IAT how to with PIC...
If you're not going to change your tune, a '98 LS1 should be able to pull 3 degrees from 95kPa, starting at 50c IAT, and from 90kPa from 55c IAT up. If you are going to change your tune {B5911} or get fancy with a dual relay setup, for different timing pulls, here is the sensor data on what resistor you will need to mimic the stock IAT sensor. The table only goes up to 90*C on a '98 so thats all I pasted. I am running two relays for my two stage progressive system. One stage pulls 3 degrees and one pulls 6 degrees using the 80c and 90c rows of the IAT Spark table (modified).
9420 ohms = 32 *F - 0 *C
7280 ohms = 41 *F - 5 *C
5670 ohms = 50 *F - 10 *C
4450 ohms = 59 *F - 15 *C
3520 ohms = 68 *F - 20 *C
2796 ohms = 77 *F - 25 *C
2238 ohms = 86 *F - 30 *C
1802 ohms = 95 *F - 35 *C
1459 ohms = 104 *F - 40 *C
1188 ohms = 113 *F - 45 *C
973 ohms = 122 *F - 50 *C
<---750 ohms would give you the default 3 deg here at 55c.
667 ohms = 140 *F - 60 *C
467 ohms = 158 *F - 70 *C
332 ohms = 176 *F - 80 *C
241 ohms = 194 *F - 90 *C
Click here to SEARCH for Resistors
9420 ohms = 32 *F - 0 *C
7280 ohms = 41 *F - 5 *C
5670 ohms = 50 *F - 10 *C
4450 ohms = 59 *F - 15 *C
3520 ohms = 68 *F - 20 *C
2796 ohms = 77 *F - 25 *C
2238 ohms = 86 *F - 30 *C
1802 ohms = 95 *F - 35 *C
1459 ohms = 104 *F - 40 *C
1188 ohms = 113 *F - 45 *C
973 ohms = 122 *F - 50 *C
<---750 ohms would give you the default 3 deg here at 55c.
667 ohms = 140 *F - 60 *C
467 ohms = 158 *F - 70 *C
332 ohms = 176 *F - 80 *C
241 ohms = 194 *F - 90 *C
Click here to SEARCH for Resistors
Last edited by Goldfinger911; Mar 6, 2010 at 10:48 AM.
If you have HPT or EFIL, select a resistor value greater than 105K and it will force the IAT to the bottom of the table, -40degF, which is currently 0. IF you have an 01-02, pull timing from .60g/cyl and higher. If you have a 98-00 use the 95 and 105kpa cells in the -40degF column. If you have an 01-02 (or 01-02 OS on your 99-00) you get a PE modifier against IAT also, which will let you add or subtract fueling from WOT, which is sweet 
Would it be alright to steal the info and add it to my site? Though I will give you credit for the info? You wouldn't believe how much I get asked for this info, lol. For me, adding more relays to my already 7 relays isn't what i want to do, so I will stick with the Interface and have as many tunes I as need/want with out changing resistors. however, that why we have come up with using the pot, then just dial in what ever resistor you like. you do have a trick way of doing your dual stage though.
Robert
Robert
If you're not going to change your tune, a '98 LS1 should be able to pull 3 degrees from 95kPa, starting at 50c IAT, and from 90kPa from 55c IAT up. If you are going to change your tune {B5911} or get fancy with a dual relay setup, for different timing pulls, here is the sensor data on what resistor you will need to mimic the stock IAT sensor. The table only goes up to 90*C on a '98 so thats all I pasted. I am running two relays for my two stage progressive system. One stage pulls 3 degrees and one pulls 6 degrees using the 80c and 90c rows of the IAT Spark table (modified).
9420 ohms = 32 *F - 0 *C
7280 ohms = 41 *F - 5 *C
5670 ohms = 50 *F - 10 *C
4450 ohms = 59 *F - 15 *C
3520 ohms = 68 *F - 20 *C
2796 ohms = 77 *F - 25 *C
2238 ohms = 86 *F - 30 *C
1802 ohms = 95 *F - 35 *C
1459 ohms = 104 *F - 40 *C
1188 ohms = 113 *F - 45 *C
973 ohms = 122 *F - 50 *C
<---750 ohms would give you the default 3 deg here at 55c.
667 ohms = 140 *F - 60 *C
467 ohms = 158 *F - 70 *C
332 ohms = 176 *F - 80 *C
241 ohms = 194 *F - 90 *C
9420 ohms = 32 *F - 0 *C
7280 ohms = 41 *F - 5 *C
5670 ohms = 50 *F - 10 *C
4450 ohms = 59 *F - 15 *C
3520 ohms = 68 *F - 20 *C
2796 ohms = 77 *F - 25 *C
2238 ohms = 86 *F - 30 *C
1802 ohms = 95 *F - 35 *C
1459 ohms = 104 *F - 40 *C
1188 ohms = 113 *F - 45 *C
973 ohms = 122 *F - 50 *C
<---750 ohms would give you the default 3 deg here at 55c.
667 ohms = 140 *F - 60 *C
467 ohms = 158 *F - 70 *C
332 ohms = 176 *F - 80 *C
241 ohms = 194 *F - 90 *C
Sure man! No prob. I am always willing to share. (especially with my PacNW peeps)
Yes the dual stage is nice and simple. You just have to make sure that the relay "closest" to the ECU side of the harness is the one that enables the higher temp (lower resistance value). I run an NX Maximizer progresive for my main stage and it has an output for timing retard. I run it to the switch side of one of the relays. That same output now also turns on my Boost-a-Pump. The second relay pulls less timing, because my second stage is a smaller shot.
Yes the dual stage is nice and simple. You just have to make sure that the relay "closest" to the ECU side of the harness is the one that enables the higher temp (lower resistance value). I run an NX Maximizer progresive for my main stage and it has an output for timing retard. I run it to the switch side of one of the relays. That same output now also turns on my Boost-a-Pump. The second relay pulls less timing, because my second stage is a smaller shot.
Would it be alright to steal the info and add it to my site? Though I will give you credit for the info? You wouldn't believe how much I get asked for this info, lol. For me, adding more relays to my already 7 relays isn't what i want to do, so I will stick with the Interface and have as many tunes I as need/want with out changing resistors. however, that why we have come up with using the pot, then just dial in what ever resistor you like. you do have a trick way of doing your dual stage though.
Robert
Robert
Last edited by Goldfinger911; Apr 2, 2008 at 10:02 AM.
Sure man! No prob. I am always willing to share. (especially with my PacNW peeps)
Yes the dual stage is nice and simple. You just have to make sure that the relay "closest" to the ECU side of the harness is the one that enables the higher temp (lower resistance value). I run an NX Maximizer progresive for my main stage and it has an output for timing retard. I run it to the switch side of one of the relays. That same output now also turns on my Boost-a-Pump. The second relay pulls less timing, because my second stage is a smaller shot.
Yes the dual stage is nice and simple. You just have to make sure that the relay "closest" to the ECU side of the harness is the one that enables the higher temp (lower resistance value). I run an NX Maximizer progresive for my main stage and it has an output for timing retard. I run it to the switch side of one of the relays. That same output now also turns on my Boost-a-Pump. The second relay pulls less timing, because my second stage is a smaller shot.
Maybe, run our cars and make a dual stage champ, hehehe.
Robert
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
