More Lotus DNA in the Stable

[Valenz]

Originally Posted by uglyduck

.... As far as fuel cells go, I am using two pump setup, one low pressure to a swerl pot and then a high pressure for the injectors...

The fuel system is one thing that's giving me problems at the moment. (A side effect of what began as a cooling problem). My Seven has a single high pressure fuel pump. The recirculate from the rail returned to a 3-port fuel filter mounted near the fuel tank (no return to the tank). The return line from the rail had a secondary aftermarket regulator installed in it. Unfortunately, that second regulator was installed backwards so there was no return flow at all and the 3-port filter is no substitute for a swirl pot anyway. Because of the high configuration of the Zetec's head cooling jacket and the relatively low radiator and reservoir tank there was an air bubble trapped in the head that caused a portion of the head to overheat and injector rail with it (since the fuel could not recirculate which would have otherwise kept the rail cool enough not to boil the volatiles in the gas). I've removed the air bubble in the head and the cooling is fine now. I'll eventually re-plumb the cooling system so that air cannot so easily become trapped in the high spots. I also need to re-plumb the fuel system, but for the time being it is enough to remove that secondary regulator. Does your Seven's fuel tank have a fuel return port? I'm thinking about making a sturdier stainless steel fuel tank with a dual pickup system to solve fuel starvation from lateral g-forces. The configuration of the fuel tank makes that redesign rather easy and although there's a weight penalty for SS over Al, the sturdier tank will be safer too plus only one fuel pump will be required and a swirl pot is unnecessary.

[tvacc]

The fuel cell I have from Fuel Safe does have a return port. I dont use it...as it is not needed on my car...but it is there. I had them put it in in case I ever put a Zetec in my car. All i would have to do is put a swirl pop and a higher compression pump up front and that would allow me to put in a zetec. the tank would have to have a line back from the front. I dont know if I would have to seal the tank (I currently have it vented) from outside air.

The sturdier tank is not any safer. From what I understand, and I may be wrong as I am not an expert on this...is that what happans is the rapid compression of the gasoline and vapor and the ramming of same across the open spaces of the tank (without foam) is what causes explosion of the tank. Basically all the cell is meant to do it stop that motion and ramming. It is supposed to give you enough time to get out of the car. it may leak...but it is not supposed to explode.

[Valenz]

Originally Posted by tvacc

... The sturdier tank is not any safer. From what I understand, and I may be wrong as I am not an expert on this...

It depends on what hazard you're trying to minimize. From the wear and tear I see on the Al tank that's in my Seven now, it's clear that it has seen some substantial impacts from road debris. SS will be much less likely to fail by puncture than Al. The deflagration/detonation type failures to which you refer are a different hazard that has to be handled differently and you are correct in that a sturdier tank will not always help in those specific situations. However, there are also other solutions to those problems. I'm still working on a better solution than foam cells for that mode of failure. Give me another week.