View Full Version : Fuel injector size ?

02-21-2006, 11:32 AM
Need to know what size fuel injectors I will need for a 496ci Stroked Mopar wedge.... will be between 600-650HP

02-21-2006, 12:14 PM
Naturally aspirated? Supercharged? Turbocharged?

Reason I ask is the "typical" BSFC numbers vary for the different engine configurations.

If you figure a "middle ground" .50 BSFC number for a naturally aspirated combo, I'd plan on ~50 lb/hr injectors.

( 650 hp X .50 lb/hp/hr (BSFC) ) / 8 (# of injectors) * 1.2 (20% headroom on the duty cycle) = 48.75 lb/hr per injector.

If you're running turbo/supercharged, expect a higher BSFC. To play it safe use a .65 lb/hp/hr BSFC number in which case you'd be best off with 64 lb/hr injectors.

Don't forget to match the injectors (high or low impedence) to your ECU.


02-21-2006, 03:15 PM
i've have 160's in my 710.

John Monnin
02-21-2006, 05:54 PM
A good page for calculating injector size, Theres is a nice automatic caluculator there


Stealth316.com has a lot of great technical article especially if you are going turbocharged

Using the fuel injector sizing program 50lb/hr injectors @80% injector duty cycle and 50% BSFC are good for about 640 HP, Blown353 made a good suggestion

02-21-2006, 06:43 PM
nice... thanks guys... My plan is to for a while, run a 8:1 compression and hopfully get 650HP from it... The engine is not built yet but I am just doing the headwork right now... I want in the end around 800HP with a Procharger system... but I can always upgrade injectors later on - I want to get all the computer non-sense done ahead of time.... So I'll start looking for 50lb injectors --- dumb question but do any factory applications use these ?

03-29-2006, 05:39 PM
I dont think so. Most stock engines run 30lb injectors or smaller

04-06-2006, 01:37 PM
I can give you a smoking deal on some low-impedance 65-pound injectors if you call me.

Low-impedance injectors capable of supporting 900 horsepower. I ordered more than I needed, and now I have 7 extra sets to either sell or return. I'd rather sell them to be honest with you.

These injectors MSRP for about $630 a set. Give me a call. You won't believe the deal.

These are only recommended for after market type ignition systems with the appropriate drivers for low impedance injectors.

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