So... Learning odd things at the Dyno. Need input.

[jon1440]

So what I'm about to say is going to go against the 99% in here, but hang with me. I'm still questioning it and really not liking it.

Overview of setup: 370 10:1, Aeromotive 5.0GPM variable speed Pump, matching Fuel Regulator (Aeromotives Recommendation) Fic 1650s, 91 octane with 7% E, NGK 7 plugs. Return system. -10 feed and return, -8 through the rails, parallel feeding through the back of fuel rails and onto the regulator. 58psi fuel pressure.

My truck is on the dyno and tuner tells me he cant get the fueling to lean up without making the VE take a step down or leveling off. Never seen a VE just flat line or head lower as boost rises. At this point I'm stumped and slightly confused. I can hear the engine breaking up in the 4K region. He trys a couple other things and nothing is changing. At this point he double checks with me on fuel pressure and make sure he knows the regulator is boost referenced. He makes another run on dyno so I can watch gauge to see what pressure is doing. The fuel pressure rose in step with boost pressure. At this point Im thinking everything is working just as it should. Just adjust the VE and get on with it. Well at this point hes telling me the pressure is to high to start with and the boost reference is adding more of a problem. Well, from my understanding anything past pressure equilibrium (boost) what we witness from the pressure gauge is not what the injectors are actually flowing but is compensating for the pressure against the injector from the boost. If I see 68psi from the gauge because of the boost, the injectors are still flowing the same as they would at 58psi. Now without the extra 10psi (via boost reference) the injectors would actually be flowing 48psi, while the gauge still shows 58psi.

At this point he explains that my pump and injectors are over kill. ON 91 OCTANE. I can understand this. Wasn't expecting much out of 91 other than to have my truck function fairly well. The fuel system was designed to flow the correct amount of E85 at high boost. So we still have breaking up in the mid range and I cant think of anything that would be causing it. I explained to him I setup the injectors in the tune based on 58psi, FIC's data was based on that and I didnt want to go through the trouble of scaling. Truck ran fine cruising around. he suggests lowering pressure and I'm fine with that. I wont be stressing the pump at a lower pressure and I believe the injectors will work fine there. I lower to 43.5 best I can and he makes another run. It helped a little but still breaking up. Heres where it gets questionable. He says to unhook the Boost reference off the Regulator. What??????

I dont know what to think about this and he explains he has multiple people running around without boost reference making good numbers and no death to the engine. Tells me boost reference is only needed when the injectors are properly sized and the pump cant maintain the pressure. So he talks me into it, and make a pass. To my surprise it helps. But now the engine is breaking up around 5700 rpms.


So I'm completely stumped now. Trying to understand what the hell is going on. Is my engine beginning its death or is it happy with this.

We go ahead and mix in E85, bringing the blend to 55%. Motor is liking it and seems to be happy up to 5700 or so. I'm still getting a miss fire randomly so I decided to stop. Fuel ratio was maintaining. No recordings of spark knock. No spark being pulled.

I'm going to look at the plugs. I'll post images and the tune if anyone cares to look and see what the hell is going on. He said he was moving the VE 1% in the area trying to figure out the miss but clearly it seemed to be an ignition issue. I'm hoping coils. I dont think preignition because this was happening in the lower RPM's with the reference hooked up.

I want to go back to using the reference but unclear if its needed.

Truck made 860 at 16lbs so far. I want to work these issues out plus a couple more before going back.

Attachment 118780 Dyno tune STFT enabled reference line connected 43.5 base pressure.hpl

Heres a link to the original thread on LS1tech. Have pictures of spark plugs afterwards. https://ls1tech.com/forums/forced-in...eed-input.html

[chadtunes]

Hey,

I'm an old motorcycle mechanic and new to tuning FI so if I sound stupid and I'm totally wrong, that's why.. I'm still learning and taking classes.

Question- you switched to speed density but left the STFT's on.. And the MAF is disabled.. Don't you tune the VE table without any of that stuff enabled?
Wouldn't you be fighting with this trim even when the engine is in power enrichment? I'm asking because I don't know.

I attached part of your graph starting at 12:57 where you start to run it up and you can see the trims level out when I'm guessing it goes into PE.. Lambda is .69 right around the area you say it's breaking up? That's like 10.14 AFR? And the Eq ratio is 10% higher like it's trying to pull fuel out still?

I'm familiar with measuring HC's and CO's to troubleshoot rich misfire's on motorcycles. I would think your engine is breaking up because its choking on fuel, not the spark breaking up? Wouldn't you see that on the graph if it was?

C

[kingtal0n]

Run a manifold referenced fuel system 38 to 42psi base
The lower the fuel pressure base the more the fuel pump will ultimately be able to flow, highest volume rate is at lowest pressure


The fuel pressure issue has nothing to do with engine breaking up if air fuel was on target


E10 is very sensitive to temperature so your logs should always show IAT and if preferably EGT.


Sounds like too much pressure is blowing out the spark and possibly damaging the engine
Inspect plugs for damage, when the engine is tuned on cheap plugs switch to iridium NGK heat range 8 plugs at least with .0265" gap.
Rather blow the spark than brittle fracture failure.

10:1 is not a super boost friendly compression ratio. Gasoline is not a boost friendly fuel to begin with. High IAT and High compression exacerbate the fuel already poor behavior.

Do not use excessive timing and do not run with high IAT. Limit boost based on IAT and time. Whether 7psi or 17psi, 2 seconds or 10 seconds, whenever makes 117*F+ Air its time to upgrade the intercooling.

[jon1440]

Run a manifold referenced fuel system 38 to 42psi base
The lower the fuel pressure base the more the fuel pump will ultimately be able to flow, highest volume rate is at lowest pressure


The fuel pressure issue has nothing to do with engine breaking up if air fuel was on target


E10 is very sensitive to temperature so your logs should always show IAT and if preferably EGT.


Sounds like too much pressure is blowing out the spark and possibly damaging the engine
Inspect plugs for damage, when the engine is tuned on cheap plugs switch to iridium NGK heat range 8 plugs at least with .0265" gap.
Rather blow the spark than brittle fracture failure.

10:1 is not a super boost friendly compression ratio. Gasoline is not a boost friendly fuel to begin with. High IAT and High compression exacerbate the fuel already poor behavior.

Do not use excessive timing and do not run with high IAT. Limit boost based on IAT and time. Whether 7psi or 17psi, 2 seconds or 10 seconds, whenever makes 117*F+ Air its time to upgrade the intercooling.

Changed to 43.5 and connected the reference line. I agree with all you said. Plan is to cruise on the street with low boost and straight E85 at the track. Checked the plugs twice at the dyno and also lowered gap to .020. Nothing changed. I?m leaning towards coils.

While data logging on my own the BE was making a 1.0 Lambda jump in a split second. Logs showed I was avg. 15% over fueling. Pulled half and smoothed VE, and repeated again with better transition to BE and now was averaging about 10% off. Still getting the miss fire, but nothing under load around 3500-4000 where it usually would happen. Log is not picking up on spark retard or engine knock.

[jon1440]

Hey,

I'm an old motorcycle mechanic and new to tuning FI so if I sound stupid and I'm totally wrong, that's why.. I'm still learning and taking classes.

Question- you switched to speed density but left the STFT's on.. And the MAF is disabled.. Don't you tune the VE table without any of that stuff enabled?
Wouldn't you be fighting with this trim even when the engine is in power enrichment? I'm asking because I don't know.

I attached part of your graph starting at 12:57 where you start to run it up and you can see the trims level out when I'm guessing it goes into PE.. Lambda is .69 right around the area you say it's breaking up? That's like 10.14 AFR? And the Eq ratio is 10% higher like it's trying to pull fuel out still?

I'm familiar with measuring HC's and CO's to troubleshoot rich misfire's on motorcycles. I would think your engine is breaking up because its choking on fuel, not the spark breaking up? Wouldn't you see that on the graph if it was?

C

My cruise area is dialed in and was just logging for BE. O2?s are ignored here and the log shows the massive miss fueling area. I go from .5% off, to 15% in BE. Also very noticeable on the street testing. So yes it was having an overfueling issue. Tuner was telling me that and had me unhook reference line and lower the pressure. The pressure decrease im fine with, the reference line was eyebrow raising. Timing was playing a part also in the beginning as it was to low for ethanol. Added some and things cleaned up until we got higher in the rpm?s.

I?m hearing dyno tuners like running without the reference line but that would throw everything off once they hook the reference back up. Completely goes against everything I?ve ever read here on the forum or anywhere else.

[kingtal0n]

You need to run the engine at low boost 0psi, 3psi and tune it there without breaking up or issues.
Then gradually raise boost

It should run great at 3psi of boost or 0psi, disable the gate so it cant make boost

Too much fuel is just as bad as too much timing both can break pistons

[jon1440]

You need to run the engine at low boost 0psi, 3psi and tune it there without breaking up or issues.
Then gradually raise boost

It should run great at 3psi of boost or 0psi, disable the gate so it cant make boost

Too much fuel is just as bad as too much timing both can break pistons

10-4. Its actually running fairly well 100kpa and under. The transition seems to be way to aggressive. I'll be keeping a close eye on both plugs and pistons. For the breaking up I'll get some different coils and try it out.

Another thing on boost management. I'm going to need another wastegate because the turbo is overpowering the 44mm. The current gate is positioned in a good spot. Exhaust runs directly into it. Its not 90 degrees off like I see alot of gates positioned so I know its not a flowing issue.

Is it uncommon to run 2 gates that are different sizes? Or would that be a problem with management of the gates opening at different times? I thought I would buy a bigger 2nd gate and if the boost creep was still an issue, I could then remove the manifold and refab it with another bigger gate.

heres the tune the dyno tune and one that I've made 2 adjustments to on the VE.

DP Dyno Tune.hptDP Dyno Tune changed flow rate vs kpa to 43.5 smoothed VE 2.hpt

[jon1440]

Dyno Tuner dialed in part throttle and PE fairly well with STFT off. Which showed up well when I was data logging. The EQ error was maintaining fairly small errors. Usually I would see the trims pegged out if my fueling was still off during cruising. Now the trims seem to be in a range they can do their job. The driveability and is pretty good. The jump from 1.0 lambda to .794 Lambda in a fraction of a second was choking out the motor.

[jon1440]

Hey,

I'm an old motorcycle mechanic and new to tuning FI so if I sound stupid and I'm totally wrong, that's why.. I'm still learning and taking classes.

Question- you switched to speed density but left the STFT's on.. And the MAF is disabled.. Don't you tune the VE table without any of that stuff enabled?
Wouldn't you be fighting with this trim even when the engine is in power enrichment? I'm asking because I don't know.

I attached part of your graph starting at 12:57 where you start to run it up and you can see the trims level out when I'm guessing it goes into PE.. Lambda is .69 right around the area you say it's breaking up? That's like 10.14 AFR? And the Eq ratio is 10% higher like it's trying to pull fuel out still?

I'm familiar with measuring HC's and CO's to troubleshoot rich misfire's on motorcycles. I would think your engine is breaking up because its choking on fuel, not the spark breaking up? Wouldn't you see that on the graph if it was?

C

Dyno Tuner dialed in part throttle and PE fairly well with STFT off. Which showed up well when I was data logging. The EQ error was maintaining fairly small errors. Usually I would see the trims pegged out if my fueling was still off during cruising. Now the trims seem to be in a range they can do their job. The driveability and is pretty good. The jump from 1.0 lambda to .794 Lambda in a fraction of a second was choking out the motor.

[chadtunes]

Thanks for the explanation.

[kingtal0n]

Enrichment needs to be gradual, hold 13.2 to 12.8 for 80KPA to 100KPA ranges dont rush to 12.5 or 12.0
100KPA usually 12.5, low compression can rush 12.0 for torque
105 to 115KPA get down into 12.2's
120 to 150KPA 12.0 to 11.8
150KPA to 200KPA 11.5 to 11.0 on gasoline or stick to 11.8 with E85
By 201KPA It is brushing 11.7 with E85 or 10.9 with gasoline on the in-car wideband, often results with 12.0:1 E85 on the dynometer wideband or 11.2 gasoline
from 205KPA to 315KPA you are holding those a/f ratio while watching(logging) IAT and EGT.
The effects of intercooling and spraying alcohol will vary depending on many factors, for example if the intake is forming ice, the EGT is very low, the a/f should not be overly rich or in the 11's on alcohol at that point, but there are things such as injector end of time tuning which can exacerbate an already over rich condition by spraying late to avoid exhaust valve opening the cylinder may wet down with fuel ruining oil film and polluting fuel and increasing engine wear of the cold cylinders.
Just like with gasoline, if the engine is hot, The EGT Is high, the IAT is getting hot, then its okay to be richer on E85 than 12's because additional cooling is wanted and there is less risk of poor vaporization. However you still must question why is the IAT getting hot, that isn't good. Pressure test the plumbing to ensure no leaks and use the correct size turbo and intercooler and it will not get hot. IAT is a setup issue, not a tuning issue. You can't tune the IAT to be reduced. Compensatory measures for dealing with high IAT are engine safety features, not tuning for power features.

E85 maybe 11.5 to 12.0 air fuel ratio gasoline scale for max output final setting,
E10 closer to 10.8 to 11.0 a/f more common at 20-30psi of boost ranges for any engine 8:1 or 9:1

High 10:1 makes the tuning a bit different. More energy smashing fuel and air together, higher temp, maybe it will need a leaner air fuel ratio for optimal chemical reaction and a colder IAT to control burn rate. OEM turbo engines from the last couple decades in Japan often featured 8.5:1 compression where 95octane gasoline was available standard and all of them are factory intercooler cars emphasis on reducing IAT.

To tune first on gasoline you remove timing to find the EGT ramp of the engine, if possible on dynojet to correlate with lost torque.
From that point a couple of degrees in and thats the lowest pressure you can use with a reasonable EGT making it the ideal timing for daily drivers.
Sometimes the timing can be negative. I think that throws off alot of news. At maybe 2500rpm and 25psi of boost the timing could be -2* btdc. Most people avoid low rpm boost because it 'bends rods' but really it just takes reduced timing to find the minimum pressure and correlate to EGT to make a positive displacement blower work well.

The engine should not break up with minimum timing setting coil D585 which is easily to 1200rwhp or more, 1000lbf-ft at any RPM

[jon1440]

Enrichment needs to be gradual, hold 13.2 to 12.8 for 80KPA to 100KPA ranges dont rush to 12.5 or 12.0
100KPA usually 12.5, low compression can rush 12.0 for torque
105 to 115KPA get down into 12.2's
120 to 150KPA 12.0 to 11.8
150KPA to 200KPA 11.5 to 11.0 on gasoline or stick to 11.8 with E85
By 201KPA It is brushing 11.7 with E85 or 10.9 with gasoline on the in-car wideband, often results with 12.0:1 E85 on the dynometer wideband or 11.2 gasoline
from 205KPA to 315KPA you are holding those a/f ratio while watching(logging) IAT and EGT.
The effects of intercooling and spraying alcohol will vary depending on many factors, for example if the intake is forming ice, the EGT is very low, the a/f should not be overly rich or in the 11's on alcohol at that point, but there are things such as injector end of time tuning which can exacerbate an already over rich condition by spraying late to avoid exhaust valve opening the cylinder may wet down with fuel ruining oil film and polluting fuel and increasing engine wear of the cold cylinders.
Just like with gasoline, if the engine is hot, The EGT Is high, the IAT is getting hot, then its okay to be richer on E85 than 12's because additional cooling is wanted and there is less risk of poor vaporization. However you still must question why is the IAT getting hot, that isn't good. Pressure test the plumbing to ensure no leaks and use the correct size turbo and intercooler and it will not get hot. IAT is a setup issue, not a tuning issue. You can't tune the IAT to be reduced. Compensatory measures for dealing with high IAT are engine safety features, not tuning for power features.

E85 maybe 11.5 to 12.0 air fuel ratio gasoline scale for max output final setting,
E10 closer to 10.8 to 11.0 a/f more common at 20-30psi of boost ranges for any engine 8:1 or 9:1

High 10:1 makes the tuning a bit different. More energy smashing fuel and air together, higher temp, maybe it will need a leaner air fuel ratio for optimal chemical reaction and a colder IAT to control burn rate. OEM turbo engines from the last couple decades in Japan often featured 8.5:1 compression where 95octane gasoline was available standard and all of them are factory intercooler cars emphasis on reducing IAT.

To tune first on gasoline you remove timing to find the EGT ramp of the engine, if possible on dynojet to correlate with lost torque.
From that point a couple of degrees in and thats the lowest pressure you can use with a reasonable EGT making it the ideal timing for daily drivers.
Sometimes the timing can be negative. I think that throws off alot of news. At maybe 2500rpm and 25psi of boost the timing could be -2* btdc. Most people avoid low rpm boost because it 'bends rods' but really it just takes reduced timing to find the minimum pressure and correlate to EGT to make a positive displacement blower work well.

The engine should not break up with minimum timing setting coil D585 which is easily to 1200rwhp or more, 1000lbf-ft at any RPM

Thanks you. I'll continue to study this.

Was looking at the plugs afterwards and whats your take on these? Just trying to understand the plug reading.

https://ls1tech.com/forums/forced-in...eed-input.html

Tried uploading here but cant get it to work.

[kingtal0n]

If you drive around and idle on plugs the only thing you can really do is make sure they all look similar to identical with no damage or obvious sign of issue. And make sure there is no carbon buildup or signs of running rich for prolonged periods. There are some indications of a timing mark on some of the plugs but you can never be too sure using them as a reference once the plugs have more time on them. Looking for melting, damage, coloration, compare with plugs that you just drive around normal on. Have one set just normal driving and another set that you used with high boost and ideally they should look the same with the long run time history embedded. The plugs after 50k to 100k miles should look like they did with 10k miles if the engine is tuned properly, iridiums can last that long. Mostly clean plugs when running gasoline air fuel ratios of 15:1 for idle and cruise.

[jon1440]

In my tune I've been trying to figure out why the massive jump in fueling and I what I noticed is, the open loop fueling has my ratio 1.06-90kpa, 1.10-95kpa, 1.15-100kpa. My PE is set to 1.175-95kpa. BE is 1.18-105kpa. The PE to BE transition looks easy enough. The massive jump from open loop 1.06-90kpa to 1.175-95kpa is what I'm noticing when it hesitates during the transition. Going from 13.84 to 12.49 is alot to happen at once. My tune is up above if anyone wants to looks. I know we need to go into PE and then to BE. but whats best to smooth this out? Change open loop 95 and 100kpa to 1.175 and smooth back down? Or set my PE at 1.1-95kpa and then start the transition back in BE? The BE would ramp up faster but maybe a little leaner around 100-115kpa might not be to bad?

[GHuggins]

I have personally set PE to something like 12.5 in the higher rpms while maintaining 13ish below 3500 rpms and then set BE to 11.5 and then to come in around 4psi. It doesn't hurt anything to have it leaner in normal PE as this even helps to get the turbo spoiling... You can also change injection timing and ignition timing both to transition things more smoothly. Easier to do with smaller turbos and on a gen 4, but can be helped the same way on a gen 3. Retard injection by adding to boudary .3 if memory serves then pull some timing below 3000 while adding back in a small chunk around 3500...

[jon1440]

I have personally set PE to something like 12.5 in the higher rpms while maintaining 13ish below 3500 rpms and then set BE to 11.5 and then to come in around 4psi. It doesn't hurt anything to have it leaner in normal PE as this even helps to get the turbo spoiling... You can also change injection timing and ignition timing both to transition things more smoothly. Easier to do with smaller turbos and on a gen 4, but can be helped the same way on a gen 3. Retard injection by adding to boudary .3 if memory serves then pull some timing below 3000 while adding back in a small chunk around 3500...

I tried the transition in open loop, but of course I'll have to redo my open loop fueling. Not really liking that. I'll give it a try the other way tomorrow with lowering the PE to make the transition better. This section of the map I'm not really seeing it that much just cruising and when it does get there, I'm flying right past it into boost. The turbo seems to light off fairly well but if I cant get it better it would help the heavy ass truck get down the road.

[jon1440]

Also something else I'm not really getting a clear answer on is unreferenced vs. referenced FPR. The dyno tuner said I don't need it and he can tune around it. So far I've found 2 people talk about not using the reference line. And they are dead set on not needing it. But not much detail on how they are getting away with it. I've found 1000 people talk about how its needed.

Heres what I witnessed via my fuel gauge during a pull on the dyno. 58psi referenced, gauge rose in step with boost pressure. 58psi not referenced, pressure dropped maybe 1-2psi. Fuel pump is Aeromotives 5.0GPM Variable Speed. This was performed on the low setting.

Now, just because the gauge is showing fuel pressure, what gauge is telling me fuel output of the injector when boost pressure is working against fuel pressure? There isn't a gauge for that. The spark plug is the last thing to observe.

So now if I go unreferenced, and I know the above is happening, what is going on with tuning process to compensate? And how is it a fuel system can get to a point that the injector output can be forcefully shrunk in output size but still be able to tune fueling for best performance? Seems like instead of adjusting the VE table to adjust fueling we would be using the boost pressure to shrink the injector ouput to target best efficiency.

Where did the line draw that the VE couldn't be adjusted any further and I needed the help of boost pressure?

I've been told maybe the return is to small, or I have a clog somewhere. -10 feed and -10 return. I cant see why the same size return would be an issue. Considering I have something in the middle of path consuming quite a bit of the product.

[kingtal0n]

Lets start the list of Pros to referenced regulator:

1. Keeps fuel cooler
2. Pump will last longer
3. Injectors flow the most fuel
4. Easier to idle tune
5. Takes stress off all fuel system components
6. Allows low base pressure to be adequate for boost setups
7. ____________________ <--- there has to be more


1. con to referenced regulator:
You need to run a vacuum line from the regulator to the engine which is annoying if the regulator is in the rear of the vehicle so that is why they got rid of it on those rear mounted regulators, to reduce complexity at the cost of fuel pump wear & tear

edit: Oh I Just thought of another con to referenced regulators.
2. They need a whole extra fuel line running from the tank to the engine bay, to handle return fuel.

Isn't that super annoying tho? A whole extra fuel line. No wonder they moved it into the trunk. Yeah guys, thats way better, thanks

[jon1440]

Lets start the list of Pros to referenced regulator:

1. Keeps fuel cooler
2. Pump will last longer
3. Injectors flow the most fuel
4. Easier to idle tune
5. Takes stress off all fuel system components
6. Allows low base pressure to be adequate for boost setups
7. ____________________ <--- there has to be more


1. con to referenced regulator:
You need to run a vacuum line from the regulator to the engine which is annoying if the regulator is in the rear of the vehicle so that is why they got rid of it on those rear mounted regulators, to reduce complexity at the cost of fuel pump wear & tear

I'm set on running the reference line and I can't see a benefit to not running it. The tune file is easy enough to adjust, given the correct adjustments are made. For me anyways, the regulator is under the hood and I can remove a variable in the tuning process.

Also it was brought to my attention that because I'm running a reference line, that not only my injector flow rate should be a constant across the board, (I was aware of this) but also the offset vs. voltage vs. vac table would need to be adjusted. Copy the 0 column and paste throughout. Is this correct?

[kingtal0n]

but also the offset vs. voltage vs. vac table would need to be adjusted. Copy the 0 column and paste throughout. Is this correct?

No the reference has nothing to do with injector delay. The delay is a mechanical property of the injector or solenoid depending how you look at it and is dependent on many factors including temperature, voltage, pressure, internal movement, orifice design, etc...

The map used for pressure/voltage is necessary no matter what you do with the reference. It should also have another axis for temperature and calculate fuel density and so forth.... but that level of resolution isn't needed I guess. Or else it happens elsewhere.