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Discussion Starter #1
I have a pc5 on my gen 3 drag bike. Recently I did some dyno work and got the AFR where I wanted it, the PC5 worked great establishing a NA map. Once happy with that I started spraying a 20 hp shot of nitrous at it. It went lean at first, as expected since I didn't make any changes to the map. I then added upwards of 35% fuel in the 80-100% TPS cells from 7000-13000 rpm and it literally made no difference to the AFR. I double checked the adjusted map was sent to the PC5 as well as double checking I had the map switch in the proper position to run map 2. After all this, there were still no changes to AFR.
At this point we stopped before the motor got hurt.

My question is: does anybody know what % fueling the primary and secondary injectors perform at wide open throttle? Aside from going back to the dyno to make another pull and see the duty cycle of primary injectors, I can only assume the primaries are maxed out and can spray no more. I do not have a SFM on my bike, yet, so as of now I no control over secondary injectors.

thanks in adavance.
Medic B
 

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On the G3 only, the upper rail injectors are just a token, G4 and 5 upper rail injectors are capable of handling extra fuel trim as all 8 are the same. G3 only when your adding fuel add only to the bottom rail. It is better for tuning to add to top only if possible but not Possible on G3. I have in the past modded a G3 air box to take the 4 injectors.
 

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Generally, the injector split is a phasing thing... ie: as the uppers come on it starts trimming the lower injectors out, switching them in effect. I don't know the % for the gen 3 off the top of my head, but chances are that it is phasing the bottom injectors out quite a bit. That would make sense in your situation, as changes to the bottom injectors at high RPM would have proportionally less and less impact as it moves the split to the higher injectors.

There is usually enough lower injector size available to make a shit ton of power, but moving the physical injection point further away from the inlet valve at higher RPM usually yields some free power... this is why they transition the load from the lowers to the uppers as RPM rises, even though they technically don't NEED the extra injector size at all. If I were in your boat I'd try running your changes on the upper injectors only for high RPM, and perhaps use the 'map switching' input activation on your nitrous button... it would run normal off the spray that way.
 

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Discussion Starter #4
With my current setup, I only have a PCV and don't have the ability to make changes to secondary injectors. I have a map switch so I can change from NA map to Nitrous map. The nitrous itself is ran through a controller.
As for duty cycle and such, I've heard at WOT and high rpm's the secondary injectors do as much as 80% fueling with the primary injectors trimming back to only 20%. This new information about the gen 3 only injectors is news to me, then again, this is all news to me. I thought all was well until I got on the dyno and saw what was actually happening.
 

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With my current setup, I only have a PCV and don't have the ability to make changes to secondary injectors. I have a map switch so I can change from NA map to Nitrous map. The nitrous itself is ran through a controller.
As for duty cycle and such, I've heard at WOT and high rpm's the secondary injectors do as much as 80% fueling with the primary injectors trimming back to only 20%. This new information about the gen 3 only injectors is news to me, then again, this is all news to me. I thought all was well until I got on the dyno and saw what was actually happening.
According to my Woolich software, injector balance for Gen 3 is 50/50 split at WOT and 10,000 + RPMs and its 30/70 split for Gen 4 at WOT and 10,000+RPMs.
 

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Good info Box!

At a 50/50 split you would be seeing half of the effective change with the PCV, at best... not ideal. But something seems fishy... 20hp would be about a 12% increase in power for you, no? Even at a 50% reduction that 35% extra fuel should cover you back to the non-nitrous AFR. Hell, spraying a 38hp shot only moved my AFR about half a point IIRC. Did you try loading the adjustments into both maps to see if the map switching feature wasn't working? Assuming that the PCV is actually working, I'd start to look at fuel pressure under load if it were me.......
 

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Discussion Starter #9
I’ll do some more investigating.
I have a hunch fuel delivery might be part of the problem. I believe my fuel supply line that goes to the primary injectors has a kink in it.
Thanks for the info. All very helpful info
 

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Unlikely to be a pinched line on G3 that's a G4 issue. How did you add 35% because you cannot add that much in a single change if I remember correctly on the PCV.
 

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Unlikely to be a pinched line on G3 that's a G4 issue. How did you add 35% because you cannot add that much in a single change if I remember correctly on the PCV.
The autotune won't add that much in a single change (with the factory set restrictions that you can change). The PCV will take whatever number you put in there up to something ridiculously huge like +200 -100 or something like that.

Silly question but I've done this myself and wondered why my settings didn't take or change. Did you actually "send" the map once you were done tweaking it? If you have autosave setup once you plug in the PCV does it show you the new map or the one before you added fuel?
 

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Discussion Starter #12
I’m not running an auto tune. I data log a hit on the track then pull the data and manually change the map, save it and send it to the desired map position.
As for changes, I highlight the areas I want to change and increase of decrease by whatever amount I want.

To go back through the process, I took the bike to the dyno, and started with a 0 map.
Got the afr where I wanted for NA
Then added nitrous to that map and continued adding fuel.
All in told I was adding up to 35% above the zero map and it wasn’t changing the afr, so we stopped.
According to power commander website you can add up to 250% and subtract up to 100% of factory fueling.
The ecu has been flashed but this shouldn’t have made any changes to the fuel tables.
 

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I’m not running an auto tune. I data log a hit on the track then pull the data and manually change the map, save it and send it to the desired map position.
As for changes, I highlight the areas I want to change and increase of decrease by whatever amount I want.

To go back through the process, I took the bike to the dyno, and started with a 0 map.
Got the afr where I wanted for NA
Then added nitrous to that map and continued adding fuel.
All in told I was adding up to 35% above the zero map and it wasn’t changing the afr, so we stopped.
According to power commander website you can add up to 250% and subtract up to 100% of factory fueling.
The ecu has been flashed but this shouldn’t have made any changes to the fuel tables.
Next time, connect the PC to the PCV and watch the duty cycle. This should tell you a lot about how much fuel is available. If the duty cycle is high, and you added %, you may have fueling issues. Plugged injector filters, low pump pressure. Sounds like the upper injectors are providing most of the fuel. If truly 20% is lower and 80% upper- there is only 66cc/min(if 330 cc/min injector) on the lower at 100% in the ECU. To get 50HP you need 17cc/min. Since the lowers are 5X less than the uppers, maybe you need to multiply 5*the % you want to add? Just spit-balling.
 
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