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Turbo2nr
10-30-2004, 06:10 PM
I have been debating where is the proper place to put a wide band 02, either for datalogging, or using it for closed loop WOT fuel correction. There are two options, stock location, before the turbo, or weld a bung in the down pipe after the turbo. I have noticed that most factory turbo cars made now days have a WB heated 02 before the turbo, like my WRX. It also uses the WB signal for WOT fuel correction. Also, I have seen some results with a NB sensor that show a richer reading after the turbo on turbobuick.com, with the same sensor, same car, same day, just moved sensor from stock to DP. How can the reading change that much, why? It was a difference of about .100 volts. Does the heat or pressure affect the sensor that much? Which place would have the most accurate reading? To be safe, I'd rather take the leaner reading. Anyone have an opinion or experience with testing?

Thanks, Scott H.

BoostKillsStres
11-12-2004, 03:53 AM
Scott,
I have my WB sensor in the test pipe where it feeds info to my WB WOT chip. Haven't had any problems with it here. The only issue is a bit of delay during non WOT operation, if I blip the throttle at idle there's a 0.3 sec delay before the WB reports the AE enrichment. During cruise mode its less than that, only about one tenth and during WOT there's so much gas velocity basically there's no delay.

From everything I've read its the heat that hurts the sensors if located pre-turbo. Most aftermarket eng mgt systems seem to have good luck with 6-12 inches downstream of the turbo, I didn't want to chip up the coating on my DP to put mine there. I'm also using the older LH1 sensor so I imagine as technology improves they'll be able to take more heat like the factory ones like your wrx. :cheers:
HTH
Mark

ijames
11-25-2004, 07:30 PM
There is lots of good discussion on this at the users forum at www.innovatemotorsports.com - they make the lm1 wbo2 that can use the cheaper bosch lsu4 or the ntk sensor. I put mine in the downpipe about even with the #4 sparkplug so it's about a foot downstream from the turbo. The wbo2 sensors can't take pre-turbo temperatures, and the pressure does cause a small error as well. PS Mike Licht at full throttle speed has the lm1's on sale right now for $309, a great price. I love mine.

Turbo2nr
11-29-2004, 08:31 AM
Thanks Carl, I love my new framed pic!

Scott H.

Turbo2nr
11-30-2004, 07:34 AM
Whoops, that was Charles who made me the Pic, Weren't you also at the track rental day a few weeks ago? Do you know how to get in touch with the Vet., Allen?