I am in the process of starting to build the fuel system for my LSx powered '75 Vega and I have a few questions for ya all.
My combination is as follows:
1975 Vega, 2800 lbs'ish when finished, 2000 5.3 V8, non ported heads, Comp Cams cam 224-228 duration at .050" .534" - .537" valve lift, using the Edelbrock single plane intake with the stock 75mm throttle body, TH350 trans, 3.50 gears in rearend using stock GM computer system that came with the truck, obviously I am going to have it reflashed to work properly with the current combination
My questions are, from anybody's previous experience, what would be the ideal sized injector for this application, I belive stock is 22 Lbs/hr?
Secondly, is there any advantage with using the stock style/shorty injectors like that came with the engine when I got it, or will the normal Bosch style injectors work fine. My fuel rails will work with either type of injector as there are two holdowns for it to compensate for height differences..
Any help is appreciated, as some local people have given me some conflicting information, and now I am totally lost

Mike

 

Anybody????????
I searched the forum, and came up with two answers, 30's or 42's.
Still not quite sure which one would be best to use?
Any help is appreciated!!!

Mike Schwochert

 

If a 26s or 28s are good for a 5.7 with bolt ons and mid modified they shoud be good for your aplication.

 

There have been different injectors over the years in LS1. 26# & 28# came stock depending on the years 1998-2002.

The best calculations I've derived is that you need 1# per 1.6 or 1.8 hp depending on if you want ot run 80% or 90% duty cycle.

26# on a V8 should be good for around 332-374HP.
28# on a V8 should be good for around 358-403HP.
30# on a V8 should be good for around 384-432HP.
42# on a V8 should be good for around 537-604HP.

I dont' think there is any benefit of a different injector as long as you are using the calculations correctly for the appropriate PSI/BAR.

A LS1 stock should be @ 58 PSI if memory serves me correctly.

 

If your car is street-driven (licensed), it is important to select injectors that are large enough but not too large. Manufacturers specify injectors that are borderline at WOT because smaller injectors provide better control at idle and low load which is necessary to minimize emissions. A race-only engine can reasonably use injectors that would be too big in a daily-driver.

 

simple:
http://redhardsupra.blogspot.com/200...readsheet.html

not so simple, but more flexible:
http://redhardsupra.blogspot.com/200...se-widths.html