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Thread: Regrounded My MAF Virtual Dyno Numbers

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Posts: 1-10 of 25
2011-12-21 03:49:52
#1
Regrounded My MAF Virtual Dyno Numbers
Ever since I went to a Z32 maf on my NA VE, going to be boosted soon, I added an extra wire to ground it at the intake manifold. Well I drove like that for a long while. Yesterday I decided to finally ground it to the intake manifold. Look at the difference!

Keep in mind these are just estimated numbers calculated from a log file. Both days had similar temperatures, ~50*F. Unfortunately I didn't test on the same stretch of road, but the terrain was about similar. My usual difference between runs/terrains is 5-10whp at most, 30whp is no fluke, definitely all gains!

Red line is yesterday's run with a bad ground. Blue line is today's run with a good ground.


The AFR's are different I know, but as soon as I re-grounded the MAF my idle went from 15 AFR to 19 AFR, thus I have to completely retune. It looks like it's reading about .20-30v lower now then it did before, thus my TP doesn't go as high as it used to.

Now keep in mind I'm running a P11 with a step down harness. P11's ground might not be as good as others. P11 FSM warns against using ECU grounds to test MAF voltages. With a different ECU and MAF, this could mean MAF ground is insufficient.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in damage
to the ECM’s transistor. Use a ground other than ECM terminals, such as the ground.
2011-12-21 03:55:51
#2
Need moar samples in the group to eliminate outliers!
2011-12-21 04:09:07
#3
Originally Posted by Viprdude
Need moar samples in the group to eliminate outliers!


brings back bad memories from statistics class.

What program/software are you using to do those estimates Vadim?
2011-12-21 04:13:45
#4
Originally Posted by Viprdude
Need moar samples in the group to eliminate outliers!


What outliers? Every single log I had before reground had much lower WHP numbers. I only have one log with new ground, I'll try to do more runs, just hard to find open roads :-P

Originally Posted by SER96VSPEC
brings back bad memories from statistics class.

What program/software are you using to do those estimates Vadim?


I'm using NismoTronic and NEMU ecu to pull the logs, export them to CSV and then Virtual Dyno is able to read them without any further modification. Granted you want your log to only have one gear run, so that you don't get conflicting information.

The way the Virtual Dyno works is, it takes the RPM and time elapsed, along with your gear ratios. The faster your rpms climb the more power you have. Very simple concept, hard formulas, and it works fairly well!
2011-12-21 04:17:49
#5
Oh, I see. I found the website for the Virtual Dyno, but I'm running Nistune in both my cars so I don't believe it will work?
2011-12-21 04:21:30
#6
Originally Posted by Vadim
What outliers? Every single log I had before reground had much lower WHP numbers. I only have one log with new ground, I'll try to do more runs, just hard to find open roads :-P


That one could be an outlier! Moar Moar MOAR!
2011-12-21 04:28:10
#7
Originally Posted by SER96VSPEC
Oh, I see. I found the website for the Virtual Dyno, but I'm running Nistune in both my cars so I don't believe it will work?


Can it export to CSV? All you need is Time, RPM, TPS, and AFR if you wish.
2011-12-21 04:31:28
#8
Originally Posted by Vadim
Can it export to CSV? All you need is Time, RPM, TPS, and AFR if you wish.


I'll have to look into the Nistune user's manual.:o
2011-12-21 04:50:19
#9
Damn you shifting early Vadim, lol. 7700 and still climbing. lol. Take her to 9k at least one pull. Dont be scared, n1's love that high rpm.
2011-12-21 04:56:51
#10
The 4CW crank and stock valvetrain say nooooo please don't!
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