For those of us who are boosting or are soon to be boosting I think it would be useful to discuss how to keep tabs on our motor's A/F. I see most people use a wideband O2 to tune and monitor their A/F...The only issue I see with this is that most people typically run it on only one test pipe/downpipe, etc. Or the other thing i have seen is running it further back but running after that cats will throw it all off. By only measuring one bank in a V config motor this could be misleading..The other bank could be running insanely rich while the other is running lean. I see one of two option to remedy this. First is too run two widebands one for each bank. At $500 + a pop I dont think that really feasible. In my case I think I am going to run an EGT for each bank. This will allow me to keep tabs on both banks at once via EGT gauges. Albeit not as easy to interpet as an Wideband O2 but WAY more cost effective. The other I do not think is possible. A Wideband O2 system that will allow you to monitor two probes independently for each bank. I am not aware of any system that allows for this but if there is please let me knoow. Any other suggestions you guys may have would be greatly appreciated.

 

Well your in luck. There is a dual wide band unit from AEM for low 600's street price. The only down side is it does not come with a display. But any 0-5v display will work fine.

Also for you Turbonetic fans the good news is you only need one wideband. Pressure affects the output of all widebands thus you must mount them after the turbo due to the high backpressure between the head and turbine inlet so, you can only use one any way.

I've measured both banks on mine and for all purposes they are the same.

EGT's are good for watching trends but not a good thing to tune by. There is no reason to spend 4 plus grand on a motor that will cost over 3 grand to fix and not by a 350 dollar wide band.
Gary

 

Guess I only need one EGT then

 

I would say you need a wideband. EGT's are very misleading. You can easily pop your motor with cold, cool, normal or hot EGT.

Mark
www.Quantum-Racing.com
Home of the Dynapack Dyno

 

Which would you recommend? I've heard good things about Zeitronix, AEM

 

I will be adding a dual wide band unit very soon myself

 

There are very few conditions...actually...none that I can think of...except for catestrophic failure of your injectors or ECU...that would cause one bank to run significantly leaner than the other. But if peace of mind is what you are going for...I like the dual channel Wideband idea.

 

I had a
Greddy wideband on Driver side
Innovate wideband on passenger side
and #1 cylinder Header has a EGT unit .....

 

This is what I am up grading to for my HKS kit to keep better tabs and have more contol over the A/F

F-CON V pro version 3.2
press sensor / intake air temp harness
VPC AT sensor
pressure sensor super wide range
A/F knock amp

 

Hey PumpedVA..... So will the F-CON V pro simply plug into our harness in place of the F-CON S? What other connections/modifications will be needed. I may look into this option also if it turns out that I am running too too rich, as we both suspect may be the case with the HKS.

 

I'm the dumb guy on the thread, still learning about how to boost safely so that when I finally strap on F/I, I know what I'm doing. Can someone give me a quick description of where a WB O2 sensor goes and how it works? Thanks guys.

 

You can tune the PRO S so you are not running rich bro. I just need to up grade to the PRO V so I can add the plenum. from my understanding the PRO S you can only tune the AF mix but so much like if you were adding headers and down pipe but not that extra mile for the plenum. I think its is the same plug and go as the pro S but I am not sure. they look the same. I am adding everything else so I can bypass my MAF for even better tuning of the AF mix.

 

I am in the same boat as you bro that is why I am adding all this to my car so I can control the air fuel mix better for safer boost. I dont know about the WB sensor just about anywere in side under the dash maybe?

 

maybe this will help as to why I am adding the WB 02

Since a lambda type O2 sensor can't read fuel mixtures much richer than 14.7, the ECU ignores the O2 sensor at WOT and reverts to "open loop" operation. In open loop, fuel requirements are calculated by inference, rather than directly computed from the actual amount of oxygen in the exhaust. This can work well, but is less precise and harder to control than when the closed loop feedback system is operating. The solution is a "wide band" (WB) O2 sensor. A WB O2 can read A:F ratios richer and leaner than 14.7:1 and allows the ECU to actively control the A:F ratio at any desired value. The problem is that WB O2 sensors are relatively expensive and require a more sophisticated ECU. Stock cars are therefore not equipped with WB O2 sensors. The various aftermarket ECU's we sell and install at Kennedy's can be equipped with a wide-band option and can function in closed loop nearly all the time.

 

I disagree. Before widebands were around I could hit a perfect AF ~11.5 with nothing more than a EGT gauge. You just have to be sure you have a good thermocouple. Cheap slow probes are useless.

 

How do you know you were hitting 11.5?
BTW, EGT's change drastically with ignition timing and heatsoaking. I agree; slow probes are pointless.

Mark
www.Quantum-Racing.com
Home of the Dynapack Dyno

 

You guys are confusing me. ...SIngle Wideband or EGT?