Originally Posted by Alan L (Post 11686351)

I use a measuring cylinder - good to 0.5ml (cc). Collect about 60-70 cc.
You need to be accurate with these if you are trying to tune the FD to better than average numbers.
Porsche manuals sometimes suggest a 10-15% tolerance between cylinders is OK. For NA cars that may be OK - and my SC is such a beast. And if you read the threads - plenty complain about the engine bucking/missing at low revs and light throttle settings. Apart from eliminating any airleaks, another likely issue is a cylinder leaner than the others - 10-15% leaner. I recently tuned my SC FD to 1-2% variation. Running real nice on low throttle.
For the boosted car, I think 10% variation is way too much. Again - I tune it to 1-2% variance. But you need to be able to measure it accurately. Collect enough fuel and have a decent way to measure it.
I have since started altering this tuning via the park plug colours. But 1-2% variance was my start point. I have exchanged the black soot colour on the plugs for a dark tan colour.
Alan