Am I Right about Gen II Fuel Injectors?

[HayaWakened]

Doing a deep dive on fuel injectors - just for the hell of it
DISCLAIMER: I have zero fueling issues, am not modifying fuel delivery in any way, just trying to understand the bike better

T/F??

• Gen II's have 8 injectors (2 per cylinder)
  • 4 Lower
  • 4 Upper
• The uppers are the 'secondary' injectors, the ones that don't come on until about 5,600 rpm / 40% throttle open (see chart)
• Theoretically, the secondary injectors could NEVER activate, depending on my throttle %

this pic/chart was copied from Post #28 of this thread: Nitrous Advice | Nitrous

What does this mean in regards maintenance?
Might the secondary set fail from lack of use?

 

[Dopey]

Doing a deep dive on fuel injectors - just for the hell of it
DISCLAIMER: I have zero fueling issues, am not modifying fuel delivery in any way, just trying to understand the bike better

T/F??

• Gen II's have 8 injectors (2 per cylinder)
  • 4 Lower
  • 4 Upper
• The uppers are the 'secondary' injectors, the ones that don't come on until about 5,600 rpm / 40% throttle open (see chart)
• Theoretically, the secondary injectors could NEVER activate, depending on my throttle %

View attachment 1631831
this pic/chart was copied from Post #28 of this thread: Nitrous Advice | Nitrous

What does this mean in regards maintenance?
Might the secondary set fail from lack of use?

I've read a few posts that have said the secondaries have clogged up from lack of use. I try to run Seafoam occasionally and make sure I got the upper revs quite often partially for that reason

 

[ColdBusa]

All the more encouragement to go WOT lots more!!!!! lol

 

[HayaWakened]

I've read a few posts that have said the secondaries have clogged up from lack of use. I try to run Seafoam occasionally and make sure I got the upper revs quite often partially for that reason

...which is what started this inquiry - secondary activation is accomplished through throttle position only??

All the more encouragement to go WOT lots more!!!!! lol

...and therefore this is the ONLY suggested maintenance aside from Seafoam? WooHoo!!

 

[Dennis]

If you never open the secondaries you have the wrong bike.

 

[FILT166]

I bought a used 08, with 5k miles and the secondary injectors were clogged up. I told the original owner there was an issue that it won’t go past 110 mph when I rode it. He said I’ve never done that. I told him, ride it again and get on it. He rode it and said it’s fine, I told him you didn’t get on it did you. He said no I’m scared. Well just cruising it will cause them to clog up as he proved this.

 

[HEMI. 392]

Doing a deep dive on fuel injectors - just for the hell of it
DISCLAIMER: I have zero fueling issues, am not modifying fuel delivery in any way, just trying to understand the bike better

T/F??

• Gen II's have 8 injectors (2 per cylinder)
  • 4 Lower
  • 4 Upper
• The uppers are the 'secondary' injectors, the ones that don't come on until about 5,600 rpm / 40% throttle open (see chart)
• Theoretically, the secondary injectors could NEVER activate, depending on my throttle %

View attachment 1631831
this pic/chart was copied from Post #28 of this thread: Nitrous Advice | Nitrous

What does this mean in regards maintenance?
Might the secondary set fail from lack of use?

Secondarys activate from toms only

 

[HEMI. 392]

Secondarys activate from rpm only

 

[HayaWakened]

Being a newb to secondary fuel injectors, I would guess the TPS is the ECU's data source for 2nd FI activation. The table shown in the orig post indicates 2FI's do nothing until about 40% WOT, regardless of RPM.

Here's my problem: a couple days ago I had the bike on the fwy, 6th gear, 80 actual MPH, and a gentle throttle roll-on to what I would guess was near 60% WOT to arrive at >140 in around 3 seconds. Okay, not a problem, really, but according to that table, I've yet to achieve even 50% 2FI activation. Hoping something like 25% is enough to blow the dust off those injectors

 

[smithabusa]

Being a newb to secondary fuel injectors, I would guess the TPS is the ECU's data source for 2nd FI activation. The table shown in the orig post indicates 2FI's do nothing until about 40% WOT, regardless of RPM.

Here's my problem: a couple days ago I had the bike on the fwy, 6th gear, 80 actual MPH, and a gentle throttle roll-on to what I would guess was near 60% WOT to arrive at >140 in around 3 seconds. Okay, not a problem, really, but according to that table, I've yet to achieve even 50% 2FI activation. Hoping something like 25% is enough to blow the dust off those injectors

5600 RPM, 40% throttle they start carrying 2% of the fuel load

 

[Mythos]

The uppers are the 'secondary' injectors, the ones that don't come on until about 5,600 rpm / 40% throttle open (see chart)

I'm not sure if the upper row is the secondaries or if it's the bottom row. I just know I bought my Bazzaz Z-Fi because at the time, the Dyno Jet PC5 could only manage four injectors. I guess DJ expanded the capability of the PC5 so that it could do both primary and secondary injectors some time ago. Back in 2010 when I was enquiring about the use of the PC5 with the busa's 8 injectors, I was being told that tuning the primaries doesn't matter much. Maybe the primaries are capable of adding as much fuel as is necessary for basic mods. Even so, if the bike has 8 injectors, I want to have control over all 8 injectors.

 

[smithabusa]

I'm not sure if the upper row is the secondaries or if it's the bottom row. I just know I bought my Bazzaz Z-Fi because at the time, the Dyno Jet PC5 could only manage four injectors. I guess DJ expanded the capability of the PC5 so that it could do both primary and secondary injectors some time ago. Back in 2010 when I was enquiring about the use of the PC5 with the busa's 8 injectors, I was being told that tuning the primaries doesn't matter much. Maybe the primaries are capable of adding as much fuel as is necessary for basic mods. Even so, if the bike has 8 injectors, I want to have control over all 8 injectors.

Lower primary, upper secondary for sure

 

[smithabusa]

 

[Busa Quick]

Sorry for reviving an old thread.

I was looking for information on anyone that is adjusted the injector balance map.
I just tried it today, with no other changes and a previously good running engine.

I started by adjusting the 70% to 100% throttle settings above 2,800 RPM. The result is not what I expected. The engine actually started running rough at partial throttles in all the gears right at 2800 RPM. I would say it was using the IAP map instead of the TPS map.

It seems the ECU editor injector balance map may not be quite correct. I think the change I made did not reflect what the table indicated.

Has anyone done this successfully and can share their map? I would only like to see it for reference as it's unlikely anyone has an engine set up exactly like mine. My engine is now a 1507 NA, with cams and mild port.

Thanks in advance.
Mark

 

[smithabusa]

if you aren't running out of fuel, i wouldn't mess with it honestly. Especially if you aren't monitoring air fuel while doing this. Mainly used on turbo bikes etc where you run out of fuel with the standard injector split

 

[Busa Quick]

Thank you for the reply Smithbusa!

The problem is that I am running out of fuel at full throttle at around 5000rpm to 8500rpm.
According to ECU editor, I cannot set the cells higher than 400 on the fuel table. Somehow I've got them as high as 480 but then started having weird problems and it was always around the area that had the high fuel numbers.

So the only reason I want to just a table is I do think I need more fuel, and this would be the cheapest way.

I'll be honest I didn't expect my engine to run strong enough to need this much fuel, but the weather is cool and it is running extremely well so I must be in the ballpark. I'm data logging my runs during my tests to record my air fuel ratio.

 

[smithabusa]

Thank you for the reply Smithbusa!

The problem is that I am running out of fuel at full throttle at around 5000rpm to 8500rpm.
According to ECU editor, I cannot set the cells higher than 400 on the fuel table. Somehow I've got them as high as 480 but then started having weird problems and it was always around the area that had the high fuel numbers.

So the only reason I want to just a table is I do think I need more fuel, and this would be the cheapest way.

I'll be honest I didn't expect my engine to run strong enough to need this much fuel, but the weather is cool and it is running extremely well so I must be in the ballpark. I'm data logging my runs during my tests to record my air fuel ratio.

what happens to air fuel when it runs rough? Bringing it in at 2800 rpm, maybe is a little on the low side, what are you doing with balance, 50/50?

 

[Busa Quick]

Hopefully you can see in this picture, I am trying to bring in the extra fuel mainly at 60% throttle and above. And I'm trying to ramp it in. Also see that I did not make any changes 30% or below. However the problem I'm having is that small throttle openings around the 2800 RPM range just when I'm trying to ease on the throttle to get going. It goes so rich that it tries to kill the engine and barely runs. If I clutch the bike to get it around something like 4000 RPM it will run but is rich. If the engine ran okay but was just rich I could eventually tune this out. However the result of making this adjustment has been so dramatic that I'm not sure if it's working the way I expect it to.

 

[Busa Quick]

This is a picture of the TPS map take a look at the area around 11% throttle. I could not show you an IAP map because I had so little data with the engine running so poorly.

Before my changes my air fuel ratio was in the ballpark of 13.0 in most of the cells.

I did not expect my injector balance changes to affect this small throttle opening.

 

[smithabusa]

yeah that is weird, for sure this goes away if you put the balance map back to normal?