convince yourself that you've improved it.

I give up.

 

[4drfocus]

So, now that we have two parties (eco nuts & throttle jockeys), I have seen AIS delete kits on fleabay from time to time.