DIY Warm-Air Intake

[jray3]

I didn't realize until recently that my 2000 Honda Odyssey actually has a tiny radiator in the air filter box that only gets coolant flow in very cold conditions. Does anyone know if that feature was on many other models, and has it been modded to function as a WAI for not just warmup, but also for reduced pumping losses on the highway? On this thread I haven't seen any intake temperature goals under different conditions. I'd rather not just "go hotter 'till she pings".

[t vago]

Originally Posted by jray3

I didn't realize until recently that my 2000 Honda Odyssey actually has a tiny radiator in the air filter box that only gets coolant flow in very cold conditions.

I also did not know about this feature, and would also like very much to know if any other models had this feature installed from the factory.

Originally Posted by jray3

I'd rather not just "go hotter 'till she pings".

I don't worry so much about that. Even if the intake air is heated to near the boiling point of water, the fuel spray from the injectors should cool the air to a few degrees above ambient. This happens because the fuel cools off the intake air as it vaporizes and sucks in latent heat of vaporization from the heated air. I already heat the air in my Magnum to about 40 or 50 F above ambient with a old Ford Probe heater core.

[teoman]

Do we have any data on what the ideal intake temperature should be?

It would be fairly easy to create a switched input for the wai.

[mwebb]

Originally Posted by teoman

Do we have any data on what the ideal intake temperature should be?

It would be fairly easy to create a switched input for the wai.

warmer air is better for combustion but less 02 as warm air is less dense ;
colder air is denser , more air = more 02 = more power available at WOT

mr computer
already has control of fuel and timing so
mr computer
will match air temp to a calculated value of timing and fuel volume which will be corrected in a feedback loop
from inputs from the AFR or 02 sensor in the exhaust

you
can not change anything

mr computer has control
so
heat the air as much as you feel will help ,
watch knock retard values in your scan tool and when they start to increase
beyond the baseline value
stop increasing air temp

of course you need a baseline scan data test graphed or logged of knock retard
at various loads
and ambient temperatures
before you begin your modification

[teoman]

Thank you for the feedback.

I am fairly familiar with the workings of the ecu.

I was planning on reading the iat from the canbus and establishing a pid loop with a servo that moves a flap between 2 intakes, one that is cold and the other ducted to the exhaust manifold.

It should be fairly straightforward creating the control loop (wish the obd2 protocol would be faster) and an analog sensor in the manifold could be preferrable.

Would the input temp be dependent on rpm or load? Obviously you would want cooler air if accelerator is %100 in case of emergency.

[jray3]

Originally Posted by t vago

I already heat the air in my Magnum to about 40 or 50 F above ambient

Good, thx. Running 1200 highway miles this past weekend with the Odyssey upper grill blocked and over 90 degrees ambient temps, I usually saw 120-124 degree intake air temp on my scangauge (and coolant temps of 190 to 217). That plus a lot of time spent at altitude of over 2000 feet must've really thinned out the intake air, but no problems. The van delivered 24 mpg steady at speeds of 75-80 mph for 300+ mile stretches. Not bad for an engine with 226k on the clock!

[t vago]

Originally Posted by jray3

Good, thx. Running 1200 highway miles this past weekend with the Odyssey upper grill blocked and over 90 degrees ambient temps, I usually saw 120-124 degree intake air temp on my scangauge (and coolant temps of 190 to 217). That plus a lot of time spent at altitude of over 2000 feet must've really thinned out the intake air, but no problems. The van delivered 24 mpg steady at speeds of 75-80 mph for 300+ mile stretches. Not bad for an engine with 226k on the clock!

No, not bad at all, sez I. The 2000 Odyssey was rated at 23 MPG on the highway. That you got 24 under sustained high speed highway driving says a lot.

[Daschicken]

Originally Posted by teoman

Would the input temp be dependent on rpm or load? Obviously you would want cooler air if accelerator is %100 in case of emergency.

The more air you are sucking in, the cooler the air will be. When I am coasting with the engine idling, intake temps go 40+ degrees F above ambient temperature. Driving around with steady throttle I think was around 10-20 degrees F above ambient.

[teoman]

I had in mind some sort of electronics wizardry to get the air from the hottest part of the exhaust manifold and keep it at a fixed temperature no matter the airflow. ( but i sold that car, and now have a turbo car, so i am not sure if this is such a good idea).

What i should have asked is, should the input temperature be dependent on rpm and load. Or is a fixed X F or C best or is there a more complex algorithm.

[t vago]

I can get a good 60 degree F difference between ambient and intake air temperature in the winter time. In the summer, the difference drops to about 40 F or 30 F.