Final word on injectors
Thread Starter
Safety Car
Joined: Jul 2001
Posts: 4,871
Likes: 15
From: Detroit's West Side MI
Final word on injectors
Yes, I did a few searches but didn't find the answers to all of my questions. So, here goes, these should be easy for you guys...
1. What size are stock 1993 LT1 injectors? I've heard 23.8# and 22.0#
2. Will the ECM notice a difference between an aftermarket 24# and a stock?
3. Why the hell are stock injectors $105 each yet a whole set of FMS 24# or 30# is about $225?
TIA
1. What size are stock 1993 LT1 injectors? I've heard 23.8# and 22.0#
2. Will the ECM notice a difference between an aftermarket 24# and a stock?
3. Why the hell are stock injectors $105 each yet a whole set of FMS 24# or 30# is about $225?
TIA
Safety Car
Joined: Sep 2002
Posts: 4,030
Likes: 6
From: Maryland
Originally Posted by ScaryFast
Yes, I did a few searches but didn't find the answers to all of my questions. So, here goes, these should be easy for you guys...
1. What size are stock 1993 LT1 injectors? I've heard 23.8# and 22.0#
2. Will the ECM notice a difference between an aftermarket 24# and a stock?
3. Why the hell are stock injectors $105 each yet a whole set of FMS 24# or 30# is about $225?
TIA
1. What size are stock 1993 LT1 injectors? I've heard 23.8# and 22.0#
2. Will the ECM notice a difference between an aftermarket 24# and a stock?
3. Why the hell are stock injectors $105 each yet a whole set of FMS 24# or 30# is about $225?
TIA
Hope things are going well (read--wrapping up) with the build!
1) 23.8# is correct.
2)Yes the larger inj. will change the amount of fuel so it will effect A/F.
Whenever you get new injectors, you need a change in your chip. Injector size should be mentioned here on the forum when we talk about a heads/cam change, because for road racing, the bigger inj. are just as necessary as changing the stock tune.
3) LT4 inj. are also very, high, I checked last year. GM wanted $6k for an LT1 shortblock when I called. Well, that was the whole motor, they didn't have a short block option. I am guessing it's just supply and demand. They must have very few spares for the injectors.
Thread Starter
Safety Car
Joined: Jul 2001
Posts: 4,871
Likes: 15
From: Detroit's West Side MI
Originally Posted by sothpaw2
Howdy,
Hope things are going well (read--wrapping up) with the build!
1) 23.8# is correct.
2)Yes the larger inj. will change the amount of fuel so it will effect A/F.
Whenever you get new injectors, you need a change in your chip. Injector size should be mentioned here on the forum when we talk about a heads/cam change, because for road racing, the bigger inj. are just as necessary as changing the stock tune.
Hope things are going well (read--wrapping up) with the build!
1) 23.8# is correct.
2)Yes the larger inj. will change the amount of fuel so it will effect A/F.
Whenever you get new injectors, you need a change in your chip. Injector size should be mentioned here on the forum when we talk about a heads/cam change, because for road racing, the bigger inj. are just as necessary as changing the stock tune.
Anyway, I hesitate to get excited because I've had breakthroughs in the past, but after all the weeks of R&R (repair and replace, not rest and relaxation) the car idles. Yes, it idles. It hasn't idled on it's own in 7 months. Baby steps...
It's looking like a combination of injectors that were too big (30#) and spark plug wires. It runs smoothly at idle, but three or four cylinders are running waaaay cooler than the others (40* C vs 220* C) and the car backfires. So either the wires are bad at those cylinders or they're not getting fuel. Either way there's an uncombusted mixture kicking out the **** of the car.
Tonight will tell the story, new wires and back to stock injectors. If it's still not done then it goes to Rottie at Powerhouse tomorrow.
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
Scaryfast, Im going to give my take on this.
It is true that the factory programming says the injectors are 23.8lbs. But keep in mind that this is with a pressure of about 43.5lbs.
Now the ford injectors are rated at 38-39lbs. So a 24lb ford injector is going to flow about 26 or so at 43.5 lbs.
I may be wrong but this is my opinion.
It is true that the factory programming says the injectors are 23.8lbs. But keep in mind that this is with a pressure of about 43.5lbs.
Now the ford injectors are rated at 38-39lbs. So a 24lb ford injector is going to flow about 26 or so at 43.5 lbs.
I may be wrong but this is my opinion.
Thread Starter
Safety Car
Joined: Jul 2001
Posts: 4,871
Likes: 15
From: Detroit's West Side MI
Originally Posted by 93 ragtop
Scaryfast, Im going to give my take on this.
It is true that the factory programming says the injectors are 23.8lbs. But keep in mind that this is with a pressure of about 43.5lbs.
Now the ford injectors are rated at 38-39lbs. So a 24lb ford injector is going to flow about 26 or so at 43.5 lbs.
I may be wrong but this is my opinion.
It is true that the factory programming says the injectors are 23.8lbs. But keep in mind that this is with a pressure of about 43.5lbs.
Now the ford injectors are rated at 38-39lbs. So a 24lb ford injector is going to flow about 26 or so at 43.5 lbs.
I may be wrong but this is my opinion.
Race Director
Joined: Jan 2002
Posts: 12,261
Likes: 85
From: O'Fallon Missouri
"If you are using the Ford/SVO/Bosch style, you'll want to multiply their rating by 1.056 (24#=25.34, 30#=31.68, 36#=38.02, 42#=44.35, etc.), to accomodate the lower fuel psi rating at which they operate (Ford's 39 vs. GM's 43.5)."
Found this on a tuning page.
-Mike
Found this on a tuning page.
-Mike
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
Originally Posted by STL94LT1
"If you are using the Ford/SVO/Bosch style, you'll want to multiply their rating by 1.056 (24#=25.34, 30#=31.68, 36#=38.02, 42#=44.35, etc.), to accomodate the lower fuel psi rating at which they operate (Ford's 39 vs. GM's 43.5)."
Found this on a tuning page.
-Mike
Found this on a tuning page.
-Mike
assuming the above pressures are correct, if you take 43.5 and divide it by 39 it equals approximately 1.12 So if you multiply the 24lb injectors by 1.12 that would equal 26.88 lbs. and not 25.34lbs. Not sure where they come up with the figure, and again I could be wrong. Also, keep in mind the computer will do a certin amount of correction.
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Le Mans Master
Joined: Aug 2004
Posts: 5,141
Likes: 7
From: Metairie Louisiana
injectors
I installed the ford SVO 24's about a week or two ago. They were recomended by most people on the forum I talked to. It was a very easy install. It started a little rough at first. I thought something was wrong. After a couple of minutes of driving the computer must have adjusted something because it kicked in with some serious pick up while in the middle of accelerating. I din't change any computer settings or fuel pressure but a custom tune is on the way.