Quote:
Originally Posted by SmellyCat
tjts1, I really like that cover you have under your car. I'll add that to my list
Here is what I read about hot air cold air
The hot air intake functions by drawing in air from near the engine, which has been heated due to internal combustion. This warm air causes the fuel mixture in the car to drop, thereby lessening how much fuel is used and increasing mileage.
The Volvo already has hot air intake with a thermal flap in the air box that goes to exhaust Manifold. (Mines rigged to open all the time) Once the car heats up it switches to out side air to increase HP.
Cold air = More O2 More fuel more power lower mpg
Hot air less O2, less fuel, less power Better MPG
It works with MAFs but not cars with MAPs
You can un hook the hot water lines to the intake manifold to get even more HP but less MPG. Turbos' have intercoolers to cool the air before the throttle body. again more HP. SC
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The theory is all well and good but it doesn't work on these engines. Your MAF sensor will die an early death because it can't handle the extreme heat you're throwing at it. It wasn't designed for this. The thermostatic flap as it leaves the factory is designed to maintain a minimum of 70f in extreme cold temps. When it fails, it always goes into the hot air only side and it quickly murders the MAF sensor. The MAF also has a temp sensor built into it and it will cause the engine to delay ignition timing which kills economy, increases HC and NOx emissions. Switch it back to all cold air and you'll see an immediate increase in mileage. With all the other modifications you've done, you should be in the low 30s by now. Your car has AW70L transmission with a lockup torque converter which is a big advantage over older 740s, 240s and 940 turbos.
I have worked on many volvo red block and white blocks, replaced more failed MAFs and thermostatic intakes than I care to remember.
http://www.matthewsvolvosite.com/for...48301&p=239490
http://www.volvoclub.org.uk/faq/Engi...ermostatChange