drilling LPG injector bigger, but loosing power
drilling LPG injector bigger, but loosing power
hi guys,
i have nog been around a while. Been tuning my LPG injection setup:
Im keeping update in my MSEXTRA topic:
https://www.msextra.com/forums/viewtopi ... 4cd5e0853e
I was having 105-110% duty cycle at max rpm, that is around 4500 rpm with my Big Block and wanted to fix that. My reducer has more then enough power for my engine and pressure is fine. So wanted to drill out the injector nozzles a little more.
They were 2.65mm and I opened them up to 3mm. It didnt fix it. I changed nothing after reinstalling, started my engine and thought I noticed the wideband correcting and adding fuel. At first I thought could be low pressure in my LPG tank, but then took it for a spin and it wont pull over 30-50% TPS and or about 2000-3000rpm. It will get very bad lean spikes and stutter and puff really bad...
I then thought it could be the nozzles I had used in my intake. So i replaced them with the little bit bigger nozzles that came with the Valtek 30 BFC injectors. But theat also didnt help.
I have had nothing but trouble with these Valtek 30 BFC injectors. So Im at the point of tossin them and getting other bigger injectors. But hope somebody can share a light on it, maybe there is something Im not seeing?
i have nog been around a while. Been tuning my LPG injection setup:
Im keeping update in my MSEXTRA topic:
https://www.msextra.com/forums/viewtopi ... 4cd5e0853e
I was having 105-110% duty cycle at max rpm, that is around 4500 rpm with my Big Block and wanted to fix that. My reducer has more then enough power for my engine and pressure is fine. So wanted to drill out the injector nozzles a little more.
They were 2.65mm and I opened them up to 3mm. It didnt fix it. I changed nothing after reinstalling, started my engine and thought I noticed the wideband correcting and adding fuel. At first I thought could be low pressure in my LPG tank, but then took it for a spin and it wont pull over 30-50% TPS and or about 2000-3000rpm. It will get very bad lean spikes and stutter and puff really bad...
I then thought it could be the nozzles I had used in my intake. So i replaced them with the little bit bigger nozzles that came with the Valtek 30 BFC injectors. But theat also didnt help.
I have had nothing but trouble with these Valtek 30 BFC injectors. So Im at the point of tossin them and getting other bigger injectors. But hope somebody can share a light on it, maybe there is something Im not seeing?
storage/project: 1974 GMC 25HUNDRED Suburban - fresh rebuild 350 small block - TH350-NP203 - 4.10 gears - IMPCO425 mixer
driver/project: 1977 GMC C15 Suburban - 454 big block - 4L80E- LPG VSI - 3.08 gears
sold: 1986 Chevrolet Suburban K20 Silverado
driver/project: 1977 GMC C15 Suburban - 454 big block - 4L80E- LPG VSI - 3.08 gears
sold: 1986 Chevrolet Suburban K20 Silverado
Re: drilling LPG injector bigger, but loosing power
Bearing in mind I have read your MS forum thread I am wondering if you have changed the injector setting in TunerStudio yet. If you have what did you change it to? What you are describing are classic symptoms of incorrect injector settings in any tuning software. Also I am wondering if your injector dead times would change because of drilling the injector out.kikkegek wrote: ↑Mon Jul 05, 2021 1:46 amThey were 2.65mm and I opened them up to 3mm. It didnt fix it. I changed nothing after reinstalling, started my engine and thought I noticed the wideband correcting and adding fuel. At first I thought could be low pressure in my LPG tank, but then took it for a spin and it wont pull over 30-50% TPS and or about 2000-3000rpm. It will get very bad lean spikes and stutter and puff really bad...
Have you changed the tune itself since this change?
Fuel flow requirements calculations
Engine air flow requirement calculation: CFM = Cubic Inches x RPM x Volumetric Efficiency (VE) ÷ 3456
Engine air flow requirement calculation: CFM = Cubic Inches x RPM x Volumetric Efficiency (VE) ÷ 3456
Re: drilling LPG injector bigger, but loosing power
nope, I havent changed anything in the settings. nothing. I wanted to see if it would go rich, because of the bigger flow.
storage/project: 1974 GMC 25HUNDRED Suburban - fresh rebuild 350 small block - TH350-NP203 - 4.10 gears - IMPCO425 mixer
driver/project: 1977 GMC C15 Suburban - 454 big block - 4L80E- LPG VSI - 3.08 gears
sold: 1986 Chevrolet Suburban K20 Silverado
driver/project: 1977 GMC C15 Suburban - 454 big block - 4L80E- LPG VSI - 3.08 gears
sold: 1986 Chevrolet Suburban K20 Silverado
Re: drilling LPG injector bigger, but loosing power
If your duty cycle was 105-110% WOT @ 4500 rpm with a 2.65mm orifice your settings were out to begin with. It isn't uncommon to see 101 or 102% but any higher indicates an incorrect setting. Before you drilled them out to 3mm what was the AFR reading at WOT @ 4500 rpm?
It is possible, because in effect you have not told the ECU you have changed anything, you have gone so rich that the O2 sensors are "confused" and read lean due to higher amount of fuel burn changing the exhaust gas composition. I've seen it happen on E10 (but that is an oxygenated fuel) so wonder if it could happen on LPG. This is just a theory and is probably implausible.
What you need to do is calculate your fuel flow and change your settings in TunerStudio. Just as an aside what's the internal size of your hose between the injector fittings you drilled out and manifold fittings?
It is possible, because in effect you have not told the ECU you have changed anything, you have gone so rich that the O2 sensors are "confused" and read lean due to higher amount of fuel burn changing the exhaust gas composition. I've seen it happen on E10 (but that is an oxygenated fuel) so wonder if it could happen on LPG. This is just a theory and is probably implausible.
What you need to do is calculate your fuel flow and change your settings in TunerStudio. Just as an aside what's the internal size of your hose between the injector fittings you drilled out and manifold fittings?
Fuel flow requirements calculations
Engine air flow requirement calculation: CFM = Cubic Inches x RPM x Volumetric Efficiency (VE) ÷ 3456
Engine air flow requirement calculation: CFM = Cubic Inches x RPM x Volumetric Efficiency (VE) ÷ 3456
Re: drilling LPG injector bigger, but loosing power
14.5 - 15.0storm wrote: ↑Mon Jul 05, 2021 4:10 pmIf your duty cycle was 105-110% WOT @ 4500 rpm with a 2.65mm orifice your settings were out to begin with. It isn't uncommon to see 101 or 102% but any higher indicates an incorrect setting. Before you drilled them out to 3mm what was the AFR reading at WOT @ 4500 rpm?
it runs fine below 30-50% TPS. But when I slowly increase the throttleIt is possible, because in effect you have not told the ECU you have changed anything, you have gone so rich that the O2 sensors are "confused" and read lean due to higher amount of fuel burn changing the exhaust gas composition. I've seen it happen on E10 (but that is an oxygenated fuel) so wonder if it could happen on LPG. This is just a theory and is probably implausible.
see this log:
5mmWhat you need to do is calculate your fuel flow and change your settings in TunerStudio. Just as an aside what's the internal size of your hose between the injector fittings you drilled out and manifold fittings?
storage/project: 1974 GMC 25HUNDRED Suburban - fresh rebuild 350 small block - TH350-NP203 - 4.10 gears - IMPCO425 mixer
driver/project: 1977 GMC C15 Suburban - 454 big block - 4L80E- LPG VSI - 3.08 gears
sold: 1986 Chevrolet Suburban K20 Silverado
driver/project: 1977 GMC C15 Suburban - 454 big block - 4L80E- LPG VSI - 3.08 gears
sold: 1986 Chevrolet Suburban K20 Silverado
Re: drilling LPG injector bigger, but loosing power
Ok it was leaning out.
Is this slowly increasing free reving or slowly increasing under load?
Spiking!!! before you do anything else pull your plugs and check them. If they are ok refit them but if they look dodgy at all replace them.
Ok, so that's not a restriction.
EDIT: I just looked at the screenshot again. It's difficult to identify the labels for each line colour but it looks to me like you have a spark misfire. If this is correct it will create the lean condition you are experiencing.
Last edited by storm on Mon Jul 05, 2021 5:10 pm, edited 1 time in total.
Fuel flow requirements calculations
Engine air flow requirement calculation: CFM = Cubic Inches x RPM x Volumetric Efficiency (VE) ÷ 3456
Engine air flow requirement calculation: CFM = Cubic Inches x RPM x Volumetric Efficiency (VE) ÷ 3456
Re: drilling LPG injector bigger, but loosing power
14.5 and 15 is rich...remember LPG is 15.5 stoich....16 and beyond is leaner....below 15.5 is richer
plugs have al been replaced recently and are brand new. like 100km ago.
slowly increasing free revving its fine. Under load is where it will go lean above 30-50% TPS
plugs have al been replaced recently and are brand new. like 100km ago.
slowly increasing free revving its fine. Under load is where it will go lean above 30-50% TPS
storage/project: 1974 GMC 25HUNDRED Suburban - fresh rebuild 350 small block - TH350-NP203 - 4.10 gears - IMPCO425 mixer
driver/project: 1977 GMC C15 Suburban - 454 big block - 4L80E- LPG VSI - 3.08 gears
sold: 1986 Chevrolet Suburban K20 Silverado
driver/project: 1977 GMC C15 Suburban - 454 big block - 4L80E- LPG VSI - 3.08 gears
sold: 1986 Chevrolet Suburban K20 Silverado
Re: drilling LPG injector bigger, but loosing power
Not at WOT it isn't. WOT needs approx 0.90 Lambda which is about 14 AFR.
Edited my post above, I think you have a spark misfire. If it free revs fine but does this under load you are probably loosing spark.
Fuel flow requirements calculations
Engine air flow requirement calculation: CFM = Cubic Inches x RPM x Volumetric Efficiency (VE) ÷ 3456
Engine air flow requirement calculation: CFM = Cubic Inches x RPM x Volumetric Efficiency (VE) ÷ 3456
Re: drilling LPG injector bigger, but loosing power
from all I have read that is not quit true. LPG is a gaseous fuel and has no benefit for rich mixtures under WOT.
liquid fuels like gasoline will get a cooling benefit from running rich mixtures, while with gaseous fuels anything more then stooich just adds heat and not power.
source:
check out 5th rcomment from the topfrom Michael_au
https://www.hpacademy.com/forum/general ... ion-tuning
as for the spark. I find that hard to believe, but Ill check it. I have swapped to LS D585 truck coils and run them at a very safe 30ms dwell time. these coils are considered indestructible. and wouldnt dropping spark cause pisrich mixtures from unburned fuels in stead of these lean spikes?
liquid fuels like gasoline will get a cooling benefit from running rich mixtures, while with gaseous fuels anything more then stooich just adds heat and not power.
source:
check out 5th rcomment from the topfrom Michael_au
https://www.hpacademy.com/forum/general ... ion-tuning
as for the spark. I find that hard to believe, but Ill check it. I have swapped to LS D585 truck coils and run them at a very safe 30ms dwell time. these coils are considered indestructible. and wouldnt dropping spark cause pisrich mixtures from unburned fuels in stead of these lean spikes?
storage/project: 1974 GMC 25HUNDRED Suburban - fresh rebuild 350 small block - TH350-NP203 - 4.10 gears - IMPCO425 mixer
driver/project: 1977 GMC C15 Suburban - 454 big block - 4L80E- LPG VSI - 3.08 gears
sold: 1986 Chevrolet Suburban K20 Silverado
driver/project: 1977 GMC C15 Suburban - 454 big block - 4L80E- LPG VSI - 3.08 gears
sold: 1986 Chevrolet Suburban K20 Silverado
Re: drilling LPG injector bigger, but loosing power
Lol mate thanks for quoting me, did you see this part?kikkegek wrote: ↑Mon Jul 05, 2021 5:21 pmfrom all I have read that is not quit true. LPG is a gaseous fuel and has no benefit for rich mixtures under WOT.
liquid fuels like gasoline will get a cooling benefit from running rich mixtures, while with gaseous fuels anything more then stooich just adds heat and not power.
source:
check out 5th rcomment from the topfrom Michael_au
https://www.hpacademy.com/forum/general ... ion-tuning
I, personally, wouldn't go lower than 0.92 - 0.90 (lambda) on a naturally aspirated engine unless dataloging was able to verify if any increase in richness is actually benefiting the engines output.
O2 sensors "read" combusted fuel and create a voltage output that tells the ECU what the mixture is based on the combusted fuel. If the fuel is not combusted, and this is what I think is happening in your case, the molecular structure of the fuel hasn't changed so the O2 sensor is not "reading" actual combusted fuel but rather is "reading" air/fuel mix of which 90% is oxygen.kikkegek wrote: ↑Mon Jul 05, 2021 5:21 pmas for the spark. I find that hard to believe, but Ill check it. I have swapped to LS D585 truck coils and run them at a very safe 30ms dwell time. these coils are considered indestructible. and wouldnt dropping spark cause pisrich mixtures from unburned fuels in stead of these lean spikes?
Fuel flow requirements calculations
Engine air flow requirement calculation: CFM = Cubic Inches x RPM x Volumetric Efficiency (VE) ÷ 3456
Engine air flow requirement calculation: CFM = Cubic Inches x RPM x Volumetric Efficiency (VE) ÷ 3456
Re: drilling LPG injector bigger, but loosing power
Looking at the screenshot of your datalog I see an event in graph 1 that appears to preceed (albeit momentarily) corresponding events in the other graphs.
Graph 1 the yellow line drops dramatically momentarily before the lean spike in graph 5. You also have a rise in MAP (red line in graph 1) at the same time as the yellow line drops.
Graph 2 the rpm drops at the same point.
Graph 3 green line increases (is that gas pressure?).
Graph 4 white line (pwm?) and red line (duty cycle) both have momentary increases and then drop dramatically.
Graph 5 as mentioned above shows the lean spike.
So we know the engine runs fine free revving, this only happens under load. If I am reading the screenshot correctly all your vital signs are good except for spark which I think is the yellow line in graph 1. After spark drops out the other vital signs react. If I have read the screenshot incorrectly I'll blame my old eyes, I am waiting for my new glasses to arrive next week.
Graph 1 the yellow line drops dramatically momentarily before the lean spike in graph 5. You also have a rise in MAP (red line in graph 1) at the same time as the yellow line drops.
Graph 2 the rpm drops at the same point.
Graph 3 green line increases (is that gas pressure?).
Graph 4 white line (pwm?) and red line (duty cycle) both have momentary increases and then drop dramatically.
Graph 5 as mentioned above shows the lean spike.
So we know the engine runs fine free revving, this only happens under load. If I am reading the screenshot correctly all your vital signs are good except for spark which I think is the yellow line in graph 1. After spark drops out the other vital signs react. If I have read the screenshot incorrectly I'll blame my old eyes, I am waiting for my new glasses to arrive next week.
Fuel flow requirements calculations
Engine air flow requirement calculation: CFM = Cubic Inches x RPM x Volumetric Efficiency (VE) ÷ 3456
Engine air flow requirement calculation: CFM = Cubic Inches x RPM x Volumetric Efficiency (VE) ÷ 3456
Re: drilling LPG injector bigger, but loosing power
we seem to meet everywhere ...doesnt help to meet you under different aliasses
but yeah, that was very valueable indeed. And youre welcome for qouting
as for the ignition. here is my ignition table. As you can see above 80 kPa MAP the timing drops from 34 to 29. Never had problems in that area. But then again, I never drive like this, slowly increasing the throttle to WOT...I usyally either drive easy like in the 10-20% TPS range or stamp it and make the transmission kickdown and drive at 80-100% TPS. hahaha
So I guess Im pulling my plugs and see what they look like. I had ACDELCO #2 (rapidfire single platinum) for while I bought from a friend that ordered them for a big block. Never had problems, untill lately the #1 started fouling and I found out #2 is cold as ice hahaha...then bought a set of stock temp R45TS (stock premium replacement).
but yeah, that was very valueable indeed. And youre welcome for qouting
as for the ignition. here is my ignition table. As you can see above 80 kPa MAP the timing drops from 34 to 29. Never had problems in that area. But then again, I never drive like this, slowly increasing the throttle to WOT...I usyally either drive easy like in the 10-20% TPS range or stamp it and make the transmission kickdown and drive at 80-100% TPS. hahaha
So I guess Im pulling my plugs and see what they look like. I had ACDELCO #2 (rapidfire single platinum) for while I bought from a friend that ordered them for a big block. Never had problems, untill lately the #1 started fouling and I found out #2 is cold as ice hahaha...then bought a set of stock temp R45TS (stock premium replacement).
storage/project: 1974 GMC 25HUNDRED Suburban - fresh rebuild 350 small block - TH350-NP203 - 4.10 gears - IMPCO425 mixer
driver/project: 1977 GMC C15 Suburban - 454 big block - 4L80E- LPG VSI - 3.08 gears
sold: 1986 Chevrolet Suburban K20 Silverado
driver/project: 1977 GMC C15 Suburban - 454 big block - 4L80E- LPG VSI - 3.08 gears
sold: 1986 Chevrolet Suburban K20 Silverado
Re: drilling LPG injector bigger, but loosing power
correct. see timing table in previous poststorm wrote: ↑Tue Jul 06, 2021 12:21 amLooking at the screenshot of your datalog I see an event in graph 1 that appears to preceed (albeit momentarily) corresponding events in the other graphs.
Graph 1 the yellow line drops dramatically momentarily before the lean spike in graph 5. You also have a rise in MAP (red line in graph 1) at the same time as the yellow line drops.
yes, probably from the drop in timingGraph 2 the rpm drops at the same point.
yes thats (railpressure - MAP) = LPG injection pressure....some LPG injection suppliers call it Psys in their tuning-softwareGraph 3 green line increases (is that gas pressure?).
correct pw and duty and they increase because MAP increasesGraph 4 white line (pwm?) and red line (duty cycle) both have momentary increases and then drop dramatically.
Graph 5 as mentioned above shows the lean spike.
So we know the engine runs fine free revving, this only happens under load. If I am reading the screenshot correctly all your vital signs are good except for spark which I think is the yellow line in graph 1. After spark drops out the other vital signs react. If I have read the screenshot incorrectly I'll blame my old eyes, I am waiting for my new glasses to arrive next week.
storage/project: 1974 GMC 25HUNDRED Suburban - fresh rebuild 350 small block - TH350-NP203 - 4.10 gears - IMPCO425 mixer
driver/project: 1977 GMC C15 Suburban - 454 big block - 4L80E- LPG VSI - 3.08 gears
sold: 1986 Chevrolet Suburban K20 Silverado
driver/project: 1977 GMC C15 Suburban - 454 big block - 4L80E- LPG VSI - 3.08 gears
sold: 1986 Chevrolet Suburban K20 Silverado
Re: drilling LPG injector bigger, but loosing power
lolololol. I've been a member of HPA for years, started out as Storm but someone asked me to use my real name so I changed it to Michael AU.
If your plugs are ok check the rest of your ignition system.
Fuel flow requirements calculations
Engine air flow requirement calculation: CFM = Cubic Inches x RPM x Volumetric Efficiency (VE) ÷ 3456
Engine air flow requirement calculation: CFM = Cubic Inches x RPM x Volumetric Efficiency (VE) ÷ 3456
Re: drilling LPG injector bigger, but loosing power
checked the plugs on the side where my wideband reads. They look fine.
Whats else in the ignition system should I look for?
Whats else in the ignition system should I look for?
storage/project: 1974 GMC 25HUNDRED Suburban - fresh rebuild 350 small block - TH350-NP203 - 4.10 gears - IMPCO425 mixer
driver/project: 1977 GMC C15 Suburban - 454 big block - 4L80E- LPG VSI - 3.08 gears
sold: 1986 Chevrolet Suburban K20 Silverado
driver/project: 1977 GMC C15 Suburban - 454 big block - 4L80E- LPG VSI - 3.08 gears
sold: 1986 Chevrolet Suburban K20 Silverado