Another turbo ?

Marc Kinton · 05-12-2010, 06:21 AM

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.

Bill Grubbs · 05-12-2010, 07:27 AM

Quote:

Originally Posted by Marc Kinton

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.

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

buzzinhalfdozen · 05-12-2010, 08:31 AM

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

Ed Wright · 05-13-2010, 01:27 PM

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.

Jim Wahl · 05-13-2010, 01:38 PM

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

LNorton · 05-13-2010, 04:26 PM

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

Jimi B · 05-14-2010, 08:45 PM

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..

MOTORSPORTS Innovations · 05-17-2010, 07:03 PM

Quote:

Originally Posted by buzzinhalfdozen

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

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.

Jimi B · 05-17-2010, 11:23 PM

Quote:

Originally Posted by MOTORSPORTS Innovations

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.

Why?

Harry 6674 · 05-19-2010, 12:04 PM

Quote:

Originally Posted by MOTORSPORTS Innovations

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.

Lots a variables. Tell us about your setup.

05-12-2010, 06:21 AM	#1
Marc Kinton Member Join Date: Jun 2007 Location: Youngsville, NC Posts: 326 Likes: 0 Liked 0 Times in 0 Posts	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.

05-12-2010, 08:31 AM	#3
buzzinhalfdozen Senior Member Join Date: Sep 2006 Location: Bellevue Ohio Posts: 984 Likes: 0 Liked 11 Times in 8 Posts	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 __________________ Joe Buchanan SS/BX 3117

05-13-2010, 01:27 PM	#4
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 390 Times in 170 Posts	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. __________________ Ed Wright 4156 SS/JA

05-13-2010, 01:38 PM	#5
Jim Wahl Veteran Member Join Date: Jan 2002 Location: Central Florida Posts: 5,843 Likes: 665 Liked 683 Times in 129 Posts	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 __________________ Jim Wahl....NHRA #2239 S/SS - IHRA # 8 Stock, D2 Stock Champion (forever I guess) 2019 Baby Gators Stock Champion 2009 D2 National Open Stock Champion 1981 D2 West Palm Beach LDRS SS Runner Up Past President, Southern Stock / Super Stock Association.

05-13-2010, 04:26 PM	#6
LNorton Senior Member Join Date: Apr 2004 Location: RacerTees.com Posts: 505 Likes: 0 Liked 4 Times in 2 Posts	Re: Another turbo ? Marc, shot you a message on FB. Get back at me! __________________ Lee Norton - N229 STK IHRA H/FIA - NHRA O/SA RacerTees.com

05-14-2010, 08:45 PM	#7
Jimi B Member Join Date: Nov 2005 Location: Cincinnati Posts: 226 Likes: 0 Liked 0 Times in 0 Posts	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.. __________________ Jimmy Bowling BF/S 3808 www.facebook.com/jimib1980