How far are you guys letting EOI drop?

[Higgs Boson]

easy solution:

set the whole SOI table to 280 and leave all the other tables stock (EOI, gap windows etc)

280 gives plenty of time for injection in all conditions except highly modified WOT and starts injection late enough to make sure the exhaust valve is closed.

if the stock ecm runs out of pulse width to inject before 180 it will back up SOI by itself up to the max injection angle.

[Jonblarc7]

Thanks I will give that a try.

[cadillactech]

For starters I created two pids that inverse GM's SOI and EOI values relative to TDC. The GM cal expresses this BTDC and as an engine builder it has to invert the numbers. I look at 0 degrees as TDC of the intake stroke and 180 as BDC of the intake stroke. "If" you can spray from 0-180 you know your always in the sweet spot of the intake cycle. Once the piston comes off BDC you are starting the compression stroke. Spraying another 10 degrees from BDC is fine bit after that you start trying to spray into a cylinder that is rising in pressure at a fast rate...ever try spitting into the wind? Does work out... If the injector tries spraying into a combustion chamber that is very turbulent it won't mix. This is more an issue on high boost engines with camshafts (which is everything today). If you continue to let the controller move the EOI to far into the compression cycle your also heading towards spark impingement which is when the spark goes off. Not cool.

If you have a engine that is spraying at say 20 degrees ATDC and the spark is ending at 240.... start the injection earlier and pull the EOI back to 190-180 and you will typically clean up power and more importantly not misfire and crack a piston. There is no debate on if your out of fuel. You only have so much time which equates to so much fuel mass and it has to be delivered at the right time. period.

The 5 gas shows this clear as day as the hydrocarbons are up dramatically which is indicating you are not burning the fuel. As I had started prior if you have an ear for it you can hear the difference of a motor that is crisp vs a motor with poor cylinder mix..

Hope this makes sense...

Great information Howard, makes a lot of sense! Thank you for sharing your expertise!

[Jonblarc7]

easy solution:

set the whole SOI table to 280 and leave all the other tables stock (EOI, gap windows etc)

280 gives plenty of time for injection in all conditions except highly modified WOT and starts injection late enough to make sure the exhaust valve is closed.

if the stock ecm runs out of pulse width to inject before 180 it will back up SOI by itself up to the max injection angle.

Just want say thanks Higgs, That worked perfectly. For the first time since I cammed my truck I can stomp it from a light on 93 and not look like a diesel.

[cadillactech]

Just want say thanks Higgs, That worked perfectly. For the first time since I cammed my truck I can stomp it from a light on 93 and not look like a diesel.

Thats good to hear.

Higgs, do you usually set the SOI to 280 no matter what the cam and let the ECM back itself up or do you go through the trouble of calculating the EVC angle and using that as SOI?

[Higgs Boson]

Thats good to hear.

Higgs, do you usually set the SOI to 280 no matter what the cam and let the ECM back itself up or do you go through the trouble of calculating the EVC angle and using that as SOI?

Admittedly, I have been tied up with other things and haven't been doing a lot of tuning lately except messing around with my own cars, but yes, it is what I defaulted to after many long hours of calculations and then trial and error and then simplification. It is what I would do if I were to tune another one today.

After realizing at some point that the ECM didn't want to inject after BDC, or at least have an SOI so close to BDC that it would start to run like sht, knowing that getting it back up to TDC or before would be injecting into an open exhaust valve, and seeing how short injections were with DI at everything but WOT, then noticing that SOI would still rise up to TDC or before under load if needed, I was like, wtf am I doing.....? Decided to just put SOI in the middle of the intake stroke and everything I tried it on would run smooth and clean.

[cadillactech]

Admittedly, I have been tied up with other things and haven't been doing a lot of tuning lately except messing around with my own cars, but yes, it is what I defaulted to after many long hours of calculations and then trial and error and then simplification. It is what I would do if I were to tune another one today.

After realizing at some point that the ECM didn't want to inject after BDC, or at least have an SOI so close to BDC that it would start to run like sht, knowing that getting it back up to TDC or before would be injecting into an open exhaust valve, and seeing how short injections were with DI at everything but WOT, then noticing that SOI would still rise up to TDC or before under load if needed, I was like, wtf am I doing.....? Decided to just put SOI in the middle of the intake stroke and everything I tried it on would run smooth and clean.

Great info, I will try that on the next DI car I get.

[lucas287]

easy solution:

set the whole SOI table to 280 and leave all the other tables stock (EOI, gap windows etc)

280 gives plenty of time for injection in all conditions except highly modified WOT and starts injection late enough to make sure the exhaust valve is closed.

if the stock ecm runs out of pulse width to inject before 180 it will back up SOI by itself up to the max injection angle.

Higgs - what are your thoughts on doing this with the stock cam and stock VVT tables? I'm thinking of the large amount of cam retard and how that sort of correlates to the SOI table

[engineermike]

FYI the Ford stuff SOI is specified in a table and it’s locked in to that value, so it won’t advance (or retard) it from the specified values. I’ve looked at a lot of stock and modified ecoboost and coyote files and they all run SOI 330 - 336 BTDC at wot (24-30 deg ATDC).

[Higgs Boson]

Higgs - what are your thoughts on doing this with the stock cam and stock VVT tables? I'm thinking of the large amount of cam retard and how that sort of correlates to the SOI table

no need to overthink it. just do it. ;-)

[TriPinTaZ]

Just wanted to come in here and post up some real world test results. After a bunch of testing I have confirmed that the car is FASTER on E55 with the EOI staying close to 180. Even with the additional timing by going to E60-E75 the car never goes any faster. In fact is is the either the same or slower at some point. I believe this is directly related to the end of injection happening too far into the compression stroke(which isn't new information to many on here). But I can say, from my testing, if EOI starts going past 170(10 degrees or more into the compression stroke) the car doesn't go any faster and then starts to slow down. This would confirm to me that on the LT4 platform, you will actually start losing HP up top if you're injecting more than 10-20 degrees into the compression stroke. I don't think it is significant until you surpass 20 degree into compression.

All my testing was done in the real world using draggy 0-130, 60-130, 100-150, and 1/4 mile runs. My best 60-130 runs on E56 were half a second faster than my best runs with E68, E70 and E77. I had some E63-E65 runs in there too but the results were inconsistent due to conditions, however it seems like they would have been 1-2 tenths slower than my best E55 runs. I also lowered E content to E50 and didn't pick up anything at all. I surmise from this, as mentioned above, if EOI goes beyond ~165 you will start losing HP after the peak torque RPM.

[cadillactech]

Good to see some empirical evidence!

How much timing were you adding between the E55 and E60-75?

[TriPinTaZ]

Good to see some empirical evidence!

How much timing were you adding between the E55 and E60-75?

By E70 there was about 1 degree more timing than E55, maybe a little more.

[sevinn]

Thanks for the data...makes sense to me! And honestly seeing as how by around e60 you're getting most of the octane benefit of ethanol I don't see much point in extending the fuel system to run more.

[engineermike]

I played with eoi on a dyno today. Again, this is Ford…

Eoi only seems to really affect it above 6500 rpm. I’ll use 7000 rpm as the point of reference:

I’ll call 60 deg btdc my baseline.
At 108 deg btdc, it gained 75 hp
At 113 deg btdc, it gained 85 hp
At 118 deg btdc, it gained 85 hp
At 133 deg btdc, it gained 80 hp. It knocked on this pull, probably due to less gdi blend.


This is all on pure 93.

[cadillactech]

I played with eoi on a dyno today. Again, this is Ford…

Eoi only seems to really affect it above 6500 rpm. I’ll use 7000 rpm as the point of reference:

I’ll call 60 deg btdc my baseline.
At 108 deg btdc, it gained 75 hp
At 113 deg btdc, it gained 85 hp
At 118 deg btdc, it gained 85 hp
At 133 deg btdc, it gained 80 hp. It knocked on this pull, probably due to less gdi blend.


This is all on pure 93.

Is this BTDC of the compression stroke?

[engineermike]

Is this BTDC of the compression stroke?

Yes.

[lt1z350]

Ok that makes sense, even on the GM side, since compression injection would have a much different charge motion and more change of fuel puddling since the piston is coming at the injector versus running away from it.

Do you like the XDI pump setup? XDI has a setup for the LT motors now, looks like a belt driven HPFP that can deliver enough fuel for 2000hp plus. Could be fun!

The xdi pump for gm was a train wreck for one only worked on z06 two it didn?t work on z06 shear belts alignment issues. Talked to a few shops on both gm injectors and that pump and all had big problems with anything gm from that company. 6thgen mike tried to make it work on his 8 second 16 SS. And it never made it down the track on that stuff. Why see it floating around used at half the price of new people trying to recover some losses I assume. Even their gm injectors had big issues from what I have seen posted. Especially the 65 percent ones. Fic has become a go to on injectors really and lingenfelter pump setup when ever trying to eek out every last bit.
As for all the soi eoi comments I?ve seen on many logs soi going into the 400 range which yes seems extremely out of wack but when a car can make 820/850whp on bolt ons meth and ported lt4 blower I quit questioning so much of the soi and what I was seeing as the power being made was extremely good for no cam and no head work. 370s seems to be more common and on my own car with a cam and heads I have seen mph loss at the track on logs with it in 360s vrs 370s 380s. I start to question if hptuners is even logging some things correctly anymore. The fact you have to add that pid on a zl1 from under diesel/ injector timing to begin with is just weird.
So I quit trying to use math and common sense on some things and just shoot for what works and makes the most hp no matter what I see on a log. Then try to recreate it again. Trial and error rather then math and common sense on some of this stuff. I really think so much we see on logs is not correct to what?s really going on.

[lt1z350]

The xdi pump for gm was a train wreck for one only worked on z06 two it didn?t work on z06 shear belts alignment issues. Talked to a few shops on both gm injectors and that pump and all had big problems with anything gm from that company. 6thgen mike tried to make it work on his 8 second 16 SS. And it never made it down the track on that stuff. Why see it floating around used at half the price of new people trying to recover some losses I assume. Even their gm injectors had big issues from what I have seen posted. Especially the 65 percent ones. Fic has become a go to on injectors really and lingenfelter pump setup when ever trying to eek out every last bit.
As for all the soi eoi comments I?ve seen on many logs soi going into the 400 range which yes seems extremely out of wack but when a car can make 820/850whp on bolt ons meth and ported lt4 blower I quit questioning so much of the soi and what I was seeing as the power being made was extremely good for no cam and no head work. 370s seems to be more common and on my own car with a cam and heads I have seen mph loss at the track on logs with it in 360s vrs 370s 380s. I start to question if hptuners is even logging some things correctly anymore. The fact you have to add that pid on a zl1 from under diesel/ injector timing to begin with is just weird.
So I quit trying to use math and common sense on some things and just shoot for what works and makes the most hp no matter what I see on a log. Then try to recreate it again. Trial and error rather then math and common sense on some of this stuff. I really think so much we see on logs is not correct to what?s really going on.

Well curiosity on my own cars sent me looking at a lot of logs.
Trip your on to something here for sure. While I have seen cars dyno really well on what seems to not be correct on the soi eoi numbers to math on cam specs my own car I went back over some 4.70-4.90 60-130 times and then again on a 9.30@150 mph which was only 5.2 60-130 and the faster times the eoi is lower closer to 160/170. Vrs 180-185 on the 9.30 which I thought was damn good on a ported stock blower.
Here is what?s weird the soi is always the same 370/375 yet eoi is changing a lot more though no tuning changes on table so it?s how the ecm is doing it?s math so on. I messed with this on the dyno on a 980whp 2650 17 zl1 moved soi around wot in the table. But what I didn?t pay attention to was eoi so now need to go look at some more logs. Good thread and thanks for bringing this to light.

[TriPinTaZ]

EOI will start dropping when you're running out of fuel and the SOI won't advance that much to help. I was tuning a ZL1 with max effort stock blower setup with meth that was peaking around 19spi. SOI was ~366 and EOI was ~165, stock fuel system, with quite a bit of meth. Temps dropped and the boost hit 21 psi. This tanked the fuel pressure and while SOI stayed around 365, the EOI fell to 30! Yes 30. The fuel pressure dropped and the injectors were staying open right up until spark. We have made some changes to get the car safe again in the winter. I knew we were close to the limit and I advised to run a lower E mix but you know how that goes. I can't be there to make sure the car is on E55 vs the E78 the owner had in the tank. Point is, the EOI is a direct reflection of injector pulsewidth regardless of the SOI on the Gen V. If you're going beyond 6.0ms by redline then you're likely dipping beyond max HP area and soon to be tanking the high side fuel pressure and going lean. Spraying too far into the combustion stroke can cause detonation, hot spots and maybe even pre-ignition under the right circumstances. I aim for a peak of 5.5ms of pulsewidth at redline. Then if it gets really really cold you can stretch it to 6.0 and the fuel will still be safe but you will have a fall off in power near redline because the SOI will likely drop below 130. I have a couple of guys I tune for that run the car on the edge, but we make adjustments for winter time and always log the car when the weather changes. These aren't the typical tuning clients though. Other than these guys I would never tune a car that close to the edge. But they are out there in Mexico, Texas killing it and people are astounded how those cars are so quick.