Yamaha Banshee Microsquirt setup - tuning questions

[Whitbread]

Hello gentlemen! I've gotten leaps and bounds accomplished in my tuning process and have the bike extremely rideable now. Just have a few simple questions for the experts here. For backround info, I'm running MS2 code in the microsquirt. Motor specs are 355cc, 1500-11000rpm range, about 70hp at 8000rpm, two 36mm TB's, one 240cc injector per cylinder, LS2 coils. I really need to step up injector size as I'm at 95% duty cycle right now at WOT. But for rough tuning in purposes it's close enough.

First off, I attached the tune file and if anyone could take a look at it and make sure there aren't any glaring newbie mistakes, I'd greatly appreciate it. Before the wideband fouled out, my a/f's are perfect at idle, cruise, moderate tip in, and WFO. In neutral, it revs super snappy and cleanly. My main question here for the experts is how to get rid of the bog that occurs when letting the clutch out to take off from a stop when tps values go higher to 30-40%, but the rpms are still very low for a period of .3-.5 seconds. Right now the bike stumbles through the rpms slowly for about 1-2 sec then picks up and away we go! A/F readings were too unstable in these conditions to get a good indicator, it seems like it wants more fuel as when I stab the throttle a few times to trigger the accel enrichment function it will pull out of the bog. In the VE table is the area from 55% -80% fuel load and 1700-4500rpms where the bog happens. If I richen that area up in the VE table, it makes the bog better. However, when you free rev it's too rich and stumbles through that area on the table.

When it quits raining I can take some logs and videos to help better demonstrate the conditions. Thanks in advance!

[24c]

Hi Whitbread,

It seems you've answered your own question with your symptoms, you want more acceleration enrichment.
Are you using MAP as well as TPS to trigger acceleration enrichment?

Mike

[Whitbread]

I switched over to Alpha N mapping and the bike is much happier. Solved the off idle hesitation and the throttle is as crisp as ever. However, I still have an issue that's shown up in speed density, ITB, and now alpha N modes. With quick light/ moderate throttle jabs, it snaps just like it should. However, after a full WOT stab, the throttle is unresponsive for a moment. It can be easily seen in the datalogs where rpms are falling but tps is 100%. If I rip through the gears without letting off throttle, it never misses a beat. But if I let off to shift, the throttle becomes unresponsive for 1-2 secs and then everything comes back to normal and its pinging again (2 stroke pipe ringing). If it was a fuel pressure issue, it should fall flat on the top end. But as I said before, if I never let off, it never acts up. The tps reading is stable all the way through. Has anyone ever run into this before? I'm fighting a charging issue so don't mind the battery voltage dropping at the end of the log, it has the exact same behavior with a full charge.

Thanks in advance for any insight. I attached a log of free revving in neutral where the tps can be seen at 100% but revs are still falling.

[24c]

Hi Whitbread,

At first I thought you might be chucking too much fuel in and bogging the engine when blipping the throttle.

However, if you look at your RPMdot & TPSdot, vs RPM, you will see the "ECU" is ignoring some of the TPSdot changes.
I think your threshold settings in acceleration enrichment rate/response are clashing, but it's not something I've played with.

Mike

[Whitbread]

Hi Whitbread,

At first I thought you might be chucking too much fuel in and bogging the engine when blipping the throttle.

However, if you look at your RPMdot & TPSdot, vs RPM, you will see the "ECU" is ignoring some of the TPSdot changes.
I think your threshold settings in acceleration enrichment rate/response are clashing, but it's not something I've played with.

Mike

Interesting, I thought I adjusted all the settings in AE so that they wouldn't clash and would provide full enrighment as all the way to redline if I open the throttle fast enough to trigger. I'm by no means as expert on this subject either though so hopefully I'm missing something silly. I'll try turning AE off tomorrow and see what that does.

[Matt Cramer]

I see you've got EGO control disabled; that leaves me flying blind when it comes to whether your fueling is accurate, as that also disables logging. You will want to turn EGO control on and set the controller authority to zero to log this.

I'd typically set decel fuel amount to 100% when starting out to prevent it from pulling fuel on overun.

The scale on the TPSdot AE is a bit odd - your lowest TPSDot value is 110% per second, but then it goes to 807% per second (opening the throttle in 1/8 of a second), and then goes to even faster throttle openings. I would bring the numbers down a bit as you usually don't need values for over 400% per second, and the amount of fuel it's adding is fairly small.

[Whitbread]

EGO is disabled right now so I don't foul out another $45 sensor. I've been going off feel and plug readings to get it lean enough to not immediately foul the sensor out. I feel I'm ready to put 02 back in, but I wanted to get this unresponsive throttle issue nailed down first.

My bike is thumb throttle and the itbs have a quick open cam on them so my idle to wot snap is really that quick, I can actually go off the right end of the chart while watching it. Should I still bring the tpsdot numbers down?

[Whitbread]

AH HA! Figured it out the hesitation/stumble/unresponsive throttle today. Talked to my friend Tyrel who has a banshee motor that he microsquirted and turbo'ed in a frankenstein cafe racer that he just built and is in the tuning phase. We put our heads together and figured out that the motor must be getting flooded in the high rpms when the throttle is chopped and the AE shot only makes it worse. I read up on the overrun fuel cut and enabled it with settings that match my engine's powerband and voila! Now we're cooking with hot sauce! Throttle response between shifts is exactly like it should be.

I couldn't be happier with the microsquirt endeavor, that was the last funny quirk and now its time to put the wideband back in and get the A/F dialed.

I attached the updated tune if anyone does a similar project in the future.

[tune2mbt]

Hello, I realize this is an older post but I see where there was supposedly a file uploaded but I am not seeing it to download.
Where is this file located for download? I may be going down a similar path and this will help.

TIA

[tune2mbt]

Anyone?

[billr]

Start a new thread. You probably can't find that old info because attachments are periodically purged, and this is a very old thread.