Loss of low end after slip on and K&N

K

kjonas75

New member
A few weeks ago a installed a Graves slip on and K&N Air filter.

I've noticed there has been a slight drop in low end, and I assume this is normal as my old GSXR600 also did this. It was much more noticable power drop on the gixxer.

I am getting my new PCV later this week and hoping it will fix this power drop in the low end.

Will the PCV fix this drop in low end, back to what it used to be ?
I assume doing the airbox mod will further cause a drop in low end power ?



kjonas
 
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V

Vapordan

Guest
The pcv should return things back to normal. I'm not a fan of these gadgets but they do work.
 
V

Vapordan

Guest
lyric911 said:
If they work, why aren't you a fan of them? :confused:
Click to expand...

You are forcing my hand here. My gripe with the PCV is that, based on my research, it is essentially a software hack. Due to emissions regulations, ECUs are not programmable; there's no interface so it cannot plug into the software to affect the AFR in the correct way. From my research, what it accomplishes is to distort the inputs to accomplish an optimal AFR. Most of those do so by modifying the engine temperature signal, sending a cool signal to richen the mixture or a hot signal to lean the mixture. Note that the actual engine temperature is not changed. The fundamental problem with this approach is that the ECM uses many other inputs besides engine temperature to calculate the exact mixture to send. There's a very real possibility that the ECU can become confused based on tampered inputs leading to suboptimal performance in certain operating conditions like temperature, elevation, driving habits. Other products modify the ignition timing, which causes the rotor pulse to be modified before reaching the ECM to advance or retard the timing.

Race bikes do not work in that way. They have programmable ECUs because obviously they aren't interested in emissions and they don't care for the ECU tolerances built in by the manufacturer. However, programmable ECUs are cost prohibitive for joe the plumber. Suzuki bikes buck that rule, they have programmable ECUs. I'm not sure how this is legal. Some Yamahas R6, R1 and FJ1300 expose the ability to force the ECU into programming mode by grounding certain lines going to the ECU for partially programmability via the CO Adjustment Mode. I haven't heard of one for the FZ8 and I'm not inclined to 'try it out' either. That approach allows limited programming to the fuel and ignition curves. That's not available via a hack.
 
lyric911

lyric911

New member
Vapordan said:
You are forcing my hand here. My gripe with the PCV is that, based on my research, it is essentially a software hack. Due to emissions regulations, ECUs are not programmable; there's no interface so it cannot plug into the software to affect the AFR in the correct way. From my research, what it accomplishes is to distort the inputs to accomplish an optimal AFR. Most of those do so by modifying the engine temperature signal, sending a cool signal to richen the mixture or a hot signal to lean the mixture. Note that the actual engine temperature is not changed. The fundamental problem with this approach is that the ECM uses many other inputs besides engine temperature to calculate the exact mixture to send. There's a very real possibility that the ECU can become confused based on tampered inputs leading to suboptimal performance in certain operating conditions like temperature, elevation, driving habits. Other products modify the ignition timing, which causes the rotor pulse to be modified before reaching the ECM to advance or retard the timing.

Race bikes do not work in that way. They have programmable ECUs because obviously they aren't interested in emissions and they don't care for the ECU tolerances built in by the manufacturer. However, programmable ECUs are cost prohibitive for joe the plumber. Suzuki bikes buck that rule, they have programmable ECUs. I'm not sure how this is legal. Some Yamahas R6, R1 and FJ1300 expose the ability to force the ECU into programming mode by grounding certain lines going to the ECU for partially programmability via the CO Adjustment Mode. I haven't heard of one for the FZ8 and I'm not inclined to 'try it out' either. That approach allows limited programming to the fuel and ignition curves. That's not available via a hack.
Click to expand...

Wasn't trying to force anything. You just made a statement that on the surface didn't make much sense to me.

I fully admit I don't know for sure, but it's my understanding though (at least with the PCV, I'm ignorant of the older ones) that the PCV directly adjusts fuel volume via signaling the stock ECU to pulse the injectors longer.
 
V

Vapordan

Guest
So the only way it can do this is to interfer with the signal because the ECU is not programmable (it cannot directly change the ECU). It has to say something like: I want an AFR of 13:1 and I know I can get this when the engine temperature is 45 degrees so let me change the engine temperature to 45 degrees and then I'll get my 13:1 AFR.

The racing kit on the Yamaha does it the right way, it says, hey ECU, use an AFR of 13:1. No mucking with temperature signals. That's the difference I'm not liking. That system costs 3grand versus 300 bucks via PCV.

I didn't really want to get into all of that because I'm not really done with my research yet and that kind of deep technical talk turns off moderate folks :eek:
 
lyric911

lyric911

New member
Vapordan said:
So the only way it can do this is to interfer with the signal because the ECU is not programmable (it cannot directly change the ECU). It has to say something like: I want an AFR of 13:1 and I know I can get this when the engine temperature is 45 degrees so let me change the engine temperature to 45 degrees and then I'll get my 13:1 AFR.

The racing kit on the Yamaha does it the right way, it says, hey ECU, use an AFR of 13:1. No mucking with temperature signals. That's the difference I'm not liking. That system costs 3grand versus 300 bucks via PCV.

I didn't really want to get into all of that because I'm not really done with my research yet and that kind of deep technical talk turns off moderate folks :eek:
Click to expand...

I'm interested. Have any sources on this information you have?

I did a very quick Google, but I can't go crazy at work with personal research.
 
FZER

FZER

Avid Rider
kjonas75 said:
A few weeks ago a installed a Graves slip on and K&N Air filter.

I've noticed there has been a slight drop in low end, and I assume this is normal as my old GSXR600 also did this. It was much more noticable power drop on the gixxer.

I am getting my new PCV later this week and hoping it will fix this power drop in the low end.

Will the PCV fix this drop in low end, back to what it used to be ?
I assume doing the airbox mod will further cause a drop in low end power ?



kjonas
Click to expand...

Course you could go with a new front spocket.
 
V

Vapordan

Guest
lyric911 said:
I'm interested. Have any sources on this information you have?

I did a very quick Google, but I can't go crazy at work with personal research.
Click to expand...

The authoritative manual on Bosch Fuel injection is written by Charles Probst, I've got a copy on order. It's available on Amazon. Most EFI's are licensed from Bosch. Peter Verdone has an excellent article on mapping as well. Electronic Map Theory. His resume lists him as a machinist/instructor so he's heavy on the theoretical as well as the practical.

There's a lot that I don't understand with the software implementation and I'm hoping that this book will sort it out for me. Stuff like how the AFR compensates for parameters that aren't captured and what determines the tolerance inputs etc.
 
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