17 replies to this topic

[Chris1275gt]

Hi
Any one used a colortune plug as an aid to get the mixture correct? I'm new to engines and carburettors and struggling a bit to get my ears accustomed to the sounds of exhaust and engine noises.

[luismx123]

does help if you have no clue what is right/wrong. Once you learn a mini you get a feeling for the idle. It does kind of help for higher rpms just to get a sense of whats going on inside but its a different story checking your mixture at high rpms whilst driving or stand still :/
If youre new to it, id get one. You learn a bit and it helps you develop your mini-senses ;)

[mercenary62]

ive had a colourtune for years bought in the seventies ,still going strong ,a usefull piece of kit

[unburntfuelinthemorning]

Colourtune can't lie to you.

[DeadSquare]

Getting the mixture correct, having fitted a supercharger is not straightforward.

 

I find a colourtune most useful.

 

I insert the coulortune in number 4 plug, remove the bonnet and fix a shaving mirror in such a way that I can observe the coulortune while driving at night under a veriety of conditions, and while stationary, I can adjust the carb setting as indicated.

[DeadSquare]

Colourtune can't lie to you.

Unless you are colour blind.

[luismx123]

Getting the mixture correct, having fitted a supercharger is not straightforward.

 

I find a colourtune most useful.

 

I insert the coulortune in number 4 plug, remove the bonnet and fix a shaving mirror in such a way that I can observe the coulortune while driving at night under a veriety of conditions, and while stationary, I can adjust the carb setting as indicated.

oh jesus thats an idea worth tryng.... hmmmmmmmmmmmm ill have to try that one when my minis back on the road! 
isnt it bad to drive with it for an extended period of time?
 

[MiniMadRacer]

Better to get or rig up an AFR meter if you can

[Spider]

I have one and it is good - to a point.

 

It will help you set your mixture at idle speeds, but if your engine has been modified in any way, it will first need a rolling road session to get the correct profile needle and spring sorted, otherwise, using a Colourtune will only set the right mixture at idle and could be anywhere in the spectrum when driving.

 

David Vizard did do a write up many many many years back in one of the magazines with a method of running the car on stands and using the brakes to apply load, kind of a poor mans Dyno (Rolling Road), with a maximum RPM limit of 5000 rpms (beyond which, he felt the Colourtune may melt I think) and having an assistant read the Colourtune up and down the rev range while loaded.. If you were to do this, I would strongly recommend removing the wheels first, just in case the car comes off the stands ! Though, frankly I don't recommend the method as it's pretty dangerous.

 

You could do a similar method more safely these days with an AFR Meter and for that matter, even do that out on the road.

[unburntfuelinthemorning]

 

Colourtune can't lie to you.

Unless you are colour blind.

 

That'll be your eyes lying, not the Colortune.

[phillrulz]

As I was told by a tuner “ there’s a reason I spend thousands on a AF sensor “ id say it's good to make it run but needs a road for a long term setup

[timmy850]

You don’t need to spend thousands to get a good AFR gauge. My friend has an Innovate gauge which is a couple hundred dollars and got it installed in an electronics box. Then add the sensor in the exhaust and 12v power for the gauge. Then it’s portable and easy to swap from car to car. Once it’s tuned you don’t really need the gauge. The only downside this way is the idle signal gets muddled because the sensor is so close to the end of the exhaust

You can get the weld in bung halfway along the exhaust if you want - and if you want to check the idle mixture too



Led doesn’t show up on the camera very well, but this was 13.9:1

[Ethel]

The colourtune fits to individual cylinders, something that's very hard to do with a lambda sensor on a Siamese ported A Series.

[r.tec]

When I use them I instal two on a single carb engine. There is the tendency that the outer cylinders run a bit  fatter than the inner. And with two plugs you can juggle a little to get the more or less accurate mix which is always a compromise. Next step is driving under load; then a fuel/air sensor like the k&n sensor with an in-car display comes into play. But that means that you drill the exhaust and fit a M18x1 adaptor for the sensor with a line to the display.

Edited by r.tec, 09 January 2020 - 07:40 AM.

[Ethel]

If internal combustion engines weren't on the brink of becoming history it could be worth somebody developing an electronic "smart sparkplug" along the lines of colortune - we have cheap watches that bounce a light in to your wrist to determine your blood oxygen levels so doing similar shouldn't be impossible.