Injector settings
Thread Starter
Racer
Joined: Jun 2012
Posts: 492
Likes: 1
Injector settings
So I'm swapping out my stock injectors (01 LS6) to some 72lb ones. I'm a bit unsure about what the flow rate should be. I'm using HPT. Heres what another person had for their 72lbers. Look right?
Thread Starter
Racer
Joined: Jun 2012
Posts: 492
Likes: 1
What do you mean by boost ref? Regulator? If so, then no. I'm in the process of prepping it for twin turbos. Just swapped over to 2 bar SD tune. I'll be dropping in the 72lb (750cc) injectors tomorrow. Everything else on the fuel system is currently stock for now. Once the twins go on, I'll add a BAP and retune again. But I'd like to get the new injectors going while its still naturally aspirated. What values should be in that table for 72lb (750cc) injectors? I tried a spread sheet calculator but I must have been entering something wrong. I tried with the stock injector size and it was way off of what the stock tune values showed. The table I posted above is what another member had who was using the same injectors.
Premium Supporting Vendor
Joined: Oct 2004
Posts: 23,599
Likes: 1,224
From: Providing the most proven supercharger kits for your C5/6/7 609-752-0321
You need some information like are they 72lbs at 3 bar or 4 bar? A good injector company like Injector Dynamics gives you all the proper data which is a great help in tuning.
Thread Starter
Racer
Joined: Jun 2012
Posts: 492
Likes: 1
They are RC Engenering injectors. 750cc (71lb according to their website) at the usual 3 bar rating (43.5psi). I know we run higher pressure though.
Premium Supporting Vendor
Joined: Oct 2004
Posts: 23,599
Likes: 1,224
From: Providing the most proven supercharger kits for your C5/6/7 609-752-0321
I do not have a graph in front of me, but to be properly scaled they will be somewhere in the low 80's. 82-84 for instance.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
2027 Corvette Buyer's Guide: Everything You Need to Know!
Joe Kucinski
Premium Supporting Vendor
Joined: Oct 2004
Posts: 23,599
Likes: 1,224
From: Providing the most proven supercharger kits for your C5/6/7 609-752-0321
Melting Slicks
Joined: Apr 2005
Posts: 3,418
Likes: 1
From: Chicagoland Area IL
Premium Supporting Vendor
Joined: Oct 2004
Posts: 23,599
Likes: 1,224
From: Providing the most proven supercharger kits for your C5/6/7 609-752-0321
Also I feel the boost referencing has to be taken into account or the injector goes in the opposite direction, not larger. For instance, 58lbs static fuel rail pressure with 10lbs of boost is actually producing 48lbs of positive fuel pressure.
Melting Slicks
Joined: Apr 2005
Posts: 3,418
Likes: 1
From: Chicagoland Area IL
It’s a simple Bernoulli scaling equation that most people use, good starting point but purists like DSteck will say injector test data at correct pressure trumps it. Depending on what calculator you have the ^0.5 is square root (solves the same).
Go to any online injector site calculator and it will generate same results, 3 bar to 4 bar.
Go to any online injector site calculator and it will generate same results, 3 bar to 4 bar.
Drifting
Joined: Oct 2004
Posts: 1,621
Likes: 6
Can you explain how you came up with 96? I have been on the same page with Skunkworks on this equation, just curious.
Also I feel the boost referencing has to be taken into account or the injector goes in the opposite direction, not larger. For instance, 58lbs static fuel rail pressure with 10lbs of boost is actually producing 48lbs of positive fuel pressure.
Also I feel the boost referencing has to be taken into account or the injector goes in the opposite direction, not larger. For instance, 58lbs static fuel rail pressure with 10lbs of boost is actually producing 48lbs of positive fuel pressure.
Melting Slicks
Joined: Apr 2005
Posts: 3,418
Likes: 1
From: Chicagoland Area IL
Pick a unit and stick with it (metric or standard) equation doesn't care.
Last edited by Skunkworks; Oct 3, 2012 at 12:29 PM.
Pro
Joined: Feb 2005
Posts: 652
Likes: 16
From: Upton MA
I agree with Skunkworks the injectors are 82 lbs @ 4 bar.
The injector sizing chart that you have posted from my old files are set for a non boost referenced system as I mentioned when I emailed the file to you. My system does not accomodate positive pressure. In order to compensate for boost the numbers quickly change from 10 KPA manifold vacuum to the 3 bar 72 lb injector that they are at 15lbs of boost. The additional fuel required is added in by way of power enrichment. Boost referenced is a much better way to go as long as you have enough fuel at the higher presssure required when under boost.
The injector sizing chart that you have posted from my old files are set for a non boost referenced system as I mentioned when I emailed the file to you. My system does not accomodate positive pressure. In order to compensate for boost the numbers quickly change from 10 KPA manifold vacuum to the 3 bar 72 lb injector that they are at 15lbs of boost. The additional fuel required is added in by way of power enrichment. Boost referenced is a much better way to go as long as you have enough fuel at the higher presssure required when under boost.
Melting Slicks
Joined: Apr 2005
Posts: 3,418
Likes: 1
From: Chicagoland Area IL
Drifting
Joined: Oct 2004
Posts: 1,621
Likes: 6
this is what confuses me. My Hptuners scanner tells me on my last dyno run I made 185 kpa which is about 12 psi on my gauge. Wouldnt 200 kpa = 14.5 (which is one atmosphere)?