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Roughly 5 psi of pump pressure will only increase boiling point by about what??? Maybe 20 degrees F???? Maybe 50 degrees F at the max??? I don;t really know for modern gasoline. But there is one hell of a lot more heat under the hood than anywhere on the car below the exhaust manifolds. One hell of alot more heat that just 50F above ambient.

Craig writes:
" In other words, the "slope" at the liquid-vapor transition line greatly favors pressure change."

Ok. Good point. But at this point do we have enuf temperature and pressure/negative pressure data (even just good guesses) to apply the "slope" for a final answer???? I don;t know.

PackardV8 Quote:

Here's a diagram that illustrates my point, although it is not exactly what I was looking for:



Note that the "Base fuel" line is almost horizontal on the Temp vs RVP graph. This means that a LOT of temperature must be added to make the same change as a LITTLE RPV. RPV is Reid Vapor Pressure which is the common measure of gasoline volatility, which is what we are talking about here.

EPA and Petroleum engineers have plenty of data, so this is not in doubt.

Craig

PackardV8 wrote:

THE FI pumps produce much higher pressure than pumps needed for carbs. THAT MEANS that the FI pump is LARGER in overall dimensional size and requires COOLING due to it;s very heavy duty task of providing about 10 times more pressure than a pump for a carb. The FI pump is in most cases controlled by somekind of an ecm.

Therfore, the FI pump is mounted INSIDE of the gas tank to COOL THE PUMP (NOT THE FUEL) AND because there is plenty of room in the tank to allow for the FI pump due to it;s relatively enormous size.


REPLY:

The information above is completely and totally incorrect. I might ask that you check your info before posting as it hinders the resolution of a problem.

FI fuel pumps mounted in the tank are small, some the size of a D cell battery. The entire assembly including filter and tank sending unit are large but weigh very little, much plastic.

They use very little electricity and are very efficient, thus produce little heat. It does not need cooling, what you say is so misleading.

We have sold the in-tank pumps for 57 Eldorado, the first production car to use one, fairly small. "MOdern" in tank pumps for Vega (very small),70's Riviera (bigger) and modern FI pumps as described above. I've had each type in my hands. That's how I gained my knowledge to post it here to help other Packard owners.

ok. I got a little carried away on indicating an enormous size of the actual pump itself. But not the cooling issue.

The in tank pumps supply much greater pressure than a pump for carburetor. Which means more heat. Regardless, i've seen too many of the IN tank pumps go bad due to some owners constantly running only a 1/4 tank of gas at a time. The gasoline surrounding the pump helps to keep them cool.

Botom line: production application of pumps inside of tanks are not placed INSIDE of the tank for the purpose of eleminating vapor lock.

Why did Cadillac put the 57 pump INSIDE of the tank??????

Craig,

Just got a chance to review all of your enlightening posts in this topic. Thanks for having the patience and taking the time to instruct/enlighten us all. It's 40+ years since I had those courses and some of it has now returned.

I learned din college that the difference between a good student and a poor student is that the good student waited until AFTER the exam to forget the material.

Had a '40 Henney 120 Limousine Hearse in college, mint maroon velvet interior, Henney Level-Draulic, 19,000 miles, what a beauty, about a 95 point car. Had symptoms just like
those we are discussing. Problem?? Drive for 10 miles, starved for fuel and then stopped. Let it sit for 10 minutes,( too young for Coronas) and it would start right up and go for a while.

Removed the fuel bowl on the bottom of the fuel pump, a tablespoon of ultra-fine rust/silt in it and the brass screen was 3/4 clogged. Driving would clog it 100%, sitting 10 minutes would let some of it fall to the bottom.

I don't think those magic clothes pins were invented yet, anyway after spending $100 for the hearse I was broke.

Fred, another good Packard story!

As Gilda Radner's "Emily Litella" character said:

<i>"It's always something--if it ain't one thing, it's another."</i>

Quote:

Fred, In post #16 I wrote a rather lengthy post correcting PackardV8 about intank fuel pump size and received no comment but yours did. Maybe my Canuck accent is confusing eh?

To PackardV8:

Thanks ofr saying you got carried away on saying in-tank pumps are enormous. By giving blatanly uninformed or erroneous information yoi make the rest of yoiur posts suspect.

Lets say I make a post and say that Packard made several thousand secret cars with gas turbine engines in the 30's and they had 5000 horsepower. ETC ETC. Eventually nobody would believe anything I said.

Sop now you say yoiu were way off base on size of the in-tank pumps, but you're spot on with the cooling issue. Let me think a bit, you say you've seen many go bad due to running with a 1/4 tank. So you say you've SEEN them?? I ask, if yoiu've SEEN them how come you didn't know how small they are??

A tiny pump which uses little electricity, has tiny wires because little current is used heats up 4 gallons of gasoline to the point the pump fails?? Tell me, just how hot do the gas tanks get?? NOw it's tikem for you to fess up and say yoiu exaggerated on this also unless you can tell me why I've never encountered and overheated gas tank on a modern FI car and neither have my local mechanics.

Cadillac put the FP inside the tank of the 704 Eldorado Broughams in 57-58 because at $13,000 it was an engineerign and styling test bed with electric memory seat, stainless roof, air suspension etc etc. They were trying out new ideas, it was not a Communist plot.

NOthing in your post is correct as far as I'm concerned.

Fred Kanter Quote:

Hey Fred, I don't see any engine overhaul kits in your catalog or online at your website for these "turbine engines".

Ain't being misquoted fun? ROTFLMAO.

Craig