Best EFI System for Big Block Chevy- 1200hp+

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02-23-2018, 08:05 PM

#41

Tinkerer

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In a boat the Dominator can have dual O2 sensors. They both use the same software. I have the HP module but may go to the Dominator for that reason.

02-24-2018, 02:18 AM

#42

SFOcean

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Quote:

Originally Posted by Panther

Becase your effective compression ratio will be very high and into race fuel territory.
https://www.rbracing-rsr.com/compression.htm

That will give you the boost compression ratio; to get your dynamic compression ratio, use this (also RB Racing):

Boost Compression Ratio Calculator

You want to stay around 175lbs actual cranking compression for pump gas fuel, the formula may show a few pounds higher than actual.

02-24-2018, 07:39 AM

#43

Boatally Insane

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Quote:

Originally Posted by SFOcean

So, I plugged my numbers in and this is what I got.... just wondering if I'm going to be ok with 93 Octane.. ?

Camshaft, Rod Length, Boost and Altitude Correction to Compression

Your engine summary is as follows: Bore 4.560 inches, stroke 4.25 inches, rod c-c length 6.535 inches, with a static compression ratio of 8.62 :1. Your camshaft specifications call for an inlet valve closing of 49.7 degrees ABDC (after bottom dead center).Your chamber volume is 149.26 cc's. With this camshaft your dynamic, or effective stroke is 3.70 inches. Your dynamic compression ratio is 7.63 :1 corrected for cam timing, altitude, and rod length. Your dynamic cranking pressure, corrected for cam timing, rod length and altitude is 149.48 PSI. Your dynamic boost compression ratio, reflecting static c.r., cam timing, altitude, and 10 PSI is 12.82 :1. Knowledge is power.

02-24-2018, 10:10 PM

#44

SFOcean

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Run the numbers at 8 PSI. Maybe start running the engine there and read your plugs to see if you can put more pressure in it? Nearing 13 dynamic is high, even on 93. Hope you are intercooled LOL.

02-27-2018, 11:29 AM

#45

Lee

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Quote:

Originally Posted by turbos230

Ok I have the short blocks ready now and the heads are next, but thinking about what my solution will be on the injection.From reading here the HP EFI and Dominator are the 2 options holley offers with multiport injection like I want.Waht is the difference between the HP EFI and Dominator , different software one has better quality? How to decide

Did you personally assemble the short blocks yourself?

02-27-2018, 02:03 PM

#46

turbos230

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No I bought the small blocks ,I am going to attach the heads intake all part lifters etc and then install the injection.I can do this it is not new but calculating compression ratio, honestly this is like chineese.maybe someone will help

I just dont want to detonate my best effort at building the dream offshore boat motors
I am going to use that compression calculator once I get some more information about the engine

Last edited by turbos230; 02-27-2018 at 02:11 PM.