yeap, it seems it is that simple!

 

Yes that will work, or you can make one yourself with resistor $0.10. It bridges O2-sensor heater circuit to trick ECU into thinking sensor is still connected so it doesn't throw MIL code (see VFR mod in photo below)

It's been over 20-yrs since I worked on F4i system so memory may be slightly off. That's what we used on our FSAE kart at university. I recall we disassembled ECU and found it completely locked with no flash memory whatsoever. The ROM code and data maps were all internal to CPU so nothing could be removed and re-programmed. I had earlier decoded EPROMs from Porsche Motronic ECUs and as able to reprogram them after pulling them off circuit board. But no go with F4i ECU.

We did get lots of info from datalogging AFR with wideband-O2 and all inputs. Basically underlying base maps were super-rich in 10.0-11.0:1 range. Engine had less power with O2-sensor disconnected than connected. We searched for EU ECU which had leaner base maps because those bikes didn't have O2-sensors.

In end, we got Electromotive TEC-II system to control engine, worked with all factory sensors and allowed full control over fuel & itnition maps. Also let you program acceleration enrichment, decel cut-off, alpha-N blending, etc. Other teams used AEM, Megasquirt, MoTeC, etc. Nowadays there are way more options with plug-n-play piggybacks like PowerCommander, Bazzaz. There's outfit from OZ that has good reviews, don't recall their name...

You'll want programmable fuel and ignition maps. Can get major improvements in power by adding extra ignition-advance for use with +100 octane (PON) race-petrol.

 

Some Hitachi microcontroller or did Honda had the lettering scraped from it as well?
(...by the way, the Motronics where 80251 family derivatives?)

I am sure they very well knew many buyers would promptly put on crudely chopped slip-ons and they wanted to make 100% sure no one could blame Honda for this bad new FI stuff that broke his engine with just a slip-on swap....

Did you guys log any 4-gas data on a braked dyno by any chance? Or just wideband data?

Experienced tuner old client of mine does not like the piggy back boxes because he often found them adding latency to the injector pulses thous affecting hi-rpm fuelling timing close to the redline on track use.
What do you think would be Can's best choice given track use and ultra short slip on? I guess a complete ECU swap would be too much for a budget track bike.

 

Yes! Bosch Motronic 3.1 used 8051 CPU, pre-cursor to 8086/8088 used in 1st IBM PC! So there's lots of dev-tools available. I used IdaPro to disassemble .BIN back to assembly. Amazing thing is everything fit into 8kb! Program-code fit into 4k on CPU and data-tables on 4k 2732 EPROM. Actually contained 3 sets of data-tables: NorthAmerica, RoW, RoW (maps 2&3 same).

NA maps were much richer than RoW maps and relied on O2-sensor feedback to reduce fuel. But... full-load rows (left-back wall) was similar because O2 was ignored under high-load. That trigger was slightly complicated because it is calculated based upon combination of airflow (load) and TPS position+velocity.

Later Motronic used 8kb 2764 memory and copied CPU's program code to EPROM. Jumper on circuit board selected program code on CPU or from EPROM. This allowed me to modify software! I added feature of ignition-retard based upon ambient air-temps. I then bump up ignition maps couple degrees across board.

Yup, F4i ECU main CPU and some custom ASICs had markings blanked (aside from common supporting ICs and resistors). Very disappointing after days of work to remove potting compound that covered everything. We even tried some dye and ultraviolet light to see if there's any remnants of orginal markings, nothing. They were either unmarked from very beginning or had been mechanically shaved off. Well, at least it stopped us from wasting any more time with that ECU as it wasn't programmable anyway.
Slip-on doesn't increase anything but noise. Yeah, every single manufacturer uses rich WOT fuel to prevent engine self-destruct in event you get bad petrol in boonies on super-hot day. Or let bike sit and end up with clogged injectors. I usually get +5-10% increase in power by by leaning out mixtures. Even more on carby bikes, +20% on my race Ninja 250. For example, here's Euro Ninja 250 EFI model with only mod being ECU re-programming. Just leaning out too-rich factory mixtures resulted in +14% power increase!!!



Just free O2 since all we cared about was power. We wanted to cram as much O2 into engine as possible and made sure it fully combusted. Max-power was generated at lambda = 0,85-0,90.

I don't like piggybacks either because they're just an adjustment layer on top of ECU's true maps. Must be old units they're talking about. PC-V or Bazzaz have no delays, super basic function of input, scale pulsewidth, and output. At 12000 RPMs, there's 5ms of time to make that adjustment. Easily 10x more than needed.

Making ignition adjustments is different and does require delay of one engine revolution. If you wanted 25-BTDC ignition, how can you do that when spark can't be detected until factory output of 20-BTDC? Can't go back in time. Piggyback will have to wait until next engine revolution to fire at more-advanced 25-BTDC. For non-flashable ECUs, piggybacks work quite well. However, I prefer re-programming ECU whenever possible.

For this minimal-budget F4i I'd get offset woodruff key to advance ignition rotor 3-6 degrees for +95 PON petrol. Extra advance will burn more petrol and reduce rich mixtures.

Although cost of piggyback with ignition-adjustability may actually cost more than Microsquirt...

 

For any kind of upgrades away from 100% stock, I suggest very 1st acquisition is fully-digital wideband O2-sensor with datalogging. Gives you precise data you can analyse from comfort of your sofa later. Much, much more accurate and safer than trying to stare at tiny 50mm gauge while running 4th-gear WOT to redline on city streets! Only fully-digital wideband O2-sensor with datalogging I've found is from TechEdge.com.au. Their DIY 2Y0 kit is extremely capable unit for its price!

I built their original DIY 2A0 kitover 25-yrs ago and have used it to tune numerous autos and motobikes. Still using it today along with newer 2Y0 unit. Support and instructions are superb, better than any other I've encountred.

Kit as pile of parts before and after assembly. Took me weekend afternoon. New ones are even easier with pre-made SMD boards. You will NOT find better combination of accuracy, functionality and convenience anywhere, regardless of price!


Here's Toyota AE86 I tuned when they first came out. Used hill to datalog final result to get high-load without too much speed.

YELLOW - AFR from wideband
TEAL - factory O2-sensor

At time=5850, we hit hill and I give it some throttle ~80%. ECU goes into open-loop and ignores O2-sensor. Uses underlying maps only. I had reprogrammed map to lean out mixture -10-15% from too-rich factory settings of 10.0-12.0:1. I gradually increase throttle on way up hill to maintain same speed (RPMs constant), close to 100% throttle at top. AFR remains steady.

Note factory O2 is useless, showing full-rich reading regardless (teal). Wideband AFR shows much more useful data with mixtures in desired 13.0:1 range. And it shows minor variations, indicating accuracy of reading. Earlier charts shows wildly wavey curve hitting entire box-height of variations.

After top of hill, t=6350, I gradually let off throttle to maintain speed.
At t=6450, I let off throttle completely and coast down. AFR goes to infinity as ECU cuts off petrol to injectors.

I got +10% increase in torque-curve and max-HP with software only! No hardware mods!!! also +8% in MPG

Modern hot-rodding isn't done by swapping parts like in old days (factory parts are super-optimised already), it's all done in software!!!

 

I am super happy that at last I found a guy I can talk with on such stuff!!!

Do you feel like chatting on the myriad of leads I see in those two nice posts of yours? They are so many that it is better to chat on a topic at a time despite them being interperplexed all the time... like the wideband sensor reading lean while it is not really lean in there

I have little hands-on ECU experience despite having my first 8051 assembly routines written back in '92 for use in motorcycle racing albeit for completely different use (enduro realtime timekeeping modems, never materialised though, nice those Dallas Semi. powered RAM based modules!) - however I have got a good theoretical background reading on engines since I was 12 and the dyno support part time job I had gave me good motive to read out the usual gremlins our dyno clients came upon. It is so disappointing that so many professionals fail to do basic homework before calling support...

 

Well... many "pros" really aren't that knowledgeable. They can follow instructions out of book, and that covers 99% of their work. But when it comes to that 1% they don't know, they have no idea where to even start! Multimeter? Oscilloscope? Duh... what's that?@#$!

Heh, heh, I think my ECU hacking days are over. When I started, it was new and necessary to get tuning I wanted done. Even opened shoppe specializing in Porsche Turbos (951 and 965). I got +100bhp through software alone! No hardware mods needed! Collaborated with some folks in Germany and Netherlands to do some incredible reverse-engineering. But now, there's so many options available as so many others have created open-source software to program just about any and every ECU out there!

I'm just gonna focus on optimising my '07 CBR600RR for track use and focus on getting in as much time on track as possible. Will start new build-thread on it and we can discuss there. Damn COVID cut back my training so much! Used to get in 42-46 days @ track per year, then nothing! Just crawling back... lost so much speed..

Also going to Microsquirt my NSR350 project... Honda NSR250 with RZ350/banshee engine. Amazing that an off-the-shelf product can accomplish what used to cost U$D +5K decades ago and weeks to custom-build and install. Now can be done in single day! Much more capable too!

 

Well, over here many still do not even get that proverbial "book" - I quote what I heard once upon a time when a guy described how he had an issue with his CB-1 and took it to his small town professional mechanic who promptly removed the head cover and exclaimed: "Whoa, so many valves!"...

I certainly feel old when I see how fast our "cutting edge" hard earned know-how became a depreciated commodity - something like "I want to become an airliner pilot when I grow up" thing

Now 100 braked hp is nothing to snuff at! Just from software tinkering! Now, were the guys in Germany so much afraid of the US gasoline quality ups and downs to make it THAT sure the engine won't blow up or did they have constant WOT at Death Valley in mind as their failsafe benchmark?! I do hope you made good money on that "detail"!

That is the RD350 engine even more tuned, right? Over here the RD350 was the "giants killer" for in city light-to-light drags vs all the mastodons of the '80s - we never got the quad but I heard the French guys loved it! Ehm, that NSR250, wasn't it always a V engine on it?

hey, I am lucky to have recovored so well form a out-of-the-blue stroke 3 years ago at the very old age of 46! **** those lap seconds, you sound well enough if you do proper RR use in a track! To make you feel better, over here we only got one(1) proper racing track in the whole country

 

I guess you are talking for something like that , right?
Are 6 degrees fully safe for 95PON (must be the 100RON at gas stations over here)?
Do you know if there is any plug-n-play advance retarder? So you can have a fixed, say 8 degrees pulse rotor and then choose your preferred delayed pulse advance on the retarder?
Are you aware of any leads towards an F4i Microsquirt application or maps?

 

Yes, considering stock engine runs fine on 87 PON, 4-6 degree advance is easy with +95 PON.

Not off-hand. Even "simple" circuit to vary pulses would need calibrated timer that can track changes in RPM and offset its adjustment appropriately. Easiest non-mechanical way is piggyback interceptor. MSD or J&S unit with more advanced knock-detection algorithm: http://www.jandssafeguard.com . These are based on Porsche KLR ignition-piggyback used on their Turbo models.

Here's some resources I've found:

http://www.sparetime.xtreemhost.com/...irted.html?i=1
https://www.600rr.net/threads/crossk...-videos.562545
https://www.fireblades.org/threads/a...squirt.103625/
https://www.fireblades.org/threads/a...irt-map.62881/

Simplest way is to use initial map VE=1 accross board to start.
Use alpha-N load-calculations: TPS 0-50%, then MAP 51-100% load. More stable idle.
Default parameters everywhere else should get you started.
Use wideband datalogging feedback to fine-tune VE maps.
Or use auto-tune initially to get into ball-park, then fine-tune manually.

MS-forums extremely helpful with troubleshooting issues: https://www.msextra.com/forums/viewtopic.php?t=61656
Issues with VR signal issues pop up occasionally when using factory sensors & triggers. Bosch Motronic solved this issue with custom ASIC to convert analogue to square-wave signal. Nowadays, it may be simpler to use hall-effect sensor from very beginning.