Warm Air Intake - Intercooler as an intake heater

[Eggman]

Hello foama!

Hey guys,
let me sum up a few thoughts...

1) Most enrichment occurs when it is cold. The colder, the more.The longer the car needs to warm up, the more enrichment it gets, and for a longer period. Consequence being, the colder it is, the more fuel gets burned.

2) With intake air being warmer (just as with coolant being warmer), the mapping is told it needs less enrichment (less fuel). Remember, the ECU receives A) coolant temp info, and B) intake air temp info.

3) When warming up and warm intake air is needed most, the coolant is cold. So much for a coolant-to-air heat exchanger. Of course after warm-up the exchanger will work and be beneficial, but it has definite limitations during warm-up when it is needed most.

This is where an engine block heater comes in to complement this idea. The two can work together to get things up to temperature faster.

As you likely already know, air intake heaters are not a new idea. They have been in use for many years - not for normal operation, but for faster warm-up times. Ones I am familiar with use the exhaust manifold as a source of heat.

4) Take a look at the engine assembly!
The resonator-box and the air intake snorkel are basically back to front!
If the snorkel went behind the engine instead of to the front, we would have a very simple, and equally effective warm air intake.

This would be so much easier if the two were switched... I suspect the length of the intake snorkel acts to help develop a positive pressure at the air box.

What we do not want to change is the resonance frequency (air volume!) of the total airfilter/resonance-box/intake-snorkel assembly, because it would change the torque curve.

Warmer air will also hinder power development.

It is my understanding that this experiment is intended to bring out improved efficiency at the expense of a loss of peak power. How much of this trade-off is acceptable is yet to be determined. I would argue that most enthusiasts interested in this modification are not focused on improved power, but improved efficiency in the sense that the 3A90/3A92 develops plenty of power for their needs.

I am interested in learning more about the resonant cavity of that box. Do you have any info on that, because the Mirage service manual makes no mention of it's use as a resonant cavity (unless I missed it...)

Any ideas how to get the snorkel to lead behind the engine?

Yep! Take a look at this thread: Warm Air Intake And this post in particular is the source of my curiosity.

It's been done, and while I dislike it's appearance I admire the performance.

Just for the record, The old thread " ECO Mod: Howto reduce level of enrichment when cold " shows how the ECU programming can be easily oversmarted to reduce enrichment and fuel consumption.

I remember that!

The intake air warmer idea may not require electrical modification depending on if the design needs controls to modulate temperature.


I wish Old Mech was still contributing, as he had some fine insight in these matters.

Old Mech, if you are out there, I hope you consider chiming in, and that all is well with you.