Suppose I put in a double throw relay that disconnected both secondary injectors when activated, would this help to conserve fuel ?

Looking at ways of conserving fuel right now.. it eats through it. It's running rich too.

Colleague at work wrote this short poem:

My rotors spin,
The fuel rushes in quickly,
Some may even burn.

It's quite true, a lot of fuel is just coming out the back heh, unburnt.. I know this is a problem in the computer but I cant afford to dyno or replace injectors right now..

Thoughts?

PS. Posting here because my engine is a 6-port from an FC with EFI.

 

Why not just disconnect them and drive it for a week, then check the gas mileage vs. the mileage with them connected? That'll give you your answer before doing any cutting of wires.

 

Theoretically the secondary injectors won't be coming online until 3800 RPM or so. If you're keeping it below that, it shouldn't make a difference. Above that, the fuel computer drops off the duty cycle on the primaries as the secondaries come online. The general description of secondary injectors not working is "Brick wall at 4000 RPM" - you won't be able to rev past it. This might help fuel economy, but it's nothing a lighter foot can't do.

Out of curiosity, how are you generally driving, and what kind of numbers are you getting?

-=Russ=-

 

well the fact that you have 1000cc injectors instead of the 460cc that the 13B normally runs on wouldn't have any effect on economy now would it???

 

Some tuning time with a wideband will tell if the Microtech will reign in those monster primaries.

 

Yup

 

As I said, cant really afford to change them now ... previous owner was a little silly :P

Numbers. About 11 miles/gallon or 100km per 25L.

I've been trying to drive with my foot up as high as possible without losing momentum. Not accelerating that fast. I can feel where the secondary butterflies start to open and have been trying not to let that happen as much...

Based on the position of my fuel gauge it doesnt appear to have helped much.

 

used stock injectors are cheap. The money you are wasting in gas will pay for them in a week or less probably if you daily drive the car.

If your primaries are 1000cc I'm scared to ask what size your secondaries are on. Cant you just tune down the injectors to a safe stock levels with your ecu? I'm surprised it is even driveable at all. They have to be tuned a little bit at least. I highly doubt you could even turn over the engine with 1000cc primaries. Some people even have trouble tuning down 720cc primaries.

 

or you could unwire your 5th and 6th ports?

 

You're looking at the wrong place for blame.

The Microtech isn't tuned for fuel economy - that's the problem.
Get the Microtech leaned out, and this should "solve" your problem.
It really has nothing to do with the fuel injector size; I can run 1600's on a Haltech and still get 15L / 100km easily.

The person who tuned the Microtech should be bitchslapped for your fuel economy "problems".


-Ted

 

The local rotary specialist tells me my ~10 yr old ecu is a bit crude to operate 1000cc injectors. It would surely be feasable with a new unit... I dont really wanna upgrade the computer because of the financial aspect.

She is hardly running at the moment, extremely rough, very jumpy and often it skips a beat. After just starting the fuel is coming out the exhaust onto the ground heh. The sweet smell of unburnt money, yet wasted.

Currently got a restrictive exhaust on so I can pass volume check, but my plans are as follows:
- Complete new exhaust about 2.5" (current is 3") apparently this is good way to bring down volume
- Plug in some standard injectors
- Dyno for a nice balance between economy and performance!

I wouldn't dyno on the restrictive exhaust though so that is holding me back.

What am I doing wrong?

Cheers,

 

Either get rid of the piece-of-**** Microtech or upgrade it.
I dunno what else to tell you.
You're giving us a scenario where you have very limited options.
I mean, you can convert back to a stock ECU and get better fuel economy that what you got now with an A'PEXi S-AFC!
Maybe you can dump that current Microtech to someone else and use the money to upgrade?


-Ted

 

You're literally dripping fuel out the exhaust onto the ground, and you WONDER why your fuel economy blows?

Wow. I, too, am in the category of "Amazed it even runs at all." Did they tune it for stock injectors or something, and then swap in the bigger ones?

Seriously, look into finding a set of stock injectors & ECU. It can't be worse than what you've got now.

-=Russ=-

 

I'm willing to bet the previous owner dumped in the injectors and never tuned it. Will get some injectors soon then =)

Cheers