Okay, my Amuse R1 exhaust should be here any day now (right, MG Racing?) and I've got a few other things I want to try. Keep in mind the car's being set up for stock-class autocross, so what can be done is pretty limited to a few variables - air filter, cat-back exhaust, and fluids. Here's what I have:

Air filters:
Dirty (~22k mi) stock filter
Practically new (few days in the car) JR filter
Brand new stock filter
No filter

Exhausts:
Stock system
Amuse R1 (soon!)
Wide open

Gas:
California's crappy 91 octane pump gas
5 gallons 100 octane (and a bottle of 104+ octane boost)

Tentative plan:
Run 1: Dirty stock filter, stock exhaust, pump gas
Run 2: No air filter, stock exhaust, pump gas
Run 3: New stock filter, stock exhaust, pump gas
Run 4: JR filter, stock exhaust, pump gas
--At this point I'll know the best performing filter and leave it in for the rest of the runs - the filterless run is just for grins. I'll also try to arrive at the dyno with 2 gallons of fuel or less, so that adding the 104+ and 5 gallons of 100 octane makes a significant increase in octane. Since I won't be using it much, I'm not interested in the "learning" effects of the ECU, only the immediate effects of high octane.
Run 5: filter, stock exhaust, hi-octane gas
Run 6: filter, open exhaust, hi-octane gas
Run 7: filter, Amuse exhaust, hi-octane gas (hoping for the best overall output here)

The only time I've spent on a dyno were two baseline runs last Saturday. Guessing this'll take about 2 hours to complete with the switching of exhausts, filters, and fuel? I'd like input on what I can do/not do to make my testing as scientific and meaningful as possible. I'd hate to do all this and have people discount the results because I forgot cardinal rule XYZ of dyno testing. Maybe do two runs in each configuration? Or let the car cool for a certain amount of time between runs? I have an infrared pyrometer and can measure temperature in certain places, if needed. Any other things to try tweaking, within the rules, to eek out another pony or two?

With as much monkeying as I've done with cars over the years, I'm still a newbie to this side of things, and appreciate any input you experienced guys have. Thanks so much!

 

A couple of things to consider Jason.

1. When making dramatic changes in configuration, the ECU needs a little time to adjust. I would prefer to see those adjustments made through a short driving loop after an ECU reset, but that may not be practical. However, since you'll probably take the car off the dyno for exhaust removal/install, you could at least do the "adjustment" drive then. With the airfilters the differences will be so small as to really not matter much anyways.

2. When you put in the 100 octane gas, be sure to allow the car to run for awhile to make sure the 92 octane in the fuel lines is fully displaced. Ideally you'd want to pitch the car into a few corners to make sure you had good mixing, but pouring 5 gallons in with 2 gallons will probably do a pretty good job.

3. In terms of temps and number of runs, you really need to monitor intake air temp and water temps, which can really only be effectively done with an OBDII tool (or a laptop with the appropriate software). The other option is to do multiple runs in each configuration as you have suggested. Get the car on the dyno, and make sure that you are at 3 bars on the temp gauge (this may require running the car for awhile if it has been sitting). Then make 3 passes for each config. The first pass should be a throwaway, as temps probably won't be stabilized. The next two are your data passes.

4. Consistency. Make sure your rear tire pressures are within 1 psi for each run and that the car is aligned straight on the rollers. Also, make sure that whatever fan you are using to cool the car is in the same position relative to the car for each test. Finally, whether you test with hood up or hood closed, be sure that you do it the same way each time.

Best of luck.

UL

 

Excellent, thank you Mr. Lurker, sir! That's exactly the info I was looking for. I'll do what I can to get the gas mixed up and give the ECU some time to adjust to the new exhaust system.

This'll all go down in about two weeks, at Jeff's importbuilders shop in Fullerton. Even though the system's been built for about a month, it appears I've got a bit to learn about international commerce, as things shipped from Japan have to pass through the hands of many people. In my case, from Amuse to Taka Kaira to MG Racing and eventually to me...one day...