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Old 20 Jun 2006, 04:59 am
TE Chea
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Default design flaw : F20A 's air intake gets useless heat from radiator*coolant

* via thermostat is [i] steel-piped next to & heat is transferred into
rocker cover's breather hose
http://www.autozone.com/images/cds/g...3d800cf9d1.gif
, this heated air is then sucked through PCV valve & into intake
manifold.chamber [ii] rubber-hosed into bottom of throttle body
http://www.autozone.com/images/cds/g...3d800cf4a6.gif
, & heat flows into the air passing throttle.
Both designs make air intake & cylinder head unduly hot
www.circletrack.com/techarticles/1822/ : whenever intake manifold
heats up ( esp in long trips ), torque drops & warm-starts are difficult
, both because hot air cannot expand much when heated. Ideal
temperature of air to receive injectors' spray of petrol is just 40°C =
104°F ( www.turborick.com/gsxr1127/gasoline.html para 10.2[7] ).
Intake manifold where injectors spray petrol ( near cylinder head ) &
chamber already get heat from manifold's contact with cylinder head,
EAC & Fast Idle valves ( both heated by * ), certainly do not need
more heat. If designer wanted manifold to heat up fast, then throttle
body must have a thermostat to stop * inflow when throttle is heated
to 40°C. These 2 designs make steep hill climbing slow & weak ; *
& air intake will both be @ their hottest, & torque will be lowest (
ironically, when torque is needed most ).
After I disabled these 2 designs, in 28°C air, [i] chamber, manifold
& cylinder head are cooler, benefits are many e.g. 1 can use ( cheaper
) mineral oil & lower viscosity [ii] torque ( 5% > before ) does not
drop after * heats up [iii] warm-starts are easier.


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