Why does my throttle open percentage only go to 76% max when I floor it according to the gauge? Also 15% when off the throttle. This is when the car isn't running and ignition on.
Most people tune your wide-open throttle fueling to begin cycling once 4v is hit on the throttle body when a standalone or other tuning hardware is used (i.e. DSP). My AVC-R reads 100% at wide-open throttle, as did my old SAFCII when I used it.
Most people tune your wide-open throttle fueling to begin cycling once 4v is hit on the throttle body when a standalone or other tuning hardware is used (i.e. DSP). My AVC-R reads 100% at wide-open throttle, as did my old SAFCII when I used it.
The srt4 ECU (stock flash) goes into open-loop at 2.7 volts . at that point , it stops trying to maintain a 14.7 AFR , but instead uses the power enrichment tables to target a richer AFR (10.0-11.0) based on boost/rpm .
The actual voltage at the throttle end-points is not important , the ECU will adapt to it as long as it is within the acceptable norm .
The srt4 ECU (stock flash) goes into open-loop at 2.7 volts . at that point , it stops trying to maintain a 14.7 AFR , but instead uses the power enrichment tables to target a richer AFR (10.0-11.0) based on boost/rpm .
The actual voltage at the throttle end-points is not important , the ECU will adapt to it as long as it is within the acceptable norm .
Thats cool , I just dont want people to think its ok to wait for 4 volts before they go into open loop . I dont know who the "most people" are , and I dont know your tune strategy , but I strongly reccomend going into WOT tables before 3volts . If your using a Mopar ECU of anykind .
Why ?
Because untill the WOT threshold is met (2.7v) the ECU is going for a stociometric AFR . But at 2.7 or above , you can be already into major boost & engine load , requiring fuel enrichment . If you wait untill 4 volts to enrich for boost , the motor can hurt itself .
Thats cool , I just dont want people to think its ok to wait for 4 volts before they go into open loop . I dont know who the "most people" are , and I dont know your tune strategy , but I strongly reccomend going into WOT tables before 3volts . If your using a Mopar ECU of anykind .
Why ?
Because untill the WOT threshold is met (2.7v) the ECU is going for a stociometric AFR . But at 2.7 or above , you can be already into major boost & engine load , requiring fuel enrichment . If you wait untill 4 volts to enrich for boost , the motor can hurt itself .
My DSP is tuned so open loop occurs at 4v+. I remember when WOT was not giving me 4v my WOT fueling was lean as hell. I had to do the TPS rewire to have it show 4v at WOT and incorporate the right fueling.
^^
Interesting . It would seem to me that I would want to be running richer than stoic long before my throttle plate is 90% open . For example , if traction is not optimal , its possible that I could be well into 15 psi or more and still be targeting a 14:1 AFR .
I would also think that set up to go open loop at 4 volts would also mean that during a wot pull , that if , for one second , if I lifted to say 85% throttle , that I could go back to targeting a 14:1 afr , At 18+ psi high revs
Why do you want to wait so long to go to the open loop enrichment tables ?
All the stage codes ive seen on my SCT PRP go wot at 2.7 if your DSP was set as such , you would have no problem attaining open loop . Keep in mind that a lot of air can flow past the throttle plate at 2.7 volts ! It would seem to me that it is because your DSP is set so high (4v) you were running lean . Not because your throttle voltage wont trigger open loop , you were running lean . But I am no expert .
^^
Interesting . It would seem to me that I would want to be running richer than stoic long before my throttle plate is 90% open . For example , if traction is not optimal , its possible that I could be well into 15 psi or more and still be targeting a 14:1 AFR .
I would also think that set up to go open loop at 4 volts would also mean that during a wot pull , that if , for one second , if I lifted to say 85% throttle , that I could go back to targeting a 14:1 afr , At 18+ psi high revs
Why do you want to wait so long to go to the open loop enrichment tables ?
All the stage codes ive seen on my SCT PRP go wot at 2.7 if your DSP was set as such , you would have no problem attaining open loop . Keep in mind that a lot of air can flow past the throttle plate at 2.7 volts ! It would seem to me that it is because your DSP is set so high (4v) you were running lean . Not because your throttle voltage wont trigger open loop , you were running lean . But I am no expert .
I honestly don't know when I've hit 15 psi without having the throttle down enough to hit 4v. You are right about the richness, though. I said lean and I meant to say rich. When I was hitting 9 psi at open loop my A/F was in the 9's (due to a boost controller issue). My voltage for the throttle actually exceeds 4v at WOT, so attaining said 4v is probably around 85% actual throttle percentage. I've never had a problem with fueling at any RPM at the respectable boost levels.
As far as what exactly is tuned into is not something I have the particulars to. I just know the DSP tune I'm running was done by TDS and they probably do the best DSP tuning for the SRT-4's I've yet to see. You'd really have to ask them the details because I can't say I'm anything but 100% pleased with their tunes. Zero knock, excellent A/F's, great LTFT's and awesome dyno numbers.
No idea on the SCT 2.7v tune, either. I used AGP's SCT tune for a while and they could never get me out of pig rich territory. It took me going to the DSP with people who actually know how to tune to get my car running at its optimal level.
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throttle open percentage only goes to 76% max
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