HI ducatiman!!!
Quote:
Originally Posted by arthury
What will it do to your Cats when you delete the Evap Canister?
|
Nothing, if anything it would make your cats last longer. Here's how the EVAP works:
1. when sitting, petrol in gas-tank evaporates naturally. Actual amount will vary depending upon ambient temp and humidity. Normally, this evaporated petrol just vents to atmosphere, typically through gas-cap and drain hose. On warm days when you walk into garage, faint smell of petrol is this vapour evaporated from tank.
2. EVAP system provides vent-path for evaporated petrol and collects and condenses it into canister. This is additional hose-nipple coming out of tank. It's actually connected to inside of tank rather than outside under gas-cap like drain hose.
3. EVAP canister is connected to air-box through vacuum-operated purge valve. This valve is normally closed, at idle and low-load operations with low vacuum.
4. Under high-load/high-rpm when there's higher vacuum in intake. This vacuum activates purge-valve and opens pathway from EVAP canister to airbox (which also has vacuum). More modern systems use electronics and ECU to activate purge-valve.
5. Vacuum in air-box suck out collected petrol from EVAP canister.
It's nifty system that recycles petrol that would normally be lost through evaporation and less of it ends up as smog in our atmosphere causing all sorts of issues. Rates of asthma in kids has skyrocketed in past couple decades, wonder if it's related?
Anyway, removing EVAP canister will result in lower AFR (leaner mixtures under high-load). Leaner mixtures means LESS unburnt fuel hitting your catalytic, and it would run at lower-tempertures and last longer.
Another related system is PAIR which pumps extra air into your exhaust to help cat burn up excess petrol.
Removing both would result in no changes to your bike's operation, just more polution in air. Although factory jetting for high-load is super-rich, more than 10:1 AFR. So leaning out mixtures would actually give you more power (max-HP occurs at 13.5:1 on NA engines). I'm not sure of actual amounts contributed by EVAP canister, but I don't think it's enough to actually be measureable in engine-output.