[t vago]

Originally Posted by wmjinman

Yeah, I think excessive intake air temperature is why they started putting intercoolers on turbos. Good to know yours runs well at 130, though. I'll move my target range's upper limit to there for my testing.

You reminded me... I still have these other books, from when I was interested in turbos: Forced Induction Performance Tuning, by A Graham Bell; Turbochargers, by Hugh Macinnes; Maximum Boost, by Corky Bell; and Supercharging, Turbocharging and Nitrous Oxide Performance, by Earl Davis and Diane Davis.

All of these books mention intercooling primarily as a method of cramming even more charge into the cylinders. The use of intercoolers is as a method of detonation control was mentioned as a secondary purpose (even if still important), because intake temperatures will rise as a consequence of being compressed by the boost device. The books note that detonation / pre-ignition becomes a concern when intake temperatures are well above ambient temperature, though (like around 200 F above ambient). Further, any boosted application could benefit from using an intercooler, it would seem. For instance, A. Graham Bell mentioned that even otherwise stock cars with mild levels of boost (as with an aftermarket turbo kit) can benefit from an intercooler, since he found that their stock ignition and cam settings would not need any adjustment due to boost.

This tells me that a 60 F rise in temperature is probably nothing to worry about for our warm-air intake ideas, but anything above that might merit a little bit of caution.

Originally Posted by wmjinman

And your heater core idea is probably really good for cruising with a warm engine, but if your goal includes faster warmups, the benefit of warm intake air wouldn't start until AFTER the engine was already warm enough to have hot coolant in that heater core, would it?

That is true. However, the engine starts heating up its coolant about as soon as it's started, and I have noticed decreased warm-up distances (which would translate into reduced warm-up times).

For instance, on my daily commute, I've taken the below measurements. The distances are approximate due to their being landmark distances from my house, but they do serve to point out that warm-up times are significantly reduced.

.	Stock	With WAI
Needle moves off bottom	0.9 miles	0.7 miles
UltraGauge reports 190 F	5.5 miles	3.9 miles

Using either coolant or exhaust heat, raising the intake temperature will also raise the combustion temperature, and will raise the exhaust temperature. Raising the temperatures in this fashion will raise the rate of heat transfer into the engine block, which will decrease warm-up times.

Originally Posted by wmjinman

And at the risk of being a kill-joy, if I understand right, keeping the engine nice & toasty even at low power levels, is one of our goals, right? So wouldn't the heater core air heater be undermining that effort a little? But the exhaust's heat will always be there, though, and isn't going to cool the engine down by having some heat sucked off it.

You could say the exact same thing with using the heater at full blast on an idling car. Since it's somehow able to keep operating temperature even at idle, I'd say there was still some available waste heat from the coolant to be used, especially considering that the idling engine does not suck in anywhere near as much air as that heater at full blast.