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RX& FD3S - 4th to 5th Gear WOT (slight lean out during the gear change)


Copyninja

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Good Afternoon Gentlemen,

I am having issues in finessing my afr's to stay with their target when there is a WOT gear change. 

See below the example

Here the afrs, stay in line with the target but once if shift up from 4th WOT to 5th WOT you can see the momentary lean out before everything reaches equilibrium and afrs fall back in line with their targets. How do i fix this? Why is it happening?

Also i notice my primary duty cycle hits 100% here before dropping back down. Any help with this also appreciated. 

I have attached my log file for this run.

image.thumb.png.7b7ba2f3495eddd5cf93cc0ac9ecb402.png

Kind Regads,

Pat

 

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Can you attach the tune.  It appears the leanest spike occurs just as the secondaries come in so it is possibly the accel fuel/Accel time in the staged injection settings.

But since those primaries are being maxed out quite away before the secondaries are being commanded you might have to look at some changes to the general staging also.  Can you tell us injector sizes too.  

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OP - Looks like you need to upgrade your primary FI's if they are hitting 100% duty cycle trying to reach your target AFRs. Adam's suggestion to adjust staging will help, but if you're hitting 100% DC at only 8psi MGP, you really need more fuel. You really should size the FI's big enough so that they never have to go much beyond 85% duty cycle as a safety margin. Sounds like the Injector Dynamics ID-1050's would be perfect for your FD, though you'll need to change out the fuel rails for them to fit (ID's are top feed injectors, the stock FD injectors are side feed).

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I think the issue is likely something i've missed with the injector staging data in regards to a smooth transition from primaries to secondaries coming online. Once they reach equilibrium at 12psi both primary and secondary injectors are below 60%dc. I suspect the issue has to be with the staging and not the size of the primary injectors. 

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image.thumb.png.3533552018870dc4cc05248c9b3c761c.png

image.png

The drive feels much smoother now. I have made some changes to the accel clamp to try to reduce the rich spike between gear changes from 4th to 5th but there still seems to be a lot richness there which is driving the primaries to almost 100%dc. Is this related to the accel fuel or accel time? I've tried to reduce the accel clamp load from 30 to 25 but that made no real difference. 

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image.thumb.png.42f612f27feaa187a17311fafe8e2156.png

better than before but still seems to be dumping a lot of fuel between gear changes maxing out primary dc. Perhaps the secondaries need to come in a bit earlier/higher initial percentage? or accel clamp reduced even further? Also as i stab to WOT there always seems to be this immediate lean spike followed by a lot of richness in the afrs before reaching equilibrium. Im guessing this linked to the accel clamp table?

 

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Its made an improvement but for some reason a wot shift does keep maxxing out the primary dc momentarily until the secondaries come online and then once it reaches equilibrium it's all under control. Does the link g4+ have another fuel table to which I can add additional fuel over a certain driven wheel speed at all? for eg additional 3% fuel over 200kph over the main fuel table

image.thumb.png.3e9cd837707951b5c97f95a396072dcb.png

 

 

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Im thinking in your case it might be worth trying the staging table based on RPM rather than MAP.  Bringing them in at say 4-5000RPM will probably fix that 100%DC on the primary.

To add extra fuel based on speed use a 4D fuel table something like below:

m63CF3L.png 

 

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Wont allow me to change the load to rpm on the secondary injection staging table. I'll play around with it bring the secondaries in earlier.

Thank you for pointing out the above. Thats seems extremely useful the keep the fd alive at higher speeds. 

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  • 1 month later...

I made the above changes and the primary injectors no longer hit 100% duty cycle.

However, i've run into another issue. Everytime the secondaries come online based on the rpm the primaries seem to be make the afrs too rich and then too lean for a short duration before both primaries and secondaries hit equilibrium. 

 

 

 

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  • 1 month later...

 Having issues with the secondaries coming online when load is based on rpm. It goes very rich while the secondaries come online which feels like quite a big hesitation. Is there a work around in the link g4+ software for this issue please where it doesnt do this?

image.thumb.png.80bef46de57cace92d33539783d45fd7.png

no matter what i do to this table....when the secondaries come online...the afrs shoot mega rich for some reason before settling. The staging process between the primaries and secondaries does not seem seemless! is this a glitch in the link g4+ software? 

image.png.f644742e7e498af3efe73b568eafee14.png

 

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The first rich spike I have marked in pink is caused by the spike in primary PW which is coming from the main accel enrichment.

The 2nd rich spike as the secondaries come in is caused by the spike in primary PW due to the staged injection accel fuel.  Reduce the staged inj accel fuel% should get that better.  

 

PlNEAiu.png

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Adam,

Related to the OP's questions, is there a recommended approach for adjusting the staged injection Accel Fuel & Accel time parameters? I too have been struggling to get my FD to stage the injectors in as smoothly as I'd like - mine typically trend way too rich at the initial staging point, which I figure means I should be reducing the accel fuel and/or time, but is there a preferred approach as to which parameter to tweak first? What should I be looking for in the logs to inform me which change (in accel fuel or time) would be more appropriate? I don't have the luxury of a dyno to work on, so I'm trying to make my road tuning iterations as productive as possible.

Thanks,

Pete

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