Retard timing via resistor?
Thread Starter
TECH Senior Member
Joined: Nov 2001
Posts: 7,036
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From: Lake Zurich, IL
Retard timing via resistor? I read somewhere about someone doing this.... they did it for running nitrous so they can flip a switch and retard the timing (I think it was connected with the IAT somehow... where it would trick it into thinking the incoming air was some really hot value, thus causing timing retard? this sound right?)
Anyways... anyone know how I would wire this up? I'm more of a software guy than hardware so I'm not sure what electronic parts I will need other than a resistor....
Would I wire the resistor into the IAT sensor in parallel? Normally it would not be connected, dead end, but when the switch is flipped it would become part of the circuit parallel w/the regular input...
Any help is appreciated, thanks
Anyways... anyone know how I would wire this up? I'm more of a software guy than hardware so I'm not sure what electronic parts I will need other than a resistor....
Would I wire the resistor into the IAT sensor in parallel? Normally it would not be connected, dead end, but when the switch is flipped it would become part of the circuit parallel w/the regular input...
Any help is appreciated, thanks
Re: Retard timing via resistor? This in my opinion would be the best way to wire it. It would ensure a constant electrical connection (unlike a 2-way switch).
Break one of the wire legs going to the IAT, it doesn't matter which one. Wire the resistor in series. Now wire a switch in parallel to the resistor that you just installed.
If you want to reduce timing open the switch. If you want return to the normal IAT reading, close the switch.
This will just basically add the resistance of your new resistor to the IAT resistance when the circuit is closed.
Break one of the wire legs going to the IAT, it doesn't matter which one. Wire the resistor in series. Now wire a switch in parallel to the resistor that you just installed.
If you want to reduce timing open the switch. If you want return to the normal IAT reading, close the switch.
This will just basically add the resistance of your new resistor to the IAT resistance when the circuit is closed.
Thread Starter
TECH Senior Member
Joined: Nov 2001
Posts: 7,036
Likes: 1
From: Lake Zurich, IL
Re: Retard timing via resistor? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by NoGo:
<strong>This in my opinion would be the best way to wire it. It would ensure a constant electrical connection (unlike a 2-way switch).
Break one of the wire legs going to the IAT, it doesn't matter which one. Wire the resistor in series. Now wire a switch in parallel to the resistor that you just installed.
If you want to reduce timing open the switch. If you want return to the normal IAT reading, close the switch.
This will just basically add the resistance of your new resistor to the IAT resistance when the circuit is closed.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Cool, thanks NoGo <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
I bought a potentiometer today (1.6 ohms to 49.7 kohms) that I plan on using.
I wasn't sure how to wire it , but your post confirmed it for me <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> In Parallel
Under normal driving I want the computer to do what it wants (it probably knows better than me).. but on spray I want the computer to do what I want <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> so normally add as little resistance as possible... but on spray crank it up <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Thanks again
<strong>This in my opinion would be the best way to wire it. It would ensure a constant electrical connection (unlike a 2-way switch).
Break one of the wire legs going to the IAT, it doesn't matter which one. Wire the resistor in series. Now wire a switch in parallel to the resistor that you just installed.
If you want to reduce timing open the switch. If you want return to the normal IAT reading, close the switch.
This will just basically add the resistance of your new resistor to the IAT resistance when the circuit is closed.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Cool, thanks NoGo <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
I bought a potentiometer today (1.6 ohms to 49.7 kohms) that I plan on using.
I wasn't sure how to wire it , but your post confirmed it for me <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> In Parallel
Under normal driving I want the computer to do what it wants (it probably knows better than me).. but on spray I want the computer to do what I want <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> so normally add as little resistance as possible... but on spray crank it up <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Thanks again
Re: Retard timing via resistor? aaack!
My suggestion was to take a resistor in and out of the circuit with a switch. It was to wire the NEWLY INSTALLED RESISTOR AND A SWITCH IN PARALLEL, not in parallel with the IAT resistor.
The above recommended circuit will still put the newly installed resistor in SERIES with the IAT resistor, but in PARALLEL to the switch.
WIRE YOUR RHEOSTAT IN SERIES <img border="0" alt="[judgement]" title="" src="graemlins/gr_judge.gif" />
Wiring your rheostat in parallel will actually reduce the overall resistance of the circuit and increase timing.
Parallel circuit resistance is added by taking the reciprocal of each of the contributing resistances, then taking the reciprocal of the total.
1/((1/50)+(1/4.7))) = 4.3 kohm .... <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" />
Wiring in series just directly adds resistance to the circuit.
4.7 + 50 = 54.7 kohm
This method will increase the resistance of the circuit, and make the intake air charge seem hotter and reduce your timing. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
You really only need to add about 1k to the circuit to knock back the timing.
My suggestion was to take a resistor in and out of the circuit with a switch. It was to wire the NEWLY INSTALLED RESISTOR AND A SWITCH IN PARALLEL, not in parallel with the IAT resistor.
The above recommended circuit will still put the newly installed resistor in SERIES with the IAT resistor, but in PARALLEL to the switch.
WIRE YOUR RHEOSTAT IN SERIES <img border="0" alt="[judgement]" title="" src="graemlins/gr_judge.gif" />
Wiring your rheostat in parallel will actually reduce the overall resistance of the circuit and increase timing.
Parallel circuit resistance is added by taking the reciprocal of each of the contributing resistances, then taking the reciprocal of the total.
1/((1/50)+(1/4.7))) = 4.3 kohm .... <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" />
Wiring in series just directly adds resistance to the circuit.
4.7 + 50 = 54.7 kohm
This method will increase the resistance of the circuit, and make the intake air charge seem hotter and reduce your timing. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
You really only need to add about 1k to the circuit to knock back the timing.
