| Author |
Message |
    
Sarodude
| | Posted on Friday, December 21, 2007 - 12:21 am: | 
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So, when tuning the ECU on the DYNO, what is it being tuned for? Just max HP? Are you running a sniffer and using that? Or is it diffferent compromises for when someone starts to hear detonation?
My question about what style of injection wasn't really about closed loop / open loop, but about Speed Density or Alpha N.
Anyway, this stuff is all just academic. I'm just curious as hell about it.
-Saro |
Slaughter
| | Posted on Friday, December 21, 2007 - 01:10 am: |
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Nope - you're actually tuning TWO separate big single cylinder motorcycles - the front and rear cylinders.
The single sniffer in the tailpipe gets pretty close but we REALLY MUST get oxygen ports in both pipes for dyno tuning to measure the fuel/air mixture in each exhaust. Problem is convincing everybody to do it. They get the bike running and are willing to accept banging and popping at low revs and still can't tell exactly how it's doing up high. Tailpipe just tells you that you're in the ballpark but you can't tell if one cyl is slightly lean and the other is slightly rich... no way without 2 ports.
Really need a separate set of pipes for the dyno since having fittings welded into the pipes that you plug for racing will only crack with time.
It's only money.
Basically though, you're tuning to the proper air/fuel ratio in the exhaust. Time consuming.
(Message edited by slaughter on December 21, 2007) |
Slaughter
| | Posted on Friday, December 21, 2007 - 11:56 am: |
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Saro - Just fer giggles I got some of the raw data from my fuel maps, converted it to Excel - saved as viewable images.
Gives a picture of how the maps actually look.
Keep in mind that this is an 8-bit program: full scale is 266 counts (2^8 units) Also the RPM axes are reversed (High RPM on left/zero on right)
(gotta shrink the images but I'm at work abusing computer priveleges again and it's the last day today) 
It'll give a picture of what's being done.
Each square is a throttle position/RPM and fuel call is in microseconds/58.
From the fuel table on my 1169 motor:
How it looks in Excel in 3D:
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Sarodude
| | Posted on Friday, December 21, 2007 - 12:29 pm: |
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Steve-
Your fuel data gave me one answer. The system is Alpha-N. And, just for the record, it'd be 0-255, not 266. 
Spent a lot of my youth messing about with 8-bit 6502 assembly language....
-Saro |
Slaughter
| | Posted on Friday, December 21, 2007 - 02:05 pm: |
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Yabbut first count is ZERO... therefore 266 counts is 255
Therefore, we're BOTH right...
Oh and it's circular... 266 = ZERO, 267 = 1, 268 = 2 (etc) - so I do all my math in Excel, save the tables as CSV and copy/paste into the text editor and take it from there and export to the module. Problem was when I goofed and went above 255, I inadvertently accidentally called for danged near ZERO fuel. Good thing I didn't melt the pistons!
Heck, I did programming when we were pressing pointed sticks into clay and could program an entire ARMY to march on the enemy with just two tablets... but that was then... Actually learned Basic in Applesoft Basic to drive a 2-axis template cutter but it was also open loop (no position feedback) and if the drive was off, we'd not know it if we didn't see the notch in the part - meaning we'd spend so much time checking against a drawn template
By the way - what hasn't been posted up above is the fact that ALL engine parameters can be futzed with - soft rev limit, hard rev limit, oil temp limits, cyl head temp limits, fan on/off/hi/low/reverse limits, oh and that doesn't even mention the front and rear look up tables for spark advance - just as complex as those for fuel!
Fun stuff
That's kinda why I would be a-feared to have one of these motors in the hands of somebody who thought it was just a "plug and chug" |
Gentleman_jon
| | Posted on Monday, December 15, 2008 - 08:36 am: |
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Here is one on sale on eBay, ( thanks Xbpete), that the seller claims has a street legal title.
Let the festivities begin!! |
Xoptimizedrsx
| | Posted on Saturday, April 04, 2009 - 12:28 pm: |
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By the way - what hasn't been posted up above is the fact that ALL engine parameters can be futzed with - soft rev limit, hard rev limit, oil temp limits, cyl head temp limits, fan on/off/hi/low/reverse limits, oh and that doesn't even mention the front and rear look up tables for spark advance - just as complex as those for fuel!
Fun stuff
this above stuff can be a pain to get the corrections under control. i have found a few tricks on the ecm to stop a few correction at temps in the bike but they are touchy. to much the fans run in the sun to little the bike gets hot and the fuel goes way lean.
al these codes can be applied with ecmspy but are in raw data in the eprom file. as ecmspy does not give these codes in the pages in clear view.
temp and timing reduction is the only area that difficult to scale. i just closed it off and run direct fixed timing. works great for me.
the fuel was more simple. we get the engine at full temp of that days temp at track temp. then read the afr front and rear separately. wide band only.
we know at standard temp the afr was stable at wot and open loop at our engine preferred power fuel of 13.4. when the heat was at full run the afr was at 15.4. the temp correction actually in a stock ecm and race reduces the fuel a lot. we rescaled the reduction to keep the temp fuel at 13.4 at upper temps. now when the motor cools back down the fuel is still at best value.
this is one big move I did to keep the bikes power up.
I always knew on the track on long races and high 20+ laps we had a lower lap time after about 10 laps. we use to think it was tires but with the live gauges added I saw the afr was rising on the dyno with high temps.
so if you feel your slower late in a race its you temp correction that need to be shot with a live temp gun then scale the fuel from that data.
a palm with ecmspy easily fixes this on the track. just learn where in the eprom the files are to apply the new coding and instantly see the afr go right back to the power fuel.
my fuel is 6% richer at high temp than low and normal temp to keep the afr at 13.4
all was set on temp correction tables in raw ecm code on the eprom page then burn in the changes. these dont have a actual page value you see in ecmspy except one.
lock the timing still then leave it once you have the correct offset. the temp retard is not working like i want on value changes yet.
so lock it to be direct.
all this is for the stock ecm and race ecm. not the buell race tuner i'm sure it has this data in clear view where the stock ecm tuning units doesnt.
but it can be controlled. its not hard but time consuming. and every days weather changes the finale engine temp fuel preset on full temp correction. you need live guages to stay on top of it for every day at the track.
i can post pics of my setup if needed. |
Pashlipops
| | Posted on Monday, April 06, 2009 - 05:50 pm: |
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i can post pics of my setup if needed.
Yes please |
Pashlipops
| | Posted on Thursday, April 09, 2009 - 07:44 am: |
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Wot no pics? |
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