Folks,
After much consultation with fellow List members concerning just might be
going on with my GTV, I do have a very good inconclusive report to make. I
checked and double-checked all the hoses and connections that relate to the
fuel tank. They are all clear and seem to be hooked to the correct
connections (John Fox sent me a copy of Alfa's write up of the vapor
recovery system). In the engine compartment I found the oil separator not
to be clogged and all the hoses clear as well. The very small tube from
the vapor recovery tank is to allow the vapors to liquefy and be returned
to the fuel tank rather than sucked back into the cylinders. The vapor
recovery system seems to in good shape in that it is hooked up correctly
with no obvious defects.
My guess-conclusion is that the fuel tank is great at accumulating heat on
a hot day at the track but not great at lowering the pressure quickly. My
ideas to reduce the temps at the track will be:
1. vent the tank to the atmosphere with a 'T' fitting and a valve;
for track use only
2. install a heat shield between the rear exhaust and the tank
3. run with at most 1/2 a tank of gas at the track
Thanks for all the help!!
Bruce
On Sat, Jul 28, 2012 at 6:16 AM, Bruce Giller <[email protected]> wrote:
>
> ....................................
>
> On the next session (tank was about 1/2 full by now - should have started
> with 1/2 tank), I ran the full 20 minutes and didn't smell gas (well, at
> least not nearly as much as previous session). Back at our spot, I checked
> the trunk and I could hear air loudly hissing from the filler cap (tightly
> screwed on) and from the vapor container's air breather. I could hear
> gurgling sounds from inside the tank. And when I started to pull the
> filler cap from the tank neck, fuel & air spurted out of the filler all the
> way up my arm and partially on my face - fortunately I was standing to the
> side and didn't get sprayed full on. I screwed the cap partially back on
> to let the pressure escape. After the tank was depressurized, I discovered
> that the vapor container remained pressurized. There was even more gas in
> the container than previous which I drained back into the tank once the
> pressure was released.
>
> We left before the last session. At the end of the 1.5 hour trip back
> home, I cracked open the filler cap and found no pressurization. Tank had
> about 2-3 gallons left in it. The temps in the DC area where much warmer
> than at Summit Point and the traffic much slower.
>
> So just how is the tank getting so over pressurized?? Outside source??
> My rear muffler is not too close to the tank for there is the standard
> 3"-4" gap between them. The gas tank was warm to the touch when over
> pressurized but not frying pan hot. I did replace the front resonator with
> a straight pipe but that shouldn't heat up the rest of the system that
> much. And how could it heat up almost 11 gallons of fuel so quickly on the
> track to cause the pressurization?
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