Looking at doing some fine tuning on a dellorto. I think still running rich based on the plugs, even though it drives well through the rev range and doesn't cough or bog down.

Will a colourtune get me 95% there, or is that a false economy and i should just spring for a AFR for up the tail pipe ?

If it were AFR i wouldnt be welding a bung in, just up the tail pipe and thru the back window for test runs. I assume something like this would do the job unless someone has used better options ?

https://www.carmodsaustralia.com.au/x-s ... gauge.html

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1966 Mini Deluxe - “Gabby” 34 years under restoration and counting...
1970 MGBGT
1959 MGA

One benefit of the colourtune is that you can check each cylinder individually. I tried one and didn’t have much luck, I think it was a bit too bright in the workshop that day. The main downside is you can only tune it at idle and when you pump the throttle by hand with no load on the engine

The afr gauge will give you readings under load which is arguably more important. I’ve done most of my Dellorto tuning with a tailpipe mounted sensor, which works really well except it doesn’t give an idle reading. Since swapping mine to a bung further up (which also came with a blanking screw if I want to remove the sensor) it gives really good readings at idle and a bit more immediate response

I’ve got my innovate 3728 tailpipe clamp available at the moment if you want to borrow the clamp

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I have never had any success with colourtune. I have no doubt it does wht it says but not for me. I use an ega all the time. And I am not sure how you would go about tuning individual cylinders. Finding faults in any cylinder is besr done with other methods anyway.

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Cheers Dave.

My guru says they're not accurate with modern fuels, useful for comparing the burn across cylinders, but not for actual state of tune. Besides that, you can't use a colour tune on the road or under any kind of load. They'd melt if you tried to use one on a dyno, and the spark plug is so different to whatever type of plug is in the other cylinders.

Permanently mounted AFR is significantly better

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did I tell you that I won a trophy?

Colortunes rely on a state of tune at idle, that will continue to be tuned throughout the load/rev range through a trust in the original factory design. Stoichiometric mixtures at idle will follow through the midrange and higher. The problem with modifications is that they introduce a dynamic aspect to tuning. Camshafts, head modifications, mismatched components all cause a tune at idle to be then incorrect at other load and rev points. Its lucky for us that AFRs are so accessible these days, and there's no question.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

I use an Inovative wideband with the sensor at the tail pipe, and cables through the window.
Welded a bung into a 6 inch piece of exhaust pipe which I clamp to the tail pipe for syreet runs.
For idle I slip a length of exhuast pipe onto the 6" inch pipe. This gives a good idle reading.
Have used it on many cars and works a treat.
Helps if you have a few odd bit sof exhuast pipe laying around as you need to get the joints to seal to give the correct reading.

I use a properly mounted AEM system on my turbo car. This also works well so recommend it as a guage and sensor setup.

Exactly what i was looking for, perfect set of responses and field examples looking at both sides.

Me being cheap thought i may get away with a colourtune, but not so. I had AEM in my list, and that has been addressed as well - so will go in that direction.

Great tip on how to get idle readings when not reading from extractor bung super helpful - many thanks

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1966 Mini Deluxe - “Gabby” 34 years under restoration and counting...
1970 MGBGT
1959 MGA