This is for a track hatch Ef chassis
motor b18c1 82x87
b16 head
pro1 cam
skunk 2 ultra manifold
12.5:1 pistons
Right know we are running sunnoco 104 oct fuel has been alright so far but I believe if we swich to c45 or c14+ we can make a tad more power overall.

 

The best ways to really figure it out are to :

1) First analyze the differences in the BTUs of energy that these fuels produce. You may need to contact VP or FTW or whichever company you're getting these fuels from in order to make these comparisons. Also look to chemical compound content, and see if there are major differences in percentages of toulene between the fuels. Either way, you're still having more BTUs of energy than E85 without having to go through all of the crazy fuel components to supplement it.

2) Contact the fuel supplier. Yeah, you may get a sales person who's going to give more of a sales pitch of why their fuel is better than most, but, if you frame your questions correctly, I'm sure you're get a decent answer as to which one is better for you.

3) I know this is obvious, but try it out, it may mean a little investment on your part to see if the fuel change is worth the change in your tune. Know the limits of your engine and the ability of your tuner when increasing timing and squeezing more peak power out. It may be something else holding you back other than fuel type, so be ready for it.

That's all that really can be said for gains like this with NA cars. In the end, only you'll know if any increases in peak power are worth the cost.

 

I used VP c45. Its good but expensive. On our all motor B series we picked up 10hp over c16. On our J series we picked up around 15hp with a slight compression increase. Its supposed to out perform c85 and Q16. Evens tuning went from c85 to c45 and picked up like 24hp. If your all motor racing, 10-15hp is a huge difference.