So who wants their ECU's "Chromed"?

[Chris@Rvengeperformance]

Thanks, I was able to find it.



Interesting. So there is definitely some work to be done after starting in the "ballpark".

yeah the car may drive okay in closed loop, but your part throttle open loop transitions are a little wonky until you get close, especially if the car is cold and not in closed loop yet. It is not as bad as it sounds and while I had plenty of emanage ultimate tunes that almost left me stranded the flashed ecu at its worst just feels a little doggy.

It is fairly easy to dial in, but if you are in the 550 cc range you could do a lot worse than just picking evo 560s with known factory latencies. They'll still probably need fine tuning, but not as much.

[Stealth_RT]

Actually there may be a work around for that... Sorta a plug in baro and temp sensor... I am working on that.

I'm already kind of thinking of taking an old, cut up, stock MAF and basically cutting it down to just the stock baro and intake temp sensors, then mounting it next to the air filters, and wiring it into the stock MAF plug, just to feed those values to the ECU. I read, years ago on the other forum, that someone was trying this with an emanage ultimate setup running speed density. Hopefully, eventually, a Chromed ECU will be able to run speed density directly, with just an adapter harness and sensors. DSMLink can do this, and can also be plugged directly into a GM MAF with just an adapter cable, and no MAFT needed. With any luck, and a lot of hard work by the awesome group of people working on this stuff, we'll get there as well. Of course, the DSM ECU's already had an EPROM external to the CPU, and that's what DSMLink replaces, so there's probably more memory space available to do things like Karman MAF to speed density conversion tables and whatnot. Dunno how much space is available in the 98/99 ECUs to do fancy conversions.

[99 vr4]

I'm already kind of thinking of taking an old, cut up, stock MAF and basically cutting it down to just the stock baro and intake temp sensors, then mounting it next to the air filters, and wiring it into the stock MAF plug, just to feed those values to the ECU. I read, years ago on the other forum, that someone was trying this with an emanage ultimate setup running speed density. Hopefully, eventually, a Chromed ECU will be able to run speed density directly, with just an adapter harness and sensors. DSMLink can do this, and can also be plugged directly into a GM MAF with just an adapter cable, and no MAFT needed. With any luck, and a lot of hard work by the awesome group of people working on this stuff, we'll get there as well. Of course, the DSM ECU's already had an EPROM external to the CPU, and that's what DSMLink replaces, so there's probably more memory space available to do things like Karman MAF to speed density conversion tables and whatnot. Dunno how much space is available in the 98/99 ECUs to do fancy conversions.

The problem is that the temp and baro sensors are actually part of the vortex generator.

Additionally, that would not work because the temp sensor will "heat up" with engine compartment heat. The way the system works now is that the temperature sensor changes with the temp of the intake charge which is directly effected by air flow. So that is actually worse because the ECU will see very elvated intake temperatures. It might see 120 plus when the actual charge temp is 80 . . .

[Stealth_RT]

The problem is that the temp and baro sensors are actually part of the vortex generator.

Additionally, that would not work because the temp sensor will "heat up" with engine compartment heat. The way the system works now is that the temperature sensor changes with the temp of the intake charge which is directly effected by air flow. So that is actually worse because the ECU will see very elvated intake temperatures. It might see 120 plus when the actual charge temp is 80 . . .

Gotcha, makes sense. Guess I'll wait for further developements.

[donniekak]

Actually there may be a work around for that... Sorta a plug in baro and temp sensor... I am working on that.

That would make the translator work improperly. The reason the values are fixed, it that they aren't needed. The stock ecu calculates mass airflow with the hz(volume), ambient temp, and pressure. The gm maf directly measures mass flow. Changing the signal based on temp/pressure would actually make the tune wander.

[Greg E]

That would make the translator work improperly. The reason the values are fixed, it that they aren't needed. The stock ecu calculates mass airflow with the hz(volume), ambient temp, and pressure. The gm maf directly measures mass flow. Changing the signal based on temp/pressure would actually make the tune wander.

Correct.

[99 vr4]

OMNI 3-BAR MAP

0.69 25
1.20 49
1.73 70
2.24 96
2.76 120
3.27 144
3.80 170
4.31 195
4.84 255


From OMNI 3-bar MAP sensor scalings - evolutionm.net

Basically it is real simple to scale for other MAP sensors . . . you just need to know the reference voltages per pressure and adjust the scalings accordingly

[Greg E]

Brett, there is no sensor calibration table for the MDP. Just reference voltages and an EGR table scaling. Our ROMs are too primitive.

If it was that easy, I'd have all the sensors working with the emissions by now. As it is, I have to create a scaling in excell for each sensor and cross reference that voltage to each one. I'll explain in more detail over the phone some time.

[99 vr4]

Your missing the point. there is a table 4 the map sensor scaling, even though it is only 4.egr.

[99 vr4]

That would make the translator work improperly. The reason the values are fixed, it that they aren't needed. The stock ecu calculates mass airflow with the hz(volume), ambient temp, and pressure. The gm maf directly measures mass flow. Changing the signal based on temp/pressure would actually make the tune wander.

I see so the translator converts the actual mass air flow back to a representive air flow in Hz based upon a set temperature and baro pressure to trick the ecu

so this conversion is not correct or ideal under all temperature conditions or barometric pressure conditions

this is why in a gm car they still have an iat.

on the Evo platform they are working on or have already figured it out, how to use an iat in the speed density calculations.

if you don't take into account air temperature and pressure your speed density calculations will never be correct under all conditions.