Gas

[wlewis]

What gas would be best for my Cobra's 351W crate motor and 65 Mustang 289 HiPo? E10 93 octane or 89 octane Ethanol free (marine gas)?

[Aggressor]

Aggressor is running fine for almost 10 years with 92-93 octane 10% Ethanol pump gas. Her 403 CI FE engine just turned over 21,250 miles. The last 9000+ miles have been with the Paxton blowers providing boost. The only problem to mention is the holley gaskets had to be changed in the 600's to more ethanol-friendly type.
It's an easy call - set your crate engine up to run on readily available fuel. I've driven many times to car shows hundreds of miles away and it's kinda nice not worrying about expensive specialty fuels at limited facilities.
I use the same fuel in my wife's 68 Mustang - 289 4-barrel engine.

-Geary

[Wareagle]

With regard to gasoline with 10% Ethanol, do you guys seem to have more problems with what appears to be vapor lock. I'm running an edelbrock with holly electric fuel pmp. and alot of idling or low speed in hot weather makes for issues. Of course the best answer is to keep the gas peddle depressed and the gears a changin but sometimes there are redlinghts.

rick

[Aggressor]

I had severe vapor lock problems with the first Unique I built in 1991. The smallblock would lockup as if on queue at the most inconvienient times. I was running solid fuel lines from the mechanical pump to the carbs. The solution then was to cut several inches out of the line near the carbs and replace it with rubber tubing. I switched over to Russel steel braided lines in 1992 with no problems since.

- Geary

[Slither]

What caused the performance change Geary? Was it a heat transfer issue?

[Aggressor]

Paul - I really don't have a hard lock on the reason why. The rubber tubing bit may have allowed expansion. Perhaps enough to release heat - If you compress air it takes on heat - expansion releases it -as in an air conditioner???? My engine bay has a lot of russell lines - many in direct contact with the FE. She's running hotter with the superchargers but handling it well.

If you look at the carb feed lines they both drop in front of the engine to hookup at a "T" fitting lying against the front of the engine, north of the waterpump, and under the distributor. From there they cross to the drivers side against a very hot engine. The heat at the idle set screws is so hot that the screwdriver in you hand will quickly become very uncomfortably hot limiting your tuning sessions.

I all I know is that its worked so far.

-Geary

[spd4me]

My gas line goes from mechanical pump on front side of motor up across water pump to carb. Last time I took the intake off, I slid a section of thermo sleeve over it. Also covered my brake and clutch lines in the engine area. Something on the gas I learned last week. My BP station has changed to Sunoco. The owner told me it's made in America and contains no ethonal. He also said when he had the BP supreme tested, it tested at 100% octane. The octane numbers on pump are the minimum. I remember seeing in an old Hot Rod magazine a stock mustang drag racer had a metal box that the gas line coiled up inside and he filled it with crushed ice to keep gas from vapor locking while sitting in staging lanes.
Bob

[Aggressor]

Bob - Another reason for the ice was the idea of a colder -denser charge of gasoline molecules. The same line of thinking that is current with cold air boxes under the hood to house your air filter. More cold air molecules packed together in existing space.

- Geary

[RJacobsen]

I was having a hard time starting the car when hot and figured that it was a vapor lock problem, I had originally fabricated a Fuel Log for my 2-4 set up that was attached to the engine useing the intake bolts, I figured that I was getting the fuel too hot from heat transfer from the engine so I changed to a solid line from the fuel pump to the carbs without any other engine contact. That has fixed the problem but now I have 3 (yes I built 3 of them before I had one I liked) unused fuel logs in my aluminum scrap bucket.