Anyway he said he retarded the timing on over run which Dave has explained above, & added a little more fuel on over run.
How much he retarded the timing on over run by I don't know... But basicly it only works if I rest my foot a little on the accelerator or I gently repetedly tap the accelerator... so it just starts to open butterflys in the inlet.
So if the throttle is fully closed it wont do it? Maybe a good thing in residential areas tho
Heres a little video of mine on the motorway popping & banging, put headphones in & turn volume up Not best quality tho & camera man dous decide to turn the camera the right way up half way threw