Injector Size Question

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Jul 16, 2007 | 10:03 AM

The Evil Genius

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From: Dayton, OH HAWG: "this is Off Topic...it can get a bit north of care bears and strawberry shortcake in here"

St. Jude Donor '08-'09-'10-'11

Injector Size Question

I'm going to be installing an LT4 hotcam and a set of ported heads on my LT1, along with a 58mm TB. What I don't know is what to do about the injectors. Can I run the stock size injectors, with a different tune, or do I need larger injectors for this setup, also with a different tune?

Jul 16, 2007 | 10:47 AM

BADDUCK

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From: One day you're a Comet...the next day you're dust... Arkansas

I would ask whoever is going to tune the car what they recommend.

Jul 16, 2007 | 05:25 PM

93 ragtop

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From: Manassas VA

92-93 use the same injectors, 94-96 are slightly larger. You sound like you are going to have the same setup as mine, but I am running long tube headers. I can tell you, with mine, they are maxed out, and that is with stock pressure. You could turn up the pressure a little with an adjustable fuel pressure regulator, but if it was me, I would just buy a set of 30lb ford injectors. They dont cost much more then the adjustable regulator for a LT1.
Or run stock and see how it does. If you dont do any other mods I think it will be ok. BTW I got my tune from Alvin at pcmforless and he is just about dead on with his mail order tune. His dyno tune got me 6 more hp.

Jul 16, 2007 | 08:00 PM

Corvette Kid

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From: Good health is merely the slowest possible rate at which one can die

St. Jude Donor '04-'05-'06-'07

You might get away with it depending on how ported your heads are. If you had the later 24# LT1 injectors, it'd be a better bet. They only way to know for sure how marginal you are is by logging the injector duty cycle at maximum RPM. My 24# stockers were adequate (but just barely) at 6200 RPM with fully ported heads, larger valves, headers, etc. This was when it still had a 350 inch bottom end. I changed to an AFPR and 28# LS6 injectors. Soon after installing the stroker short block, I put in the 30# FMS injectors. The 30 pounders can be run at your stock pressure. I had to bump the pressure to reap the full benefit of the LS6 units.

Jul 16, 2007 | 10:01 PM

VenkmanP

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From: VA

Consider that the LT4 came with 28# with heads that flow less than your ported heads (if they are competently ported) and a lot less cam than the hotcam.

Jul 17, 2007 | 06:02 AM

93 ragtop

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From: Manassas VA

By the way, not trying to contradict what I said above, I am still running stock, but they are at 100 % and I am going slightly lean on top.
I purchased 30lb ford injectors, but never got around to installing and retuning for them. 30's were Alvins suggestion, considering it gave room to grow, and they are cheaply available.
Are you going to be running headers?

Jul 19, 2007 | 08:20 AM

The Evil Genius

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From: Dayton, OH HAWG: "this is Off Topic...it can get a bit north of care bears and strawberry shortcake in here"

St. Jude Donor '08-'09-'10-'11

I will be running headers. Sounds like moving to the 30# SVO's is the way to go. I'm slowly building up to a 383, so if I can reuse the injectors for that, it seems to be a good idea.

Thanks for all the help!