Some years back there was a lot of talk about turbo timers to prevent turbo bearing cokeing but, for whatever reason, no one seems to know what I'm talking about. Maybe because some of the new fueling boxes have this feature built in them. What I want to do is build my own relay timer so that I can run an auxiliary 12 volt fan for about 30 minutes or less after engine shut down but I cant seem to find any kind of timer relay that can do this. There used to be aftermarket turbo timers which would run the truck for 5 minutes or so after turning the key OFF, unless you opted to override the timer with a button. Maybe there aren’t too many guys who have been on these forums for 10 years so and have no recollection of anything like I'm after. There seems to be some 2nd gen Cummins gadgets no one talks about anymore, like there was a turbo protector which used a thermocouple or tied into an existing thermocouple, and shut the engine down when the turbo reached a set EGT after the key was shut OFF….. but this isnt what I’m talking about.If anyone has idea where to get what I’m after or knows where I can purchase the stuff to put together what I’m trying to do. Thanks.

Something like this would probably work. http://www.hometech.com/hts/googlebase.html?item=EL-960

It isn't very high amperage so you would need to make it turn on a regular car relay rated for whatever amps your fan is rated to use.

To trigger the relay, you could simply wire up another car relay (anything will work, triggering the timer relay won't take much amperage) and put the positive voltage on the NC contacts so that when the truck is turned off and that relay is de-energized, it closes the set of contacts that give the timer relay 12V, which then turns the timer relay on for 30 min. That same wire that triggers it with 12V can be ran in series to a DPDT center off switch in the truck that opens the circuit from the relay to the timer relay, and leaves everything completely off in the middle, or can manually be turned on as long as the switch is on by sending 12V to the higher amperage really that runs the fan.

Here is how you would wire it. Little complex but this whole setup should cost you $50, I don't know where you're gonna find a high amperage 12V timer relay that will cost less than that. Sorry about the crappy schematic but I can't draw one very good with windows xp's paintbrush

Big version is here. http://i52.tinypic.com/jrrbcz.jpg

But maybe you can see this resized version.

There used to be a devise... I think it might have been called "TurboSaver" a spring loaded piston which would be pumped up by oil pressure when the engine was running. It was installed in the turbo's oil feed line. When the engine shut down, it kept oil pressure to the turbo for a short period of time allowing the turbo time to spool down.I believe ISSAPRO made / makes a turbo shut down timer.

Found a bunch based off of Russ. http://ttcperformanceproducts.com/turobtimers.html http://www.genosgarage.com/prodinfo.asp?number=BD-1081160 http://www.dieselmanor.com/isspro/r4130.asp I am not sure if any of them go to 30 min, looks like 10 min max or whenever the thing gets to the right EGT.