WAI vs CAI test results

[SVOboy]

Hmm, all I can say as a starting point is that the older honda ecus do not do that, I will poke around for you though.

[MetroMPG]

more notes on methodology & test conditions:

* an A-B-A-B test method was used: 3 CAI runs; then 3 WAI runs; then 2 more CAI; then one final WAI

* when switching between A and B, the car was driven for 10 minutes to allow the intake tract to either cool down or warm up to a steady temperature before returning to the "test course"

* i used about 6.9L of fuel during the test, so the car got lighter by that amount from run 1 through run 9 (plus the cool down/warm up drives_.

* the ambient conditions were as follows, based on info from an online weather station located several km from the "test road" location.

time....wind-dir...wind...gust...temp-F

12pm......ssw.......10.....10......39
01pm......ssw........8......8......38.1
02pm......ssw........7......7......39.6

(wind data in knots; the test went from approx noon to 2pm.)

* the car was warmed up prior to the test: block heater 1.5 hrs & 30 minutes of mixed city/hwy driving

[MetroMPG]

Originally Posted by SVOboy

Hmm, all I can say as a starting point is that the older honda ecus do not do that

sorry, don't do what, specifically?

matt: cool analysis. where do i get me some of that program?? i was just using the STDEV function in excel and a formula I found on a stats web site. it's close enough to the figure your program gave you for std error and std deviation for the CAI group.

[SVOboy]

Adjust timing based on anything besides knock, and then they don't even do that unless they are japanese.

[MetroMPG]

not even vacuum advance? surely timing is controlled by something dynamically.

my car doesn't have a knock sensor. and i'm running enough base timing advance that i have to be careful not to mat it at low rpm or it will ping.

[rh77]

With the WAI -- do you have a way to get the actual temperature of the air? I'd venture a guess that cold air is slipping into the mix somehow.

To answer the OBD2 question, my '98 Honda (Acura) ECU leans-out the mixture with the detection of warmer air, as shown from a datalogger. With the CAI on there, I was getting an average of -2 to -3 long-term fuel trim, whereas the WAI ranges in the -4 to -6 range. Economy was instantly noted to increase from around 26 to 31. Timing advance is all over the place, so I can't really report any changes in that department. There is a definite decrease in horsepower, especially at higher RPMs, as shown in 0-60 times. Merging onto the highway, if I have to floor it, seems like it's choked-off struggling to get to redline. Have you noticed a decrease in power?

RH77

[SVOboy]

Ah, well I took vac advance for granted. Timing is on a big table with the variables being load levels and rpms.

[Matt Timion]

Originally Posted by MetroMPG

sorry, don't do what, specifically?

matt: cool analysis. where do i get me some of that program?? i was just using the STDEV function in excel and a formula I found on a stats web site. it's close enough to the figure your program gave you for std error and std deviation for the CAI group.

I used SPSS to get my results. I was trained on SPSS and some other old powerful command line program that everyone still uses (can't remember the name now).

I might be able to swing you a copy of SPSS. I think I have one around here somewhere. I think it is generally used for behavioral research but any statistics can be run using it.

I was originally planning on programming all of this into the website and letting users simply input data and then have teh website spew out the results. I'm sure I could still do that, although it would take a while to do.

[Compaq888]

Originally Posted by rh77

With the WAI -- do you have a way to get the actual temperature of the air? I'd venture a guess that cold air is slipping into the mix somehow.

To answer the OBD2 question, my '98 Honda (Acura) ECU leans-out the mixture with the detection of warmer air, as shown from a datalogger. With the CAI on there, I was getting an average of -2 to -3 long-term fuel trim, whereas the WAI ranges in the -4 to -6 range. Economy was instantly noted to increase from around 26 to 31. Timing advance is all over the place, so I can't really report any changes in that department. There is a definite decrease in horsepower, especially at higher RPMs, as shown in 0-60 times. Merging onto the highway, if I have to floor it, seems like it's choked-off struggling to get to redline. Have you noticed a decrease in power?

RH77

I have to quote on this. i used to have a WAI and I will tell you I lost a lot of low end with it. I didn't gain any mpg either. All that happened was I gained a lot of top end. I had an Injen WAI. My mpg stayed the same. The best mpg I'm getting is with the stock intake system. As for the top end I lost .4 in the 1/4 mile thanks to the Injen WAI. that is not .04, but .4, which is almost half a second.

[MetroMPG]

Originally Posted by rh77

With the WAI -- do you have a way to get the actual temperature of the air?

yup, from the air intake temp sensor (inside the throttle body i think) - via scangauge.

To answer the OBD2 question, my '98 Honda (Acura) ECU leans-out the mixture with the detection of warmer air, as shown from a datalogger.

yeah, i'm starting to realize that to go really hardcore, a scangauge doesn't cut it. i need something to hook to the laptop to gather data for experiments, and the scangauge for normal driving. SG doesn't report fuel trim, so i can't report on those figures.

Have you noticed a decrease in power?

my car feels gutless at the best of times

i haven't stuck my foot in it to see if i notice any difference. this car doesn't encourage (or reward) that kind of driving. though i may have felt it bog down a little the other day when the AIT showed that it was really warm.