Quick EOIT Advice

[Nick912]

Hello everyone,

I'm currently finishing off dialing in fueling with the new cam in my 2011 Camaro SS, but realized that I still have the past EOIT calculations from my much larger high overlap cam. My previous cam was a 235/248 111.5 LSA 109.5 ICL, and my new cam is a 232/234 115 LSA 110 ICL. .006" cam specs in both sheets below correlate to my new cam, and I was just hoping that someone could take a look at both sheets and let me know which one of the injection timing settings seem to be more optimal for my setup. Thanks in advance!!!

INJECTOR TIMING TOOL GEN IV - Black Charts-Fbody.xlsx -Current EOIT setting in my tune
INJECTOR TIMING TOOL GEN IV (Much more advanced).xlsx -Possibly more optimal settings

If anyone can let me know which of these approaches seems closer to optimal/what I should be targeting in an N/A setup as for SOIT/EOIT, it would be greatly appreciated!


Also, if it all helpful, here is my most up to date log and tune:
2 bar SD 21.hpl
2 bar SD 21.hpt

[GHuggins]

Play with your ect values - should be +/-10 degrees

[Nick912]

Play with your ect values - should be +/-10 degrees

I'll go ahead and transfer the boundary values you provided onto my most recent tune, and adjust my normal ect values until I get the richest reading on my wideband. Thanks for pointing me in the right direction.

[kingtal0n]

what is ect usually its engine coolant temperature , but in my gen3 I don't have anything for injector phase called ECT so Im not sure

[07GTS]

yea not as much adjustment in the gen3 for eoit, i usually find that if its good at operating temps then its good for cold starts as well so the ect adjustments isnt always needed to change thru the warming up temps

[kingtal0n]

Where is boundary in the Excel file they say "520" , the stock boundary is 5.55 how does that correlate? Having trouble comparing gen4 and 3


Oh sorry is it just 5.55 = 360 + 90 + (.55*90) = 499.5

[07GTS]

Where is boundary in the Excel file they say "520" , the stock boundary is 5.55 how does that correlate? Having trouble comparing gen4 and 3


Oh sorry is it just 5.55 = 360 + 90 + (.55*90) = 499.5

alot of info in here on the gen3 https://forum.hptuners.com/showthrea...318#post559318

[kingtal0n]

Thanks, yeah I was just trying to see whats different in Gen4 since it looks like it can adjust phase per RPM like a modern stand-alone.

I really like the idea of more adjust ability but almost everything else in gen4 looks like more trouble than its worth sometimes

[GHuggins]

You should take a look at a 5th gen - you can adjust injection timing for every 400 rpms and every 4 cylinder airmass points just like an ignition timing table I personally prefer the more adjustability and being able to dial things in more to an OE level besides the fact that it can sometimes be a headache as you hinted - especially on a 5th gen - doing a tune in a couple of revisions is long a thing of the past - I've got 30 revisions in with one customer just dialing in injection timing, cam timing, ignition timing, still working on tweaking idle, still working on torque model, maf, ve, injector offsets, open loop tables and so on just for a stage 2 btr cam and soon to be ethanol all for empty truck and then towing a loaded trailer - takes more than people probably realize

With the 3rd gen you have to make a choice - a choice I don't necessarily like having to make - either economy and great drivability or mid range to high range power and torque with "good" drivability and OKish economy and hopefully an okish idle. I know emissions is what constantly drives these changes, but lots of great side effects always seems to come from them with tweaking on the performance side. Just wishing emissions/epa didn't drive the software - getting tired of having to switch back and forth between old and new software when I can't remember or figure something out just to see what I'm possibly overlooking :/

For the third gen you typically only need to change the boundary and no more than 2 or 3 from the OE setting.

[kingtal0n]

Hey Gman thanks, I was wondering if you've a minute to confirm this pic for me,


I added those words based on what I am seeing, not sure it is correct. It appears to be an idle pulse width of the injector, and the spike in the injector voltage I think is the collapsing magnetic field for opening the circuit of the solenoid.

Looking at that, and this info
https://forum.hptuners.com/showthrea...l=1#post559318

If applied to my cam card which @0.050 exhaust valve closing is -9* ATDC (9BTDC) and adding 60 or 70* for advertised duration to fully close the valve more or less, to get the spray post overlap,

I come up with new EOIT by taking OEM 5.55 (308*) and adding the 52* to reach TDC overlap plus the extra 60~ to close exhaust valve, thats about 112* to 120* extra EOIT needed, and according to the link every 90* is roughly +1.0 Normal, so 30* is roughly 1/3 of 1.0, making my final EOIT = 5.55 + 1.0 + .33 = 6.88


And as to what you are saying, injection during WOT closer to the Intake valve max velocity would be even further, right? How curious considering what a long injector duty sprays through compression stroke I guess

Just want to make sure I got all this right in my head before I forget it forever

[GHuggins]

Even though it might not make much sense, your not targeting eoit - even though everything except for gen5s is based off of that. Your targeting soit. Now with that being said I would recommend changing it and then doing sudden throttle snaps - this is quickest and easiest way with a 3rd gen - your looking for them to be crisp and responsive. You'll also want to go off of exhaust smell, but idle timing will effect that more than injection timing on a 3rd gen.

7 is as high as I ever go on a 3rd gen with rather large cams as it sounds like your describing. You might also want to try something like 5.4ish to 4.5ish - something in that window. Might just work better. Your math is correct and sound, but in a lot of instances the engine may not care about the math. Exhaust backpressure and/or boost going in play BIG roles in injection timing that the math doesn't account for, for instance.

I do have a bit of an off subject question for you - apologies for changing the thread. On the O2 simulators your running where you can change the stoichio settings to lean out cruise, do you redial in the MAF and fuel model for these - I assume it would be necessary to keep from throwing rich codes? Then how do they effect tip in transients since your air model would then be leaned out? Then do they hold up and what was the link to them again please Thinking about running them on my daily commuter - how much of a mpg increase do you typically see with them? Thank You

[kingtal0n]

Even though it might not make much sense, your not targeting eoit - even though everything except for gen5s is based off of that. Your targeting soit. Now with that being said I would recommend changing it and then doing sudden throttle snaps - this is quickest and easiest way with a 3rd gen - your looking for them to be crisp and responsive. You'll also want to go off of exhaust smell, but idle timing will effect that more than injection timing on a 3rd gen.

7 is as high as I ever go on a 3rd gen with rather large cams as it sounds like your describing. You might also want to try something like 5.4ish to 4.5ish - something in that window. Might just work better. Your math is correct and sound, but in a lot of instances the engine may not care about the math. Exhaust backpressure and/or boost going in play BIG roles in injection timing that the math doesn't account for, for instance.

Haha well my car smells even during decel with "no fuel" going in. The truck engine and exhaust manifolds have 220k so I think their insides are just... yeah that smell.
Alot different than a 4 or 6 cylinder 'ancient' smell, can't explain why though. You'd think gas is gas but something about those smaller engines smells better... anyways!

I originally had stock 5.55 and noticed a richening up moving to 5.8 to 6.2 range, I figure 6.2~ would put it spraying just before/around overlap which I was fine with. A little time to sit on the valve at least, I figured. I didn't see any big difference with 6.5 and never tired more than. Left it at 6.2 but I keep wondering if I can do better. Funny how despite all the tools we have it still boils down to trial and error though.
As with so many other things.

I do have a bit of an off subject question for you - apologies for changing the thread. On the O2 simulators your running where you can change the stoichio settings to lean out cruise, do you redial in the MAF and fuel model for these - I assume it would be necessary to keep from throwing rich codes? Then how do they effect tip in transients since your air model would then be leaned out? Then do they hold up and what was the link to them again please Thinking about running them on my daily commuter - how much of a mpg increase do you typically see with them? Thank You

Oh, hello! You are very nice I want to help you badly. I will tell you anything I know. However I've never used a MAF sensor on a Chevrolet and I never use closed loop in HPtuners.


As a computer programmer in early 2000's, of course naturally the first thing I did when I got my first stand-alone computer in 2004 was write a piece of software to dial in my VE map for me... Called it an auto tuner.
https://www.thirdgen.org/forums/dfi-...r-950-a-2.html

It makes sense in a real time tuning environment to have something constantly adjust your VE map while you drive if possible. Modern stand-alones do this now, for example Holley has basically the same thing, full map array that auto-adjusts 'trims' based on wideband and can be applied back to the VE map with a single button and start over. I bet you've seen it.

Back In 2004 there are no affordable widebands at hobby level or I would have based it off of wideband feedback instead. I think widebands are still $500+ and use a giant box LCD screen thing.
This auto-tuner was using narrowband feedback in open loop to dial the VE map while you drive, using narrowband .500~ midpoint to find stoich and then dialing up or down a small percentage (I wanted a leaner cruise in open loop and used narrowband to find the crossover point and went just beyond that). All I did was create a memory 3D map array to keep track of virtual a/f and mV O2 values and have it gradually input keystrokes to the VE map to simulate real time tuner inputs while you drive with the laptop running. You could tell it how far past stoich and in which direction too. I would always shoot for slightly leaner than 14.7 in cruise areas. I always thought I would turn closed loop back on when finished but I never 'finished' so it just stayed in open loop all the time which turned out to be how I always ran all my vehicles from then on. Closed loop was good for when I tuned a friend's car because stuff can wander you know... but for us as long as we have the gauge and an IAT potentiometer (1000Ohms is good) we are in full control of the a/f in open loop.

When widebands became available and I get rid of the narrowband completely. The first wideband I ever owned was Innovative LC-1 or something like that, it had an analog output wire you could configure manually which is where I got the idea first. I just inputted the mV output to match my desired wideband a/f, .005v for 15.8 or whatever. The ECU has no way to know if you are rich or lean because it still thinks .005v is 14.719999 and 995mV is 14.6919998.

to answer your first question: if you simulate a narrowband analog wire into the ECU has no way to know if you are rich or lean, it still thinks 550mV is the crossover point and doesn't realize .530V is 15.8 instead of 14.6999 (you choose where 14.7 is)

That said, AEM widebands don't have analog configurable outputs, at least not the cheap one I always use. So an arduino would prolly be the cheapest best option $20 done. But you need to write the code which takes time. I wouldn't bother- I just run the ECU open loop like always and shoot for sufficiently lean a/f ratios because:
A. the difference between 14.9 and 16.5:1 a/f ratio with respect to fuel economy is negligible, perhaps 1% or less. It might be worth .2mpg or something like that.
B. The 1000OHM IAT Potentiometer can adjust around .5 to .8:1 added or subtracted from the final A/F cruise value while you drive, giving you a wide range of adjustment for leaner cruise when you want or more fuel and timing (turn it 'colder' and configure the IAT vs timing map and IAT vs PE for more fuel and timing).

MAF sensor wise, I've tuned a hundred MAF JDM engines and I understand the maf completely and its nuance behavior and requirements. They can be extremely easy/fast to tune a very high quality drivability. However I would never use one if I had a MAP sensor. The final A/F on the gauge is all that matters and getting rid of the MAF is worth the extra effort to fully tune a MAP quality ECU, IMO of course. I find map can be tuned as tightly as any MAF, it just takes infinitely longer and lots of varying conditions over hundreds of days/logs to get there. HPtuners was annoying at first because of the IAT fuel adjustment 'behind the scenes' but even just 500ohm potentiometer can take care of that if you are heat soaking at a light or something. Or if the vehicle has been baking in the sun for 30 minutes after being shut off. Actually there is a HPtuners enrichment based on soaktimer afterstart I found particularly useful to combat the lean hot refires to at least tone them down, because even though the engine runs fine at 17:1 I really like to keep it 15.5's most of the time.

On to Transient tuning. In a typical stand-alone you would have the accel dTPS enrichment and dMAP to add fuel. In HPtuners the enrichment mechanism is more subtle and you probably know wayyyy more about it than I do. That said I use every table to my advantage. I set the PE to be 'just out of reach' of the modest hill climb and use the VE map to enrich my part throttle transitions instead of PE mode. Alternatively I bet you could use the stoich table to avoid adding weight to the airmass- but I don't mind the airmass increases shift pressure which is fine if a shift happened during a transition anyways and I see no down side to this strategy. You would measure the 'hill climb' map steady state cells and simply tune those for 14.2 to 14.4 or even 13.8 (depends on load and rate, gearing and weight as you are aware) outside of PE. You been tuning so long Just kind of know where I want to be when I look down at that wideband and if I don't see the number that makes us comfortable given the load applied at that instant. So the VE table is a good gauge/indicator of transient situations in this case because there are cells where you will never cruise and still outside of PE which need some enrichment. Thus eliminating dependency on internal OEM ecu transient functions.

[kingtal0n]

Heres a example of my transient fueling based on VE map


You can see my PE trigger was around 80KPA. I've done quite a bit of changes since this (it was right after I hooked up wideband to HPtuners) but its still representative of how I do things.

Notice at lower rpms near the cruise regions my transients pull 14.1 to 14.2, 14.5 even a/f and as the RPMS increase to highway speeds my transients are closer to 13.8:1 instead. Going 'uphill' at higher rpms results with fewer engine load so if you hit the same load row as a lower RPM Point it will need to be richer than it was at lower rpm. All of that transient fuel is coming from the VE map. And so is the lean cruise, 15's and such up there. I tune near 15.2 because as things heat up it will 15.4 to 15.5 and I rarely go past 15.8:1 on purpose. 500Ohms of iat is worth about 10-12*F at 90*F ambient but I never have heat soak issues on the highway, only stopped traffic and after it bakes w/ engine off.

A turbo engine spooling rapidly during a transient is reducing timing rapidly, it may appreciate aggressive timing pull (rapidly moving down the airmass timing table and timing reduction from AFR advance table as enrichment occurs) and even if you go a little too far reduced with timing, too soon, this is how we may tune the building of shaft speed and putting fire to the turbine while sparing the tires by reducing cylinder peak pressure and torque. You are prob familiar with stock cam engines tend to blow off the tires during a transient spool where it really needed the big cam to reduce low rpm cyl pressure while spool the turbo without blowing off the tires, gain some MPH first and get the boost number up faster. It depends on tire budget to some extent, more tire more torque. This is one major disparity between tuning for racing vs daily driver, a race car can spool on a T-brake w/ limiter and uses a slick tire, but the daily driver has none of that and might already be moving at low speeds. In a daily we want a powerful turbine response even if the car is cold and just recently started and with a normal tire, but the tire will slip easily especially when cold. A rapid drop in timing and larger camshaft can help soften up the hit while building boost more rapidly for the next gear where full power may be applied to the normal tires. This is another reason why it may be ideal adding weight to the VE/airmass during transient towards boost is ideal for daily drivers, reduce torque while adding shaft rpm rate and line pressure, three birds one stone. I doubt it would work as well in gen4+ But for the simplicity of gen3 it doesn't seem to hurt. I mean, the timing map is configurable by us so it doesn't matter to me whether I type the number in the timing map or lose timing due to airmass prediction... same number on the scanner I want to see during that condition, same desired mA at the force motor, same air fuel ratio target... what difference does it make what the ECU thinks?

I like to 'facilitate' the leaner cruise in multiple places. For example in the Injector size table, I increase the size of the injectors for high vacuum so the ECU thinks they flow more than they really do at 20 or 10KPA or w/e. This help nudge in the lean cruise direction without having to remove from the VE table. Its not like you ever use 10 or 20KPA regions for anything other than lean cruise or fuel cut anyways. No risk.
Open EQ I played with it slightly. If I needed to lean out without affecting airmass I'd prob use the Open EQ table.

On the VE table itself I coincide highest vacuum conditions with fuel cut situation, so the VE map is 0'd out and the DFCO is both active around the same time maybe. Speaking of which its always best to cut fuel on a decel I'm sure you know that, tune it to ensure a complete cut for saving fuel is one of the keys.
Because I have an auto I made lockup stay active during DECEL so it fuel cuts like a manual transmission on a decel.
Lockup Decel video "touch the gas crackles" when first learning to tune the HPtuners stuff.



Little things


Timing has a much greater influence on economy it seems and the factory already puts like 45 or 48*, even 50~ some places up there. I actually reduced my timing in a bunch of spots in high vacuum as I am not comfortable with seeing that kind of advance. Call it superstition at low rpm.
If you really want to dial in economy you would drive using different timing values (and a/f values if you wanted) for comparisons, just compare them in terms of miles per gallon, fill up the same station, same pump, do multiple runs (averages), use cruise control, same roads, same tire pressure, always fill to the same fuel tank height, you know the drill.

I think this is the most I've written on this forum about economy , it should give you some ideas. I am an economy connesew, connesiu, connseuqer... I really enjoy a fine tasting vintage of economy.
https://forum.hptuners.com/showthrea...l=1#post677442

Something simple as tire height or tire pressure seems to have a larger influence than A/F ratio though. The main thing for me is the clean long lasting iridium plugs... should stay super clean for 100k miles at 700hp or 800hp no issues. I always put iridium in after finished tuning on coppers, and then hit the dyno to clean it up and find my minimum timing region for daily driving. This whether chevrolet, toyota, nissan, all do 800hp and all are my favorites... same strat. Once I put that brand new iridum in the engine I'd like to never remove it again until like 10 years 100k at least. The point being, one of my rules is never look at plugs again once its tuned, don't ever touch em. Install a clean perfect new set with no fingerprints and never remove them, try not to disturb.

heres an example arduino project of a wideband simulate narrowband output
https://thedeltaecho.wordpress.com/2...p-afr-control/

In this one they used the LC-1 directly
https://forum.hptuners.com/showthrea...ow-Band-How-To

But I absolutely will never use innovative wideband for anything ever again. Even the new versions are awful if you compare or are used to the AEM which responds much faster and even starts up faster.

To be clear I do not recommend wasting the time to design a proper circuit and programming etc... Just run open loop. There are alot of small intricacies involved with attaching an external microcontroller to the ECU, as simple as it is in theory, you will need some electronics experience to know how to ground it properly, current flow direction matters, caps and resistors in the right places (some unexpected), it will likely need an isolation circuit to protect from voltage spikes which should include a transient voltage suppression inductor, and unintuitively placed diodes to provide voltage drops and return pathways for current outside of the main loop. I'm no expert myself but its like knowing enough to know you shouldn't do something to your own equipment, If you want it to be reliable and easy, just keep it simple.