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Old 06-13-2006, 12:52 PM   #1
Division By Zero
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Default MAF Scaling 3.5" Blowthrough vs Stock

I'm sure that this doesn't come as a huge shock to some of you guys but I found this interesting. Some background; I had a 3.0" MAF housing in blowthrough configuration until recently. The problem with it was two-fold. The first reason was that it needed more headroom as far as MAFv was concerned. It was maxxing out by 5k rpms around 21psi. The second and possibly equally troublesome was turbulance inside the housing.

So I set out to have another compressor pipe/MAF housing made. Instead of going the 3.25" route, I thought it might not do the job so I opted for a 3.5" piping. Well, that turnedout to be a bit overkill. I had to scale it out pretty far, about 4 times in the first part of the map IIRC. Anyway, here's the difference in scaling for reference. Oh yeah, thanks to the Enginuity software for making some of this possible.

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Old 06-15-2006, 11:13 AM   #2
happasaiyan
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ew...that looks horribly unpredictable. pain to tune?
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Old 06-15-2006, 12:03 PM   #3
Division By Zero
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Quote:
Originally Posted by happasaiyan
ew...that looks horribly unpredictable. pain to tune?

Horrible is right There's a little smoothing left but overall runs smoothly. I made small revisions a few cells at a time in the MAF table moving my way up until it eventually hit all 300's. This was making changes, flashing, test, then make more changes (no real-time tuning unfortunately with opensource tuning for now).

There's a bump in the bottom part of the curve in that map that you see which can come down a little. The bump makes the car go slightly too rich under very low load. Otherwise, the rest of the table is pretty much spot on. My goal was to get the ECU where the UTEC wasn't needed except for higher boost levels, which is needed due to the fact that the grams/sec maxxes out fairly quickly and will go lean thereafter, even though the MAFv is only 3.7v or so. A 3.25" housing would've been a better route.
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