Injection Timing Assistance Requested

[Michael_D]

My calculus is rusty, but I understand. Thanks for the clarification. I always appreciate your comments.

After messing around with the worksheet a bit, and real scanner info, I need to make significant changes to the boundary. It will be quite close to the oe settings, but with the rpm table zeroed out.

One more question though. What injector pw lengths are best to use in the 1500-2500 rpm range? WOT, moderate speed increase, or just cruise? At cruise, pw is .7 - 1.3. Moderate acceleration is 2-4, and wot at all rpm range is 6.2 - 7.4.

[Eaglegoat]

I'd use WOT. That way the pulsewidth fits no matter what.

[Michael_D]

Thanks. That makes sense.

[barum]

What injector pw lengths are best to use in the 1500-2500 rpm range? WOT, moderate speed increase, or just cruise? At cruise, pw is .7 - 1.3. Moderate acceleration is 2-4, and wot at all rpm range is 6.2 - 7.4.

I would use "typical" operating situation values. To be more specific, in a NA application:
- below 2000 rpm => average cruising pulse widths since it's all about smoothness and fuel efficiency wouldn't hurt either (I aim for the best fuel efficiency = most efficient combustion)
- between 2000 and 2500 rpm => average between cruising and moderate acceleration pulse widths given the more spirited NA cam which probably doesn't really shine in that area, anyway. Sure, you may be able to floor it, but does it do any good? Typically you are still doing some light duty driving in this range.

[Michael_D]

That's the rationale I used for the current settings, Barum. Yah, I don't hammer the go peddle much under 2500 rpm. At least not after the car is rolling, and not in first gear. Tires are too expensive.

PW varies so much with this thing.... I have ID 850's now, which are overkill for this power level. At idle, PW is 1.2 - 1.3. Then it drops when just putting down the road, under 1. I still don't get that, why it want's more fuel at idle than under light load.

[Michael_D]

Is there a "max" one would not want to NOT exceed on the boundary?

I have to set the boundary to 650 with 80 ECT to get FRC-EOIT under 30 degree from the IVC above 5000rpm. That seems excessive...... This cam's IVO is 28 btdc and IVC is 74 abdc (per my degree wheel), 670 lift.

[GHuggins]

I never see any benefit in going beyond 62ish... You still want fuel on a closed valve too with rpms to maintain a good burn...

[Eaglegoat]

I don't use the FRC, too many variables to account for. I'm not pulling the manifold and heads to get the port area. I start by keeping eoit well before ivc. I get my fueling​ dialed in. Then I push the eoit toward ivc until it goes lean. Then I move it back away a little until it isn't lean anymore. Then I fix my fueling and timing.

I'm typing this on my phone sorry if it doesn't make sense. This only applies to wot fueling.

[Michael_D]

I have to self-disclose that I misinterpreted the instructions and was targeting PPV, not ICV when I thought I needed to move the boundary back toward the stock settings.....grrrrr

I'm probably putting too much thought and effort into this. There's also a good chance I've screwed up one of the inputs on the spreadsheet.....

The engine is pretty damn happy right now after dialing in VE and MAF, but I wanted to re-visit injector timing while I still have my wide band installed.

This new cam has 60 deg of OL at .006 Greg. 284/298 @.006, 670/640 115+3. EPS asymmetric lobes.

[GHuggins]

Post the spreadsheet with your pw's and cam specs entered... Go by what Barum recommended on the pw's where your averaging wot and cruise from 1000 to 1800ish rpms / use wot from 1800 up and then idle below 1000...

[Michael_D]

Here you go, thanks!

INJECTOR TIMING TOOL GEN IV - Black Charts-FRCv21_MD.xlsx

FINAL TEST.hpl

[GHuggins]

Give this a try - due to the overly large injectors even with rpms - you may need to go to a stock ls3 vette (2010ish) setup I worked the numbers as best I could trying to keep enough fuel on a closed valve with rpms while still retarding it some into the most cylinder turbulence areas that I could, but still no guarantees at all on this...

[Michael_D]

Thanks Greg.

I take it that when a choice needs to be made between SOI on the valve, or EOI to a closed valve, it's more important to select SOI on a closed valve?

So what's so different in my set up than others? The injector size? Shorter PW than what you normally see?

[GHuggins]

Pulse Widths.... Ideal pw's to retard it is in the neighborhood of 10 being min to 13ish or more...

So, if it comes down to it in a situation like this - choose as much of eoi as possible while still maintaining a hot intake valve sitting ratio... Fuel needs more time for heat to vaporize it with rpms - at idle it's got the heat in the cylinder for the most part / with throttle and rpms you have turbulence, but not as much heat and you still need good vaporized fuel to start the burn, but you still want "rawish" fuel to slow the burn acting like an octane booster... That parts theory, but why I believe this works so well and allows for more timing and everything to be used...

[Area47]

semi related to this. Anyone have the BTR Stg4 ls3 cam specs at .60?

[Michael_D]

Pulse Widths.... Ideal pw's to retard it is in the neighborhood of 10 being min to 13ish or more...

So, if it comes down to it in a situation like this - choose as much of eoi as possible while still maintaining a hot intake valve sitting ratio... Fuel needs more time for heat to vaporize it with rpms - at idle it's got the heat in the cylinder for the most part / with throttle and rpms you have turbulence, but not as much heat and you still need good vaporized fuel to start the burn, but you still want "rawish" fuel to slow the burn acting like an octane booster... That parts theory, but why I believe this works so well and allows for more timing and everything to be used...

I finally finished recalibrating the air models and am tweaking spark.... I have a new record MPG with your suggested settings. Same stretch of road, same speed and in sixth gear. Highest I've ever seen was 28mph on the display, and it's usually 26. I saw this consistantly.

20170601_112320.jpg

The engine seems to like these settings, with one exception. I am now seeing some black smoke at WOT above 5000 rpm or so. WB is showing 12.3/1 AFR, right where I'm targeting it. Is it possible fuel is being delayed a tad too much?

[GHuggins]

It's possible it's delayed too much up top with your injectors, but it's also possible your running meth or is it even on at the moment - I just somewhat recall you mentioning meth before? Every meth car I've seen has blown some light smoke when activated... Some light smoke isn't bad, just as long as it's not looking like a diesel

[Michael_D]

I have not terminated the controller wiring for the meth system yet. That's a rainy day project. It's not real bad, but noticeable. Not diesel bad...... Just a new observation.

[GHuggins]

Make your boundary 560 from 3000 rpms up - think you might like this better with your setup...

[adunphy]

My IPW is not as linear as I'm seeing most of you run. I have my FPCM setup to increase line pressure to 60psi for anything over 80 lb/hr flow rate. As a result my IPW drops back down a bit. I've attached a worksheet with my specs and the injector timing I'm using. Any major cons/disadvantages to what I'm doing with my fuel pressure? (Low/normal fuel pressure is set to 48psi which is in effect for 90% of cruising conditions)
INJECTOR TIMING TOOL GEN IV - Black Charts-FRCv21 4.8Turbo.xlsx