Calculating injector size.
Advanced
Joined: Sep 2000
Posts: 75
Likes: 0
Re: Calculating injector size. (Hammer)
If you know what your about what horsepower you can expect with your combo then use the following link:
It should get you in the ballpark. Also keep in mind possible future upgrades.
http://www.witchhunter.com/injectorcalc1.htm
Gordon
[Modified by Switch, 6:42 PM 11/3/2003]
It should get you in the ballpark. Also keep in mind possible future upgrades.
http://www.witchhunter.com/injectorcalc1.htm
Gordon
[Modified by Switch, 6:42 PM 11/3/2003]
Burning Brakes
Joined: Oct 2002
Posts: 1,152
Likes: 1
From: Wichita KS
Re: Calculating injector size. (Hammer)
Here's another real good calculator...
http://www.rceng.com/technical.htm
http://www.rceng.com/technical.htm
Former Vendor
Joined: Jun 2001
Posts: 7,204
Likes: 6
From: St Marys PA
Re: Calculating injector size. (superlund)
I would base it on other proven setups. Too large of injectors are more of a hinderance than an advantage.
Guys like beachbum, Cork, and I are all running extremely well with 24# svo injectors. Can't see why you would need more than them.
:cheers:
Guys like beachbum, Cork, and I are all running extremely well with 24# svo injectors. Can't see why you would need more than them.
:cheers:
Thread Starter
Le Mans Master
Joined: Jan 1999
Posts: 5,135
Likes: 24
From: Long Island NY
Re: Calculating injector size. (ski_dwn_it)
Guys like beachbum, Cork, and I are all running extremely well with 24# svo injectors. Can't see why you would need more than them.
Should injectors be flow matched, or is it overkill?
Jim
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: Calculating injector size. (Hammer)
I believe the LT-1 uses 24lb/hr injectors rated at ~44psi.
Flow matching injectors is part of blue-printing your engine, much akin to flow matching the ports when porting heads. Though not "necessary" it certainly isn't over kill.
Flow matching injectors is part of blue-printing your engine, much akin to flow matching the ports when porting heads. Though not "necessary" it certainly isn't over kill.
Racer
Joined: Jul 2002
Posts: 401
Likes: 1
From: Aptos CA
Re: Calculating injector size. (superlund)
Well according to the calculator below, it would take 33 lb injectors at 42 lbs of pressure for just 425 hp. on a V8. That's interesting.
Here's another real good calculator...
http://www.rceng.com/technical.htm
http://www.rceng.com/technical.htm
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Advanced
Joined: Sep 2000
Posts: 75
Likes: 0
Re: Calculating injector size. (Hammer)
Most of the calculators are using 15 or 20% as max duty cycle. With most injectors, and depending on the rpm's involved can do close to 100%. So one could get aprox 15 or 20% more horsepower out of the calculated values. I've been told that they can hang partway between open and closed at very high duty cycles. My ASNU injector machine doesn't have an infinite range of duty cycles to verify this. I am building a circuit that should be able to see this phenomena if it exisits.
Good luck with the fresh engine.
Gordon
Good luck with the fresh engine.
Gordon
Burning Brakes
Joined: Oct 2002
Posts: 1,152
Likes: 1
From: Wichita KS
Re: Calculating injector size. (Hammer)
If you play with the RC Eng Inj calculator I posted the link to above it will reproduce the same size fuel Inj. GM used (28.8 LB/HR) in the 2002, 405 FWHP Z06.
I used the following variables;
405 FWHP
8 Injectors
.50 BSFC
76% Max Duty Cycle
58.4 PSI (Stock Z06 FI Pressure)
The RC Eng calculator comes back with a 28.84 LB/Hr injector. In my mind it can't be too far off base...
FWIW, I run the 28.8 LB/Hr Z06 Inj's in my 363 RWHP / 425 FWHP LT4 and I've seen max duty cycles in the low to mid 90% range. That's with around 12.8 AFR @ WOT
[Modified by superlund, 5:19 PM 11/5/2003]
I used the following variables;
405 FWHP
8 Injectors
.50 BSFC
76% Max Duty Cycle
58.4 PSI (Stock Z06 FI Pressure)
The RC Eng calculator comes back with a 28.84 LB/Hr injector. In my mind it can't be too far off base...
FWIW, I run the 28.8 LB/Hr Z06 Inj's in my 363 RWHP / 425 FWHP LT4 and I've seen max duty cycles in the low to mid 90% range. That's with around 12.8 AFR @ WOT
[Modified by superlund, 5:19 PM 11/5/2003]
