Supercharged Trac in Memphis on Thursday afternoon

[scott r]

Yeah, they do tuning, but they have never tuned a sport trac before. They work with mustangs and lightnings only.

 

[scott r]

Thanks for all your help Todd, and everyone else. I really appreciate it.

Doug swears it's the fuel pump. The problem is that the pump put in there with the xcharger is pulse width modulation whereas the entire fuel system of the sport trac is set up to run on a constant voltage. I don't know WHY Dave decided to put this into the xcharger kit, but if there is anyone out there thinking of buying it, DON'T until you get some kind of confirmation from Dave that the fuel pump will work as advertised or has been changed to a constant voltage model. Looks like I get to go drop another $150 today on more parts that SHOULD have come with the FOUR THOUSAND DOLLARS I originally spent. I haven't asked Dave to pay for it yet, since I don't have an actual price, but I don't think I'm going to hold my breath.

So, after I get done talking to the local Ford dealership about that GT I looked at yesterday, I'll go get the fuel pump (unless I drive off with a new mustang today haha). A new mustang and a factory warranty sounds mighty good right about now.

 

[tony brizag]

oh come on man, u run into a little problem and ur gonna give up. heck if i only had the time to tell you about all the problems i have encountered building my cars and trucks. Just keep at it. Most electric fuel pumps work in a pulse, instead of looking into the mustang pumps that are in tank, look at like the holley , barry grant inline electric fuel pumps. not just holley makes inline electric pumps, check summitt racing or jegs for different pumps man. Or look into what pound injectors you can find.



Shoot u can get 110, 140 ,160, 250, gph inline pumps. But there again i dont know a what psi range they are capable of and i dont know what psi the tracs fuel pressure needs to be. im just sayin man some people throw money at a problem instead of changing methods to try to solve it. If something is not working, step back and think about changing the method of fuel delivery. Id look into the inline pumps my self.

 

[tony brizag]

man an aeromotive fuel pump #A1000 is 600lb/hour at 45 psi using a 13.5 volt system. and its $295.99. Now that is way more than fuel delivery than u need but do you see that options are out there.

 

[scott r]

I guess the main problem is that I don't know exactly which fuel pump to get. Doug said the 5.0L mustang fuel pump would work, but I think getting that, then going through all the trouble of putting it in, and have it not work would probably set off my temper. hehe

If you figure 300L per hour, that's SEVENTY-NINE GALLONS PER HOUR. I could easily run 20, 30 or maybe even 40 pounds of boost on that kind of flow. That's what the trac has in it right now, a 300L per hour pump. I can't even FIND a mustang pump that's over 255L/hr.

It's not that I want to give up, it's just becoming more trouble than it is worth at this point. To say that the truck runs GREAT now is an understatement. Every time it gets "re-tuned" it runs like crap and I go back to the stock xcharger tune. What I really NEED is someone who knows what the heck they're doing. I've contacted Wayne, hopefully he can help me get it squared away. He seems pretty knowledgeable and he gets very high reviews here from everyone on the forums, but he hasn't tuned a supercharged trac either. Who in the world tuned the other 85 tracs?? Doug hadn't tuned one either, yet he's the one that Dave from EE is using as the tuner. Maybe a little bit more research before I bought this would have been a good idea. I thought I asked Dave every question imaginable before I ordered it, and he happily answered every one of 'em. I guess tuning was the last thing I was worried about when I bought the supercharger...when it should have been the thing I was MOST worried about.

I asked about a boost-a-pump, but doug said that wouldn't work. I just want to make sure it IS the fuel pump before I go and drop another $150 for a new one. Based on what it's doing, it just sounds more like a tuner/tuning problem than a mechanical failure to me.

I'm not going to give up on it Tony. I'll work through this, replacing everything that needs to be replaced. It's just a pain in the butt. Thanks for the pep talk though.

 

[Todd Z]

ALL VEHICLES TODAY are equipped with one of two different types of fuel pump: a positive displacement pump or a flow-type pump. A positive displacement pump traps fuel in a chamber and then pressurizes the fuel by decreasing the size of the chamber before forcing it through an outlet passage.



Chamber size can be changed by stroking a piston or diaphragm, but it can also be done by rotating vanes in an offset housing, as in a power steering pump or a gerotor oil pump. In both of these, the pumping chamber is the space between the vanes or gear teeth, and offsetting their rotation in the housing will make the chamber shrink or grow through each degree of rotation.



The most common positive-displacement fuel pump is called a roller cell pump. It uses rollers as vanes, and the spaces between them are called cells. The rollers are slotted into a disc, and this assembly rotates in a polished steel ring. As the disc rotates, centrifugal force seals the rollers against the ring. Since the disc is offset in the ring, the cells between the rollers change size. The cells are biggest near the inlet port in the chamber's end plate, and after a roller passes the port, fuel is sealed in the cell between two rollers. As the cell rotates around to where the space between the disc and ring wall decreases, fuel is pressurized and eventually forced out when the leading roller passes the outlet port.



The roller cell assembly is secured directly to the shaft of an electric motor, and fuel actually flows through the pump/motor housing. The fuel flow helps keep the assembly cool, and there is no danger of fire or explosion because there is no air in the housing. An internal relief valve controls housing pressure, and a check valve on the outlet fitting keeps pressure in the fines when the pump is turned off.



A roller cell pump can generate very high pressure, and its flow rate tends to be constant over a range of pump speeds. However, it generates pressure in pulses, so systems with a roller cell pump usually have a pulse damper. Both are usually mounted outside the fuel tank to control noise, and instead of gravity feed, there is usually a low pressure in-tank pump to supply fuel to the roller cell pump.



The most common flow-type pump is called a turbine pump. Basically just a finned wheel in a specially shaped housing, a turbine pump is capable of very high flow for its size. They've been used for years as an in-tank feed pump, but more recent designs can generate the pressure needed for gasoline fuel injection. There are several different pump designs with different shapes for the housing and impeller fins and even different numbers of impellers, but all share some of the same advantages.



Fuel flow is controlled by adjusting pump speed, and because it's not positive displacement, the pump can be dead-headed longer without damage. They do not generate pressure pulses, so they tend to be quieter and don't require a pulse damper. Also, they generate flow continuously instead of in pulses, so they can be used to operate a jet pump.



Jet pumps also are flow-type pumps, but the only moving part is the fuel itself. Technically known as a flow eductor, it consists of a simple nozzle that squirts fuel through a specially shaped tube, creating a low-pressure area in the throat of the tube. With the tube's inlet end submerged in the tank, fuel is drawn past the nozzle and into the tube where it can be piped to another nearby location in the tank.



Although a jet pump's output pressure is low, it can flow twice the amount of fuel used to power it. Typically, a jet pump is submerged vertically in the tank to draw from the lowest point and used to fill a reservoir that supplies the main pump. It's also used to move fuel from one side of a split-tank fuel system, such as the 2003-and-later Chevrolet Corvette, which has an electric fuel pump only in the left tank.



Today's vehicles have<

 

[scott r]

That's possibly more than any human being should ever have to know about fuel pumps.

Thanks Todd.