I bought my 2003 VIII a few months ago (LOVE It BTW). It was bone stock except for a HKS CBE and a VTA BOV. Has 60k miles on it. The car naturally ran like crap (it had a HKS idle stabilizer but i suspect it was tuned wrong). In a few months a put the stock IX BOV on there and took the HKS unit out. The car runs great now but I am getting about 16mpg from a bone stock evo which i drive very carefully (i am not shifting over 3k, idling as much as i can pulling up to stop light, going 1/2 throttle max) to figure out if the car is running right (granted i live in FL and have the AC on all the time). I get about 230miles per tank driving mildly.

So i was wondering if this BOV could have caused the car to run rich and clogged up the Cat? I am thinking the ECU would run it rich to compensate for the lack of air. Am i on the right track here?
If thats the case I will just replace the unit with a high Flow one.

BTW I had a FULL 60k tune-up done including plugs.

 

Reading over my OP it looks like i didn't word it clearly.

I just wanted to know if a Vent to Atmosphere Blow Off Valve can cause a car to run rich and clog up the Catalytic Converter after a few years.

Can anyone chime in?

Thanks.

 

cat should be fine, VTA BOV will cause some loss in MPG, but check for other boosts leaks, 16?!!

 

yeah ur cat should be fine but will run rich a very lil when ur shifting.