The phrase "a bit of impact" is correct and usable in written English.
It can be used to describe a small or moderate effect or influence something has on a situation or outcome.
Example: "The new marketing strategy had a bit of impact on our sales figures, but we need to implement more changes for significant results."
Alternatives: "some effect" or "a slight influence".
The Olympics had not a bit of impact on these fundamental issues.
"I can understand what he is saying too by explaining to everybody that is listening that when you put in the money that he's put in, he deserves to have quite a bit of impact in where we go and what strategy is used for the club to go forward.
Well, among those 180 papers, one was cited 97 times (that's quite a bit of impact!), but two were not cited at all, in spite of being published in such a prestigious journal.
William Hill seem to think Ennis made a bit of an impact; they've altered their odds slightly in her favour again, although Wiggins remains the favourite.
"And just in my conversations over the weekend with intelligence officials, that level of uncertainty is already having a bit of an impact on our ability to protect Americans by finding terrorists trying to reach into the United States".
In many works we have to sit tight for denouements or repeating jolts that can be dramatic or intriguing the first time around, but that lose quite a bit of their impact once you know how everything turns out, or grasp the intervals between repeating eruptions of sound and imagery.
Sadly, a bit of that impact is lost when you transfer them to PCs or televisions.
Hence, a unit on ecology essentially requires students to memorize the vocabulary of various aspects of ecology such as levels of organization, ecological succession, feeding relationships, basic biomes, and the material cycles, with perhaps a bit of human impact thrown in, and then move on after a week or possibly two, at the most.
