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Accel Fuel Tuning - Link G4+ Rx7

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Good Afternoon,

I have a fully tuned fuel table and have noticed on my logs after a mountain run that under some parts of the high boost runs through the gears my logs are showing i'm momentarily running lean or getting small lean spikes. I know my fuel table in the high boost areas is fully tuned and dialed in. I could not notice this on at all on the runs, car felt strong and pulled well.

I have attached my log file. Can anyone please advice if this is the accel fuel tuning in the Link g4+ which requires more attention to detail? So the lean spikes are occurring around 5krpm. for eg 3rd gear wot to 7krpm than shift to 4th revs drop to around 5krpm...momentary lean spike after a 40% accel fuel enrichment event....suddenly drops a bit lean and than after a few tents of a second it reaches equilibrium.

Any help or insight appreciated.

I have attached a copy of my log.

Many thanks,

Pat

Attached Files

Its a bit hard to tell if it is an accel enrichment problem or the staged injection "accel fuel" as it kind of happens in the point where both of these could have an effect. Im leaning more towards it being the staged injection accel.

It looks like you possibly want to increase the staged inj accel fuel % but shorten the staged accel time.

If that didn't help then I would try increasing the accel hold events in the accel enrichment set up.

Hey thank you, I will increase the staged inj accel fuel and do another similar run and check the logs before changing anything in the accel enrichment setup.

This is the current setup, will change it to 30% and see if that resolves it. The accel time is 75, what would be sensible margin to reduce this to?

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The "Accel time" is the number of engine cycles that the enrichment will be applied for after the secondaries become active.

If you look at your log below in the area I have highlighted in pink, where you see the primary PW suddenly step down closer to the sec PW at the end of the pink arrow, this is where the "staged enrichment" ends (Accel time). You can see the lambda has drifted rich at that point and recovers back to target after the enrichment ends so that indicates it is too long. It looks like you could roughly halve the accel time but that will probably change when you give it more Accel fuel % too.

At the beginning of the pink area where the lambda initially goes lean, its hard to tell if it is due to not enough staged accel fuel, or due to that little hesitation/double press you did on the throttle pedal. But it looks like it could do with a more staged accel fuel - but combined with the shorter time.

As a reference, our FD test car when I last tuned it using this type of staged injection enrichment (G4X now uses a more complex strategy) had an accel fuel of 85% and an accel time of 10 cycles. It has horrible Indy blue secondary injectors though so I don't know how relevant those settings are to others - just saying dont be scared if you need numbers a lot different to what you have now.

Hey Thank you so much for helping and providing the insight I needed.

I believe the indy blue are sold in the U.K as Bosch 1680cc injectors. I'm using ASNU 1500cc secondaries but running 66psi base fuel pressure so outputting approx 1748cc as per ASNU data. The data on your accel time and cycle is brilliant. I will play around with my settings and post a log.