Use MAP signal instead of TPS on DTEC?

[westrock]

I saw in the AFC tuning sticky about using the MAP signal instead of the TPS. This sounds like a great idea, though it wasn't fully explained why. So let me see if I get this right...

With the DTEC you get 4 fuel maps based on TPS position. So instead by using MAP signal you would get 4 maps based on boost levels? So you would set the first map to like 10%, which would be your vacuum map. Then 2 inbetween (like 30% and 60%), and then your final one would be at whatever your target boost is (set to like 90%). The DTEC would then interpolate the numbers like the AFC, so that as the turbo spools up or you modulate the throttle the DTEC is able to give consistant fuel delivery no matter the PSI. Does this sound about right?

Is the scale of the two voltages similar between the MAP and the TPS? Meaning the MAP goes from 0 - ~5 volts, will the DTEC be OK with that for the TPS input?

[westrock]

anyone?

[mario03srt]

Quote: Originally Posted by westrock

I saw in the AFC tuning sticky about using the MAP signal instead of the TPS. This sounds like a great idea, though it wasn't fully explained why. So let me see if I get this right...

With the DTEC you get 4 fuel maps based on TPS position. So instead by using MAP signal you would get 4 maps based on boost levels? So you would set the first map to like 10%, which would be your vacuum map. Then 2 inbetween (like 30% and 60%), and then your final one would be at whatever your target boost is (set to like 90%). The DTEC would then interpolate the numbers like the AFC, so that as the turbo spools up or you modulate the throttle the DTEC is able to give consistant fuel delivery no matter the PSI. Does this sound about right?

Is the scale of the two voltages similar between the MAP and the TPS? Meaning the MAP goes from 0 - ~5 volts, will the DTEC be OK with that for the TPS input?

Westrock,

First of all you are getting your info from the wrong forum. The SAFC is for the apexi SAFCII. Not the DTEC. If you installed the DTEC per AGP you are good to go.

Also it is not 4 fuel "maps" it's 4 "LOAD" ranges. BTW you can edit and change the 4 load ranges to a % you choose.

Do you understand closed vs open loop mode of the ecu? Anything under 80% throttle/load is closed loop.

What setup you have and the sensory outputs from that untuned setup dictates the changes.

What is you mods?

Marion

[westrock]

Yes I understand all these things, thats why I'm asking. Fundamentaly the DTEC is the same as the AFC so the logic can be applied.

I'm not suggesting that the normal way of hooking it up is wrong, because it works with many cars. I'm just wondering if there is a "different" way to do it. And at WOT I don't think there would be any difference between the two. This would be more for the transition between boost levels.

However here is my thinking. By referencing the MAP (before it goes through the DTEC) you would be able to correct fuel trims based on how the air is moving through the car. 50% throttle in 1st gear is going to give you less boost than 50% in 5th gear because the engine load is less. So if you have your MAP altering based of the TPS signal at 50% throttle the DTEC is going to add extra fuel (for the boost in the gear that you tuned for) no matter the gear or actual boost. So if you accelerate, but don't don't actually spool the turbo you could still use the same fuel map alterations as when your just cruising.

So for instance on Stage 0/1 MAP sensor 1 PSI is 2.23 volts, which is 46% of the full 4.82 volts, so you could set your first "load" point at 46% and just trim it out so that it idles good, then for everything under 1 PSI the computer would do its thing and run its own map and DTEC would just trim back fuel so that it doesn't run overly rich with the bigger injectors. Then you could set another one for like 10 PSI, to help with either spooling up or modulating the throttle just to maintain a little boost. And then you would set an upper limit of boost to optimize WOT. Now you would be able to have boost levels change and the DTEC would adapt the fuel for that.

I'm getting a DTEC with O2 Tuner with my turbo, so I'll see what I can do. My whole argument is that the turbo doesn't neccasarily follow the TPS position (RPM, gear, etc..), so by adjusting the fuel maps based on boost levels can we optimize the tune?