Duramax Fuel cooler??

[99-2door]

I was checking out my friends 2001 2500HD ext. cab 4x4 Duramax with Allison the other day and saw something interesting. In front of the fuel tank there is a cooler that is plumbed into the fuel line. Is that a fuel cooler. Why would it need that?

Anybody know.

Thanks

[GMCTech]

The cooler the fuel the better atomization, and less chance of pre-detonation.

 

Hope this helps.

[snoman]

The cooler the fuel the better atomization, and less chance of pre-detonation.

 

Hope this helps.

Cooler fuel (gasoline) is more dense than warm fuel so you would get a little more fuel per injector "squirt" but a lower temp would not increase its abilty to vaporize or atomize better because warmer fuel does atomize quicker. Given todays higher pressure fuel injection (which keeps fule in a liquid stat at much higher temps) and closed loop system (which adjusts for fuel density) it is questionable what you would gain with this. On older vehicals to low pressure fuel and carbs cooling of the fuel could help prevent vapor lock in line or in carb. In a diesel it would not be wise as in very cold weather it could promote the formation of wax in fuel which could plug filters and restrict performance.

[Colorado Kid]

The D-max uses a fuel cooler because it uses fuel to cool the ECM electronics, and because pumping the fuel rail pressure to 23,000 PSI adds considerable heat to that fuel, most of which is returned to the tank.

 

23,000 PSI does a mighty good job of atomization all by itself, resulting in fuel entering the cumbustion chambers at supersonic velocities.

 

Predetonation in a diesel only if the timing is over advanced. You can't detonate what isn't there, the fuel burns (virtually) as soon as it is injected. ("virtually" added in case any of you mechanical wizards has heard of ignition delay or ignition lag . . .these are measured in miliseconds).

[tmf6902]

the fuel rail pressure to 23,000 PSI

Wow, that's some serious pressure. Before I ask this please note I know nothing about desiel. SO when your changing a fuel filter...(I assume they have a filter)...how do you go about relieving that? When I did it on my gasser I opened the gas cap and got a bucket....but my truck idles at 46-48 psi....substatially less than 23000.

[robsawatsky]

the fuel rail pressure to 23,000 PSI

Wow, that's some serious pressure. Before I ask this please note I know nothing about desiel. SO when your changing a fuel filter...(I assume they have a filter)...how do you go about relieving that?

That pressure is at the injectors, not at the fuel lines to the tanks. Two independent fuel pump systems on diesels. One for the tank and one for the injectors.

[tmf6902]

the fuel rail pressure to 23,000 PSI

Wow, that's some serious pressure. Before I ask this please note I know nothing about desiel. SO when your changing a fuel filter...(I assume they have a filter)...how do you go about relieving that?

That pressure is at the injectors, not at the fuel lines to the tanks. Two independent fuel pump systems on diesels. One for the tank and one for the injectors.

Ahhhh gotchya.....like I said...I know nothing about desiel....half the time I can't even spell it. i before e except after c.

[snoman]

You can't detonate what isn't there, the fuel burns (virtually) as soon as it is injected.

This is true, the burn is a diesel lasts as long as fuel is being injected. Power output is controlled by the duration of the injection cycle.

[99-2door]

Thanks for the responses guys. I can see why it is there now.