New wideband install very rich under boost

[Mike T]

WB shows 14.2 at idle and progressively gets over rich under boost. I guess this is why you can't trust the NB under boost as it appears to be a little lean.

 

[Mike T]

WB starts at about 11.5 under low boost and it ends up as rich as 9.8 under prolonged boost.

 

[Mike T]

I should have phrased the above post as questions. I will be putting the car on a dyno soon to get a baseline for 93 pump gas only and I do not run alcohol at this time. I think the above afr would be ok if the car were alcohol equipped. My question is should I try to lean it out for the dyno pulls or leave it fat like this for safety? If left rich how much could it affect hp ?

 

[usetaboost]

some cars are different. some want more fuel, some want less. Just depends on the parts, air, humidity, etc

 

[TurboDave]

You should be able to go leaner than that without alky. BUT, sneak up on it. I presently use the TAF (target air fuel) table in SD2 which is around 11.3 at 220kpa map and sneaks up to 11.0 at 260kpa map. I might change those to 11.4 and 11.2 respectively since my car will easily run at 11.4 afr at 21# of boost without alky or knock.

 

[jhanson1750]

Without any help (alky or better than 93) you may be very close. The unburnt fuel is going to act as a cooling agent to keep you out of detonation. 20lbs on pump gas is up there. Like others have stated, you might try taking out some fuel in the higher boost range but watch the knock as a little goes a long way above 20psi.

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[delcowizzid]

do you have a wideband with a gauge or just fed into the ecu.do the two match

 

[Mike T]

Thanks everyone for the input. I'm good with a wrench but tuning is something I need to learn a bit more about. I'm trying to get an appointment for the dyno and would hope everything is reasonably close before going there. As long as no one thinks that the tune is so rich as to cause problems I may leave it alone and after the first pull try adding a pound of boost instead of pulling fuel as long as there is no knock.

 

[Mike T]

do you have a wideband with a gauge or just fed into the ecu.do the two match

Yes the AFX system has a big led display and it does match the PL at idle but I can't really compare the two at speed. I have glanced at the display under boost and the AFX shows 10.0-10.5