Another turbo ?
 

Ok, we got the air/fuel ratio installed and I'm getting a reading of 11.2 or so on the O2. I'm assuming this means the car is too lean? I have heard we were looking for mid 12's on this reading. Two part question, am I correct that it is too lean and do I just adjust fuel pressure for this or fuel and timing? This is a 4 cylinder turbo ford combo stocker.

Re: Another turbo ?
 

To rich... 11.2 parts of air to 1 part fuel. I have found 12.8 or so seems to make the best power (12.8 or 13.0 parts air to one part fuel). I hope this helps.

Oh, and to some extent it is better to be a little rich than lean...but you knew that.

Bill

Re: Another turbo ?
 

You didn't say when you're seeing this AFR. Under load, Idleing? 12's under full load on a turbo setup sounds a bit on the lean side, however I'm surew that there are a few turbo racers on this forum that can help. Joe

Re: Another turbo ?
 

I have only tuned street cars with turbos, but those won't live long leaner than 12.0-1.
Mid elevens works well, and leaner shows very little power increase with a turbo.
12.8-1 & 13-1 are normally aspirated numbers.

Re: Another turbo ?
 

11.2 A/F in a turbo race motor under load is ok. Better too rich that too lean, especially a turbo engine! You would be surprised how quickly those pistons go from being a solid to a liquid! Jim

Re: Another turbo ?
 

Marc, shot you a message on FB. Get back at me!

Re: Another turbo ?
 

Just backing up what others have said. Mid 11s is about where you wanna be on higher octane pump fuels. Around 12:1 or so on higher octane race fuels. There is a lot to play with afrs on spool as well, but in a drag car this is not going to be that usefull.. Especially if its a stock turbo, prob spooling fairly well anyway..

Re: Another turbo ?
 

that's the question - how much boost? My car drops more than 2 whole numbers from 12.x staging to 9.x @ 18 lbs boost.

Re: Another turbo ?
 

Why?

Re: Another turbo ?
 

Lots a variables. Tell us about your setup.