The difference between 1/4 and 1/8 is 20mph.
Do you know what mph you do in the 1/4?
If so then subtract 20mph.
I would expect (depending on variables)you would turn somewhere between abt 84 to 90mph in the 1/8.
Will your car do 84-90 in 3rd gear?
This should be enough info to answer your question.