Got a r53 mini in.
It has got kav 20% pulley on it.
Whilst running up to get heater hot holding the revs at 3500 the exhaust manifold was glowing red.
My question is being new to minis is.
Is this normal ?
I'd check the inlet manifold vacuum reference tube that goes to the fuel pressure regulator, that's a very common cause of running lean. If the pipe has slipped off the fuelling will be lean. My exhaust would be cherry red after 10 mins of idling because of that before I fixed it. You can see it without removing anything too (at least the most likely end to have slipped off)
If it's not running nicely on idle it may be the supercharger side MAP sensor, which can read lower than reality and cause a similar thing, but it can cause quite an erratic idle/occasional stalling after start.
As previously mentioned a collapsed cat can also be the issue.
could have already melted the pre cat potentially, it's worth getting the manifold off and an endoscope down from the top to check it's intact before changing stuff if it isn't obvious just checking around.... this is in good order for example, as it's a visual thing it's worth knowing I think, to eliminate it ;O)
take note these manifolds have a flange angle error around 5mm which are the reason the flexi's are know to fail prematurely, they force the rest of the system up or down hard against the central bump stops, upper iirc, and cause severe strain, they're fixable, just cut it through 90% of the way, set the position between the bump stops (they're not a mount/hanger) and weld it up again, then there is also no cat so you have to make one up out of the old main cat and a new flange.
I have a couple here cheap both requiring flexi's, one lasted well having already been altered, it has an additional wide band port added, but a broken engine mount on track killed it, the other failed no doubt from being fitted as is and came to me this way, the car still achieved 230whp with the adjusted one installed and could have been better if I'd also tidied the gasket/port match.