28pnd injector max output
Pro
Joined: Dec 2001
Posts: 708
Likes: 0
From: Renton Wa
Re: 28pnd injector max output (RichS)
in short: not enough
In long, Well it's somewhat based off many attributes. However In a ball park figure, I would say arond 400hp to 425hp. I forget the formula at the moment, But you can search on the net under Injector Caculator, and I am sure you will find something.
In long, Well it's somewhat based off many attributes. However In a ball park figure, I would say arond 400hp to 425hp. I forget the formula at the moment, But you can search on the net under Injector Caculator, and I am sure you will find something.
Thread Starter
Le Mans Master
Joined: Aug 1999
Posts: 7,339
Likes: 137
From: WilkesBarre PA
Re: 28pnd injector max output (WashingtonRacer)
Man I don't know about those calculators. For a 550 hp motor they say anywhere between 38 and 45pnd injectors. I have around 430 now with the 28# and they say I should have 34# in there.
Real world what a 5-550 HP 396 need?
Real world what a 5-550 HP 396 need?
Pro
Joined: Dec 2001
Posts: 708
Likes: 0
From: Renton Wa
Re: 28pnd injector max output (RichS)
Well in theory for an 8 cylinder N/A engine, you will want about 1lb "or more accuratly, 1.25lb per 20hp. for your current HP 28 lb should be just fine, But your right at the limit. You don't want to exceed 80% of the duty rate, so it's always better to go a little bigger than what you expect. "not too much though. just round up. If you go any higher in the HP level, you should go to a 30 lb. By the 550hp mark, yes 36 to 38 would be about perfect.
Have you have the ECU re burned for compmensate for your modifications?
Have you have the ECU re burned for compmensate for your modifications?
Melting Slicks
Joined: Jun 2000
Posts: 3,215
Likes: 6
From: Tampa Florida
Re: 28pnd injector max output (RichS)
Have you done a duty cycle log?
My LT4 with the stock injectors are around 90%...haven't done a log since some minor tuning though.
I figure the engine is around 415 rated horsepower (ie stock is 330 rated HP).
I'm using Autotap.
My LT4 with the stock injectors are around 90%...haven't done a log since some minor tuning though.
I figure the engine is around 415 rated horsepower (ie stock is 330 rated HP).
I'm using Autotap.
Drifting
Joined: Aug 2000
Posts: 1,614
Likes: 0
From: Colleyville Texas
Re: 28pnd injector max output (RichS)
MTI built 100's of NA C4 strokers and very rarely went over 30# injectors. Most of the time they were 24-28#. Read the back issues of GMHTP magazine.
Alot of good articles on 396's and injectors. It just seems properly tuned strokers do not need as big of injectors as you might think. Low 11's and 500 HP with 30 or less injectors is not that unusual. JMHO.
Alot of good articles on 396's and injectors. It just seems properly tuned strokers do not need as big of injectors as you might think. Low 11's and 500 HP with 30 or less injectors is not that unusual. JMHO.
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Safety Car
Joined: Jul 2001
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From: TurtleCreek Twp Ohio
Cruise-In III Veteran
Re: 28pnd injector max output (CORKVETTE1)
Here's some "Racer Physics"
(BHP x BSFC) / ( # of injectors x .8) = Injector Flow Rate Size
BHP = Maximum Brake Horsepower
BSFC = .4 to .5 (.4 more for TPI manifolds while .5 is more for wet manifolds)
.8 is a "scaler" used to show that the injectors shouldn't exceed an 80% duty cycle
Note: Specific fuel pressure should be used for this calculation. Most "stock" fuel injected Corvette motors fall in the 40-43 psi range. If you bump your fuel pressure to 50psi.. then use that.
Remember Algebra? Do it up!!
(BHP x BSFC) / ( # of injectors x .8) = Injector Flow Rate Size
BHP = Maximum Brake Horsepower
BSFC = .4 to .5 (.4 more for TPI manifolds while .5 is more for wet manifolds)
.8 is a "scaler" used to show that the injectors shouldn't exceed an 80% duty cycle
Note: Specific fuel pressure should be used for this calculation. Most "stock" fuel injected Corvette motors fall in the 40-43 psi range. If you bump your fuel pressure to 50psi.. then use that.
Remember Algebra? Do it up!!
