Most of us have heated throttle bodies and don't need them. Some of us, failing to see the use in a heated throttle body, have removed the (hot) coolant lines in an effort to minimize the heat added to the intake air charge. Cold air makes more power, so why heat the air? (Well warmer air makes better fuel economy but that's not it)



I was looking for something unrelated and finally found the nugget that explains this whole heated throttle body affair. 2000 and 2001 accents were not all fitted with heated throttle bodies. A new throttle body, pipe, hose set and (for some cars) a cylinder head ( ! ) are part of a retrofit kit if you really want to retrofit your 00/01 accent with a heated TB. The information below is a straight copy/paste from Hyundai TSB 02-01-004 Positive Crankcase Ventilation (PCV) Hose Relocation and Heated Throttle Body Installation - Campaign 047



(I bolded some text for emphasis)



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DESCRIPTION:



This bulletin describes the steps necessary to replace and relocate the PCV hose and install a heated throttle body on certain 2000 and 2001 model year Accents.



While driving at a steady throttle opening for an extended period of time during extremely cold ambient temperatures (below approximately -5°F {-20°C} with high humidity), moisture in the combustion blow-by gases traveling through the PCV valve and hose may freeze, blocking the PCV hose. If the PCV hose freezes, combustion chamber blowby gases are forced to exit the valve cover and enter the air intake hose through the breather hose. Because the breather hose enters the air intake hose before the throttle body, moisture in the combustion chamber blowby gases may freeze inside the throttle body idle speed control circuit and in the throttle body bore, resulting in a higher than normal engine idle speed and the throttle valve not closing fully.



AFFECTED VEHICLES:



All 2000 model year Accents and 1.5 liter 2001 model year Accents produced through February 13, 2001 and all 1.6 liter 2001 model year Accents produced through June 5, 2001 which are registered and operated in the 23 affected cold weather states listed below.



AFFECTED STATES:



Alaska, Colorado, Iowa, Idaho, Illinois, Indiana, Kansas, Massachusetts, Maine, Michigan, Minnesota, Missouri, Montana, North Dakota, Nebraska, New Hampshire, New York, Ohio, Pennsylvania, South Dakota, Vermont, Wisconsin, and Wyoming.



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So basically if you live or will be driving for a long time at a steady speed (straight flat highways) where it is colder than a witches tits AND it's humid out, THEN you MIGHT have a use for the coolant running through your throttle body. Everyone else, not so much.



By the way, if you really want to cool the intake charge, get a phenolic resin intake manifold gasket. The head heats the aluminum intake manifold which in turn heats the incoming air a WHOLE lot. A phenolic gasket prevents this heat transfer to the intake manifold. Still every little bit hurts, and it only stands to reason the hot throttle body will contribute SOME heat to the air, and therefore rob a teensy weensy un-noticeable amount of power from your engine. For absolute maximum theoretical power output (with a stock throttle body ) go head and pull the coolant lines off your TB if you live in a warm climate.

 

i'm glad hyundai australia installed TB heating. those 100 degree summers and 45 degree winters can get pretty icy.

 

is there a Hyundai Australia?

 

SRSLY? How hard was it to find the first hit on Google?

http://www.hyundai.com.au/



Edit: I did some looking earlier and found exactly ONE person who had done a bunch of before/after dynos. Claimed 1-2HP on a 300+HP V8. That tells me you might expect 1/2 to 1HP from a TB coolant bypass mod on an RD. You probably wouldn't feel it while driving, unless you have a habit of touching the throttle body while driving. That said, next time I'm in there I might do it (if I remember).

 

http://www.ws6.com/mod-8.htm 6.3 free hp

 

"average gain of 5.6 horsepower" out of 300? So then maybe 2HP for you? Better than a sharp stick in the eye, still probably too small to feel on the butt dyno.

 

It also helps with fuel atomization. When the air is cold, it's harder to burn (basically) so when the fuel is sprayed into the cylinder, it might stick to the walls or the atoms might stick together making it harder to burn completely. This is why your vehicle runs extra-rich when it's cool and not at operating temp. This is the same effect that EGR valves have. Not saying that is the #1 reason for them, but could have been part of the engineers thought process.

 

This was discovered some time ago at rdt. It isn't mentioned in the diy?



The spacers do work well. I was in on the Outlaw Engineering gb a few years back, great product.

 

they run rich when the engine is heating to get the cats to start working faster. Colder more dense air = more power.

 

wouldn't running rich lower your EGTs? i think its more along the lines of what CBowley603 said. there is a tradeoff between cold fuel not wanting to vapourise and hot air reducing the intake density charge.