banger vs whizbang

banger and whizbang both are nouns.

Word	Noun	Adjective	Verb	Adverb
banger	Yes	No	No	No
whizbang	Yes	No	No	No

As nouns, whizbang is a hyponym of banger; that is, whizbang is a word with a more specific, narrower meaning than banger:

banger: firework consisting of a small explosive charge and fuse in a heavy paper casing
whizbang: a firecracker that (like the whizbang shell) makes a whizzing sound followed by a loud explosion

Other hyponyms of banger include cannon cracker, cherry bomb, whizzbang.

banger (noun)	whizbang (noun)
firework consisting of a small explosive charge and fuse in a heavy paper casing	a firecracker that (like the whizbang shell) makes a whizzing sound followed by a loud explosion
(British informal) pork sausage	a small high-velocity shell; it makes a whizzing sound followed by a bang when it hits