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I know this topic has been discussed to death, but I think I drew some solid conclusions from my research, thus I am posting them for newbs to reference.
I got bored yesterday so I got out the old autotap and bought $4 worth of resistors at radioshack. These were their values for temp:
Actual IAT temp 41*F
680 ohm 142*F
3.3K ohm 70*F
4.7K ohm 57*F
10K ohm 30*F
I wanted to get an 18K ohm as well, but they were sold out. Since it was 41*F outside, the 10K was the only resistor that would have a chance of improving my performance.
I made several WOT runs at my secret test facility.
First, the stock IAT values:
As I made a couple passes, the IAT heated up to 50*F. The timing jumped around from 21* adv to 26* adv, but it averaged itself out at about 22* adv. The A/F ratio stayed consistent at 12.2, which is a little rich for peak performace. Best power ratio is between 13.5-14.0.
Now, the 10K results:
The IAT value stayed right at 30*F. The timing jumped from 25* adv to 29* adv, but it averaged itself out at about 27* adv. The A/F ratio fluctuated between 12.3-12.5.
Conclusion:
I gained about 5* of timing advance and leaned out by .1-.2. The slightly leaner condition should help the engine achieve best power ratio. Was there a SOTP gain? Definatley not. I do believe, however, that 5* is enough timing advance not to dismiss this super cheap mod as useless. Of course you need to use high octane fuel when attempting any timing advance.
I got bored yesterday so I got out the old autotap and bought $4 worth of resistors at radioshack. These were their values for temp:
Actual IAT temp 41*F
680 ohm 142*F
3.3K ohm 70*F
4.7K ohm 57*F
10K ohm 30*F
I wanted to get an 18K ohm as well, but they were sold out. Since it was 41*F outside, the 10K was the only resistor that would have a chance of improving my performance.
I made several WOT runs at my secret test facility.
First, the stock IAT values:
As I made a couple passes, the IAT heated up to 50*F. The timing jumped around from 21* adv to 26* adv, but it averaged itself out at about 22* adv. The A/F ratio stayed consistent at 12.2, which is a little rich for peak performace. Best power ratio is between 13.5-14.0.
Now, the 10K results:
The IAT value stayed right at 30*F. The timing jumped from 25* adv to 29* adv, but it averaged itself out at about 27* adv. The A/F ratio fluctuated between 12.3-12.5.
Conclusion:
I gained about 5* of timing advance and leaned out by .1-.2. The slightly leaner condition should help the engine achieve best power ratio. Was there a SOTP gain? Definatley not. I do believe, however, that 5* is enough timing advance not to dismiss this super cheap mod as useless. Of course you need to use high octane fuel when attempting any timing advance.
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