I posted this over in the obs side but wanted to get thoughts and opinions here too...


So I was watching Powernation and their 80's chevy truck build with a duramax and saw something interesting.....

The put a tranny cooler on the fuel return line to cool the fuel returning to the tank....

Now I see where this is helpful on a gas vehicle (not that there is a fuel return line in that application) but how does that help a diesel?

I understand if you pressurize fuel it gets hot and then returning to the tank heats up the fuel in the tank....

But with fuel gel issues why would you risk this?

Wouldn't warmer fuel flow better, atomize better, ignite better, and burn better?

I would think cooling it down would potentially cause slower burn thus increasing egts? Maybe I am wrong?

 

I thought along the same lines as you until Pocket and some others explained it in a thread a while back. I'll try to see if I can still find it.

 

my buddies '07 duramax has a fuel cooler on it. its a stock setup.

 

That is funny, we had big marine diesels and they had fuel pre-heaters on them. Just one more item to potentially leak if you ask me.

 

It is no different than an intercooler for compressed air. Simply put, the reason common rail injection uses a fuel cooler is when you are taking ambient temp fuel at say 10psi feed and then compressing/pressurizing it to 25-30,000 psi it creates a ton of heat.

The cooler is to cool the fuel on return to the tank. It is fairly common to see Duramaxes return at 250-300 degrees pre cooler on a hot day pulling heavy. We experimented with a friends truck by removing the cooler and running a temp gauge in tank and on return. Its incredible how much hotter the fuel was in the tank, especially when driven down to a 1/4 tank without a cooler.

It all depends on the injection system, The 7.3 will not benefit from it at all IMO, however you would be surprised how warm your fuel will get on an 1/8 tank or lower. Heat simply kills fuel pumps, they will cavitate earlier as well. I know there has been extensive research done by duramx engineers, as well as a couple common rail marine diesel companies as well. Regarding gelling... It does not matter if the cooler is there or not, if the cooler is gelled, so it the feed side. Its just darn cold, cooler or no cooler. Coolers on the feed side are pointless, as described above it will not atomize properly if very chilled, hot fuel does not lubricate as well either. Its a fine balance.

That being said running your tank down to E on a hot summer day pulling heavy, will likely shorten the overall lifespan of your pump. A lot, I doubt it, but I know its not a benefit for the pump... Have I done it, quite often, on purpose...no

Hope that helps.... When we are running MR12 on our race bikes. It stays in a freezer, or cooler of ice, and oh hell yeah it makes a difference, crisper, and on the dyno its good for 5-7%(under the right circumstances) more power vs 110 degree fuel out of the can over a 220 degree motor pushing off a ton of heat...

 

I just replaced the fuel pump on my 97 and noticing it is real close to the turbo for radiant heat to warm it I had some fiberglass pipe wrap so I modified it to fit around the pump and maybe make it cooler and last longer??

 

Probably not a bad thing.

 

Keep in mind the fuel goes through a nice hot cast iron head before going through the injectors.