hey everyone im going back to tpi on my 89 gta trans am but planning on aftermarket build tpi im getting a holley stealth ram from summit an also the fuel rail kit with adjustable regulator the kit does not include injectors idk what pound injectors i need also going with a set of 113 corvette tpi aluminum heads with some slight porting an also gonna get a good low to mid range power cam 5000 grand power band i need to know all of the stuff i will have to do to make this tpi get up an go an also have 300 ft.lbs torque an 300 hp to the back wheels at least

 

For the injectors you should call one of the many injector vendors on the boards. I have heard nothing but good things from http://www.southbayfuelinjectors.com and I had a good experience with injectorsplus but haven't seen much of him on the boards in a while.

 

Fuel Injector Flow Rate Formulas

N/A Engines: Injector flow rate (lbs/hr) = .45 x hp / # of injectors x 1.15

Boosted Engines: Injector flow rate (lbs/hr) = .55 x hp / # of injectors x 1.15

Nitrous Engines: Injector flow rate (lbs/hr) = .57 x hp / # of injectors x 1.15

 

HERES THE thing i need to know what size injectors will i need to feed enough for a 355 sbc this is great web site just need to be led in the right direction on what injectors to get

 

HERES THE thing bro....we need to know how much horsepower you intend to make, then we can tell you what size injectors you need. Its not as simple as "X" size engine takes "X" size fuel injectors. It doesn't work that way.

 

For example, you can make 350hp with a 17lb injector (8 of them) with the appropriate fuel supply and tune. If you want to make 400hp you'd need at least a 19lb injector. Do the math, its quite simple.

 

We know nothing about what else you have in engine and if it even matches up.
You say you want a cam that works under 5K but are using a intake that goes pass 6K.
If you want to stay under 5K get a big tube TPI setup

 

Need more info before we can help you out.

 

What more do you all need?
355 Chevy with Vette heads, light porting on the heads and around 300hp
Stealthram Intake
Mild Cam

A typical 24lb EV1 style injector should work great. Personally, I would get the older Ford Motorsport EV1 blue tops. Great injector for this application and you can still get them new. Stay away from rebuilt junk injectors.

 

Horsepower has alot to do with sizing injectors. If you are going to run around 300hp then 24lb injectors will be fine. We carry brand new bosch lll's in 24lb if you are interested either pm or call us.

 

There goes another one that can't do the math. A 24lb injector will support WAY more than 300hp my friend. That injector would certainly support 300hp but would have to run at a reduced duty cycle to do so.

You all have to keep in mind that fuel supply also has a drastic effect on how a fuel injector performs. For example, a 17lb injector running at 30psi might only support 250hp....but if you bring the pressure up to say 50psi, it might support close to 350hp.

Injectors perform optimally at around 80% duty cycle. 24lb injectors are probably going to be too big for this application. This guy really needs to consult an experienced tuner to get the best insight on what size his injectors need to be.

 

Probably the most stupid thing I have read all day. Do us all a favor and stop googling stuff and pretending to be an expert.

 

lt1 cars are running 24 pound injectors stock from the factory and they arent pushing 300hp from the factory.. and ls1 cars are using 26 or 28 pound injectors on 330hp cars... so i think that statement is abit false... in fact lots of lt1 guys use bigger injectors anyway... im running 24 pound injectors on my build and id say they are great..i might go to 26 or 28 pounds whenever i decide to step up to afr heads and a better converter.. my motor is torquey as hell just how i want it .....

 

You guys have fun with this. You all should have paid closer attention in Math and Physics class.

 

 

LT1's run 24lb injectors all day long at 275hp and are no where near close to the max duty cycle. You guys need to put down the car craft.