Running a WAI through the wringer

[theholycow]

Originally Posted by pgfpro

I don't think you can make any major gains with a WAI on a modern factory ecu

Interesting thought. I'm pretty sure that would correlate with the successes that have been reported.

[Fuel Miser]

Originally Posted by pgfpro

So on my car it was worth a 4mpg increase.

4mpg, that's signifigant. On what car did you perform your testing? Over how many miles and seasons did you see gains?

[pgfpro]

Originally Posted by Fuel Miser

4mpg, that's signifigant. On what car did you perform your testing? Over how many miles and seasons did you see gains?

This was done on my heavily modified 93 Honda turbo Del Sol.
http://www.gassavers.org/showthread.php?t=12069

For this test it was around 900miles.

I did it during last summer with the ambient temperature around 80*F average. All testing was done while running real time data logging. You can see the increase in fuel mileage on my Neptune management system in the form of pulse width and duty cycle plus mph and load values. Also I have a instant mpg readout like mpguino. That has over 2000miles worth of calibration.

[FrugalFloyd]

The good news is my WAI does raise air intake temperatures 25?F. The bad news is there's no significant FE increase related to the temperature increase.

It was 51? when I left home to drive to my test area. I drove with my WAI connected, to warm the car up faster. I P&Ged 9.5 miles, achieving 52.1 mpg, but my IAT was only 69?. I popped the hood and saw my WAI had come loose from the exhaust manifold shield. Oh well, I had to disconnect it for the A test anyway.

I forgot my GPS and left my tire pressure gauge in the other car. Oh well, again. The tires were inflated to sidewall just 3 weeks ago, and I know their pressure rises to 55 psi when hot. Roads were dry, slight breeze 0-5 mph at the beginning and end of each test, temperature between 51 and 55 (estimated) for my first test. Water temperature stabilized at 198-204? on all tests, so I'll just mention it here, once.

First A test, 31 mph cruise control. IAT 73?. 19.3 miles on .36 gal = 53.3 mpg.

Shift WAI to exhaust manifold. Wedge it in tight and put a bulge so hood helps hold it down. B test, 31 mph cruise control. IAT rose to 85? in a mile, 95? in 2 miles, 100? in 3 miles, and stayed there the remainder of the test. That part worked fine. End of test, IAT 100?, 19.3 miles on .36 gal = 54.2 mpg. A slight, but not significant, improvement

Second A test, 31 mph cruise control. IAT ended at 76?, the same 19.3 miles on .36 gal = 54.3 mpg. Very consistent. Also unfortunately, not any different from the other two tests. The second A control test actually beats the WAI. That's never a good result to see in support of your hypothesis. Ambient temperature had warmed up to about 65?.

Got to run to dinner. Will continue the report when I get back.

[FrugalFloyd]

Since I had the WAI in control position to emulate the factory air intake situation, I ran an A test next for P&G for one loop iteration. I pulsed to 40 mph and glided back to 25 mph. IAT stabilized at 73?. My Scangauge loses miles during glides, so half the test route is actually 9.65 miles, but the SG measured it at 9.4 miles. I consumed .15 gal., for 64.7 mpg. That's a nice 10 mpg increase over cruise control.

Then I switched the WAI back over the exhaust manifold for one last B test of the 31 mph cruise control regimen. IAT stabilized at 100-103?. My Scangauge recorded 19.3 miles on .35 gal, or 54.8 mpg, the smallest measurable fuel economy improvement from the earlier ABA results. At the end of this test, I estimate the ambient temperature was up to 70?, and stayed there for the next test, too.

Lastly, I ran another single iteration of the test loop with the WAI connected - the B test for P&G. It's interesting to note the EOC dropped the IAT to 91? v. the 100-103? steady driving IAT. 9.5 miles on .14 gal, for 65.8 mpg. Again, a barely measurable, and probably insignificant difference with the WAI in place, compared to the control (A) test resuls of 64.7 mpg.

So I guess pgfpro has it right. Newer cars' ECUs don't allow WAIs to benefit FE. The reason those S series Saturns have a reputation for responding to WAIs is because they're 20 yr old technology.

[theholycow]

Why does your scangauge lose miles?

[FrugalFloyd]

Originally Posted by theholycow

Why does your scangauge lose miles?

AFAIK, it's not registering distance when EOCing. Long term miles are taken from the ECU, so those figures remain accurate. Current trip distances are incorrect, but tank and day miles are accurate.

[FrugalFloyd]

Summing it up:
A1 (control) test 31 mph CC = IAT 73?, ambient 51-55?, 53.3 mpg
B1 (WAI) test 31 mph CC = IAT 100?, ambient 60?, 54.2 mpg
A2 (control) test 31 mph CC = IAT 76?, ambient 65?, 54.3 mpg
B2 (WAI) test 31 mph CC = IAT 100-103?, ambient 70?, 54.8 mpg

A3 (control) test P&G = IAT 73?, ambient 65?, 64.7 mpg
B3 (WAI) test P&G = IAT 91?, ambient 70?, 65.8 mpg

It's possible to look at these same figures, and argue the WAI does give a fairly consistent 1 mpg or 2% FE increase. The fly in the ointment is the B1-A2 overlap, and the consistent rise with increasing ambient temperature.

I suppose I could do BAB testing, and long-term testing, but wonder if it's worth it. What do you think?

[theholycow]

I don't guess that additional BAB or ABAB or BABABABABAB testing will produce more significant results. Your results are well within any reasonable margin of error and show that in your tests it probably had zero effect on your fuel economy.

There may be additional factors that will affect long term testing, if you're willing, but I'd guess there's a pretty good chance that it may never make a difference in your vehicle.

[pgfpro]

Originally Posted by SentraSE-R

Summing it up:
A1 (control) test 31 mph CC = IAT 73?, ambient 51-55?, 53.3 mpg
B1 (WAI) test 31 mph CC = IAT 100?, ambient 60?, 54.2 mpg
A2 (control) test 31 mph CC = IAT 76?, ambient 65?, 54.3 mpg
B2 (WAI) test 31 mph CC = IAT 100-103?, ambient 70?, 54.8 mpg

A3 (control) test P&G = IAT 73?, ambient 65?, 64.7 mpg
B3 (WAI) test P&G = IAT 91?, ambient 70?, 65.8 mpg

It's possible to look at these same figures, and argue the WAI does give a fairly consistent 1 mpg or 2% FE increase. The fly in the ointment is the B1-A2 overlap, and the consistent rise with increasing ambient temperature.

I suppose I could do BAB testing, and long-term testing, but wonder if it's worth it. What do you think?

I think your test results are solid and good enough for me. Thanks again for all the data!!!