No, you cannot get a word with 8 letters that doesn't have any vowels. It's impossible, but you can get a 7 letter word without vowels, which is rhythms. There is, however, several obsolete words without vowels; symphysy, for example (which means the union of two bodies).
There are 6 vowels and 7 consonants so there is 1 more consonant
There is no one-word 8-letter palindrome in English, apparently!
to simplify.
The long word "antidisestablishmentarianism" has 17 consonants and 11 vowels. The Guinness Book of World Records "longest English word" is 45 letters long and has 25 consonants and 20 vowels: Pneumonoultramicroscopicsilico-volcanoconiosis (a hyphen has been added so that it will display here) But the ratio between consonants and vowels is greatest in words such as "prompt" (5 to 1), "strengths" (8 to 1) and "strengthlessness" (13 to 3). (see related link)
Cloister
withdraw
The 8-letter word that contains four 'N's and the other four letters are all vowels is "announcer."
spinning
Dopamine. I'm sure that there are others but I can't think of them at the moment.
The only 8-letter word with 5 vowels in a row is queueing.
for vowels=8/13; for consonants=5/13; sample space |S|=13
You can not make a word because there are no vowels.
There are 310 words without the 5 main vowels, and the only 8 letter one has a "y" in it. So I don't believe there is any dialect of English where a word could be made with just the letters: HHGTTRWN
Putyujl
The word western has 8 letters, two of which are vowels.
zoonosis
Uncommon