Thread: Ignition timing?
08-26-2010, 06:36 AM #1
Sorry I missed the webinar due to work but thanks for puttin up the recorded version on the web, I watched the first one and its informative and will watch the next one tommorow.
Questions mate, I know we are not suppose to play with the ignition timing but GaryW showed me a couple of adjustments to suit where I take my ski with the fuel availible.
I run my Motec FZS around the Gold coast on Aus 98 and an ignition overall trim set at 2 in my ECU manager.
When I take the ski upto sommerset dam sometimes the best fuel on the dam is standard OZ premium 95 so I adjust my ignition trim back 3 to -1 on the overall trim.
But would like to play safe as the fuel up there even though the pump says premium could be old 95 as its an old servo and would have low volume through it especially over winter or if I take the ski somewhere where they only run Aus 91, like lennox head for surf riding.
whats the trim number to adjust to play it safe to bring back the timing to run on 91?
Also, with regard to rev limits, mine set at 8500, my flat water RPM s is at about 8400 which is great in the rare flat water we get up here, but most of the time I am in the rough stuff and it can bounce hard on the limiter when riding fast through the chop and you can feel the ski losing acceleration in between the waves when fast riding through the chop, evenin small choppy water where the ski can become unhooked and loaded real quick at fast speed, I am running a 13/24, but was thinking putting a bigger prop like a 13/26 on to get my flat water RPM down to just over 8000 so when in the chop the ski has more time to recover between the 8500 limiter and say a 8000 flat water rpm, is this thinking correct from what I understand you were talking about in the rev limits part of the webinar?
I am not too worried about top end as high 70's is fast enough for me but also don't want to kill the acceleration upto 75 as this is usually the fastest you can open these things up here in the chop.
08-27-2010, 02:06 AM #2
I need to see your MAP
The over all trim is only relevant to how much ignition timing is in the main map, could be anything in there.
Some logging would be ideal so I can see how much boost you are making and how good the intercooler is, both these things are critical
Yes your rpm limit is too close to your clean water rpm, I need to also check some of the other settings to do with the rpm limit so again need to see your MAP
You could lift the rpm limit and that would certainly make the ski much faster in the chop, trouble is you risk a larger over rev which is not good, it comes down to a reliablity thing, if you prop back too much then it will lose quite a bit of power due to the lower boost, I would go a little bit of each, try to aim for the rpm to be max at 8300 clean water, lift the rpm limit up to 8650. That wll help a lot and it wont lose too much power.
08-27-2010, 05:48 AM #3
Tks Pete for the reply,
Whats the best way for you to see my map, can I email it to you ?
I know how to email LD files but its my map you need isn't it.
My ski usually gets around 190kpa boost at 8400 with the et low boost wheel.
I am going to try a 13/25 next to get backto 8200-8300 range as soon as I get a new clutch fitted. Your right 8400 at with the 8500 limiter makes the ski feel like it stop starting at top end in the choppy stuff, probally why it keeps blowing clutches as well.
08-27-2010, 07:01 AM #4
I also can send you a LD file as well to look at. Just let me know via PM on how to send my map to you and I will email them down to you tolook at.
Its rare maybe once a year this ski will need the lower octane but I want to play safe, and the less power won't worry me as I am sure there will be more than enough to pull the kids around on a tube at the dam,lol.
08-27-2010, 07:50 PM #5
Send him your .E35 config file that is located in 'C:\motec\M800-v35' and log file that should be by default in 'C:\motec\Logged Data' once pulled from the ECU.
08-28-2010, 04:55 AM #6
08-29-2010, 08:11 AM #7
You need do a wot log, watch IAT temps, and then watch for knock. Whats your wot afr?
08-29-2010, 08:23 AM #8
08-30-2010, 12:21 AM #9
Got your file and thought I would reply to the thread.
Your ignition timing is 24 degrees at 190 kpa at 40 degrees celcius
This is with the 2 degrees in the over all trim, I have to say thats right up there for 98 octane, I would pull out 1 from that because not all fuels are created the same and 98 goes off quite quickly.
Make it 2 if you want the reliability.
1 more for 95 and another 2 for 91.
That is playing on the cautious side and canot be the ultimate advice as all engines are different.
People reading this should also consider that ignition timing is different for different air and engine temps as well, so you cant take what I say here and apply it to your own machine necassarily.
You asked about the speed loss by going from 8400 to 8200, there will be some as you will be making less power due to the lower boost and lower RPM, some of that will be made up for by the fact that you have a steeper pitched prop but not all i am afraid, testing will tell. Ultimately its certainly the way to go for reliability and its what I would do in your situation.
Good luck and keep us in the loop.
08-30-2010, 05:00 AM #10
I will run with an overall trim of 0 on the 98 just to play safe, and will also knock it back to say -2 for the 95. Just in case the fuel is a little sub standard.
Cheers for the tips mate.
Guys, this is what Motec support is all about, send a file and get responses in less than a day, awesome. Worth every penny.
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