33% is right at what i had to add. my fuel system is good for roughly 1000rwhp on c16. thats not enuff system for me to run e85 at the track. my street tune is about 680rwhp and e85 rocks there but i dont like the loss in gas mileage so i went back to 93+meth. Clark e85 is supposed to have more exhaust energy and spool quicker...can you tell a difference?