Motor lugs when hot or ETMS?
Extreme HDF Member
Joined: Feb 2015
Posts: 10,907
Likes: 8,758
From: Galt's Gulch - MI
The MOCO didn't add the EITMS to prevent damage from overheating of the engine, it was for rider comfort and not for engine protection, reliability or fuel savings, they've stated so on many occasions, such as right here:
http://www.harley-davidson.com/en_US...S?q=inner-beat
EITMS is purely for rider comfort. When it activates and shuts off the rear cylinder, its not because the motor is overheating. Its designed to reduce the heat radiating from the rear cylinder to the rider.
Thanks to the EPA and the uber-lean tune forced on HD riders were complaining about heat from the rear cylinder and this is how the MOCO appeased the complainers. HD has no preference if you use the EITMS or not, if it were truly effective at engine heat management don't you think HD would at a minimum 'recommend' it should be left active? They know it doesn't improve the performance of the engine
Many new vehicles are using cylinder shut-off but again, it has nothing to do with heat management but rather fuel economy at cruising speeds. The only true way to reduce heat on your HD is to remove the influence of the EPA and get a proper tune in place. Additional benefits can be had with fluids that are more resistant to thermal break-down, oil coolers with fan assists, and external fans such as the Ward's fans.
The EITMS is nothing but rider preference based on their heat comfort level...
Outstanding HDF Member
Joined: Aug 2012
Posts: 3,217
Likes: 90
From: Detroit
Some of the GM engines (and maybe others) are able to be driven without coolant, in an "overheat limp mode", which involves rotating which cylinders are fired and which are dropped. A cylinder will fire, and then take a time out, just pumping cool air, before it fires again.
Prior to the Harley system we've been discussing, pre-07 fuel injected Harleys had a heat-management system which worked in several stages, depending on how hot the engine got:
First, the idle speed would be reduced.
Second, the mixture would be fattened up.
Third, the continuous firing of cylinders would be dropped, with both front and rear cylinders taking part in the dropouts or shutoffs. These too would do a cool air stroke mixed with firing strokes.
It appears that Harley is pretty careful about using the term "overheat" in their literature.
Good golly, if it became widely known that these air-cooled engines can overheat when stationary, people might buy something else instead.
Better to say that it's for rider comfort.
Last edited by Warp Factor; Sep 29, 2015 at 09:44 AM.
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