does this make scence at all??

Moxie · 03-29-2001, 12:36 PM

I love this thread. I love this board. It's nice to see guys like Jeff taking time to help others along. Mr. Chambers, have a cookie.

Somebody mentioned running plugs 2 ranges colder than stock. Personally, I recommend against it. I have found it is hard to get accurate plug readings with plugs that cold. I recommend staying with one range colder than stock. Like I said, this is based on personal preference. Of course, I sell and install nitrous systems, so most of my experience with plugs is on the bottle. If you guys have different experiences, sound off. I always like to learn new stuff.

As for injectors, here is the rule of thumb I learned from a guy at Siemens, an OE supplier of injectors.

lb/hr (fuel) = (Max. HP x BFSC) / (# of injectors)

Max. HP is a realistic estimate or a known value from dyno testing

BSFC is Brake Specific Fuel Consumption. Typically, BSFC for a normally aspirated or nitrous engine will be 0.45. For a turbocharged or supercharged application, use BSFC=0.55. Dyno testing can provide exact BSFC data. For a safety margin, you can use .5 for n/a engines, and .6 for supercharged/turbo combos.

# of injectors should be one per cylinder, if possible. For some applications, additional injectors are utilized.

Once a value (lb/hr) is obtained, use the closest injector size above that value.

Example: 302 c.i. Ford 8 cylinder, naturally aspirated, 350 horsepower:

lb/hr (fuel) = (350 x .45) / 8

lb/hr (fuel) = 19.6875

This engine has exceeded 19 lb/hr, so it's time to use 24 lb/hr injectors.

You can insert injector rates into the equation, and solve for max. HP level of a given injector:

19 lb/hr= (Max. HP x .45)/8

152= Max. HP x .45

337.78= Max. HP

------------------
Moxie Racing

The Nitrous Oxide Information Site

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
What cheap bolt-on can I make next?	Gautam	Blue Oval Lounge	2	09-24-2001 11:32 AM
Finally time to make some power	97snakedriver	Modular Madness	9	06-15-2000 12:00 PM
What will make my 98 gt faster than 98 cobra	Eminent18	Modular Madness	3	05-27-2000 03:24 AM
To make a cobra	Eminent18	Modular Madness	2	05-26-2000 09:21 AM
does anybody make 90/10's for 96 up cars	jameshensler	Modular Madness	3	11-20-1999 07:46 PM

03-29-2001, 12:36 PM	#16
Moxie Registered Member Join Date: Aug 2000 Location: Plymouth, MI Posts: 254	I love this thread. I love this board. It's nice to see guys like Jeff taking time to help others along. Mr. Chambers, have a cookie. Somebody mentioned running plugs 2 ranges colder than stock. Personally, I recommend against it. I have found it is hard to get accurate plug readings with plugs that cold. I recommend staying with one range colder than stock. Like I said, this is based on personal preference. Of course, I sell and install nitrous systems, so most of my experience with plugs is on the bottle. If you guys have different experiences, sound off. I always like to learn new stuff. As for injectors, here is the rule of thumb I learned from a guy at Siemens, an OE supplier of injectors. lb/hr (fuel) = (Max. HP x BFSC) / (# of injectors) Max. HP is a realistic estimate or a known value from dyno testing BSFC is Brake Specific Fuel Consumption. Typically, BSFC for a normally aspirated or nitrous engine will be 0.45. For a turbocharged or supercharged application, use BSFC=0.55. Dyno testing can provide exact BSFC data. For a safety margin, you can use .5 for n/a engines, and .6 for supercharged/turbo combos. # of injectors should be one per cylinder, if possible. For some applications, additional injectors are utilized. Once a value (lb/hr) is obtained, use the closest injector size above that value. Example: 302 c.i. Ford 8 cylinder, naturally aspirated, 350 horsepower: lb/hr (fuel) = (350 x .45) / 8 lb/hr (fuel) = 19.6875 This engine has exceeded 19 lb/hr, so it's time to use 24 lb/hr injectors. You can insert injector rates into the equation, and solve for max. HP level of a given injector: 19 lb/hr= (Max. HP x .45)/8 152= Max. HP x .45 337.78= Max. HP ------------------ Moxie Racing The Nitrous Oxide Information Site