Dyno tuning technic
07-26-2016, 04:42 AM
#23
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670 out of Bobs combo with dyno headers and no accessories, seems like about as much of a home run as mine, he told me my engines sucked and I messed them up, yet he's still playing with his while I am out boating!
07-26-2016, 04:49 AM
#24
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First runs were to test some parts. These final runs were to tune the parts I ended up buying. Should have been done months ago but a few things came up and here we are. Not too concerned, other things are happening. Not sure how much of a change should be seen on O2 due to a jet change? Maybe he knows something we don't about the accuracy of the equipment? Maybe O2 isn't working right and he won't say so? I'm thinking he has some old school thinking like that article MT posted.
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Straight bottoms and flat decks
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07-26-2016, 04:51 AM
#25
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I get ya. Plus, it was 90 degrees and 40% on the day we ran. Maybe a little rich is a good thing anyway for when it's cooler/ denser.
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Straight bottoms and flat decks
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Last edited by bck; 07-26-2016 at 05:41 AM.
07-26-2016, 06:38 AM
#26
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I think EGT's are often misunderstood. High EGT's, are often an indicator of too late of ignition timing. However, high EGT temperatures, do not always mean that the cylinder temperature is hotter, it simply means that the heat, is simply being sent out the exhaust valve more , which shows on the gauge. Too much timing advance, can show a lower EGT, but also increase temperature INSIDE the cylinder/chamber. This is why with too much timing, detonation can happen, burnt plug electrodes, etc.
The concept of ignition timing, is simply to fire the plug at the right time. The engine, will tell you what that time is. If the power picks up, you're in the right direction. If power falls off, wrong direction. This is where a dyno is invaluable.You really shouldn't be crutching an engine, with a certain amount of timing, to control EGT's. You want the proper amount of timing, as well as fuel mixture.
I personally believe tuning off EGT temperatures alone, is a bad idea, in a gasoline engine.
The concept of ignition timing, is simply to fire the plug at the right time. The engine, will tell you what that time is. If the power picks up, you're in the right direction. If power falls off, wrong direction. This is where a dyno is invaluable.You really shouldn't be crutching an engine, with a certain amount of timing, to control EGT's. You want the proper amount of timing, as well as fuel mixture.
I personally believe tuning off EGT temperatures alone, is a bad idea, in a gasoline engine.
07-26-2016, 06:50 AM
#27
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Big reason for EGT guages, was to 'keep a tune' on an engine. Meaning, once engine is all good and out in the field, if any of the EGT's changed, then something is up and time to find out what it is.
07-26-2016, 07:02 AM
#28
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Exactly SB.
Lets say you are cruising along at 4000rpm, with 30 deg of timing. Your egt is 1400. You bump timing to 32. Egt goes to 1360. You didnt necessarily cool the cylinder down, you just cooled the exhaust valve.
On the flip side, if you retard the timing, egt will raise, but you may have cooled down the peak cylinder temperature.
Too much timing can be negative work, causing a power loss, ans extreme temps inside the cylinder. Too little timing , hot exhaust valves ans wasted power as well.
How do you find optimal timing? The dyno. And you dont find it by looking at the afrs, brake specifics, egts, etc.
Bck, what kind of timing curve setup did you have in the daytona boxes ?
Lets say you are cruising along at 4000rpm, with 30 deg of timing. Your egt is 1400. You bump timing to 32. Egt goes to 1360. You didnt necessarily cool the cylinder down, you just cooled the exhaust valve.
On the flip side, if you retard the timing, egt will raise, but you may have cooled down the peak cylinder temperature.
Too much timing can be negative work, causing a power loss, ans extreme temps inside the cylinder. Too little timing , hot exhaust valves ans wasted power as well.
How do you find optimal timing? The dyno. And you dont find it by looking at the afrs, brake specifics, egts, etc.
Bck, what kind of timing curve setup did you have in the daytona boxes ?
07-26-2016, 07:18 AM
#29
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If you look at how mercury marines Thunderbolt V worked, its pretty cool. It uses MBT timing, (mean best torque)
It would increase timing during cruise, until it no longer sees an rpm increase . If it sees an rpm decrease , it then retards timing slightly.
Whats happening here, is the ign module is tuning the engine to its optimal state, by power output of the engine. You can do this on the dyno as well., by monitoring the power changes.
Again, the proper amount of timing , is the one that makes the best power.
It would increase timing during cruise, until it no longer sees an rpm increase . If it sees an rpm decrease , it then retards timing slightly.
Whats happening here, is the ign module is tuning the engine to its optimal state, by power output of the engine. You can do this on the dyno as well., by monitoring the power changes.
Again, the proper amount of timing , is the one that makes the best power.
07-26-2016, 07:22 AM
#30
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your guy has been doing that for a long time I'm sure, but AFR readings are (in my opinion) the way to go, you want to get high tech run 1 per cylinder, I played with the EGT deal years ago...its a crapshoot on some setups
