You wont read AFR from sticking something up yer pipe
, you need the O2 sensor in the pipe.You could fit a AFR gauge kit they are cheap & the mini doesnt have a lambda sensor.
You could, but what good would it do?
AFR/Lambda value! ROFL!!!!!!!
In the day the best thing you could do with anything you stuck up the exhaust pipe was a CO meter reading.
This is beginning to remind me about the story I heard of the AA man who turned up to a broken down MGB. Apparently he spent 15 minutes looking to find somewhere to plug in his diagnostic!!!
You basically have 4 things to tune.
Rocker gaps.
Points gap (if it isn't converted to electronic)
Timing, (i.e. by rotating the distributor until it is right)
Fuel mixture and tickover setting.
SUs are designed to give correct fuelling across the rev range which is handled by the profile of the needle. Or needles if it is a twin set up.
There must be loads of books you could buy on it. I have Vizards book on tuning the A series engine, but even a Haynes will tell you how to set up a basic tune. And I do know yours isn't a basic one.
Plug cuts are a very reliable way of seeing if the mixture is correct. You can try using a Colortune but I find they only work on brand new SUs as inevitably they wear where the throttle/butterfly spindle passes throught the bushes on the body of the carb, which allows air past them.
Shame you aren't closer we could have fun with this and I have all the old skool equipment necessary!
I find it hard to believe that you are nearly my age yet this is a black art to you. Maybe you drove fords in your youth!!
I would go with all of what you said, as TBH there's not much else you can do on old Skool, except let it breath in & out then tune to suit
My limited knowledge is a bit like this.
So I have an AFR gauge and its not at 14.7? Well no it wont be most of the time, and you don't want it to be all the time.
You only benefit from an AFR if you can tune the ECU to squirt more when demand is needed, then only if you know when its needed
. Its a black art. Then you really don't care how much fuel you use(I had a programable ECU on the single turbo RX7 with wideband sensors
)So back to the original issue.
Catch cans are fine. open lines on an induction manifold may not be desired, where are they?, long time since I worked on an SU powered engine car so cant remember where the hoses go, but they are a pretty good carb and do compensate for demand under loading by design.
If its emissions are fine for MOT (does it need 1?) then its close enough to be good enough.
For the SU tuning not much can be done except a different needle (profiles change).
If it runs fine leave as standard, its a little pocket rocket to be driving around town in by todays standards
and I bet you get loads taking pics and waving.J
