Holly fuel pump. What do I do?

skipnrocks · Jan 11, 2015

So I started shopping for a fuel pump for my buggy and realize that it is a whole can of worms to get the right fuel pump. It would seem that it requires a specific psi and flow rates to work properly.

SO here is what I have. I have a higher compression tune port injection 383 that should be in the 550 hp range.

So here is what I cant seem to find. What psi pump do I need and what flow rate will be sufficient to maintain 6000 rpm?

And last but not least what compression rating do motors hit when they require alcohol?

pholmann · Jan 11, 2015

High compression doesn't require alcohol. Higher compression requires higher octane. What is your compression ratio?

skipnrocks · Jan 11, 2015

I am not a 100 percent. I bought the motor built. I know the deck has been modified to raise compression. I was thinking it was supposed to be 11 or 11.5 :1 but I suppose I will have to test it when it gets ready to run?

pholmann · Jan 11, 2015

You will probably need to mix 50/50 93 octane and 110 octane race fuel. 11-11.5:1 needs about 100 octane to keep detonation down.

skipnrocks · Jan 12, 2015

Do I just run a compression check to know for sure what my compression is? If so what psi would corelate to an 11:1

pholmann · Jan 12, 2015

That is a pretty complicated deal. The cranking pressure alone wont give you that. But, you can do a cranking pressure compression test and get some ball park info. To do a true compression ratio figure you would need to know your combustion chamber size in your heads, your piston height, your head gasket thickness, etc. Do a compression test and report the numbers. If you aren't over 200psi you should be ok for 93 octane. Pushing it but still ok.