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Old 01-14-2011, 11:06 AM   #1
RaceFaceXC
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Default Dyno experiments; ECU theories you want tested?

I have the opportunity to use a dyno tomorrow and depending on the schedule of the daily hosting me, I may have extra time to try out some changes in tunes and see what results I get. I have one experiment I want to try pertaining to fuel ratios and rpm/load but I may haver extra time to try other things. I won't be able to do any hardware changes so anything I try has to be ECU related. If you have any ideas, lay 'em on me.

Looking at you, Ty, BRR, Jay, etc.
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Old 01-14-2011, 11:31 AM   #2
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what do you have for heads/cams/headers/intake/exhaust, or anything else relevant?

I'd be interested to see where your timing/AFR ends up for MBT.
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Old 01-14-2011, 01:35 PM   #3
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I'm interested in seeing what correlations you can find between EGTs and power. More heat should = more power, up to the point that too much combustion is happening well after TDC. I've heard of some road tuners using EGTs to help find peak power, and that would be very useful for on-the-fly tuning at track and autocross events.
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Old 01-14-2011, 01:36 PM   #4
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Also, can you run on really high octane race gas and find true MBT, then see how close you can get on pump 91/93? Particularly if we're talking about a high compression/high RPM motor.
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Old 01-15-2011, 03:50 AM   #5
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First, run the car at 12.0, 12.5, and 13.0 AFR (dead-nuts on), optimize timing for each AFR individually, and compare power output on optimized states.

Second, if it's a load-holding dyno (meaning you can tell the dyno not to let the roller speed change no matter how much or little power the car puts out), create a grid of 2500, 2750, 3000, 3250, 3500 RPM on the X-axis and 0.40, 0.50, 0.60, 0.70, 0.80 g/rev on the Y-axis. Set the dyno to hold speed for each of those RPM setpoints. Then use the throttle to get the engine to each load setpoint. Advance timing (via the OBD-II increase timing command to make this faster). Find out if stock timing really is MBT or if advancing timing in the mid-RPM, mid-load ranges increases power output. If it increases power output, that means it also increased fuel economy.
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Old 01-15-2011, 10:08 AM   #6
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Quote:
Originally Posted by williaty View Post
First, run the car at 12.0, 12.5, and 13.0 AFR (dead-nuts on), optimize timing for each AFR individually, and compare power output on optimized states.

Second, if it's a load-holding dyno (meaning you can tell the dyno not to let the roller speed change no matter how much or little power the car puts out), create a grid of 2500, 2750, 3000, 3250, 3500 RPM on the X-axis and 0.40, 0.50, 0.60, 0.70, 0.80 g/rev on the Y-axis. Set the dyno to hold speed for each of those RPM setpoints. Then use the throttle to get the engine to each load setpoint. Advance timing (via the OBD-II increase timing command to make this faster). Find out if stock timing really is MBT or if advancing timing in the mid-RPM, mid-load ranges increases power output. If it increases power output, that means it also increased fuel economy.
+1
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Old 01-15-2011, 07:28 PM   #7
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+1
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Old 01-16-2011, 11:06 AM   #8
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Well guys, bad news for you all wanting some data... The car on the dyno b4 mine, a porsche 928 twin turbo, broke some belt on the dyno itself. So my session was late and very brief since the shop employees were waiting to go home. I did gain 12 hp over what I had already tuned by adding a little fuel and reducing timing 1 deg in the high load/high rpm range.

It was a mustang dyno, so it does have load holding capabilities and I may have other chances to play with it in the future. If I do, I'll post here.

For my motor and setup, mbt was 13.3 afr tapering evenly to 12.8 from 5600 to 6500.
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Old 01-16-2011, 07:27 PM   #9
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nice gains - have a plot for us to see?

also, what kind of mods/setup are you running?
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