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Thread: Tuning for Blow Thru MAF

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2012-01-02 16:32:17
Tuning for Blow Thru MAF
I was wondering what changes to the tune is needed to run the MAF blow thru vs. stock placement.

I'm just trying to get a insight on what you guys are doing to get this right.
2012-01-02 18:04:53
As long as you are running a non-restrictive maf (ie DE maf) you shouldn't have to update much at all.

When I went from draw through to blow through, I my fuel mixture was a good bit richer, thus I had to adjust it via K value. I later found out the reason for this too, I was running a BPi Flow Stack directly on the maf while draw through, and while blow through it was on the turbo intake pipe. Without a flow stack my Draw through AFR's where similar to the blow through ones.

I think the Flow stack itself helped the maf read the airflow a little more accurately thus my maf voltage was slightly lower, thus I was running leaner. When I go turbo again I will be able to data log the maf voltage differences between the two .
2012-01-03 00:45:22
That makes a lot of sense. I'm running the Z32 on my car and had it both ways with very little difference in how the car ran. The reason why I asked was I heard some Subaru guys saying you have to rescale the MAF for it to work good.
2012-01-03 01:41:53
I've heard of that, but honestly your wideband will be the judge . If your wideband shows richer AFR's just reduce the K value. Something to keep in mind is, especially if you dyno tune the AFR's, your low-mid load AFR's might be the ones mostly affected by the maf change. Like in between shift richness, cold idle richness, etc, that's all fixable by playing with the K value.

Now if you have TunerCode then leave K value alone and use Current Injector size , this way you don't have to worry about rescaling the TP scales. Though I doubt you will have to change the K value more then 1000 points (on a b13).
2012-01-03 02:13:55
Thanks for clearing that up.
2012-01-03 03:46:58
2012-01-03 04:29:26
Pretty much sounds like you could do this on a stock ecu car....a bit richer sounds like
2012-01-03 04:56:57
Originally Posted by boomstickracing
Pretty much sounds like you could do this on a stock ecu car....a bit richer sounds like

If your turbo and running a stock ecu you have far greater things to worry about. But if your running a DET ecu then yes, you can do that, get an adjustable FPR and you can make it leaner/richer as needed.
2012-01-03 21:12:06
I would be scared to run a de ecu on a det....LOL
2012-01-03 22:05:37
Back in the day that's the only option we had. Then we would run a piggyback to control the fuel. The JDM ECUs had that speed limiter at 120mph, so most people preferred them over over the JDM ones. Now we have so much options it wouldn't make sense to use them without a daughterboard.
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