shind3

I'm writing here to hopefully get some support from the DBW S2000 community in gathering datalogs of a specific scenario. A lot of us are struggling with hesitation during throttle tip-in as can be read in the following threads.

https://www.s2ki.com/s2000/topic/112...edy-solutions/
https://www.s2ki.com/s2000/topic/871...on-at-low-rpm/
https://www.hondata.com/forum/viewtopic.php?t=17928


Can a few people with a FlashPro run the following test procedure and upload logs? Also state whether you feel the car experiences any hesitation or not during throttle tip-in

Start Log.
Hold 10% throttle for 4 seconds.
Change to 40% throttle quickly then hold for 4 seconds.
End Log.


Thanks for your time.

Gernby

I believe this is the issue and fix.

https://www.s2ki.com/s2000/topic/783...s-in-flashpro/

shind3

I'm guessing you didn't read any of my posts in the other threads.

No worries, lots to read there. The following picture should summarize in less than 1000 words...

Gernby

I read enough of the threads to think that the issue is NOT what you think it is. What I see in your screen shot is that your ignition is being retarded. Did you read the thread that I wrote about that issue 5 years ago?

Here is an updated screen shot, which shows the "new style" knock tables.

shind3

You think retarding ignition by 5 degrees is causing the AFR to drift 2 whole points lean?! And why doesn't the AFR stay lean afterwards? You can see the STFT goes away and returns to 0 with this 'retarded ignition' theory of yours.

And yes, I've read through that and associated threads a lot. I have a good understanding and I agree it is mislabeled as 'knock retard' when it should be called an 'octane ignition trim' as you stated in your posts.

Are you going to post datalogs of the test I suggested?

shind3

As you know, timing retards as load increases. Are you saying 16 degrees of timing at 3000 RPM at 88kPa is retard enough from ideal to let the AFR drift lean by 2 full AFR points? If so, what about later in the log. Same conditions IGN, MAP, RPM but 0 STFT and stoich AFR.

Not to mention, the AFR starts drifting lean WAY before it hits those 4 cells that are part of your 'retarded ignition' theory which are close to atmospheric pressure.

The AFR starts drifting lean as soon as MAP starts increasing quickly. Keep in mind the AFR line has a slight time lag so shift it to the left a bit to see it more in tune with combustion AFR.

Gernby

What I think is that the AFR is not your problem. The 5 degrees of knock retard that appears in your datalog is MUCH more likely to be causing your issue. You can definitely feel the difference between 21 and 16 degrees on the low cam. If you datalog at WOT from 1800 RPMs to 4K, do you see the dip in IGN between 2500-3000? If so, that's your issue.

I'm running DBW ITB's now, so my datalogs wouldn't be very helpful to you.

Gernby

As you know, timing retards as load increases. Are you saying 16 degrees of timing at 3000 RPM at 88kPa is retard enough from ideal to let the AFR drift lean by 2 full AFR points? If so, what about later in the log. Same conditions IGN, MAP, RPM but 0 STFT and stoich AFR.

Not to mention, the AFR starts drifting lean WAY before it hits those 4 cells that are part of your 'retarded ignition' theory which are close to atmospheric pressure.

The AFR starts drifting lean as soon as MAP starts increasing quickly. Keep in mind the AFR line has a slight time lag so shift it to the left a bit to see it more in tune with combustion AFR.
[/quote]

You know I'm a eTuner, right? I've tuned over 100 '06+ S2000's on FlashPro, so I do know a bit about this. I'm not saying that the IGN retard is causing your lean AFR. I'm saying that IGN retard is much more likely to cause your symptoms.

shind3

Do you agree that an AFR change to about 17 is a problem?

I have been tuning engines since 2005. Mostly Subaru engines but this isn't my first rodeo either.

Are you going to post logs as requested in the first post of this thread? That is really the point of this thread. If you want to discuss otherwise, there are 2 other threads I linked to which might be more suitable.

Gernby

No, I don't agree that your lean blip that lasts less than 1/10th of a second at low RPM with a very significant change in MAP is enough of a problem to talk about.

I don't have any experience with Subarus, so I don't even know if they are MAP based.

I'm not going to post datalogs of my ITB setup, since anything you find in them would just misguide you.

I personally just think you WANT it to be an AFR issue, and that is getting in the way of you resolving the actual problem.

Is there some reason why you don't want to fix the problem with your knock control, which is gleamingly obvious in your datalog?