Fitting A Lambda Sensor On A Carb Engine

[johnnyboy666 195 1 Cars]

Hello,

I'm heading towards a point with my TU3s build, that would greatly benefit from some air/fuel ratio data. So i was considering fitting a lambda sensor and a gauge, but would like a bit of advice.

 

Would i be correct in assuming that the sensor should be as close to the head as possible?

 

I have a 4-2-1 manifold, so should it be fitted after the secondaries merge to the single pipe? (Im thinking this would avoid effectively reading only one cylinder)

 

Would it be too far back to mount it in the centre section of the exhaust , directly after the join to the 4-2-1? As this would make life easier with regards to welding a bung in, and potentially using the centre section on other cars.

 

Any advice would be appreciated

Cheers

[oldkiteman 6]

Id fit it in the section where all the pipes converge and fit 4 wire one with a heater.

[johnnyboy666 195 1 Cars]

Cheers, I've got a 4 wire one I was planning to use. Does the heater mean that it's ok to have it a little bit further back?

[Tom Fenton 1,542]

Johnny, what are you trying to measure, the narrowband sensor in my opinion isn't really much help, all it really will tell you is that the engine is either lean or rich, and it is slow to react so of limited use in a real time situation. To be honest you can usually tell yourself by the way it drives or by pulling a plug out if its overall lean or rich anyway.

A wideband on the other hand is far more use, it will tell you at any point whether its lean or rich and by how much. It is what the rolling road guys use for setting up, in years gone by they were a lot of cash, but these days you can buy a kit with sensor and gauge for around £150. I personally would recommend the AEM stuff, i have fitted numerous now, all the electronics is contained within the gauge, hook up a live and earth and connect the multiplugs and you are away.

As an additional feature the program for pump fuel on the AEM is program 00, which means when you turn it on it will display P00 for program 00, which one of my mates always finds hysterical. He is easily amused.

[johnnyboy666 195 1 Cars]

Ah, so is a narrow band more of an on/off type thing, but a wideband gives increments?

I was hoping to put a gauge next to the rev counter so I can tell whats happening at different parts of the range. I'm trying to see if I can get some decent results from the Solex carb, at the point where people would normally replace it with a DGV/bike carbs/twins etc. I've I've been using the 'bum dyno' but it could do with some calibration! It's a bit tricky to tell sometimes what overall effect I'm getting with different jetting, and if getting seemingly more power at one part of the range, is causing adverse affects at other parts.

 

Just having a cursory glance at some wideband stuff, would it be possible to use an OE lambda from a car that has a wideband as standard, and connect that to a gauge, or is there more to it than that?

[Tom Fenton 1,542]

Have a read here

 

http://www.enginebasics.com/EFI%20Tuning/AF%20Ratio%20Basics.html

[johnnyboy666 195 1 Cars]

That's handy cheers.