I was reading the microtech forum and someone had said that if you have under a quarter tank of fuel, you'll lean out. One, how does a surge tank correct this and why is it that this was never an issue with the factory ecu and now is with the Microtech?

 

I'll take a stab at it:

Because if you're running modified, you've probably upgraded your fuel rails/injectors, thus you're pumping more fuel all the time. On top of that, the surge tank is supposed to eliminate "fuel slosh", i.e. cutting out due to lack of fuel. With a .25 tank of gas, you're prone to fuel slosh because there is nothing in the 93 tanks to stop it. I believe the 94's and up had a way to combat this, but I'm not entirely sure. Basically, you get it with most any aftermarket ECU's, because you're more demanding on your fuel system.

 

My tank has a pocket for the pick up. I realize that the fuel is being moved faster and recirculated faster. So the surge tank goes in the fuel tank???

 

I think it would happen with any setup..even the stock ecu. But I guess it gets more serious when you have greater fuel demands with bigger boost which is more likely to damage your engine in the event of fuel starvation.

 

Basically, a swirl pot/surge tank, is taking out any design flaw that may cause a lean condition on turns, and in general, with low fuel. The design makes it damn near impossible to have no fuel available to the pump. A small cylindrical tank with hose at the bottom will not dry up going around a turn. It is being fed constantly by a "primary" pump.

I have this type of setup in my Rx2, whose tank was never designed for a fuel injection set up. the extra $350 for pump and tank is definetly worth the insurance.

If you have an older car, like a first gen, or classic rotary, I would recommend it. I had an FD and never bothered, but I also never let it get below a qtr of a tank.

 

^+1. I need one in my FD though, I'm able to hit fuel cut with half a tank if I accelerate/corner hard enough.

 

I was the one who said that.

The fuel surgeing is only an issue with large amounts of fuel being moved.

I dont know why people are so scared to stick a surgetank and an 044 pump in. Its fairly easy to do and is a cheap gurantee, $220 USD gets you their. not that much considering engine is worth $2000+ at minimum.

 

say your fuel pickup is on the left side of the tank and you drive around a left hand corner... all the gas will want to slosh over to the right side of the tank(far away from the pickup) now your pump is pumping nothing but air

but by adding a small tank between the main tank and the injectors you will limit(possibly eleminate) the chance of running out of fuel.

the surge tank has one inlet line and two outlets (for simplicity purposes) the one inlet is constantly fed by the main fuel pump (filling the surge tank). If the surge tank fills up the overflow outlet will send the fuel overflow back to the main tank... the other outlet is at the bottom of the surge tank and uses another fuel pump to send the fuel up to the injectors

for more extreme setups you can run two pumps in the main tank... one on the left... and the other on the right, so no matter what direction you are turning... there will always be fuel going to the surge tank

 

Their is a problem with your theory.

If the pump on the left has no fuel to pick up itll pump some awesome air bubbles into your fuel line which means your engine will lean out.

In tank setups are all ghetto and a waste of money.

 

Ok, I understand. With aftermarket tanks, they are filled with foam to reduce fuel slop. When I read about the surge tank, it made me think about the other day when I was returning home from an hour away trip. Almost home I was leaning out and the car ran really bad. But I wasn't running hard, and I was on the interstate. I haven't checked yet, but I think my fuel filter is clogged so I brought some home the other day. When I got down on it, it stoiched and ran fine but wouldn't idle for squat. I'll do that before I start to think of having an ecu or tuning issue. Although from reading the thread with the pump setting issues, I think I do need to adjust my pump settings.

 

Might have picked up some ****, blocked the fuel filter and possibly damaged the pump.

Were you giving it a squirt when it was low on fuel? if so have you possibly damaged the engine?

the above reason is why i dont like intank setups.

 

I'm not sure what your calling a squirt, but it wasn't really low on fuel. I don't think any damage was done, but if it has, just something else I have to fix.

 

Squirt could mean bring it boost etc.
Do a compression test. couldnt hurt.

 

Just an update, the fuel filter was clogged and changing has fixed the problem. Apparently, I need to pay a little closer attention to the way it idles. It idles a lot better now than before, although it still pegged at 11.0. It leans out going down the road but I think I'll make an adjustment to the pump setting. It stays around 13.5 to 14.7 going down the road and richens to the 12's under boost.

There is some stuff I have used in the past to recoat motorcycle tanks. It's called a cream kit. Anyone know where I can get a kit large enough for a full size fuel tank? There about $50.00 dollars for the motorcycles and they cover up to a five gallon tank.