Here is what i building i have gone thru alot of debate of a 396 or 383 and here is what i decided well i have no choice now because i all ready ordered all the parts, here ya go what kind of rear wheel hp do you guys think i will be putting down? i know there a some pretty similar set-ups out there.

LT-1 block bored .40 to make it a 384
Eagle 4340 3.75 crank
Scat 6" I beam Rods
SRP Forged pitons11.9 with a 58cc head
Piton rings are filed to fit
Also deck will be decked
Comp Ratio will probalby around 12.5 to 1
LT-1 heads ported by LLoyd Elliot 2.02/1.60 valves flowed 265
Ported intake 52mm TB
Comp 306 cam 112lsa
Comp 1.6 RR's

1 3/4 Long tubes
3" true duals w/ X pipe and bullits

PCMforless.com tune
30# inj

TH-350
10 bolt 4.56's

I will be also running juice sometimes 150 to 175 wet shot

What kind of RWHP?

 

You definately need bigger injectors, 30# will not do it.

I need to get 36# with my setup. Just had a BIG discussion in the thread "You think my 22 lbs. Injectors are MAXED out @ 400 HP?"

You may need bigger injectors than me...

 

I have allready had the discussion with Brian Herter @ pcmforless.com and he said that the 30# inj should have no problem uless i go to a turbo or a blower.

 

Have you ordered everything yet? I'd go with a bigger cam. I would expect at least 400 rwhp on that setup tho. Probably close to 430, maybe more. GMHTP made 430 with their 396 on a CC305, and good torque.

30lb injectors will be plenty for this app. I forget the actual math behind it, but you can get away with a smaller injector on a larger motor. MTI made 500+ rwhp on their 427 with stock injectors. Probably would have made a little more with a bigger one, but it wasn't running super lean. I think it has something to do with the longer stroke, or rod ratio, but I forget...anyone know?

 

You are seriously mistaken if you need 36# injectors when you are trapping at 103.

 

I am still trying to figure out where his other 125hp are going. I ran a 13.3 at 102 with a 110,000 mile stock lt1 and a 2800 vig.

 

Oh his dyno said 288RWHP, which I don't see how that is 400 fwhp.

 

That dyno run was before Longtube, !CAT and CAI.

330rwHp is what it's at now. = 396fwHP

I'm sorry you are right, 36# are more than enough, I just forgot to mention that I have plans the buy a blower



Oh yeah, My injectors aren't big enough, that's why my times suck...

93's only have 22#, which max out @ 391 fwHP!!

Let's say your motor puts you @ 400 rwHP, that about 480 fwHP, now let's do the Injector formula...

Injector Size x Cylinders x DC / BFC = 453

30# injectors will support 453fwHP @ 85% DC. I'd look into bigger one's my friend.

 

Im just going by what Brian said at pcmforless.com and he has tuned hundreds maybe not even thousands of PCM's for LT's & LS's so im not saying you dont know what your talking about im just doing what he thinks i need to do. Also he told me if i was going to run a dry shot i would need 36+ inj but for a wet shot no problem with 30# and a 384 w/ a 12.5 to 1.

I would like to buy a bigger cam but i want to see what this 306 cam will make, its nothing for me to dao a cam swap and springs.

 

id estimate 420 ish rwhp on the motor with good tuning.

 

I undertand, but look at it from this point of view, If you wanted a dry shot, you won't have to buy bigger injectors and re-tune your PCM again! You can't run on 30# forever, so why buy twice? You can find a set of 36# for the price of 30#, so if I were you, I'd go bigger.

With a Combination Motorsports Head & Cam package, I think you could hit 460 rwHP...

Let's use got_hp?'s guesstimate for another injector formula:

420rwHP = 502fwHP

Injectors @ 85% Duty Cycle:
30# = 453 fwHP
36# = 544 fwHP

So you see why I recommend the 36#. With making that kind of horsepower you'll be using almost 80% of the 36# injectors duty cycle. That's about the recommended limit for those injectors! Some people do 85% though. Plus it leaves you room for more mods, not to mention that bigger cam you want!

 

Well here is were is stand, i have 30# inj right now and thats the program in the pcm is for 30#. I will dyno the car when i get the motor in and the wide ban will tell me if its running lean i will adjust the fuel pressure and if tha does not fix it then i will adj timming and the fuel curve with LT1 Edit and if tha does not work then i will buy a new set of 36# inj or what ever i need.

Thansk for help and info ZPaul2Fresh8 im just trying to see whats a good average for RWHP with my combo and not debating on which inj. i should use

 

yup, thats about right, according to RC Engineering's injector calculators......if youre using the stock LT1 fuel pressure.

keep in mind, the fuel injectors will support a lot more power than that........but they will be going over 85% duty cycle which isnt recommended.


im doing heads/cam right now, and im going with some 42#ers just to have some extra for when i put in a stroker bottom end in the future.

 

I understand. I'm more than happy to help. Goodluck on the engine and let us know what happens.