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Author Topic: How to tune timing on the road?  (Read 6173 times)
Beaviz
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« on: May 18, 2016, 01:37:23 AM »

How do you guys tune the timing maps?

I guess that the best solution would be to have a dyno and be able to set the ECU to a constant RPM and gradually raise the resistance of the dyno brake and adjust the timing accordingly.

But in our case we already have some well working "base" maps from the factory calibration and most of us only have the option to log on the road.

Assuming that boost, fueling etc. is all good. Would a good way be to cap the load using e.g. LDRXN to each point of the load axis in the timing maps, log and adjust accordingly? In this case wouldn't it make most sense to start adjusting from the lower RPM, log and continue upwards?

Or do you do it differently?
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nyet
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« Reply #1 on: May 18, 2016, 11:00:02 AM »

Depends on what sorts of timing changes you are trying to make.

If you are tuning for pump gas, the stock timing tables are just fine up until just before peak boost and about the last 2 load lines.

If you are tuning for e85, w/m or race gas, you absolutely need a dyno.
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vwaudiguy
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« Reply #2 on: May 18, 2016, 11:11:04 AM »

A lot of times what it likes in static condition will change once you do a sweep. We have a load based dyno, and keep at a set RPM, and make adjustments based on load. You can only do this realistically up until 4500 rpm or so on a turbo car, and do the top end in sweeps. We always do road logs after it's been on the dyno anyway. I would say if you have a good tuned base, logging on the street is the best, although it's not particularly safe, unless you're prj that has access to an airport strip.  Smiley
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Carsinc
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« Reply #3 on: May 18, 2016, 06:59:25 PM »

A lot of times what it likes in static condition will change once you do a sweep. We have a load based dyno, and keep at a set RPM, and make adjustments based on load. You can only do this realistically up until 4500 rpm or so on a turbo car, and do the top end in sweeps. We always do road logs after it's been on the dyno anyway. I would say if you have a good tuned base, logging on the street is the best, although it's not particularly safe, unless you're prj that has access to an airport strip.  Smiley

Wait you don't have access to a airsptrip or at least a closed road?
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J.Laborde
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« Reply #4 on: May 18, 2016, 08:07:57 PM »

Not only this, however do you use Lemmiwinks or WinOLS/Tunerpro? I understand tuning for E85 is more then just the adjustment of KRKTE. :/
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grifrowl
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« Reply #5 on: May 18, 2016, 10:56:38 PM »

I have been using logs of timing retard from day-to-day driving to dial in timing for pump gas on my own car recently. I plot rpm and load of all datapoints where timing pull occurred give me a better idea of what regions need work. Here's an example of said plot from about 6 hours of driving in various conditions at temperature.

Obviously mbt methods on a dyno would be best.
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Beaviz
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« Reply #6 on: May 19, 2016, 01:19:44 AM »

Thanks a lot for your comments!

I will only be tuning for pump gas and higher load than stock. So what nyet proposed with changing the last few load lines is what I am aiming for. Was just wondering how other people did or if I missed something.

But to adjust the last few lines do you cap the load and log or just do some runs and adjust with the same base map?
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grifrowl
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« Reply #7 on: May 19, 2016, 09:27:00 AM »

But to adjust the last few lines do you cap the load and log or just do some runs and adjust with the same base map?

I have found in the past that dialing in spark from constant load and rpm is not necessarily useful at high loads (when tuning our turbo ktm 575 formula SAE car from no basemap), and I think vwaudiguy's comment supports that. You might be best off deriving your timing in higher loads by curve fitting to get a start and then road logging some sweeps and making iterative adjustments from there.
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Instigater
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« Reply #8 on: May 22, 2016, 06:26:51 AM »

How would you tune ignition for best efficiency in low load and low rpm sections when fuel type is changed to LPG or E85?
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