NefMoto

I like to look at my timing table in true timing ( time (ms) btdc ) rather than angle btdc and thought maybe someone else would too. Here's how;

Apply this conversion to each column. ( let me know if there is an easier way )

TimingAngle / ( rpm * 0.006 ) = time (ms) before top dead center

The reason I like to do this is because it gives you a great indication of where your peak torque is. It will generally be the lowest value because that will be where you have the highest load. Granted a veteran tuner can see this in the angles but I like to see it both ways.

For anyone interested here is the conversion to come up with the equation.

1rotation/1minute =
360degrees/60000ms =
.006 degrees/ms

Rpms * .006 degrees/ms =
Degrees/ms

TimingAngle/(degrees/ms) =

Time

Here is a good reading about this method --> http://www.nrteam.org/tech/68 (http://www.nrteam.org/tech/68).

Nice username :)

You can set up VisualME7Logger to display and graph this information by using the following expression:


When logging this information what should we be looking at?  At WOT, my Jetta is pulling a pretty even .6ms all the way to redline.  What is optimal time for WOT, cruising, part throttle...etc?  Can anyone provide examples?

I will add it to ECUxPlot as well. Thanks!

Here is another great thread of ignition timing calculation. All we need to know is the timing/angle when we need to fire the spark plug to allow mixture explosion produce most of it force/pressure at the best moment for maximum power (MBT).

In theory we can do all calculations as complex as we can but talking real data (cylinder pressure per ignition timing plus other factors) will tell us if we are doing right or not. Of course an theoric aproximation will allow us to reach the best timing with the less effort possible. That is what I suppose ignition timing (msec) vs flame speed is all about.

Here is another great post about it calculation --> http://www.ecuconnections.com/forum/viewtopic.php?f=2&t=81 (http://www.ecuconnections.com/forum/viewtopic.php?f=2&t=81).

It would be interesting to see someone populate a table with the theoretical values based on combustion chamber geometry and see how that table compares to KFZWOP.

That would be very cool. I've always wondered how they decide optimum torque.

I have heard about using a spark plug build in a pressure transducer to get best MBT possible.

I have these for my car.

Jealous... which one did you get?

http://www.optrand.com/products.htm#top

Did a quick conversion on mine using the above maths ion 1st post and my stock timing is curently about 0.5seconds between 3250rpm and 5800rpm and then goes to 0.6x onwards to 6250 when log stops

Latest ECUxPlot includes true timing ...

JUst downloaded the latest one there.... Pretty handy!

Looks like I can have a touch more advance, as well as looking at knock logs, if the 0.6ms theory is correct :P

If you are riding knock recognition, there isn't much you can do other than:

1) water/meth
2) better gas
3) richen AFR
4) less boost
5) numb KR (not recommended unless you have detcans and a ton of experience).

No true logs at the moment after I re-gapped plugs.   Thats the plan for this weekend and add the finishing touches to my boost map and then look at timing.

How do you come up with that conclusion?
You got 0.5m/s and you wont to be at 0.6m/s bc it is the most optimal?
IE: If i look at my true timing logs, I am at 1.1m/s at highest load and taper to 0.6m/s at redline.
I am tuned for e70.
How do you interpret that?
How do i come with optimal results for Ethanol?
Thanx!!!

Flame speed

I think understanding the math and physics of timing is important. But I personally would never tune timing from a desk. I might make a guess but IMO you need to measure power and check your knock correction to dial in timing. ESPECIALLY when ethanol is involved. You can go past MBT without seeing any knock in some cases.

So if he would increase timing at certain rpm, it would increase flame speed. Off course:)

Sure, but there are no knocks on e85.
Tuning it to perfection on the street is very difficult.
This method helps a bit, I believe.

The calculation is heavily dependant on flame speed which will be completely different with different fuel.

As tb44 said, this is more of a sanity check than anything. It's just another angle to analyze your data.

I believe that.
Can any of you great minds do some calculations on e85?
Would be great to have that info as well.

Come across this.  Any use to you?

(http://i216.photobucket.com/albums/cc228/frenchconnector/Logs/FLAMESPEED-1.gif)

Course it does, every info is good :)
Thanx mate!!