Ok... so, I was wondering what you guys though. Is an electric fuel pump better than a mechanical fuel pump.

PERSONALLY, I truely believe for a carbureted motor, an electrical fuel pump is much better than a mechanical fuel pump. I have no FACTUAL information, just observations that I've made myself. Feel free to comment (that's why I'm posting this).

I'm building a custom set-up on an 81 TransAm right now, and people are telling me I should go with a mechanical fuel pump. But the motor that I got originally (original from how I got it) came with an electric fuel pump.

It seems to me that the electric fuel pump gives you better and quicker starts... you can build up fuel pressure well before you even start to crank the car... a couple pumps of the gas pedal before you start the motor gives you enough gas to get the motor started, and the chamber that holds the additional fuel is replenished instantly with the electric fuel pump all before the motor is even cranked.

Are there any benefits to having a mechanical fuel pump?

Remember, I can get an adjustable fuel pressure regulator with a fuel return line already on it.

 

Mechanical pumps are less expensive.

I'd prefer to use a electric pump with a bypass back to the tank. This virtually eliminates any vapor lock and keeps the fuel cooler.

I'd also think you can save an HP or two with an electric pump.

 

electric pumps can creat MUCH higher fuel pressure than mechanicals can. plus as said before all you have to do is turn the key on to get fuel flow going.

The only problem is that most aftermarket electric fuel pumps out there are junk. I'd look into getting an in-tank pump.

 

What EXACTLY is vapor lock? Because I think I WAS (past tense) experiencing this with my Volkswagen Bus.

Basically, long story short, the VW bus was using an electric aftermarket pump when I bought it. It also had the original RUBBER fuel lines... the fuel lines were SOOO Deteriorated that I'm pretty sure there were little holes and leaks. As a matter of fact, when I went to where the line attached to the tank, I tapped the fuel line to make sure it was ok, and it instantly sprung a leak and fuel dumped everywhere. The fuel line literally crumbled. The car had very little power at that point.

But THEN... I purchased steel fuel lines, and using my pipe bending tool I attached a steel fuel line directly to the gas tank (threaded) and ran the line directly to the electric fuel pump (also threaded). I then ran another steel line HALF-WAY to the motor also threaded, and screwd it into a glass fuel filter. From the fuel filter to the carbureter was about a half-foot distance. I I used a thick rubber (but flexible) brand new line.

INSTANTLY... I noticed a MASSIVE.. I mean MASSIVE difference in performance. I also noticed that.. before, the glass (see through) fuel filter was only filling up half way before hand. Now with all steel lines, the fuel filter was completely full with fuel.

Fuel pressurizing times take only half as long as they did before.

So.. was that vapor lock? What exatly was it doing?? Sucking in air rather than just 100% fuel?

 

RJR99SS, I wonder if they sell an in-tank fuel pump for my 81 TransAm?

 

they may sell one, i saw an aftermarket site that sold aftermarket in-tank fuel pumps, i forget what it was though, try doing a search.

Vapor lock is basically the metal fuel line getting too hot and vaporizing the gas in the line. The gas dosnt exactly flow too well then.

A guy i knew used to walk into rush hour traffic in the summer back in the 70s with a couple of line wrenches. He'd charge people $20 to magically cure their vapor lock by cracking their fuel line open and venting the vapor out, then closing the line back up.