Everyone one has their own opinions, but what is the main purpose of EFI?

 

With EFI you never have to dink around with a carb. Say you live close to sea level, and go riding in the mountains you should run perfect the whole time, same with going from summer to winter.

 

as long as they use an o2 sensor. it may be better up hills to

 

Well, from my view as it relates to cars, which I am sure you can relate to a bike or quad....Control. A carb, for the most part, is fixed. It has a give size jet, a few other parameters, etc but for the most part it acts the same accross the board. With electronic fuel injection the ECM can vary fuel delivery on the fly while taking multiple variables into account. This will yeild, if the ECM is programmed correctly, a better running engine through out its operating range. For example lets look at a simple (very simple) drag race situation. Say all signs point to the motor running lean. To richen up you change carp jets. You do fatten up the motor but in effect you move the fuel curve up accross the board. The same jet is used by the carb regardless of engine variables at play. Any RPM points where you may have been fueling correctly just became overly rich thus killing performance at those points. With an EFI the ECM will take certain things into accout (what things and how many depends on the system) and attempt to correct, on the fly, for even performace at any RPM in most engine situations. Tuning the ECM allows the user tweek many settings based on RPM range as oppsed to accross the board.

In a nut shell the over all idea is better control due to taking account of variables that effect engine efficency.

In the quad world I think the Bombardier guys have it going on (other may as well, I have just been reading some of their forums recently) as their quads are EFI and have been for a while. Apparently there is SW out there they use to tune their motors as they like. They can choose to leave it alone and run the factory program or they can "tune" it to fit their needs.

Brent

 

Is this true? I thought the only EFI on the market was the Polaris Sportsman 700? What Bombardier ATV's are EFI and when did this happen?

 

I think it is, to some level. In reading some of their forums I have seen refrences to getting some software to rework the ECM to fix some factory "errors" in some quads. Not sure how many models that applies to.

Brent

 

tta583's first post is 100% correct. with EFI you get better performance across all rpm, temperature, and barometric pressure ranges. But this isn't what is driving the industry to switch over to expensive EFI from relatively cheap carburetors. There are new clean air standards the EPA is going to apply to off road internal combustion engines in the coming years. EFI is cleaner burning in addition to all the performance perks. One of my farming magazines had an article last year how the tractor industry is scrambling to make cleaner diesels to meet the coming new standards and the article went on to say that it was for all off road engines. So I imagine the chainsaw and lawnmower industries are spending big bucks now to try to be able to meet the new standards too. What will be cool when the EFIs take over, is the computer control aftermarket will spring up (like it has for cars) to offer big performance gains by swapping out a chip.

 

Bomb is not putting EFI on the quads, the Polaris 700 EFI was the first, there is a kit available, I believe, to put EFI on the DS650s so when they mod the bloody **** out of them like they do all they have to do is tinker with the ECM instead of going thru Carb hell