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Posted by turboglenn, Apr 5, 2008
Tuning & Engine Management - 4G63 EPROMS, ECU, MAF, knock, EGT, wideband, datalogging, fuel trims, etc. Read this Forum's Strict Guidelines.
Can i ask why he want's to? The maf setup is very good, and if you over run it, or rev too high, it is capable of a simulated speed density pretty much. Use a map sensor and fake maf signal and it will extrapolate the figures for you.
V2 has Speed Density features already. I use it.
All you need is a MAP sensor (no intake temp), but you still need to use a MAF for idle and part throttle conditions. You activate "Fake MAF" + "Use MAP" and there you have it, Speed Density.
You tell the ECU at what MAF Hz that you want to ignore it and instead use the MAP sensor to calculate injector duty cycles.
Tom and Dave have said V3 "might" have speed density support, but the last thing I've heard from them indicates it isn't going to happen.
You could theoretically use a MAFT-pro to run speed density with DSMlink, but why would you? A 2G or EVO MAF works flawlessly, and as Jeff said, you can clamp it and use a MAP sensor to effectively go SD if you overrun the MAF.
Do I need calibrate GM Maf when use "USE MAP" +"USE MAP"
just click on this two fautures and tada..done??Cus I did that calibrating.. and my Boost est is way off my GM3Bar Map..
How do I tell the ECU what MAF Hz I wants ignore MAF??
I would think you have to calibrate the maf if the ecu is going to be going off of its readings at all when full throttle.
Go to ecu/logfile and click on airflow. You will see on the right side of the box that opens a spot that says "switch over".
Here's how to calibrate the MAF-T using a map sensor:
maftcalibrationbyloggedboost [ECMTuning - wiki]
This is correct. The FakeMAF feature is dependent on airflow metering at the switchover point, meaning if your metering is off at the switchover then it will be off by that much for the rest of the RPM band.
DSmap is the best and cheapest way to run speed density.
Yes, you need to calibrate the MAF up until the switchover point. Just as stated above, if your airflow calibration is off at the switchover point, it will also be inaccurate by the same amount once in SD mode.
I switchover at 2400Hz because there is an airflow slider right at that frequency. Therefore it is very easy to calibrate right at that frequency.
Did you do the correct math regarding your calibration. All you need to do is plug in the BoostEst and Actual boost data, into my formula on my website. I can calibrate a MAF with one 3rd gear datalog.
Here is my log with Fake MAF + Use Map activated. Notice how the AEM5Bar and BoostEst are lined up perfectly at my 2400Hz switchover and then it begins to diverge as VE drops when you get closer to redline.