English isn't my native language, just letting you guys know. I can't wrap my head around about which is the correct form. Once I get or once I'll get? For example: Once I get my car fixed, I'll go.
In the section tense simplification in subordinate clauses, Swan (Practical English Usage, p573) states:
If the main verb of a sentence makes it clear what kind of time the speaker is talking about, it is not necessary for the same time to be indicated again in subordinate clause.
Go is the main verb in the sentence Once I get my car fixed, I'll go. It is used with a future construction (will), so there is no need for the verb in the subordinate clause (get) to use the same future construction.
Swan notes further, with relevance to the OP's example:
Present tenses are often used instead of will + infinitive to refer to the future in subordinate clauses.
Swan's examples include:
- I'll write to her when I have time. (not ...
when I will have time.)
- I'll go where you go.
So in summary, the grammatical form here is:
Once I get my car fixed, I'll go.
or, reversing the clauses:
I'll go once I get my car fixed.