LNF Injection Angle question

[extremevx]

I have and LNF in a Solstice with a ZFR, stage 1 cams with fuel lobe and homemade 5th. Inj. setup.
I have purchased the Larger injectors from ZZP. They mention shortening the injection window for optimum operation. I assume this is done in the Injection Angle HOM Single Low and HOM sigle High tables. right now in my Hom single Low from 5000 up and 105% load, I am 349. On my Hom Single High, I am running 340 at the same areas. Now this is with e47. Now it seems to me that to shorten the injection time I would have to raise the values in those areas to say, over at least 360 to maybe 380. Is this a good starting point for these injectors? And it would seem also that less fuel would be going out the exhaust valve since we would be injecting after TDC rockover on the exhaust/intake stroke...Those with more experience with this please chime in... Posted my two tables as they are now in the car.

[cobaltssoverbooster]

lnf only uses single low iirc
injection window tends to follow cam phasing for the most part. would it hurt you to remove window timing, not really...will it cause problems, depends on what area you are shifting and by how much you moved it.
you just took your first step to a full ecu re-adjustment.

[extremevx]

I got it backwards. I thought the numbers in the table were the degree in crank rotation the the injector opened. After reading cobaltssoverboosters thread on this subject I now know the number represent the angle in degrees that the injector is open before the static point at which the ECM closes the injector. My tune is pretty good now. I dont really want to have to go back and tweak all the tables again. But I guess its all part of the fun. I was hoping I could just narrow the window and make the duty cycle of the injector come back to stock. Tell me if my assumption is correct. If you install injectors that are 14% larger as these from ZZP are supposed to be, I would think now that the ECM would have to send a duty cycle to the injectors that is 14% less in order to flow the same amount as the stock injectors. That being said, wouldnt the Ecm automatically compensate without having to close the window down in the table? I mean, wouldnt the ECM just look at the wideband and adjust the AFR on its own and send the required duty cycle to the injectors to make the desired AFR? It seems to me that all these injectors do is delay the onset of fuel rail pressure drop at a 14% higher load than with out them. What about increasing the Injector constant by 14%? I may just play around with these to see what happens.

[MikeM173]

Bare with me because I have not had to mess with any fuel tables in a while and I have not personally tuned the Opel injectors.

Injection Angle Hom Low is what is used for normal operation. I can not say for sure but I am pretty sure the High table is used during issues. This would make sense because the Injection time is started so much later though I could be wrong. It is commonly thought that the ECU doesn't use it at all. Back to the good stuff.

I have a thread on her that completely describes the use of the Injection Angle table. It is strictly used for when the injector will start to spray. Depending on when you set it will depend on how long the injector stays on to maintain it's Air/Fuel ratio. Since you changed out your cams it is in your best interest to readjust this table to fit your cams and fit your cam table. Please reference the other post for how it all works and the pictures I drew up describing it all for the LNF. The specs for your cams should be available either on ZZP's website or through them so you can properly set them up. It is in your best interest to completely draw out everything for stock vs the aftermarket cams so you can actually tune them fully, and then tune the Injection Angle correctly.

As for your question. On the website they reference tuning it for the Pulse Width. Pulse Width is determined by what the ECU is seeing from the wideband, and where your cams are set up and Injection Angle starts. To be honest I have a very strong feeling that if you properly tune what I said above you would have tuned properly for the Opel Injectors. I would have to actually look at the fuel tables that are available to make sure that nothing else should be changed. It could be possible that something else should be changed and us stock people do not have to due to already having proper operation. If you could upload pics of all the tables available along with the description I could help out more (I am at work and do not have my laptop with me to view).

Please read my other posts and either ask the questions here or there if you need more help. I have a small post on Cam changes though I do not go into enough detail and I have thought of making a new one.

[cobaltssoverbooster]

high table is never used mike. the tables rely on an intake manifold valve position and the lnfs dont have the valve. chris told us a few years back that table isnt used.
injectors are corrected for by changing the injector offset but its not necessary if your not seeing a large change across the board. i ran these injectors in my lhu motor and never had a problem with the old coding from the lnf injector settings.
keep in mind though my injector windows had been dyno tuned so i cant say they made a change there just at wot i didnt notice much difference.

all my current addition fuel systems run a second injection rail run off a second computer.

14% less on time is only .5-.75 ms less at max allowed open which is around 7.5-7.8 ms.

[extremevx]

Thanks for the info. 14% to me is not alot. I would think the bosch ecu would barely notice. Now if the injectors were 30% bigger I could see there being a difference to tje ecu. Im going to go ahead and plot my cams out and adjust my injection angle to that. Im am thinking about welding injector bungs on my intake manifold and hooking up a LE5 injector rail to the Schrader valve on the fuel line and getting and tuning it with a split second controller. I just never like the 5th injector. I know it works but it just looks like a quick fix to me...hooking up a sequential fuel injection system like on the FRS just looks more professional to me. There is UK company that sells an ECU that can control both sequential and GDI at the same time. Its relatively cheap compared to a motec. Its like $2500 and can also blip your throttle if you wanted to run and smg trans.

[MikeM173]

Extremvx I will gladly hook you up with a tune for your 5th injector setup haha I need one. It's either that or I continue with my cam job haha.

As for the 5th injector if I remember other peoples discussions (I've never seen how it sets up) the fuel comes out in a mist and add that to the fact that the boost pressure is so much you should not have to worry about one cylinder seeing more fuel then the other so I would not worry about it unless your pushing an extreme amount of power. Just my opinion.

I need to get the specs for the cams so I can draw out the diagrams and design my tables around them so when I have a customer with them Iaalready have the files ready and they aren't waiting for me to do that. Good luck though and let us know if you need any more help.

[cobaltssoverbooster]

when i use methanol race fuels and need a ton of fuel i use the megasquirt ms3 pro to control timing and an additional 2 more staged fuel rails.
boost in those motors have been mechanical but the ms3 handles that extremely smooth as well and does it by gear or speed which helps me retain traction before half track in 1/4 mi.

ms3 also controls wot shifting and sequential blips as well. cost is only 1100 and its waterproof with a built in knock sensor circuit and can transfer system. damn hard to beat for the cost.

Mike the 5th injector is in the center front of the manifold just to the right of the throttle body. it gets injected into the evap line spot and the manifold last i checked makes a 90* turn built into the casting. not the most friendly aiming of an injector but due to its centered location the injector does get enough fuel to all cylinders.

trying to get a major cam company to commit to vvt and custom grinds not off-the-shelf takes a lot of effort. If you go that way Mike you will be happy im sure but good luck in the beginning trying to get them to understand and help.

[codename Bil Doe]

If you know the cam specs and are just looking to get the grind lmk. My friend has been grinding cams on the side for a race shop for over 10 years. His grinds include everything from prototypes to sprint cars, GT3 cup cars, vintage racing, European classics, even stuff from the early 1900's. One-off grinds are more expensive, but he's done them all. More engines than I even knew existed.

[Area47]

change the injector constant 14%. dick with the rest as needed.

[MikeM173]

Thanks Area, I've never installed them so that helps a lot. That should be an easy catch though as soon as they are installed to see that fuel trims are off. Again thank you.

[extremevx]

Cobalt, do you run the megasquir 3 as a piggy back to the bosch wcu? I understand that the megasquirt cant run the bosch fuel pump or the gdi injectors.

[cobaltssoverbooster]

well the first one did, but all of the new setups are making the bosch a piggyback. the new setups fake almost every circuit out on the bosch so i can just use the ecu to control the injectors then the rest is ms3 pro.

[extremevx]

So your saying the new megasquirt ms3 pro can emulate the bosch ecu?

[cobaltssoverbooster]

no im saying that i have it it control secondary fuel sources, ignition, boost, and nitrous.
i send false inputs to the bosch ecu and use it only for factory fuel injector control nothing else.

[Japeatr]

inj scaling.jpg

here is what we used