Return style tuning on a lsj

[darkmanx]

ok , On the lsj the infector vs kpa tables are maxed out at 63.5 on the 79lb injectors on a base of 43.5 psi my static flow is 76.64 and a base of 58psi my static flow is 88.5. my question is , is there a table that i need to modify to add to the 63.5 flow rate or just leave it at that? If so what table is it?

[dont_blink]

Yes. Your injector modifier vs. volts table just below the main injector table. So for example, if your 79s flow at exactly 79lbs at a 3bar base pressure (You need to make sure they do), then I would set your injector table to 39.5 across the board and set your multiplier table to 2.0 to make things easier.

Also, you will need to find the latency values for those injectors for the delta pressure you need to run (rail pressure vs. manifold pressure). If you intend to run a 3bar base pressure then you will need to know the dead times at around 300kPa differential. If you are going to use like 50psi for a base, then you need the dead times at around 350kPa differential. This is info I never could find for the 79s, but then again I ran a $500 set of ID 1000cc injectors that came with all that data when I bought them. You will set your MAP and VAC tables to the same values in every single row across the board, with the columns being the eaxct same from one to the next for that given differential dead time. I know OTTP uses them a lot and tunes them so I would assume they have this info. If not you may need to send the injectors out and have them benched for dead times, short pulse adders, and actual flow. An injector that large on a motor that small without using the proper dead times will cause some serious stumbling and other issues.

You will have all the info I have when I get to my laptop, I'm not going to leave you hanging.

[darkmanx]

yeah sadly i dont think ill ever find that info either and i dont think ottp has it. So if my vacum is at 15inhg at idle which is around -50 kpa then just copy the -50 kpa table in the offset vs map and vac tables across the board?
thanks for the help in advance

[dont_blink]

No. You want it set at 0 vaccum, so 1bar or 100kPa. The whole point of a pressure based fuel system is that the regulator adjusts pressure on its own and all you have to do is tell the PCM basically how long to open them for and how soon to fire them and how long they will take to close based on voltage and pressure. You kind of need that info with a pressure based system or your shit is going to be all kinds of out of whack. Worse comes to worse you send the injectors to Yaw Power or something and have them flow benched. I gave up on the 79s and 80s because no one ever had any info on them and you could never get ahold of the manufacturer to get the proper values. So I just stepped up to real injectors instead to make my life and driving my car easier.

[darkmanx]

Everyone running return on 79 annd 80 are doing it the way i said, im not saying your wrong because im no expert on the subject and i know your a perfectionist. so your saying you copy the 100 kpa table from the vac tables across the board to the map and vac tables? and whats wrong with the other way that everyone seems to be doing it?

[dont_blink]

Because I would like to know where they got the offsets from? If they are using the stock offset tables then those injectors are going to be WAYYYY out of whack. Technically the 100kPa table is the one to use, but you have to have the proper latency tables for those injectors first and you should be using the offsets at your given delta pressure. In other words each psi of base fuel pressure is going to cause the injectors to open slower or faster. Your FPR will do the rest after the PCM takes into account the dead times and pulsewidths.

[darkmanx]

Because I would like to know where they got the offsets from? If they are using the stock offset tables then those injectors are going to be WAYYYY out of whack. Technically the 100kPa table is the one to use, but you have to have the proper latency tables for those injectors first and you should be using the offsets at your given delta pressure. In other words each psi of base fuel pressure is going to cause the injectors to open slower or faster. Your FPR will do the rest after the PCM takes into account the dead times and pulsewidths.

most seem to follow this guide
http://www.hptuners.com/forum/showth...n+style+tuning

[dont_blink]

Yes, but those values are for 60lb injectors. You are running 79s.

[jimbos'ss]

so far no one gotten any info on the 79lbers so its just best guess right now with them, i have used the tuning guide in that link and it works fine for me without any stumbling issues

[dont_blink]

You're using the 60lb offsets for the 79lb injectors? I guess if it works okay then there is your answer darkman. It's not the best solution, but it's the only one we have for those 79s unless you wanna send one out for testing.

[jimbos'ss]

You're using the 60lb offsets for the 79lb injectors? I guess if it works okay then there is your answer darkman. It's not the best solution, but it's the only one we have for those 79s unless you wanna send one out for testing.

no absolutely not, i am using the ifr modifier table to modify the stage 2 injector settings. eventually someone will have to send a set out for testing, unfortunately its low on my priority list right now. especially seeing as my car is running fine as is.

[darkmanx]

You're using the 60lb offsets for the 79lb injectors? I guess if it works okay then there is your answer darkman. It's not the best solution, but it's the only one we have for those 79s unless you wanna send one out for testing.

yeah , most just modify the table and none has had a problem yet, so i guess ill try that too