How to Safely adjust timing
Jul 12, 2006, 01:20 PM
#31
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Here's an example of a ignition table that wouldn't feel very smooth when jumping from the 180 to 200 load regions at 1250rpm (sudden increase in timing that could result in knock) and at 5000rpm (sudden drop in timing that could feel like a rapid loss in torque).
I purposefully left the timing values out so you couldn't recreate this table yourself.
I purposefully left the timing values out so you couldn't recreate this table yourself.
Jul 12, 2006, 01:38 PM
#32
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Originally Posted by SuperHatch
Here's an example of a ignition table that wouldn't feel very smooth when jumping from the 180 to 200 load regions at 1250rpm (sudden increase in timing that could result in knock) and at 5000rpm (sudden drop in timing that could feel like a rapid loss in torque).
I purposefully left the timing values out so you couldn't recreate this table yourself.
I purposefully left the timing values out so you couldn't recreate this table yourself.
Nice post as usual.
Jul 12, 2006, 01:40 PM
#33
Originally Posted by SuperHatch
Here's a nice 3D representation of the stock timing table... notice how as load and RPM are compared, the stock ECU timing table follows a smooth ramp up of timing as RPM increases... the 3D representation makes this eas to see...
When you adjust your timing cells you want to make sure that the ramp rates between cells aren't too drastic. This could lead to all sorts of problems... a sudden "safe to knock" transition and a rather non-smooth seat of the pants feeling as you traverse different timing cells (rolling on and off the throttle rather than treating the gas pedal as an on-off switch).
When you adjust your timing cells you want to make sure that the ramp rates between cells aren't too drastic. This could lead to all sorts of problems... a sudden "safe to knock" transition and a rather non-smooth seat of the pants feeling as you traverse different timing cells (rolling on and off the throttle rather than treating the gas pedal as an on-off switch).
Jul 12, 2006, 02:39 PM
#35
Originally Posted by SuperHatch
Here's an example of a ignition table that wouldn't feel very smooth when jumping from the 180 to 200 load regions at 1250rpm (sudden increase in timing that could result in knock) and at 5000rpm (sudden drop in timing that could feel like a rapid loss in torque).
I purposefully left the timing values out so you couldn't recreate this table yourself.
I purposefully left the timing values out so you couldn't recreate this table yourself.
Jul 12, 2006, 02:52 PM
#36
i see how you reference the timing load cell by referencing the datalogged timing and rpm and looking at the map to find the load cell, but once your car isn't stock, how do you follow the fuel being that the AFR you datalog doesn't correspond to the AFR target in the map for a specific RPM?
Jul 12, 2006, 02:56 PM
#37
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Once you chart your timing through the load cells in the timing map, you should be able to use the same pattern on your fuel map. I.e. if the ECU was hitting 260% load at 5000 RPM, then look at the 260%, 5000 RPM fuel cell. Your logged AFR will rarely correspond exactly to the AFR target value in the fuel map, especially once you start modding.
l8r)
l8r)
Jul 12, 2006, 03:11 PM
#38
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Originally Posted by C6C6CH3vo
Im not an expert but I personally don't feel that this graph is a good method to judge the quality of a timing map. Dont ask me why - I dont know, but I do know there's so many more important factors at play than load vs rpm
1.) The flat timing ranges basically assume that at 200% load you can run the same amount of timing as you can at 260% load.
If you take a moment to think about that, it doesn't make sense. Simply put, the ECU calculates the load value based on the mass of air being pushed into the engine. At 260% load value you will be pushing more air into the engine and (hopefully) mixing it with more fuel, resulting in a more powerful combustion (more fuel + more air = bigger release of energy), which means that you should be able to run more timing at lower load values.
2.) Sudden changes in timing, no smooth transitions. This can cause detonation, both from a sudden increase or decrease in timing.
3.) It is very difficult to log against flat timing maps. If you logged 5 degrees at 4000 RPM and your timing table shows 5 degrees from 180% to 260%, then it makes it very difficult to pin down exactly where your ECU is running through its maps
l8r)
Jul 12, 2006, 03:29 PM
#39
Timing curve is suppose to be a smooth transition as load increases and with that graph he is showing the difference between a well adjusted timing map and poorly adjusted timing map. If you have seen the aem software, once your timing map is adjusted properly and you look at in 3d you will understand as the graph will be smooth as butter.
Jul 12, 2006, 03:51 PM
#40
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Originally Posted by C6C6CH3vo
Im not an expert but I personally don't feel that this graph is a good method to judge the quality of a timing map. Dont ask me why - I dont know, but I do know there's so many more important factors at play than load vs rpm
The taget numbers under load should be determined through dyno and road logging and then you can use the graph to smooth things out
Flash Evo by Ecutek has some great 3 d maps you can spin about in all directions and its very helpful
Aem is the same
Jul 12, 2006, 04:25 PM
#41
Originally Posted by Ludikraut
Once you chart your timing through the load cells in the timing map, you should be able to use the same pattern on your fuel map. I.e. if the ECU was hitting 260% load at 5000 RPM, then look at the 260%, 5000 RPM fuel cell. Your logged AFR will rarely correspond exactly to the AFR target value in the fuel map, especially once you start modding.
l8r)
l8r)
Jul 12, 2006, 05:12 PM
#42
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Thank you very much Al for the responce, also everyone else who chimed in. I think i get it a little more now. I still have to pick up a wideband. I figured i would do that before i go and try to sign up for the dyno day with you guys alwaysinboost. I don't want to look unprepared. I just want to try to understand it and the info that I recieved in this thread has helped alot..
Jul 12, 2006, 07:00 PM
#43
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You really should have a WB but if your only going to tune your car on the dyno then you don't 'need' one because they have one there. However there is a big difference between tuning 3rd gear on the dyno and tuning 1st-5th on the street with real load in real driving conditions.
The map I made on the dyno is childs-play compared to the one I made on the street.
The map I made on the dyno is childs-play compared to the one I made on the street.
Jul 12, 2006, 07:07 PM
#44
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I am so jealous of you alwaysinboost being that we have the same mods. You have less miles than me, I have thought about loading the maps that you have posted being that my car has been across the country 2 times and 12000 of my 50000 miles have been highway so all i can say about my evo is 18000 of my 50000 miles ok so 32000 are city. I can't be more happy even with the gas mileage increase that I have gotten thanks to evoscan and evoflash. To even say that it is a great time to have a evo. Is a total understatement. No dissrespect to you Alwaysinboost in what you said. You sold me great exhaust and I can do nothing but brag on megan racing...... Thank you again Al for posting again in this forum.