Bob W.

I logged some data (three back-to-back 3rd gear pulls) tonight with the lower air horn reinstalled, and compared the MAF data to 3 previous 3rd gear logs WITHOUT the lower air horn installed. Both sets are without the flap, obviously. ECU was reset before both series. I used 7800rpm for my peak MAF values, because I had to cut short of redline on one of the runs....this eliminates rpm as a variable.

Series 1: 3rd gear, NO air horn, ambient temp 96 F

Pull #1 MAF = 153.94 g/s at 7800rpm
Pull #2 MAF = 153.78 g/s at 7800rpm
Pull #3 MAF = 148.89 g/s at 7800rpm

Average MAF with NO air horn = 152.20 g/s at 7800rpm

Series 2: 3rd gear, WITH air horn, ambient temp 82 F (note temperature difference compared to series 1!)

Pull #1 MAF = 149.89 g/s at 7800rpm
Pull #2 MAF = 146.61 g/s at 7800rpm
Pull #3 MAF = 146.06 g/s at 7800 rpm

Average MAF WITH air horn = 147.52 g/s at 7800rpm

Difference +4.68 g/s WITHOUT air horn (+3.17%).

So even though the logs WITHOUT the air horn were done at 14 degrees F warmer outside temperature, peak MAF was still 3% better...correcting for temperature would yield an even greater difference (one of you engineers can probably figure out exactly how much).

Take these data as you wish, but I know what I'm going to do with MY air horn. I really think the primary function of this piece is to serve as an attachment point for the flap and actuator mechanism. It also protects the flap itself when fully open. The PROBLEM is that the air horn moves the inlet point too close to the aux radiator and some other structures cluttering the area, effectively blocking the intake slightly.

Bob W.

if someone wants to do the temperature correction, I can run another t-test, but honestly I don't think it will be significant anyway....having only 3 values in each series doesn't give you enough statistical power, but I'm not going to sit there and do 30 runs, OK?

Sprocket73

The horn is actually in 3 pieces, 1. the funnel part of the horn 2. The flap & actuator 3. The base thats against the airbox. have you removed everything? Or just part of it? Thanks

RI A6

Wuss!

Bob W.

not sure what you're looking for, but it seems to vary considerably (both between runs and between cylinders). if you just want the raw files, I can email them to you.

These are all Cylinder #1 WITH the air horn installed:

<img src="http://spreadsheets.google.com/pub?key=pNJ4LvDM7O3ElJKVUXGf_Kw&oid=2&output=image " />

<img src="http://spreadsheets.google.com/pub?key=pNJ4LvDM7O3HV5nTQ_y-iSQ&oid=1&output=image" />

<img src="http://spreadsheets.google.com/pub?key=pNJ4LvDM7O3HJwyE65tDXSQ&oid=1&output=image " />

RI A6

You're pulling a lot less timing than I am today, and look a lot like timing did on my dyno run in January.

Bob W.

ygm

ToblertheDog

<center><img src="http://pictureposter.audiworld.com/70770/img_0791.jpg"></center><p>

daveak05

Nice! : )

kem

brillant!