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SVTPerformance's Chain of Restaurants
Tuning À la carte
Fuel Open Loop TP setting
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<blockquote data-quote="decipha" data-source="post: 16872063" data-attributes="member: 74327"><p>No, that's incorrect</p><p></p><p>That value is TPREL in ad counts.</p><p></p><p>An a/d count is the analog to digital conversion used for integrated circuits.</p><p></p><p>On ecu power up the lowest throttle position voltage ad count becomes RATCH.</p><p>RATCH is the lowest throttle position voltage since ecu power up.</p><p></p><p>TPREL is relative throttle position.</p><p></p><p>TP Voltage - RATCH = TPREL</p><p></p><p>As you hit the throttle and tp voltage increases it is subtracted from RATCH to give you relative throttle position voltage.</p><p></p><p>There are roughly 200 ad counts in a volt.</p><p></p><p>If your at 1.125 volts on the tps at closed throttle then your at 225 ad counts.</p><p>(1.125*200==225) This becomes RATCH. So RATCH = 225 (closed throttle volts).</p><p></p><p>If you go WOT and the tps voltage climbs to 4.6 volts then-</p><p></p><p>4.6*200==920 ad counts</p><p>920-(RATCH==225)== 695 is your maximum TPREL at WOT.</p><p>THAT IS NOT 69% throttle its 100% throttle.</p><p></p><p>Some vehicles can reach 750 ad count TPREL at wot. Some can only reach in the 400s - typically common on modified cobras.</p><p></p><p>If you have a higher boosted engine then that needs to come down quite a bit. I've hit over 10 lbs of boost at only 200 TPREL before on 03-04 cobras.</p><p></p><p>Attached a screen shot of the base values I start with in all my 03/03 cobra tunes.</p><p></p><p>Also worth noting is that I have my own custom load/boost threshold code I use as well to force open loop power enrichment when in high boost regardless of this look up as well.</p></blockquote><p></p>
[QUOTE="decipha, post: 16872063, member: 74327"] No, that's incorrect That value is TPREL in ad counts. An a/d count is the analog to digital conversion used for integrated circuits. On ecu power up the lowest throttle position voltage ad count becomes RATCH. RATCH is the lowest throttle position voltage since ecu power up. TPREL is relative throttle position. TP Voltage - RATCH = TPREL As you hit the throttle and tp voltage increases it is subtracted from RATCH to give you relative throttle position voltage. There are roughly 200 ad counts in a volt. If your at 1.125 volts on the tps at closed throttle then your at 225 ad counts. (1.125*200==225) This becomes RATCH. So RATCH = 225 (closed throttle volts). If you go WOT and the tps voltage climbs to 4.6 volts then- 4.6*200==920 ad counts 920-(RATCH==225)== 695 is your maximum TPREL at WOT. THAT IS NOT 69% throttle its 100% throttle. Some vehicles can reach 750 ad count TPREL at wot. Some can only reach in the 400s - typically common on modified cobras. If you have a higher boosted engine then that needs to come down quite a bit. I've hit over 10 lbs of boost at only 200 TPREL before on 03-04 cobras. Attached a screen shot of the base values I start with in all my 03/03 cobra tunes. Also worth noting is that I have my own custom load/boost threshold code I use as well to force open loop power enrichment when in high boost regardless of this look up as well. [/QUOTE]
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SVTPerformance's Chain of Restaurants
Tuning À la carte
Fuel Open Loop TP setting
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