i have a polaris sportsman 800 and i was wondering if i had to do anything special to install the k & N Airfilter? as in re jet or anyting to the motor.......

 

I'm pretty sure the new Polaris 800 is EFI, which means you wont have to re-jet it at all, seeing as how there are no jets. Other than that, the K&N filters bolt in just as a regular filter would.

 

hhhmm i don't know what i was thinking thats right no jets i have a predator and i ment to put that one on here instead.duh

 

I just asked my dealer about a k&n for carb and he said said there good for carbed machines but doesn t recommend them on the efi's because their so finely tuned. just my 2 cents

 

HUMMM...that doesn't make much sense.....On EFI...they adjust for more or less air flow automatically.....And usually from a factory in stock form....they have they detuned the machines..for the normal people so adding a K&N filter to a EFI allows more air which would increase your power..how much depends on how much the stock filter was restricking air. I now buy K&N filters for all my cars..You wouldn't think they would make much difference but they do..>More power and better gas milage!! ON EFI machines they are worth the money..On carb machines you don't gain as much unless you re-jet.

I wish my kodiak had a EFI...I now see why I don't like carbs..I added a UNI filter...Now I'm a hair to lean....with the stock filter I was too rich... Without rejeting (which I won't do) I'm SOL. So I'm running it on the lean side for more power but I also run the risk on motor damage...Its not super lean so I think I'm ok.

 

You talking about a pretty sophisicated EFI system to allow for modifications of the intake/exhaust.

I am no expert on ATV EFI systems but I'm pretty sure they operate on a pre-set curve, that is they accomadate for atmophere changes sure, but they do not accomodate for intake changes, exhaust changes etc.


In order to do that you would need to "chip" it like they do in cars/trucks, this would change the curve and you could fine tune it for modifications. You might even need to hook it to a laptop with an exhaust gas monitor sensor and remap the entire power curve while on a dyno.

I don't think ATV EFI systems allow for all of that stuff, I think they are just factory set on a particular power curve and only make minor changes for elevation.


A carbed system will allow you to modify your quad to limitless porportions, but I would be careful doing ANYTHING to an EFI system. Specially ones so simple and basic as an ATV's system.

Here is a site that explains it better than I would


This explains ATV EFI systems and why you can't make mods without modding the EFI too

 

ATV EFI systems do not remap themselves for intake/exhaust changes. it is a preset curve, for a certain amount of air and a certain amount of gas. it will not correct itself after you change over to a K&N filter. like Dirtydude said.

 

Humm very interesting.... So is a car different? Like my 99 Honda accord. I added a K&N and definatly feel more power and am getting more MPG. You say it adjusts for atmospheric conditions..well isn't that just allowing more or less air into the carb..same thing a different air filter would do?