fuel cooler thingy

[Superjuiced]

My car has A/C but its not been installed since I've owned it, the pump is out but some of the hoses are still in there. I thought as I'm tidying it all up I wanted to take out as much that isn't being used. One hose goes from the a\c pump into what must be a cooler that cools the unused fuel before it is returned to the tank. I wanted take the a/c hose out and cap off the a/c side of the cooler. I can't imagine the gas side will have any function as the a\c ain't there so I can't see what harm it would do.

See pic its just behind the pas bottle, fuel hoses goes in top left and out top right a\c hose is out the sides left and right.

Thanks in advance guys.

[Boatbuoy]

I think the fuel cooler is on the inbound side of the fuel rail (not the tank return). Other than that you are correct, if the compressor isn't connected then your AC system must be 'open' to the environment and therefore has no gas in there.

[Tanguero]

On mine and all others I have seen the cooler is on the return side of the fuel rail. The fuel should come directly from the pump to the rail and return via the pressure regulator and the cooler.

[TvrJohn]

Currently taking mine out also, driven by access to sort out my leaking steering rack pinion drive.

[Superjuiced]

mine goes tank, pump, filter, fuel rail, cooler then back to tank. The cooler still had the original weld marks on it so ive taken it out and given it a buff. will find some nice stainless steel caps and blank off the a/c inlet outlet. The hoses are heavy with some chunky fittings, I'm wondering how much Ferrari would charge to save that bit of weight!!

[viku]

Boatbuoy said:

I think the fuel cooler is on the inbound side of the fuel rail (not the tank return). Other than that you are correct, if the compressor isn't connected then your AC system must be 'open' to the environment and therefore has no gas in there.

In my car the cooler is also between pump and fuel rail.

[Boatbuoy]

Tanguero said:

On mine and all others I have seen the cooler is on the return side of the fuel rail. The fuel should come directly from the pump to the rail and return via the pressure regulator and the cooler.

I stand corrected - every day's a school day!

[pmessling]

I remember talking to joolz about it and he said does make a difference come summer if your ac is working as it does cool the fuel much better being gassed up.

[Superjuiced]

I wonder how it works for those who have no a/c?

[jamieduff1981]

My A/C is present but doesn't work. I didn't appreciate this cooler was even there until recently. Or rather, I'd seen it and hadn't given it any thought to see what was plumbed into it and therefore what it was for.

I don't like things not working so the aircon will be addressed this spring.

[Tanguero]

I did some measurements a while ago and having the aircon running will drop the return fuel temperature by between 10 and 15 degrees.

[Vee8ight]

I wonder if putting cooler first would increase bhp as cooler fuel will take some heat out of the intake charge and then more charge can fit in the cylinder.?

[morebeanz]

Tanguero said:

I did some measurements a while ago and having the aircon running will drop the return fuel temperature by between 10 and 15 degrees.

I wish I had realised that was how it worked!

I've always been more concerned with the water temperature in very hot weather and so kept the air con off...

[Tanguero]

Vee8ight said:

I wonder if putting cooler first would increase bhp as cooler fuel will take some heat out of the intake charge and then more charge can fit in the cylinder.?

Theoretically it certainly should, however I suspect that on the real system is a bit more difficult to determine what would happen.

If you cool the fuel before it goes into the rail it will be subject to heat soak while it is there, and presumably the return temperature would be higher than if it was cooled immediately before returning to the tank. That might mean that the tank temperature rises, which will increase the temperature of the fuel coming in to the fuel cooler. Whether that would off set the effect of having the cooler before the rail or not is anyone's guess. It would certainly be interesting to do some measurements with it connected up the other way round.

[Superjuiced]

lots if interesting thoughts. Interesting on the temperatures but I don't know if that's is going to have any noticeable effects on daily performance. I don't think the A/C has been installed for a long time and the car has been on 1/4 mile runs and been to France and back in the height of summer. but I'm going to keep the hoses and mounting for A/C in so it can easily be plumbed in should I feel that it's needed. I've polished it up and just waiting for some new hoses before it gets plumbed back in. I used a 3m unitises wheel which is amazing for buffing up all sorts of metal.

[ridds]

morebeanz said:

Tanguero said:

I did some measurements a while ago and having the aircon running will drop the return fuel temperature by between 10 and 15 degrees.

I wish I had realised that was how it worked!

I've always been more concerned with the water temperature in very hot weather and so kept the air con off...

You'll be more annoyed when I tell you that when you put the AC on the second rad fan stays on too! So will actually help cooling the engine!

The fuel cooler with AC running will help you most when you are using the car in town and low loads. During this operation most of the fuel will loop round or through the rail and straight back to the tank being heated by the pump and radiated heat from the engine.

The best way to fix the issue is replace the fuel system with a return-less system or one that has the regulator/bypass away from the engine as this will reduce a lot of the heat transfer. This still doesn't help the heat from the pump though.