Airbox mod pics anyone?
- Thread starter lothodon
- Start date
lyric911
New member
You basically only need the rim that holds the air filter to remain. Anything else is restricting air flow. Cut out the restriction.
Hmm, and the cpu just detects the airflow and dumps more fuel to compensate? Sorry this is my first fuel injected bike, it sure is nice have having to mess with the jets.
lyric911
New member
To take full advantage, you'll need some method of flashing a map. PCV is the popular choice. From the factory they run stupid rich though, and leaning it out a little should net a tiny bit more power.
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Vapordan
Guest
No, it's doing a lot more than that. But the final outcome is as you describe, an air/fuel mixture. That is really all the combustion chamber cares about.
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Vapordan
Guest
you do mean the opposite right? Bikes are lean to meet emissions.
MotoRick
Motorcycle Fanatic
I would think so too.
FZh8in
New member
+1. It's definitely super lean from the factory. When I put my PCV on I had to make my map much richer to make the bike run like it should
Black Widow
Avid Rider
I guess a EFI bike is different from car/truck EFI gas engines when it comes to fuel mapping. With a vehicle if you change intake air(increase or decrease) and change exhaust backpressure( less restrictive muffler, remove cat), the Mass airflow meter or Manifold Absolute Pressure sensor( depending on design), in conjuction with the Oxygen senor(s), will relay incoming air volume and density to the ECM and thus ECM controls injector pulse width to compensate for extra air and achieve a 14.7:1 air fuel mixtue(stoichiometric,meaning the ultimate mixture for a clean efficient burn), without useing any aftermarket programmers. Please educate me on how a bike cannot do the same, i know it has an )2 post CAT , is there no intake air measurement used on a bike.... curious and wanting to learn more about bike mapping. I am the guy to keep engine,mapping, exhaust stock on my 8, but like to learn is all.
lyric911
New member
No, I mean rich. And I'll give my reason more as a question:
Somebody that has a stock bike (at least as far as tune/intake/exhaust is concerned) - when the exhaust is cool, wipe your finger on the exhaust outlet. Is there soot on your finger now?
If so, that's unburnt fuel that made it to the exhaust, which means a slightly rich tune.
This is done from the factory because the catalyst + AIS will take care of any unburnt fuel (and the ais wouldn't be necessary at all if there weren't unburnt fuel). If it's tuned lean, you're going to wind up with valve and ring damage.
Edit: I do not know the target AFR used by the stock tune for the closed loop area of the stock map. Nor do I know the target values that were used when Yamaha created the open loop map either. When I say that the stock tune is rich, I mean richer than 14.7:1. Adding more fuel will still likely make more power as the extra fuel will allow the burn to be cooler and more controlled.
Edit 2: Since I have a PCV and an auto tune, if I have some free time this weekend I'll load up the stock map again and see what the AFRs are. Granted, I won't be able to see them under load. Most of my experience is with cars rather than bikes. I suppose it's possible that they come lean, but every exhaust I see has soot.
Edit 3: With edit 1 I was trying to say that the stock tune may be rich while still being leaner than max power.
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lyric911
New member
The stock O2 sensor only adjusts fuel in the closed loop area of the map. Figure G in the below linked pdf has that range highlighted. http://www.powercommander.com/downloads/22-040/install/pcv/eng22-040.pdf
The open loop area - which is the rest of the map - is a predetermined fuel map and is not adjusted by the o2 sensor.
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Vapordan
Guest
Take a step back.
Bikes come from manufacturers COMPROMISED for emissions, see stoichiometric curve in below post. I love that word because it exactly captures the behavior. Every critical part of the bike forms part of that compromise chain. Added a new slip-on? So that removes the compromise on the exhaust but the electronics is still compromised. Wonder why the airbox hole is so tiny? Emissions compromise. Sure the ECU will adjust and it should do so in the exact same way as the car (for the most part), but it is adjusting according to its 'strategic objective' which is to compromise the output ratio for emissions keeping it to the right of stoichiometric ideal. Put a bigger hole in the airbox? still compromised.
However, a PCV is TUNED for performance. That necessarily implies that the compromise (at least in the electronics) has been removed. The evidence for that is in the torque smooth out between 4 - 5k rpm for remapped bikes. It's a different 'strategic objective' which places a higher premium on performance. The mere fact that you started by replacing your stock muffler for a performance slip-on implies that you are less interested in emissions and more interested in performance. You've removed the compromise in one area so it makes sense to remove the compromise on the electronics in keeping with your new 'strategic objective' of performance over emissions.
Those kinds of questions show that you aren't interested in smoking the shit that everybody repeats on the Internet. Good stuff.
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Vapordan
Guest
So the convention is to refer to this as a lean mix, see the stoichiometric ideal. We're on the same page. Bikes come from the factory with a compromise that moves the AFR to the right of ideal max power, lamda 0.86. PCVs would attempt to move them back to the left, ideally to wherever max power is calculated at for that bike, at that temperature, at that pressure, at that location, for that batch of gasoline etc. I assume here that stoichiometric ideal varies based on environmental conditions, e.g., water will boil without fire (AFR = 1:0) in space but needs fuel (14:1) at sea level to accomplish the same.
Notice that it's not practically possible to approach max power and still get better gas mileage than a compromised bike. Well yes (the far right-end of the curve) but your power output would suck a la turtle speed.
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Black Widow
Avid Rider
ya, now i understand better. Thanks guys.
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Vapordan
Guest
I am in the process of wrapping up some deep research on mapping which I want to post eventually. What's Important now is to state that mapping and tuning for power is not without its negatives. Consider carefully if a map, custom or otherwise is best before diving in. Engines that are tuned for power fail faster and require more servicing. Also, the way in which mapping done is by, and large, a software hack which can cause unstable behavior in certain conditions. Enjoy the map, just understand that there is absolutely no free cheese inspite of what a vendor may claim.
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WARPTH
Guest
only if the warranty concern is directly in line with the modification.
so if you blow your motor due to a lean out. than no. yamaha wont cover it.
if your control box goes faulty, than running the bike lean had nothing to do with it so its still covered by warranty.
well in australia anyway.