16 Gal Gas Tank in 325e??

[porschelou]

Hello
Need some help -
We endurance race our 86 325e - 18-24hr long races. We have a m30 motor in the car so is drinks the gas. I can get 1.5hrs on a 14 gal tank before it starts to starve. I need to get closer to the 2hr mark where we need to swap drivers. I would like to install the "i" tank = 16gal. Does anyone know if the "i" tank will fit??? Any other ideas to get more gallons in the car. I heard the M3 had an optional tank that mounted inside the trunk but have never seen one.

We can run a fuel cell but the cost goes way up..

Thanks

[SmokeE30]

more then just the m3 had the extended range tank, ive seen them come up for sale on here before but not often as they werent a super popular option. maybe somebody one on here they would want to get rid of but you may have to wait a bit to find one. i would just go smokey yunick style and coil a bunch of huge ass fuel line somewhere to hold the needed capacity you need, i think he used 11 ft of 2" fuel line coiled up to ad an extra 5 gallons of capacity to circumvent the nascar maximum tank size regulations.

[jlevie]

You can swap to the 63l tank. And you can fit that tank with two pumps to allow almost complete use of the fuel under racing conditions. There is a thread in the track section describing how I did this (and how I would do it next time).

[porschelou]

Thanks Jlevie!

Good write up.. One question - with the larger tank how does he factory get the gas from one side to other without a second pump?

[iwantspeed]

trunk mounted auxilary tank
found in the rare parts thread

http://www.r3vlimited.com/board/showthread.php?t=95869&highlight=rare+parts&page=20

[FLG]

Thanks Jlevie!

Good write up.. One question - with the larger tank how does he factory get the gas from one side to other without a second pump?

Theres a little line on the bottom that connects the two tanks, the one on the driver side sits a bit higher than the passenger side.

[jlevie]

Thanks Jlevie!

Good write up.. One question - with the larger tank how does he factory get the gas from one side to other without a second pump?

The 55l (early) tanks have a crossover tube between the tank halves. The 63l tank has an internal siphon operated by fuel returning from the engine bay. In the general case, the late tank is more prone to early starvation, especially if the pump is a little weak. When the pump starves, flow through the siphon is reduced and thus fuel stays in the left side, aggravating the starvation issue.

But the late tank can be easily fitted with a transfer pump in the left side to lift fuel in the right side where the high pressure pump is. With a dual pump setup you can run the tank down to less than 4 gallons before encountering starvation.