Need advise...A/F ratio\'s

[JayDee]

A CO closer to about 7 would put you more in the ballpark for tuning,but as max has said you are better off using a wideband.
From the voltages you are getting from a stock sensor and pfc, you are rich .95v is a ballpark figure, but DO NOT tune with the stock sensor.(These figures are guides and will vary from car to car)

Jason

Have you still got a cat? and where did you take the readings from?

[Oliver]

Originally posted by maximtaylor
CO (carbon monoxide) and CO2 (carbon dioxide) are directly related to air fuel ratio.

As a general rule, as CO goes up, CO2 will go down. It is possible to use conversion tables to convert your CO content or CO2 content to an air/fuel ratio.

This method is only generally used for setting up vehicles to within manufacturers tolerances (where they normally quote a standard CO or CO2 level).

For tuning, a good wideband (oxygen sensor) setup is far more accurate.

Hope this helps a little!

Regards

Max

It helped!  Thanks Max

Hopefully my own WB on the way. It will help make my tuning a lot more precise and accurate.

[Oliver]

Originally posted by JayDee
A CO closer to about 7 would put you more in the ballpark for tuning,but as max has said you are better off using a wideband.
From the voltages you are getting from a stock sensor and pfc, you are rich .95v is a ballpark figure, but DO NOT tune with the stock sensor.(These figures are guides and will vary from car to car)

Jason

Have you still got a cat? and where did you take the readings from?

So, 7.0 CO is ball park. The tuner thought I was lean from 2-4000 and rich from 4-6000 rpm. Thanks Jason. Atleast I have some idea of CO reading.

The reason I posted the PFC volt readings. I just changed my O2 sensor and it is reading the same as the old O2 sensor. I was hoping to hear what others see on there PFC\'s. Just for reference purposes.

I have just installed a Knight Sport Metalit catalyzer (high flow) and the dyno reading was from a Wide band in the tail pipe. I will have my own WB in a few weeks and will have a better idea what\'s going on so, I can tune it right for the next dyno run.

Thanks again Jason

[JayDee]

I use to see .95 on the pfc but on my car that is still slightly rich.
You will want to place the wideband in front of the cat.
Unless your wideband has a temp compensation I would have a bung placed in the bottom of the downpipe, if it has you can put it in place of the stock one, and turn O2 control off in the PFC.

The leanness maybe from the airpump giving you a false reading low down, it does cut off at @ 3000 I think.

Also be wary of wideband that are not yours, we have had someone\'s DIY reading 16.1 A/F ? full thottle, mine read in the 10\'s

Jason

[Fish]

Here is some good information on wideband and A/F stuff.

Taken from NoPistons forums.

Dan

[Fish]

I have moved this as it covers both T11\'s and FD\'s, and the information is of a general(ish) nature.

Dan

[FD3Typer2]

Hi.

Have any guys out there in the UK bought a wideband meter from the USA? If so, how much customs duty did you have to pay? I just wanted to know how much the thing will cost in all.

Thanks

Trev

[Oliver]

Fish - Thanks, I found this on the thread you posted. Some good basic info... helped me understand things a bit better.

http://auto.howstuffworks.com/framed.htm?parent=question257.htm&url=http://www.interro.com/techtips.htm#anchorchart2


Jason - I was thinking about attaching the wb sensor,  5-6 inches down from the DP / HF flange. Just before the high flow cat. The air pump does cut off around 3000...but maybe I have a bad ACV? A few weeks back, I posted a thread about my metering oil nozzle may be faulty. I have since purchased 2 new nozzles from Jimmy\'s in the UK. I have read that if not working correctly it can have an effect on emissions? Will fine out after they are replaced?? My plan is to change the nozzles (top of the rotor housing... ) and hopefully the WB will arrive soon after and give a second go at the dyno.

P.S. Is that your engine compartment in your photo?? if so, looks very clean!:) Also, do you have a WB unit?

//Oliver

[JayDee]

Yes that is a good place to mount the sensor. I don\'t think it would be your ACV, see what readings your wideband give.
With the wibeband in the tailpipe you can get false readings especially if you have a big exhaust tailpipe, at low air flow.
Yes I do have a wideband and datalogit.
Thanks for the comments on my engine, I have just got to make it go as good as it looks now. (must beat Evil rotor on Oct 12th)

Jason

[DRAGON]

What, with that little rotary choker you call a turbo!

[JayDee]

We shall see!!
You sorted my part yet?, so I can beat you:D
Just remember the wideband and datalogit are in my hands;)
You know I am not worried about this engine, going to have some fun finding a limit!

Your motor wont spool till Bristol

[Fish]

Originally posted by JayDee
Your motor wont spool till Bristol

Is that after leaving from Glasgow???

Dan

[DRAGON]

You just wait until Mr Apex seal says hello to Mr Exhaust turbine, and then we will see if the roller bearing was a good choice!:rollin

[JayDee]

maybe, but as long as it lasts one run:cool
ported engine, bigger turbo here i come

[DRAGON]

In light of your recent comments, i have to inform you of a new delivery date for your parts, this will be the 13th of Oct.:wave