I believe that the Buick 3.8L injectors are about 30 lb/hr units. Even with a new chip program, they are beyond the ability of the Fiero ECM to control properly.
What a co-incidence Dennis. I was just looking at your site and noticed you used 24 lb Ford units. I assume these work well and Fiero right? There is plenty of them on ebay at present. My plans are for 30 thou over 2.8 with 8:01 compression ratio forged pistons and a T3 Turbo running decent boost. Heaps of other plans but that is the basic idea. The ECM will be modified or thrown out altogher in favour of a aftermarket unit.
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09:48 AM
Pyrthian Member
Posts: 29569 From: Detroit, MI Registered: Jul 2002
I don't think they would be 30lb. The stock Buick GN is 28lb. The largest I have found that would run with the ECM are 24lb. The 28lb will not idle. Make sure they are high resistance (14-16 ohms), not low (2-4 ohms)....Paul
It depends on how much final HP you are planning to have. Here's some numbers I ran through the Fuel injector calculator at RC Engineering for you.
12 psi boost in a 2.8 could theoretically produce approx 260 HP. The 2.8 puts out approx 160 HP (at least that's what it's rated at from the factory) at 1 atmosphere and 12 psi is approx .8 atmosphere (160 * 1.8 = 288, then subtract approximatly 10% loss through heat to come up with HP rating that you want to build for). Based on that HP rating, you would need 27.5 Lb/Hr injectors running at 45 psi fuel pressure constant.
If you run a rising rate fuel pressure regulator (1 pound increase in fuel pressure to 1 pound boost) you will be able to use 25.5 Lb/Hr injectors at 12psi boost, but make sure to install and Air/Fuel ratio meter to be sure that you don't go lean.
------------------ As Alice Cooper once said...
quote
Feed My.... Frankenstein!
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09:23 PM
Dennis LaGrua Member
Posts: 15146 From: Hillsborough, NJ U.S.A. Registered: May 2000
What a co-incidence Dennis. I was just looking at your site and noticed you used 24 lb Ford units. I assume these work well and Fiero right? There is plenty of them on ebay at present. My plans are for 30 thou over 2.8 with 8:01 compression ratio forged pistons and a T3 Turbo running decent boost. Heaps of other plans but that is the basic idea. The ECM will be modified or thrown out altogher in favour of a aftermarket unit.
I would believe that 24 lb injectors would be plenty big for a turbo 2.8L. If you use the Fiero ECM it's a good idea to use only a large enough injector to support the maximum HP that your engine will make. Since you will be using an aftermarket ECM ; control larger injector may be easier. However, large injectors on a small engine require only a very small pulse width at idle to provide enough fuel. Using too large of an injector can lead to an unstable or erratic idle that is hard to correct.
