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.

[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_NovaResource]

Originally Posted by 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

Only when the engine is cold does that valve direct warm air off the exhaust. It's done to help the engine warm up quicker. Once the engine gets to operating temperature, the valve switched over to cold air.

If you check your car you will see the vacuum line from the valve goes to a thermostatically controlled vacuum stitch. Only when the engine coolant is cold does engine vacuum pull the warm air intake valve open.