HAI Experiment

[GasSavers_NovaResource]

Not my test:
http://www.techno-fandom.org/~hobbit.../results-1.txt

Conclusion: the warm-air intake kit does absolutely NOTHING for the steady-
state efficiency of the Prius. I would posit that with the lower intake
temperature and denser air, more fuel would be injected per charge to
maintain a stoichiometric burn, but since that produces more power then
the throttle would simply be closed a little more to keep engine output
in check to hold the same highway speed. The tradeoff either way apparently
balances to zero out on the highway. I believe I had a significant enough
IAT delta between runs that if there was to be any effect on mileage, I would
have easily see it. Unfortunately I didn't try to log and then average
out a TPS reading, which might have been revealing, but it wouldn't have
really mattered in this mileage-comparison test anyways.

Think about it, Toyota spends unknown amounts of money researching and developing a system where hot coolant is pumped from the engine into an insulated thermal container upon shut down so so it can be pumped back into the engine later to improve cold startup fuel economy. Then they spend more money to equip hundreds of thousands of cars with this complex arrangement. All in the interest of gaining a tiny MPG and emissions advantage for cold starts. Yet Toyota (nor any other automotive engineers) have never added an inexpensive WAI to gain the claimed fuel economy improvements. Maybe it's because they know there is no benefit just like the above tester found out.

Something to think about.

[GasSavers_maximilian]

You always seem to completely ignore the fact that WAI hurts horsepower and may raise NOx emissions. If you want to sacrifice hp for mpg without raising emissions (in fact lowering them), putting a smaller engine in the vehicle is a much better way to approach it. That's not a realistic option for most of us.

I got the 3" aluminum flex duct I needed to try it on my Accent, but I want to establish a new baseline since I recently put tape over my upper grille as an initial grille block. I don't drive much so it'll be a while before I have any data to contribute. I may wait even longer before posting so I have enough tanks to constitute a more useful sample size.

[Jay2TheRescue]

Yes it has been installed by automotive engineers... My 1981 Buick (O2 sensor & computer controlled) and my 1986 Chevy truck (Not computer controlled) both have WAI from the factory... Plus my old 1980 Bonneville, my 1974 Chevy truck, and my 1981 AMC Spirit all had WAI from the factory. The only vehicle that I have ever owned that didn't have it is my 1998 GMC truck.

-Jay

[GasSavers_BEEF]

jay,

don't discredit his findings, it took him 3 hours to dig up that snipit of data. you shouldn't correct him in a mere 5 minutes.

I guess the search continues.

[Jay2TheRescue]

Oh, but I spent more than 5 minutes... After I made that post I went out to the parking lot, raised the hood of my 1981 Buick and took a pic of the air intake with my cell phone, emailed it to my laptop, where I edited it in paint, adding notations of what's there, and here it is...

[theholycow]

That data has been presented here before, and as before, I don't think it applies to non-Prius cars. The Prius is special, operates differently, is utilized differently, and even runs on a different cycle...and again, it still only applies to one model. The Prius engine is already run under heavy load to operate in the best parts of the BSFC map, which means that it has no use for the [theoretical, if you must] effects of a WAI.

[GasSavers_BEEF]

that does have an advantage over the DIY kind. doesn't it close off at WOT. that way you can have your cake and eat it too.

power when needed.

that is one thing I have missed. when some yahoo comes flying up on me. he goes to pass. I don't have a chance (like I really had a chance before.lol)

[GasSavers_maximilian]

If they used to come installed why has the WAI fallen out of favor then? The emissions issues?

[Jay2TheRescue]

Actually, WAI was part of the emissions control systems back then. It warmed the intake air so the gasoline would atomize better and burn more completely. It was a way to help carbureated engines run more efficiently. Also, if your intake air was always the same temperature you could more precisely dial in the mixture for both emissions and economy.

-Jay

[GasSavers_maximilian]

That makes a lot of sense. Not to stir things up, but one could argue that those changes mean a WAI coming from the factory doesn't really prove too much these days.