I installed LUCAS 42.5's in my 2000 GTP years ago. The tuning specs were not available from ZZP, and I have only seen a few tuners who posted their best guess!
Has anyone ever come across the specs to fine tune these injectors??
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I installed LUCAS 42.5's in my 2000 GTP years ago. The tuning specs were not available from ZZP, and I have only seen a few tuners who posted their best guess!
Has anyone ever come across the specs to fine tune these injectors??
This might be what you're after. It came from an LS so might not fit up perfectly as the discussion indicates.
https://forum.hptuners.com/showthrea...ectors-w-data)
Best of luck.
Look through the repository and check what others have done.
In reality you can set the first box from 40 to 42 and the last box at 43 to 45 and scale the boxes evenly between them.
Having an EXACT number is not as crucial.
unbolt the rail and make a test connector by purchasing an injector pigtail repair kit for 1 injector. on one side make a long lead with alligator clip to affix to ground. on the other lead wire in a low tension push button that that also has an alligator clip to attach to a 12v source (or a spade to plug into a fuse position).
the other option is to manual override one injector in hpt scanner user i/o command window, if the ecu supports it.
get a container of large size, stop watch, and a scale without timeout feature. a kitchen scale for measuring various foods is plenty. only needs to read a few pounds. 1 gallon of fuel weighs 6 lbs. so 42 lbs in one hour is about 7 gallons of fuel. 42 lb/hr / 60 min/hr is 0.7 lb/min which is 0.116 gallons = 439ml for 1 minute on time. 30 seconds of on time would be half of that so...~220 ml. at 1 minute your only talking 1/2 lb of fuel you need to contain and measure. its really not that much.
zero the scale with empty container on it. manually override the pump to supply pressure with the cars system. your going to override the injector with the push button but at the same time you need to start the stop watch. if your container is large enough you can spray and collect fuel for 1 minute. if not you can spray and collect for thirty minutes.
when your time is up weight the container again in pounds (lbs). if you collected for 1 minute, times the weight by 60 and you get lb/hr flow at 100-101 kpa manifold pressure flow rate value.. if you collected for 30 seconds then times the weight by 120 and you get lb/hr flow at 100-101 kpa kpa manifold pressure flow rate (assuming your baro pressure is around 100-101 kpa or sea level)
from here you can use a flow rate calculator to change the flow rate based on delta pressure change. as vacuum goes up use a higher pressure. you can populate every cell by using the calculator or find the ends and use linear interpolation feature. This works fairly well for fixed rail pressure systems.
for 1:1 referenced systems just populate the whole table with your calculated value from the test.
as Zero Boost stated, "accuracy is not crucial" to get running efficiently. Any error in the test will be washed out by the ve table or maf table adjustments, whichever gets used.
I personally record volume per on-time using one of the inputs on my mpvi pro interface and a volumetric cylinder that is rated for 500 ml. I am usually testing larger injectors like 850 cc and larger for flow restriction due to inlet filter or internal issues and need the large cylinder volume to extended my test time window. since the accuracy of the 500 ml is ? 2.5ml by eyeball and annotation lines every 5 ml, i choose to pour it into a 100 ml cylinder with ? 0.5ml accuracy by eyeball and 1 ml annotation lines. 1 ml = 1cc so, all i have to do is record how many ml per time i get and divide volume by time to get flow per 1 second. multiply that by 60 to get 1 minute worth of flow and there is my new 100-101 kpa manifold value in cc/minute. you can change the units of the flow rate table to cc/min and enter the values from the test directly. when done switch back to lb/hr and you know your flow in both. you can also use the hptuners unit converter built into the software or use online conversion calculators which are abundant and free. you still would repeat the linear interpolation the same was as mentioned above but its better than standing there and taking wild stabs into the dark.
not everyone has this measuring stuff or the parts to build a voltage reference leg that steps 12v down to 5 volts with minimal current which is why i mention the less accurate way of weighing fuel weight. it does get you in the ballpark but it wont get you any offset data. for that you need to have them characterized if you cant get data from another individual. the guys on the megasquirt and home built efi forums have been using these methods well before me and have good results.
i use glass cylinders so i dont have to worry about the $8 plastic cylinders warping and melting from chemical reactions with pump gas, methanol, or nitro.
sorry for the long post, hope it gives you ideas for determining flow rates.