I upgraded from a megan o2 housing, stock ic, stock inlet pipe, stock bov, evo 8 turbo w/ 10.5 hotside.

to an
invidia 02 housing, ets ic and piping, vta tial bov, FP inlet and evo 9 turbo with FP inlet housing.

My afrs at cruise stay around 10-11. WOT afrs are spot on. No leaks. No CELs.

 

Are you still on a MAF?

 

If you're still on MAF then your bov is opening under cruising conditions, bleeding off air that has been accounted for by the maf, causing it to run rich. At WOT the pressure causes the bov to shut and run fine!

 

Get a heavier spring for your tial. Great write-up by the TiAL rep http://highboostforum.com/forum/show...OV-information

 

Hey it would be nice for you to tell us what the issue was.

 

Yes, I'm still on MAF and do have a heavier spring. I have a new Tial Q valve. I'm reading about -11.8 psi at idle. I had a -10 psi spring in there, but went with a heavier one that I don't know what the rating is. Tial does not make one for vacuums lower than -11.

Also, AFRs at idle when the car is cold are on target. Once the car is up to temp the afrs are off at idle. I don't have any stumbling, rough idling or stalling while driving. The car is very smooth.

 

what color is the spring? and is it -11.8 psi or 11.8 in/hg? and you say the car drives smooth?

 

Front o2?

 

yeah, my tuner seems to think it's the front o2 sensor. Is there a way to check if its bad besides the obvious?

It's -11.8 psi vacuum, not inches of mercury. Yes, the car runs smooth. No surging, flutter etc. Power comes on nicely. Around 3500 RPMs I'm spiking to 23 lbs. If it wasn't for my wideband and the poor gas mileage I would say there was nothing wrong with the car.

I think the spring color is red, but that doesn't matter because it's not one made by tial. It's stiffer than the -10 psi one I had in there originally from tial. That one caused driveability issues. AFRs were off then as well.

 

Whats the 02 feedback doing in Evoscan when cruising at these AFR's?

 

o2 feedback trim is staying pegged at 25%. Yeah, my afrs are off when the trim is pegged at 25%. Does that mean the system is trying to add more air to lean out the AFRs?

 

Im going to 2nd this. Did a drive from CO to WI like the conditions you are describing, cost a ton in fuel.

 

My car is doin this too, and i havent changed any parts? What else could it be? Thanks

 

Its either a bad front 02 sensor or the Tial Q with the stock maf. Is your service engine soon light on? I had the same cruising a/f ratio when I tried out the Tial Q with stock maf. Since then I switched back to a Synapse DV recirculated, cruising a/f is perfect. FYI, Synapse sells an adapter flange so you can use their DV with a Tial UICP flange, v-band clamp, o-ring, etc.

 

No CEL. I want to stay with non-recirc. bov.