O2 sensor removal - closed-loop vs. open... (boost related)

That spinning thing that makes all of the cool noises. OE and Aftermarket.

Moderators: Helpinators, Moderators

Post Reply
NuwanD
Second Gear
Posts: 478
Joined: Wed Mar 26, 2003 4:23 am
Location: Troy, Ohio / Toronto, Ontario
Contact:

O2 sensor removal - closed-loop vs. open... (boost related)

Post by NuwanD »

Really wasn't sure where to put this post, but it is related to boost and MBC's so why not here? :o

I'll be soon running a Manual boost controller on my car. Apparently the stock boost solenoid only allows full boost when the throttle is at least at 55% open. When an MBC is installed full boost can now be reached on partial throttle (below 55%). However, the ECU runs in closed-loop mode and apparently results in a slightly lean mixture. There are ECU upgrades/tunes/piggy-backs for the WRX that alter the signal from the TPS to the ECU so the engine enters open-loop mode earlier and safely runs richer. But i don't know of any such "chips" for my car, and the cost of such an upgrade is excessive for my means. From what i've gathered the car will run only in open-loop mode if the O2 sensor is disconnected. Aside from mileage concerns would disconnecting the O2 sensor work in this situation? Any seriously bad issues with doing this? Or is the slightly lean mixture in closed-loop mode not lean enough to do any damage?

thanks in advance :D
Nuwan
1992 Open Class Legacy Turbo
2004 Forester XT
2000 Impreza 2.5RSC (Supercharged)
1990 Rover Mini 1000
NuwanD
Second Gear
Posts: 478
Joined: Wed Mar 26, 2003 4:23 am
Location: Troy, Ohio / Toronto, Ontario
Contact:

Post by NuwanD »

I got an answer from the toronto-subaru-club site; i guess i could share it here. The car would only run well at WOT, and would be running very rich. Gas mileage will be absolutly horrible. The car will have problems running at anything other than WOT, should be rough, and the rich mixture will quickly clog my cats.... i should get those darn things removed anyways. Looks like i'm gonna have to start monitoring EGT and A/F to see how lean the car gets. Apparently it shouldn't be too bad.
Nuwan
1992 Open Class Legacy Turbo
2004 Forester XT
2000 Impreza 2.5RSC (Supercharged)
1990 Rover Mini 1000
RaZor
In Neutral
Posts: 40
Joined: Wed Oct 16, 2002 1:13 am
Location: Charny, Qc

Post by RaZor »

Check out on the board, there are couples of topics about that. Only thing I can tell you is that I did run the car without the O2 plugged for a tank of gas. I run a MCB as well. The car feels much more smoother at part trottle full bost. But it runs like shit at WOT. Pretty not what they tought on the Toronto Board hey!! But the check engine is always on.

Cool thing, I did a lot more distance with the tank of gas then with the O2 plugged!!!
Post Reply