I was digging around rcengineering and thier calculators comes up with about 30lb/hr injectors needed for a 400HP motor. What are the stock 94LT1 injector ratings? I have access to some nissan 370cc (around 30ish lb/hr) injectors that seem to fit, but I don't know if that will be an improvement over stock.

I know that I won't pushing 400HP on my high mileage LT1, but I don't want to have the injectors lean me out when I stomp on it.

 

24lb/hr stock LT1 injectors

 

Blue,

Stock injectors are 24lbs/hr.

If your really not trying to do anything to the motor the stock injectors are fine. Just upgrade to some SVO injectors or Accel's.

Jay

 

Thats what I was thinking. Hopefully it has enough metering control to idle the same. I'm sure the PCM will pick up on this change. Its a pretty smart system. Thanks a bunch, I'll be sure to post effects. Especially if I use the Nissan injectors.

I know that the 24lb/hr stock injectors are "fine", but I want to make sure that I don't starve. Its high mileage, but I'm always hitting that 6500k rev limiter. Maybe I'll start by installing a wide band?

 

http://www.rceng.com/technical.htm

At the bottom, I used my friends dyno numbers of 320hp, stock 24lb/hr injectors, and 52psi fuel pressure to get 0.56 BSFC.

Using 0.56 in the fuel injector sizer calculator gives 32.65lb/hr (343cc).

 

I highly doubt the nissan injectors will have the same type electrical connectors. and stock injectors are good to almost 450hp

 

http://www.grandsportregistry.com/lt1vslt4.htm

If the stock injectors are good to 450hp, then why did chevy increase them from 24lb to 28lb for the LT4 when it only makes 330hp at 5800(from 300@5000)? The site linked above notes that the injector rating was increased because of the extra "RPM's" that the LT4 pushes. So while I don't have an LT4, I would like to push that HP sometime this summer.

Would increasing the fuel pressure be a simplier way to do this? I would have to increase the pressure by 1.36 times the base pressure to do an equivalent of a 24-28lb jump. Would all of the lines and pump would support this?

 

good to as in they are max'd at 450hp. the part about the extra rpm is due to the increased pulse width at higher RPM. yes you can bump the fuel pressure for the same effect, but this is a backwards way of doing it. does it work, yes to a certain point. once you start hitting higher duty cycles you need to bump up the injector size. this may or may not be a factor depending on how much HP you plan on going up to.

*edit* and I need to apologize, I had my thinking backwards. the stock PUMP is good to 450hp, not the injectors. the fuel lines you won't have to worry about until around the 800hp range, and even then they are usually adequate

 

How do the LT1's respond to a port/polish? I'm planning on doing an upper end rebuild here this spring, and i figured I'd gasket match and otherwise clean it up. The bottom end sounds strong so I might as well move forward!

 

Gasket match doesn't do much for the heads, most of the LT1's respond to bowl work more than gasket matching.