Fuel Injectors

[billybaloneey]

Originally Posted by Jeffvette

You are supposed to use the 21lb for the LT5. If you use the 19lb accels you will lean out the motor.

Order Accel 150821 cut off the alignment tab and remove the lower o-ring on the injecotr body for the primaries and install.

Thanks for the explaination and tip.

Got your PM cliff. The 205's will be fine for your app. If you are planing on a little juice, I would step up the injector size. Keep in mind, there are several stroker motors running the factory injectors.

[Polo-1]

I know what their site shows, but when you call them and ask for injectors for the LT5 you will get the 205cc.

I'm in the middle of a cammed 402 build. I would think it should have much larger injectors (600-650hp) A call to Marc, and he said no need. 205cc will work fine He tunes these more then anyone I know.

[Dynomite]

Originally Posted by Polo-1

I know what their site shows, but when you call them and ask for injectors for the LT5 you will get the 205cc.

I'm in the middle of a cammed 402 build. I would think it should have much larger injectors (600-650hp) A call to Marc, and he said no need. 205cc will work fine He tunes these more then anyone I know.

Marc mentioned some time ago in a discussion that 205s are good for 600 hp (what you stated above confirms that). Marc also mentioned that 225s are too big for the LT5 engine with the modifications I am doing (just now in an e-mail related to camshaft bolts and modified chip)

This is the second time I am having the chip modified as I do not know when to stop on the modifications

Originally Posted by Jeffvette

The 205's will be fine for your app. Unless you are planing on a little juice.......

If Jeff says it...it has got to be true as Jeff knows my modifications more than anyone ..........thanks Jeff

I am assuming that the fuel rail (fuel pressure regulator/fuel pump) puts out about 50 psi and that fuel pressure does have an effect on nozzle sizing and fuel lbs/hour/injector

I am also assuming that the fuel pressure regulator is not adjustable

[Dynomite]

LINGENFELTER Performance Engineering does have an adjustable fuel pressure regulator for the LT5

http://cgi.ebay.com/ebaymotors/LT5-Z...Q5fAccessories

Does this mean you can up the fuel pressure as you like with LINGENFELTER fuel pressure regulator resulting in more lbs fuel/hour/injector?

Does this mean you can go from 205s to greater than 205 capability using 205s just by adjusting the fuel pressure?

[XfireZ51]

Originally Posted by Dynomite

LINGENFELTER Performance Engineering does have an adjustable fuel pressure regulator for the LT5

http://cgi.ebay.com/ebaymotors/LT5-Z...Q5fAccessories

Does this mean you can up the fuel pressure as you like with LINGENFELTER fuel pressure regulator resulting in more lbs fuel/hour/injector?

Does this mean you can go from 205s to greater than 205 capability using 205s just by adjusting the fuel pressure?

The answer is yes. Fuel pressure affects flow rate. If you look at your calc above, the 16 injectors at their rated flow will support something like 540hp assuming rated pressure and an 80% duty cycle. Changing fuel pressure should be accompanied by a change in the BPC in the cal and some changes to the VE tables. An issue that "could" arise is a desired PW for idle that is too small for adequate control resulting in an uneven idle. If I read correctly, the new ZR1 uses a variable FP to deal with higher hp while using only 8 injectors.
My 84 used a VAFPR that varied FP from 10psi at idle to 20psi at WOT. That gave a PW that was good for smooth idle and enough flow rate at WOT for a 75% DC and a 12:1 AFR.