So here's what I did. I took a stock TB I bought used from JLM, a 60 mm and a 62 mm TB, each from M7, and spent the morning doing HP runs with my GTech. I started with the 60mm because that was what was on my car. I have a place I do runs, and after each one, I drive down the freeway to the next exit, come back to my test spot, and run again. I did at least three runs of each TB (60mm, 58mm, 62mm and 60mm again to look for shifts). Since there was different cooling times between each series, I threw out the first run, and then looked at the rest. This was how I conditioned the car for each run. To make matters worse, I ran low on gas, and had to go get some. I measured before and after with the same TB to look for differences, and only got three gallons so I didn't change the wieght too much. Another thing that sucked was that my laptop battery died after just the first two runs, so I didn't get BiM-COM data (work's getting me some new computer stuff, but it's not in yet... Grrrr). Anyway, I didn't really see that much difference, which really surprised me. It also means that the benefit I thought I saw before from the 60mm was most likely environmental.

TB changes were done in about 5-10 min.
I did 4 runs with the 60 mm
I did 6 runs with the 58 (getting gas after the first two)
I did 4 runs with the 62.
I did 3 runs with the 60 mm to test baseline.

Best Runs Overlayed. Black = 62 mm, Red = 60 mm, Green = 58 mm

Baseline Data from first and last 60 mm session. Also give you an idea about measurement repeatability.

Here's the overlay of the 58 mm data before and after getting a little more gas.


So, what's this all mean? I think my car's breathing is being held up elsewhere. I've got the HAI, OBX-header and the one-ball. But I'm still running the stock SC tube, supercharger, intake, head and cam.

Also, this means that until the rest of my car breathes better, I'm trading some flat spot effects for a bit of throttle response.

Thanks to the M7 guys for letting me hold onto the 62 mm TB for some extra time so I could run all three. And I'd love to hear comments and suggestions.

Matt

 

I hate to be a weenie, but I can't make out any of the data; too tiny for my eyes/monitor

 

I have some RPM calibration error in the GTech, and the weight ain't right. It's reading right around 160 peak HP, and about 150 ft-lbs torque peak (both not corrected). But all the HP curves overlay pretty much within the noise bands, and I found that a bit surprising. Honestly, I coldn't tell which curve I was looking at unless I read the file name....

Matt
I'll re-do the photos at 800x600 and it should be better on your eyes!

 

Oh, I remember the laptop dying on me also when I was working with you on the IC and scoop testing via BiM-COM. Fond memories of that, and trying to keep the laptop from flying around with a couple of bungie cords .

Sounds like you are done with your testing... but if not, and if you get a new laptop, or yours fixed, I think using BiM-COM to see manifold pressure might be a good way to evaluate these; the rate of increase and max boost come to mind...

I'll be getting a 60mm from M7 sometime next week. Thanks for experimenting Mat, and for sharing!

Slightly OT - As you alluded, the engine is essentially an air pump, and we're doing our best to help it pump more and more. Along the way we try to ascertain how we're progressing, and with that, what mods work better than others; as you just did. Since a higher performance MINI is spitting-out more exhaust gases than a lesser modified one, is there some way to measure the volume expelled? Something that essesntially acts like a turnstyle and/or an anemometer, logging the attendance and rate at which they're moving. It would seem that there should be some type of device that one could put somewhere in the exhaust path to do this...

Sorry Matt... I've got a few beers in me, and I start think out loud.

 

The vairable to measure in BIM-COM is the upstream MAP. That value should get closer to zero at WOT as you eliminate restrictions. Thats the variable Andy measured to make sure the HAI was doing what its supposed to do.

 

Zero on a boost gauge, but 1000 mBar ambient (or whatever your ambient is). Thanks to Matt for doing this testing, interesting stuff. Also, you may want to pick up a 12V DC power adapter for the laptop, I've had great success with these:

http://www.lindelectronics.com/

IMHO, they are better than OEM (extruded aluminum housings, great build quality, etc.