I'm hoping to get input on solutions to a vapor lock issue. The car is a home built Ferrari 250 GTO recreation with a supercharged EFI LS motor along with a C5 style torque tube and transaxle. So front engine setup with under car exhaust and a 22 gallon fuel cell in the rear of the car. The fuel pump is external to fuel cell, is positioned rearward of the fuel cell and vertically just above the bottom of fuel cell. The fuel lines run on the outside of the chassis (so not near the exhaust) with the feed and return lines entering the engine compartment about 8 inches from the engine with a direct route to the regulator/fuel rails (so above a header but not close to it).
I've had the car on the road for about 3 weeks now and have experienced what I believe is a vapor lock about a half dozen times over that period. At first I thought it was a faulty fuel pump, but after replacement the issue still persists. The fuel lines are all stainless tube plus the hoses you can see above. The fuel lines all flow freely and I've changed the fuel filter even though it still looked new. The cell vent line is not blocked and flows freely. I opened up the fuel cell that's equipped with a "fuel collection box" and foam filled and everything including internal hoses and fuel sock looks brand new with no apparent issues.
A few days ago after fuel pump replacement, I took the car out for a test drive starting with a full tank of fuel. After about 40 miles of driving (a mix of in town and mountain twisty) and on an uphill stretch, the engine hitched a couple of times, quit and wouldn't restart. After sitting by side of road for about 20 minutes, the engine restarted and made it about 5 miles up the hill before stalling again. It stalled again one more time before reaching home.
My hypothesis is that it took 40 miles of driving to heat the fuel in the tank to a point where it reached a temperature subject to vapor lock. I believe the vapor lock is occurring in the 2 foot long suction line between the fuel cell and pre-filter/fuel pump but this is only a guess. I say this because the fuel pump sound changes with a surging sound just prior to the engine stalling. The ambient temperature was mid 80's at the time and elevation about 5,000 feet.
Subsequent to this, I insulated the fuel cell with DEI tunnel/floor insulation (3/16" thick with outside foil cover) and wrapped exhaust pipes in near vicinity of fuel cell with exhaust/header wrap. The 2.5 inch stainless steel pipes do run right under the fuel cell.
After this, I participated in a driving event this past weekend and the engine stalled again on a steep uphill stretch with the same symptoms. It's running fine one minute and then just stalls. After waiting about 20 minutes, it restarted, I headed downhill to the nearest gas station, added 9 gallons of cool fuel, and the car made it home without further issue.
My plan is to wrap the entire exhaust system that goes through the chassis backbone with exhaust wrap. I already insulated the mufflers about a week ago but that was to try to reduce heat transfer into cockpit. I'm fueling the car with premium pump gas. If the additional exhaust wrap is not enough, what then????
I've had the car on the road for about 3 weeks now and have experienced what I believe is a vapor lock about a half dozen times over that period. At first I thought it was a faulty fuel pump, but after replacement the issue still persists. The fuel lines are all stainless tube plus the hoses you can see above. The fuel lines all flow freely and I've changed the fuel filter even though it still looked new. The cell vent line is not blocked and flows freely. I opened up the fuel cell that's equipped with a "fuel collection box" and foam filled and everything including internal hoses and fuel sock looks brand new with no apparent issues.
A few days ago after fuel pump replacement, I took the car out for a test drive starting with a full tank of fuel. After about 40 miles of driving (a mix of in town and mountain twisty) and on an uphill stretch, the engine hitched a couple of times, quit and wouldn't restart. After sitting by side of road for about 20 minutes, the engine restarted and made it about 5 miles up the hill before stalling again. It stalled again one more time before reaching home.
My hypothesis is that it took 40 miles of driving to heat the fuel in the tank to a point where it reached a temperature subject to vapor lock. I believe the vapor lock is occurring in the 2 foot long suction line between the fuel cell and pre-filter/fuel pump but this is only a guess. I say this because the fuel pump sound changes with a surging sound just prior to the engine stalling. The ambient temperature was mid 80's at the time and elevation about 5,000 feet.
Subsequent to this, I insulated the fuel cell with DEI tunnel/floor insulation (3/16" thick with outside foil cover) and wrapped exhaust pipes in near vicinity of fuel cell with exhaust/header wrap. The 2.5 inch stainless steel pipes do run right under the fuel cell.
After this, I participated in a driving event this past weekend and the engine stalled again on a steep uphill stretch with the same symptoms. It's running fine one minute and then just stalls. After waiting about 20 minutes, it restarted, I headed downhill to the nearest gas station, added 9 gallons of cool fuel, and the car made it home without further issue.
My plan is to wrap the entire exhaust system that goes through the chassis backbone with exhaust wrap. I already insulated the mufflers about a week ago but that was to try to reduce heat transfer into cockpit. I'm fueling the car with premium pump gas. If the additional exhaust wrap is not enough, what then????