Throttle heating

[chris.richard]

Like others, I dispensed with the hot water flow to the throttle butterfly because I wanted to keep the intake cool. There is a good argument that the airflow is so great that it won't be heated measurably, but I decided to ignore that. I've read dire warnings of iced up throttle butterfly if there's no heating. Thinking about this again recently, I decided that I definitely can't see a good reason to keep it. Direct throttle bodies don't have heating, do they? Putting a plenum between the throttle and cylinder head won't make much difference will it, or do direct attached throttle bodies get heated directly from conduction from the cylinder head? And carburettor icing is due to the cooling from the latent heat of vapourisation of the fuel, isn't it? Since no fuel is vapourising in the throttle, it won't get cooled this way. Or am I barking up the wrong tree? :confused:

[guy mayers]

Hi Chris - wasn't the issue not one of heating the plenum but of bleeding air pockets out of the system to stop overheating the whole engine?

Guy

[chris.richard]

I don't think so - I can't see that feeding water through the casting of the TB would help bleed air pockets? My feed is diverted into the expansion tank.

[kens]

I have direct experience from a friend. The worst result was found on a road trip with his wife and infant on a cold foggy day. The air moisture iced up and restricted the air inlet stopping the engine. It is amusing now.

So, you can opt out of throttle warming if you avoid long drives in cold fog. I once accumulated about 1 cm of ice on the tips of aero mirrors while on a long drive in cold fog. These are the same conditions that cause small airplanes to drop out of the sky without wing deicers.

Best regards,
Ken

[Arthur]

Chris,

Sounds about right all the way down the line.
I've only ever had trouble with unheated carbs evaporating all that juice. Never had a problem with this thing.
Including 12 months in Wales in winter.

Arthur.

[CorseChris]

Bypassed it on mine a while back. Haven't done long trips in freezing fog but I have used it on cold damp mornings over the winter no problem.