AC line running to FPR?

[cleavon]

The car is an 87 325e with a later model i engine. I didn't do the swap so I'm unsure of what was actually done.

Next to the passenger side shock tower there is a canister in the line thats coming from the compressor into the evaporator. The canister is part of the line(no fittings on either end) and it has two lines coming out of the top of it that run along the top of the firewall to the drivers side. One connects to the back of the fuel pressure regulator and the other runs underneath the car to the rear. Any ideas as to what's going on here?

[101]

That's the rare and highly sought after fuel cooler option. :)

Apparently this was installed on a few of the later 86 and early 87 production cars and was designed to route the return fuel through the air conditioning circuit to cool it before returning it to the tank. Think heat exchanger.

You can safely bypass all that crap and remove it from the car if you want. Then route the return fuel line directly from the fuel rail to the metal return line under the car. There's less chance for leakage with the extra lengths of hose and joints removed.

[cleavon]

I guess I can can look forward to some performance gains if I get the ac working..

Thanks for the info

[roguetoaster]

Wow, that's a hilarious and idiotic system that I was unaware of previously. Right up there with the zyklon (cyclone) separator in air boxes, albeit for different reasons.

[ELVA164]

Can you post some pictures of the setup for posterity?

[101]

OP will need to do that. I've tossed the remnants already.

Here's the diagram off RealOEM ...

http://www.realoem.com/bmw/enUS/showparts?id=1254-USA---E30-BMW-325e&diagId=16_0301

[TobyB]

Wasn't it a quick and dirty fix for high temps and high altitudes? Fuel vaporization would
cause the car to lose power/ quit altogether.

One Pro3'er used it as a loophole to put a fuel cooler on...

t

[jeffnhiscars]

For those of us who remember carbs, they were very susceptible to vapor lock. I think the higher operating pressures of FI reduced that a lot but obviously bmw felt obliged to create a system that, in theory, would prevent it.