PW Exhaust Brake - OT

Hi, Oil Slick.
The only issue that I can think of is that there might be an increased possibility of doing some damage within the exhaust brake system while the engine IS cold. But I YAIN'T an 'Ex-Spurt'.

Just my 0.02.

Can't think of any immediate problems but I'm also mindful that the optimal way to warm it up is the way the engineers say, which is to drive it moderately. Thanks in advance for doing the research Mike ! : ) I'm guessing that there's some interesting tech going on with the lowered cylinder scavenging as a result of that back pressure and the resulting reduced combustion - sounds counter-intuitive that it would warm the engine up faster but hopefully someone knowledgeable will be able to explain what's going on.

Do it all winter long. For ten years never had a problem

you have to do something to warm them up mike, they don't burn enough fuel to stay warm on their own, we did many tests on the cummins engines that were in dodge trucks, they actually cool down faster if you let them idle for an hour while in the store versus shutting the engine off and restarting the truck an hour later. I'm talking about the actual block temperature, not the warmth of the vehicle cabin. the new dodges since 2007 that were equipped from the factory with the exhaust brake, when you turn the exhaust brake on and the engine is cold, it revs the engine up so it can warm up faster and the exhaust brake gives it a slight load to actually have to burn some fuel and create some heat.

my duramax has a terrible heater in it, and my suburban has identical heater core and system and it cooks you out. the difference is the thermostats, the suburban thermostat is set at 92 c, the duramax has 2 thermostats, one at 81c and the other at 85 c, if you cover the front of the truck right in. with a tarp, and work the snot out of the truck on the hill, the heater will actually perform and start to cook you out, but when you coast down the hill on the other side, it cools right off again.

if you checked, you would probably find that your cummins thermostats will close if you leave the engine running at idle in temperatures below 15 degrees f without either idling the engine up or being able to able a load to the engine to make it burn some fuel and create some heat.

btw, the new variable geometry turbos on the new 6.7 fords, 6.6 duramaxs. and 6.7 cummins engines actually act as an exhaust brake and put load on the engine to help them warm up faster in cold weather. not sure at what the temp requiremnts are for the computer program but it is lower than you think it would be. I think that a lot of them use 0 f as their cutoff for going into high idle mode and such,

I do it all winter long with my 05, no problems.

Like rmyram says it won't warm up without doing it.

Bruce P

The 7.3 Powerstroke had an exhaust brake for the exact purpose of warmup. It could be reworked to actually work as a brake, but Ford said it would void the warranty. ..When my truck goes into warmup mode, the idle jumps up to 1000 RPM, with the straight pipe it sounds like the turbo generator in the back of a jet aircraft. ..

One way to look at it is a diesel cycle pulls in a full chamber of air which cools the combustion down then only burns enough fuel (myram) to push the piston away, and then in theory the end of combustion process will leave the chamber in the same temp as input. A SI engine on the other hand does not load the cyl full of cold air and therefore will(can) heat during an idle.

This is the beauty of a CI(Diesel) cycle, it more closely approaches the Carnot cycle, as Rudulf tried to accomplish.

If a diesel idles without shutters or have some way to restrict radiator heat exchange it will get cold and soot up in the winter.

My 06 dodge has an exhaust break by Jake Brake that came on the truck when new. It is hooked into the computer system which speeds the idle system up and shuts the break off when the temp reaches 190, no problems so far at 190000 miles.