GregBBRD

Porsche decided that a fuel cooler was needed on the 928. Obviously, this was not an accident and they had some reason for doing this. Anybody out there know where there is any technical information about horsepower gains from cooler fuel?

gb

toofast928

The fuel cooler was intergated into the A/C system. So the fuel was only cooled when A/C was operating. For street use, I bet the HP gain is minimal.

I wrapped my fuel feed and return hose in thermo protect. Fuel stays a few degrees above ambient temp.

Tony

Vilhuer

Official reason for adding cooler was to prevent vapor lock on hot days when AC is on.

Shane

I know of one shark that is currently running just fine without the fuel cooler. I'm tempted to make mine disappear as well.

Lizard928

mark that one more, 86 engine and no cooler

perrys4

Here is a link with another link inside it. Not usre if it gives any real facts but a litle digging in the site might get you some answers.

http://www.eng-tips.com/viewthread.c...=189415&page=1

dr bob

We used to cool the fuel on drag cars, thinking that it would somehow cool the incoming air. All that really did was move the point of vaporization down a little further into the manifolds though. Most manifolds had coolant crossover passages built in so cold fuel was heated up anyway. In the FI cars, cooler fuel is more dense, but there's no real advantage.

In the 1970's and 80's, hot weather would cause fuel vaporization in CIS cars, as the fuel was routed through the engine bay. The bulk of the fuel was returned to the tank, then pumped forward again to have more heat added each cycle. Adding the fuel cooler was one way to try to reduce the heating problem. This was done by Porsche, while at the same time Bosch was recommending a higher-pressure pump to help mask the symptom.

I spent a bit of time at Standard Oil in Brea and Fullerton in the early 70's, working on fuel blends and engine controls in conjunction with a couple major US car manufacturers. All were looking for that holy grail solution that would allow reasonable mileage (not great, mind you...) and meet new emissions standards for California. We played with a lot of options. Most blends that flashed well for low HC output would also flash well before they made it to the carburetor on a hot day.

RennPartsDirect

For those who removed the cooler from 84+ 928s can you share how you connected the fuel rails to the fuel return line after you removed the cooler? Yes, I know this thread is four years old...

FLYVMO

Remember that the original fuel cooler actually only cools the fuel that is returning to the tank. Not the fuel going to the engine. Most likely for vapor lock control.

Cheers!
Carl