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| How much is too much timing? https://www.slantsix.org/forum/viewtopic.php?t=53260 |
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| Author: | Sam Powell [ Sat Sep 07, 2013 6:48 am ] |
| Post subject: | How much is too much timing? |
How much is too much? Of course detonation is a clue, but there are operating conditions that do not induce preignition, in which one might exceed the practical limits, that is exceed the max HP attainable and not know it. I noticed that the Dart ran better when it was cold. It felt lighter under the toe, so to speak. At first I thought it was because of warm up enrichment of fuel, but the AF gauge said otherwise. Then I started paying attention to the timing, and began to see the effects of the cold advance table in MS II. You can create a table that adds as much timing as you want at users specified engine coolant temps. At dead cold I have it set to add 7 degrees and it tapers off to zero added at full warmup. So when first driving it, I noticed the timing was indeed way advanced over the base maps specs. At times it was as high as 52 advanced. So, I decided to add 4 degrees across the board, below 85 KPA and take out a few degrees of the cold advance when really cold. It now idles at 15 instead of the 10 before. So the question is, how will I know when I have gone to far? What will I feel or experience? I have watched the vacuum gauge, and it will cruise nicely on level ground at 40-45 mph in 4th gear at 1500 rpm pulling 15 inches of mercury (I wish the gauge were in KPA). It idles at 18. It seldom drops below 10 unless I come to a fairly steep incline. I went back in last night and brought those cells that were over 50 back down to 50, but just wonder what I am doing right now. It would be so nice to have a steady state dyno to use. Sam |
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| Author: | Aggressive Ted [ Sat Sep 07, 2013 9:51 am ] |
| Post subject: | |
Sam, Quote: So the question is, how will I know when I have gone to far? What will I feel or experience?
Good question! I find that going past 60 degrees hot (200 degrees) you will start to get a slight ping on the freeway and the engine looses it's punch. However, in the winter or as long as the car is not running not too hot (160- 180) I can get away with it and never hear a thing and it still feels punchy. The plugs look good too. Depending on the cam you have you may experience something different but on a stock or near stock like and RV cam I have found 60 degrees to be the borderline. My engine will tolerate temps up to 225 degrees at 52 degrees all day long up and over the mountains with a load on the hottest days no problem. |
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| Author: | Sam Powell [ Sat Sep 07, 2013 10:49 am ] |
| Post subject: | |
Thanks. That helps. I am glad i put the 180 thermostat in. Sam |
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| Author: | Aggressive Ted [ Sat Sep 07, 2013 4:12 pm ] |
| Post subject: | |
I run the high flow racing style stats (160 and 180) in the summer for that extra margin of safety. I also run alcohol/water injection after 2000 rpm. I feel it is beneficial in two ways....it offsets the extra timing and keeps the head and valves clean. The idle is nice and crisp even at 550 rpm stopped at a lite or when caught in traffic. In the winter I go back to a 200 or 205 degree stat which is really nice when your driving on ice and snow for weeks on end. The fans never come on unless I am sitting still in traffic over 20 minutes without the heater on. I also switch to the smaller air dam in the winter. |
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