fuel injectors

[shadowbandit]

Like the title says trying to figure out what injectors to go with. 235/243 .629/.613 110 LSA that's the cam I'm going with not sure yet but le2 or le3 heads on a fully forged 355 aes building me. The car has a stand alone nitrous system and will be getting 200hp shot off the plate kit from nitrous outlet. There will be c16 in the stand alone. So I'm just trying to get the injectors right for the car. The car will be driving on at all time is a 50/50 mix of 100 and 93 so please let brotheren help please.

[Injuneer]

Injector size is a function of flywheel HP, brake specific fuel consumption (determined by combustion chamber efficiency and quality of the tune), and maximum injector duty cycle (a function of injector design). Using moderately conservative assumptions, I've found the you can estimate minimum injector size by multiplying flywheel HP x 0.07. That's based on a BSFC of 0.476 #/HR/HP, and limiting duty cycle to 85%.

Bottom line - you are looking ar 36's up to 520 flywheel HP, or 42's up to 600 HP. There is no downside to going oversize on injector size, within reason.

All the above is predicated on normally aspirated applications. Since you are using a wet system, this is valid for your application.

[shadowbandit]

Well that just made a lot of sense thank you so much so now to ask what's the best injector brands have you found car should hope to make around 700 wheel hp I'm hoping

[Injuneer]

The Bosch 3 looks like a good deal, based on the videos posted by Fuel Injector Connection.

I have a very old set of original Bosch 78#/HR low impedance injectors I bought used 14 years ago, and they are still working fine. I run a dry shot (total fuel through the injectors), and make 800HP/800lb-ft at the flywheel. I've measured losses of 12.1% (703 @ the RW) through a T56, and 21.9% (625 @ the RW)through a TH400 with non-locking converter. That's why you have to use flywheel HP to size the injectors. My BSFC was measured at 44.4 #/HR/HP on the engine dyno, which appears to be a very efficient number.