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Old 02-21-2013, 04:17 AM   #27 (permalink)
EcoModding Lurker
Join Date: Jan 2013
Location: Oregon, US
Posts: 43

ZoomFreakingZoom - '88 Mazda RX7 Convertible
90 day: 19.02 mpg (US)

Geo - '96 Geo Prizm Base
90 day: 32.42 mpg (US)
Thanks: 2
Thanked 2 Times in 2 Posts
Originally Posted by Davinator61 View Post
The issue I have is NOT with my t-stat, as it is already the maximum available opening temperature, and is working as it should, as of my last drive. What IS the issue is the temperature of the AIR going into the engine cylinders through the intake manifold, from outside the engine compartment's exhaust manifold side, where a lot of the heat-flow seems to be concentrated.

Also, I'm basing my idea on a "heat riser" on the intakes of older, carburated vehicles to not only warm my vehicle up to operating temperatures faster, but to also keep the intake air temperatures warmer than outside-the-vehicle temps, or even ambient engine compartment temperatures, as well, using heat off the Exhaust Manifold to do so.

Plus I'm not looking to increase Horsepower and Torque in the upper RPM band (3300-5000), but to improve fuel efficiency in the mid-range power band (1650-3300 RPMs). In fact, I DON'T give a Rat's Fat Ugly Tuchus about upper RPM band gains, as I've already done a number of mods on my engine block for better air flow (Ported and Polished Head, Roller-Tipped Rocker Arms, Anti-Pump-Up Valve Lifters, Oversized Intake & Exhaust Valves).

All I REALLY care about is squeezing as much fuel efficiency out of my I-6 as I can, based on what I've observed over the years as to what works v.s. what doesn't, even if my Upper Power Band suffers. Cold Air Intakes have NOT worked for me in my current vehicle's application, so I'm going the opposite direction to see what that will do, that's all. Do you now understand my reasoning a little better?

Is your jeep throttle body injected?

Carb'd engine did get their intake air from a hot source when warming up, but once the car was warm, it had a mechanism to switch to colder source. Also, Fuel injectors make it much less important since they evaporate the fuel better.

If you say it gives you better mileage, I'll buy that.
1988 rx7 convertible. Streetported, racing beat header and presilencer replacing all 3 catalytic converters. Atkins 6 port sleeves. K&N cone filter intake. 22mpg average, 27mpg max. Spreadsheet (updated regularly):
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