Ignition timing for turbo or supercharged renesis - post your maps
11-07-2010, 06:38 PM
#127
The OP actually posted my base timing map. Not too pleased by that, but, whatever.
As a datapoint, peak cylinder pressure at 350 g/sec of flow on the Renesis happens in 20° of crank rotation on 91 RON/MON. Since we want that to happen at about 15° ATDC...
As a datapoint, peak cylinder pressure at 350 g/sec of flow on the Renesis happens in 20° of crank rotation on 91 RON/MON. Since we want that to happen at about 15° ATDC...
11-07-2010, 07:57 PM
#131
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I meant the map posted above by SC-ed. That was in the materials made available to paying customers of the Calibration Seminar.
11-07-2010, 09:12 PM
#132
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Yeah what he said lol. But anyways as far as timing last time I played with it this was my map...not really set for power but it works and last time I dyno'd at 8 psi I was hitting 305 and had a pour tune...now I'm pretty well tuned to 14 and you can definably tell a huge difference between 8 and 14 so I'm guessing I'm 350+ oh and I have the 3.9 gears as well
Thanks for posting this!
Anyone have any comments on the timing for this? I may consider using it...
Last edited by BlackStealth; 11-07-2010 at 09:21 PM.
11-07-2010, 10:36 PM
#136
Otherwise, she looks good!
Honestly, do you know what you are looking at? Did you compare the net timing of that Int-X display to the timing grid above? Do they even look remotely similar to you?
11-07-2010, 10:44 PM
#137
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no, I don't fully understand what I'm looking at, which is why I'm asking you if it's a good map. Otherwise I wouldn't be asking at all.
Last edited by BlackStealth; 11-07-2010 at 10:50 PM.
11-07-2010, 10:55 PM
#139
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As I stated before, I'd like to use a new timing map for my car, and as a baseline for when it goes on the dyno for additional tuning. It's also a good way of learning how a good map looks versus something that doesn't, so that I can begin to make adjustments myself eventually. We aren't all experts here.
11-07-2010, 11:17 PM
#140
As I stated before, I'd like to use a new timing map for my car, and as a baseline for when it goes on the dyno for additional tuning. It's also a good way of learning how a good map looks versus something that doesn't, so that I can begin to make adjustments myself eventually. We aren't all experts here.
11-08-2010, 12:25 AM
#144
It is called mechanical advantage and brisance... timing in a vacuum cannot really be "good or bad", for example, some run more ignition with a richer AFR, some do the opposite.
The flame front propogagation varies with each degree of angle, as well as each molecule of fuel and air.
So you asking for a good timing map, would be like me asking for a good touch up paint for my car... sight unseen over the internet without the whole picture it is basically impossible to do. If you know the principles of it, then you can look at others maps and adjust them to your own car; but if you do not - then someone elses basemap is irrelevent to you.
That being said... if you want to play with fire then by all means go ahead. Here is the base map I typically use, on my turbo, east coast gas, east coast temperatures, humidity etc.... but if you think it is apples to apples, load it up and have at it.
The flame front propogagation varies with each degree of angle, as well as each molecule of fuel and air.
So you asking for a good timing map, would be like me asking for a good touch up paint for my car... sight unseen over the internet without the whole picture it is basically impossible to do. If you know the principles of it, then you can look at others maps and adjust them to your own car; but if you do not - then someone elses basemap is irrelevent to you.
That being said... if you want to play with fire then by all means go ahead. Here is the base map I typically use, on my turbo, east coast gas, east coast temperatures, humidity etc.... but if you think it is apples to apples, load it up and have at it.
Last edited by Kane; 12-05-2010 at 07:21 AM.
11-08-2010, 12:37 AM
#145
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Crap Kane beat me to it.
That's the primary issue with looking at individual tables and trying to make determinations without taking into account the rest of the tune. Even so, the effects at the tailpipe will not always be represented as a 1:1 ratio within the map itself. Intellectuality discussing the topic is always a plus but if you're expecting to post a map and be told "yes" or "no" then you're going to be disappointed.
That's the primary issue with looking at individual tables and trying to make determinations without taking into account the rest of the tune. Even so, the effects at the tailpipe will not always be represented as a 1:1 ratio within the map itself. Intellectuality discussing the topic is always a plus but if you're expecting to post a map and be told "yes" or "no" then you're going to be disappointed.
11-08-2010, 01:03 AM
#146
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All of your comments make sense, and I understood the concept when I was looking for something that I could use as a base map. The comment by MM, as quoted above, is not warranted as he's suggesting that the map is full of issues, and ultimately is useless.
Anyway - the main reason why I wanted to know if certain maps were 'conservative' or 'safe' is because my current ignition map doesn't really resemble any of yours - so I wanted something as more of a guide/aid to know that I'm on the right track in tuning.
Last edited by BlackStealth; 11-08-2010 at 01:23 AM.
11-08-2010, 01:46 AM
#147
All of your comments make sense, and I understood the concept when I was looking for something that I could use as a base map. The comment by MM, as quoted above, is not warranted as he's suggesting that the map is full of issues, and ultimately is useless.
Anyway - the main reason why I wanted to know if certain maps were 'conservative' or 'safe' is because my current ignition map doesn't really resemble any of yours - so I wanted something as more of a guide/aid to know that I'm on the right track in tuning.
Anyway - the main reason why I wanted to know if certain maps were 'conservative' or 'safe' is because my current ignition map doesn't really resemble any of yours - so I wanted something as more of a guide/aid to know that I'm on the right track in tuning.
Does this help ?
11-08-2010, 06:08 AM
#148
12-03-2010, 07:48 AM
#150
Think I'm starting to grasp timing, maybe 
question though, it seems like there are large steps in all these timing maps. Just as an example take Kanes map on this page. At 4000 rpm the first 5 load columns are all at 43.5 degrees then the next column steps down to 40 degrees. Why is the timing not tapered down for a smooth curve? I see large chunks like this in all the maps shown.
Also what is the mathematical equation for determining timing? Google has failed me here. Seems like if you know peak pressure in the chamber, AFR, RPM, Load, spark duration and heat, you should be able to plug that into a calculation to determine the optimal spark timing?
question though, it seems like there are large steps in all these timing maps. Just as an example take Kanes map on this page. At 4000 rpm the first 5 load columns are all at 43.5 degrees then the next column steps down to 40 degrees. Why is the timing not tapered down for a smooth curve? I see large chunks like this in all the maps shown.
Also what is the mathematical equation for determining timing? Google has failed me here. Seems like if you know peak pressure in the chamber, AFR, RPM, Load, spark duration and heat, you should be able to plug that into a calculation to determine the optimal spark timing?
Last edited by Tampa1stRotor; 12-03-2010 at 07:59 AM. Reason: edited compression ratio to peak pressure