O2 sensor gauge

[88Hillman]

The 88" currently has a GM V8 with Q-Jet carburetor.  It's run relatively well since I did the conversation in terms of power and economy compared to the stock 2.25.  It's always run hot and now has considerable leakage, both air and fuel as well.

The current plan is to install a rebuilt carb from some experienced guys in the US (there are still older guys that know this stuff!) It's interesting that they said with "modern carb tuning" on that carb you don't need to adjust for weather or elevation or pretty much anything else.  They bench test every carb on the same engine too.  While I do trust their expertise over mine, I'd like to see what the actual ratios are.  That's where the O2 sensor comes in.  Does anyone have recommendations about voltage gauges to use for this application?

I also had the crazy idea of putting a switch in line so I could use the same gauge to see the system voltage most of the time.  Flip the switch to monitor the O2 sensor output when tuning.

Thoughts?

Cheers,
Kirk

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[Matt H]

Without EFI it's really not that useful to have an O2 sensor. Chrysler experimented with an electronic fuel control carburetor years ago but it was superseded by EFI pretty quickly. The main issues are the complexity of making adjustments to the fuel/air ratio and ign timing on the fly. 

If there is nothing you can do to change fuel delivery on the fly above what a carb is already capable of, then knowing a 0-5v reference of the average Lambda sensor is not going to help. You could use it to aid initial tuning I suppose but on a full manual carb that operation is performed at a specific load, temperature and engine speed so its value is limited.
Compensating for speed, load, engine temp, fuel temp, air density, throttle demand etc under changing road conditions is a sliding scale of calculations that get pretty involved and really only managed properly by EFI.

I love the old carb tech but it's hard to beat the modern bolt on TBI conversion now available for domestic V8's if you want to see real improvement.

Just my 2c.

[Red90]

You need a wide band one and you need a good one or they lose accuracy....so they cost. Narrow band ones are reliable, but tell you nothing useful.

https://www.innovatemotorsports.com/products/mtxl_plus.php

[88Hillman]

That is a nice looking unit... and you are right about being spendy.

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