Low Z noise problems
Moderators: jsmcortina, muythaibxr
Re: Low Z noise problems
[/quote]
good question. I'd say Q3 but I would want to try it each way[/quote]
Um... I am a bit confused by your answer?
Q3 -> 47uf_cap -> Q9 (which is lifted and connected to 12v outside of megasquirt)
or
Q3 -> 47uf_cap -> Megasquirt board at the Q9 12 volt hole
I guess the question is, does the cap filter noise within the Megasquirt or does it absorb the energy from the PWM flyback and thus prevent noise from being generated in the first place?
good question. I'd say Q3 but I would want to try it each way[/quote]
Um... I am a bit confused by your answer?
Q3 -> 47uf_cap -> Q9 (which is lifted and connected to 12v outside of megasquirt)
or
Q3 -> 47uf_cap -> Megasquirt board at the Q9 12 volt hole
I guess the question is, does the cap filter noise within the Megasquirt or does it absorb the energy from the PWM flyback and thus prevent noise from being generated in the first place?
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Re: Low Z noise problems
good question. I'd say Q3 but I would want to try it each way[/quote]svocapri wrote:
Um... I am a bit confused by your answer?
Q3 -> 47uf_cap -> Q9 (which is lifted and connected to 12v outside of megasquirt)
or
Q3 -> 47uf_cap -> Megasquirt board at the Q9 12 volt hole
I guess the question is, does the cap filter noise within the Megasquirt or does it absorb the energy from the PWM flyback and thus prevent noise from being generated in the first place?[/quote]
It filters noise from the injectors
Peter Florance
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Co-Driver 1999 BMW E46 DSP car.
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Co-Driver 1999 BMW E46 DSP car.
Re: Low Z noise problems
as i have problems reaching the same place in megamanual twice... i can't find the place when it was written about low Z inj and wasted spark.... sorry
Re: Low Z noise problems
could You tell me, couse i read in ms III manual, that with low z injectors i shoul use about 3ohm resistors... could you tell me if i can use same resistance for PCB in MS II?? because the calculator on the side told me to use 10ohms, but injectors don't want to open... i tried also 5ohm, but also they do not open. i wanted to use resistors with low Z injestors to use double fuel in semisequence (two channels working on both maps, theinjectors would be switched by the relays) but my low Z don't want to open with reccomended resistors. i would try with lower resistors, but don't want to burn anything in ms
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Re: Low Z noise problems
Your settings should be set for high Z if you use resistors. Are you using the correct settings?kubeq_sq wrote:could You tell me, couse i read in ms III manual, that with low z injectors i shoul use about 3ohm resistors... could you tell me if i can use same resistance for PCB in MS II?? because the calculator on the side told me to use 10ohms, but injectors don't want to open... i tried also 5ohm, but also they do not open. i wanted to use resistors with low Z injestors to use double fuel in semisequence (two channels working on both maps, theinjectors would be switched by the relays) but my low Z don't want to open with reccomended resistors. i would try with lower resistors, but don't want to burn anything in ms
I don't bother; I use low z injectors with the recommended settings. If you use enough ground wires and add the capacitor I mentioned above, you should not have a problem.
Peter Florance
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Co-Driver 1999 BMW E46 DSP car.
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Co-Driver 1999 BMW E46 DSP car.
Re: Low Z noise problems
Peter,
Are you saying you run the Low-Z injectors directly off the MS3-X board with some suggested settings, or using the PWM function of the V3 main board? Sorry for my confusion...
FWIW, I tried a set of Low-Z injectors running via PWM from the V3 mainboard, and had NO noise issues at all. It was a very pleasant experience. Unfortunately, I had damaged a rod bearing about the same time that I tried the bigger injectors, so I didn't get to fully "test" them. More soon though!
Thad
Are you saying you run the Low-Z injectors directly off the MS3-X board with some suggested settings, or using the PWM function of the V3 main board? Sorry for my confusion...
FWIW, I tried a set of Low-Z injectors running via PWM from the V3 mainboard, and had NO noise issues at all. It was a very pleasant experience. Unfortunately, I had damaged a rod bearing about the same time that I tried the bigger injectors, so I didn't get to fully "test" them. More soon though!
Thad
--'98 Dodge Neon ACR Turbo - MS3 beta test car - Sold
--'97 BMW 540i/6spd - Single Front/Top Mount Turbo 550+ HP - MS3+MS3X V3.0 - Sold but ripping in Vegas
--'97 BMW 328i 5.3 L33/TH400 Swapped drift car - MS3+MS3X V3.0 Full Sequential - Turbos And Radiator In the Trunk 9.6@144 on a 1.55 60ft
--'97 BMW 540i/6spd - Single Front/Top Mount Turbo 550+ HP - MS3+MS3X V3.0 - Sold but ripping in Vegas
--'97 BMW 328i 5.3 L33/TH400 Swapped drift car - MS3+MS3X V3.0 Full Sequential - Turbos And Radiator In the Trunk 9.6@144 on a 1.55 60ft
Re: Low Z noise problems
i.m running them now as a low z injectors using pwm and flyback boards build in PCB v3.0.... but i wonted to run them as high Z, because my petrol injectors are high Z, so can i use 3ohm resistors with my 2 ohm ijnectors (3 connected per channel)will ms board last out that current? about 7 Ampers per channel??
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Re: Low Z noise problems
No, V3Tjabo wrote:Peter,
Are you saying you run the Low-Z injectors directly off the MS3-X board with some suggested settings, or using the PWM function of the V3 main board? Sorry for my confusion...
FWIW, I tried a set of Low-Z injectors running via PWM from the V3 mainboard, and had NO noise issues at all. It was a very pleasant experience. Unfortunately, I had damaged a rod bearing about the same time that I tried the bigger injectors, so I didn't get to fully "test" them. More soon though!
Thad
I am also running them on the V1.04 MS2Sequencer, which is the same output hardware as MS3X
Peter Florance
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Co-Driver 1999 BMW E46 DSP car.
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Co-Driver 1999 BMW E46 DSP car.
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Re: Low Z noise problems
You mean you're running low-Z injectors in saturated mode? And nothing gets too hot? How much duty cycle are you running on these?Peter Florance wrote:I am also running them on the V1.04 MS2Sequencer, which is the same output hardware as MS3X
Jean
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Re: Low Z noise problems
I'll have to look at a log. Injectors are fairly small, so I'd say probably 70-75% when I'm flogging on it.racingmini_mtl wrote:You mean you're running low-Z injectors in saturated mode? And nothing gets too hot? How much duty cycle are you running on these?Peter Florance wrote:I am also running them on the V1.04 MS2Sequencer, which is the same output hardware as MS3X
Jean
Fully sequential so maybe there is more time to cool?
I'm not the first person to run these exact injectors on a sequencer.
Peter Florance
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Co-Driver 1999 BMW E46 DSP car.
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Co-Driver 1999 BMW E46 DSP car.
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Re: Low Z noise problems
I don't think this is a good idea. The fact that it runs and hasn't caused issues yet doesn't mean it's correct. Running sequential doesn't give more cooling time because at 75% duty cycle, no matter how many squirts you use you have 25% of the time to cool off. And actually with a single pulse, you will be in current limit mode for a longer period so it may even be worse.Peter Florance wrote:I'll have to look at a log. Injectors are fairly small, so I'd say probably 70-75% when I'm flogging on it.
Fully sequential so maybe there is more time to cool?
I'm not the first person to run these exact injectors on a sequencer.
The reason I don't like it is that this will have an impact on the dead time because you shut down the injectors with 5A running through them. Also, if the drivers ever go in thermal shutdown, it's going to be at the worse possible moment. It will be at high load/RPM when duty cycle is high and likely the temperature is also high. If they go in complete shut down, it's not too bad since it would basically be fuel cut. But if they go in shut down during the pulse (and even worse, repeatedly) then you get a (sustained) lean situation. This is a nice recipe for engine melt down.
So I would never recommend people do that and this is also the recommendation for MS3 as far as I know. Relying on a safety mechanism for normal operation is not a good practice.
Jean
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Re: Low Z noise problems
I tested 2.5R low-z injectors with the MS3X and while I didn't get into thermal shutdown mode, the board was hot enough that you could smell it and the injectors boiled water.
That's why I state that resistors MUST be used with low-z. However, I don't think you need to use a very large value three to four ohms seems like a good compromise.
James
That's why I state that resistors MUST be used with low-z. However, I don't think you need to use a very large value three to four ohms seems like a good compromise.
James
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Re: Low Z noise problems
Jean, I don't recommend for or against it on MS3x. I'm beta testing to find out how it does.racingmini_mtl wrote:I don't think this is a good idea. The fact that it runs and hasn't caused issues yet doesn't mean it's correct. Running sequential doesn't give more cooling time because at 75% duty cycle, no matter how many squirts you use you have 25% of the time to cool off. And actually with a single pulse, you will be in current limit mode for a longer period so it may even be worse.Peter Florance wrote:I'll have to look at a log. Injectors are fairly small, so I'd say probably 70-75% when I'm flogging on it.
Fully sequential so maybe there is more time to cool?
I'm not the first person to run these exact injectors on a sequencer.
The reason I don't like it is that this will have an impact on the dead time because you shut down the injectors with 5A running through them. Also, if the drivers ever go in thermal shutdown, it's going to be at the worse possible moment. It will be at high load/RPM when duty cycle is high and likely the temperature is also high. If they go in complete shut down, it's not too bad since it would basically be fuel cut. But if they go in shut down during the pulse (and even worse, repeatedly) then you get a (sustained) lean situation. This is a nice recipe for engine melt down.
So I would never recommend people do that and this is also the recommendation for MS3 as far as I know. Relying on a safety mechanism for normal operation is not a good practice.
Jean
On V3 boards, it absolutely works. I don't understand why all the hacked up boards, lifted and separated 12v lines etc.
Peter Florance
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Co-Driver 1999 BMW E46 DSP car.
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Co-Driver 1999 BMW E46 DSP car.
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Re: Low Z noise problems
I'm just curious. Did you scope the outputs to see if you were actually getting the full pulse width and not some shortened ones?jsmcortina wrote:I tested 2.5R low-z injectors with the MS3X and while I didn't get into thermal shutdown mode, the board was hot enough that you could smell it and the injectors boiled water.
And just as a note, the heat will come from 2 sources: the over-current limitation and the flyback. With inline resistors, you will completely eliminate the first and significantly reduce the second (which is proportional to the square of the current).
Jean
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Re: Low Z noise problems
No not yet.racingmini_mtl wrote:I'm just curious. Did you scope the outputs to see if you were actually getting the full pulse width and not some shortened ones?jsmcortina wrote:I tested 2.5R low-z injectors with the MS3X and while I didn't get into thermal shutdown mode, the board was hot enough that you could smell it and the injectors boiled water.
And just as a note, the heat will come from 2 sources: the over-current limitation and the flyback. With inline resistors, you will completely eliminate the first and significantly reduce the second (which is proportional to the square of the current).
Jean
I was working more with the new VR circuit testing. The Monkey had many miles with the same output hardware, so that was not my first concern.
Peter Florance
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Co-Driver 1999 BMW E46 DSP car.
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Co-Driver 1999 BMW E46 DSP car.
Re: Low Z noise problems
ehh, could You help me, couse i;ve made today some driving at low z injector setting at lpg and when my flyback board turns on my car starts struggle, as it has gas in fuel rail, i can't accelerate, i have loss syncs... i've made upgrades told by ryniobl and that's how looks my board :
if You see anything wrong please tell me... my low z just don't work with resistors, they don't open :/
if i would like to use resistors with them what resistance whould they have?
if You see anything wrong please tell me... my low z just don't work with resistors, they don't open :/
if i would like to use resistors with them what resistance whould they have?
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Re: Low Z noise problems
I'm guessing something is not functioning correctlykubeq_sq wrote:ehh, could You help me, couse i;ve made today some driving at low z injector setting at lpg and when my flyback board turns on my car starts struggle, as it has gas in fuel rail, i can't accelerate, i have loss syncs... i've made upgrades told by ryniobl and that's how looks my board :
if You see anything wrong please tell me... my low z just don't work with resistors, they don't open :/
if i would like to use resistors with them what resistance whould they have?
Can you scope the outputs and post a picture?
Peter Florance
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Co-Driver 1999 BMW E46 DSP car.
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Co-Driver 1999 BMW E46 DSP car.
Re: Low Z noise problems
and here is a problem... i haven´t got a scope :/ the biggest chances are that i shuold change which part?? if it is necessary i will go on scopy to my friend, but You have to write my step by step how to scope and what, because i've never done it... :/
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Re: Low Z noise problems
I agree. Seems there are a lot of urban myths flying around.Peter Florance wrote:On V3 boards, it absolutely works. I don't understand why all the hacked up boards, lifted and separated 12v lines etc.
James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk
My Success story: http://www.msextra.com/forums/viewtopic ... 04&t=34277
MSEXTRA documentation at: http://www.msextra.com/doc/index.html
New users, please read the "Forum Help Page".
My Success story: http://www.msextra.com/forums/viewtopic ... 04&t=34277
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Re: Low Z noise problems
scope middle leg of Q1 and Q5kubeq_sq wrote:and here is a problem... i haven´t got a scope :/ the biggest chances are that i shuold change which part?? if it is necessary i will go on scopy to my friend, but You have to write my step by step how to scope and what, because i've never done it... :/
that's all I need to see
Peter Florance
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Co-Driver 1999 BMW E46 DSP car.
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Co-Driver 1999 BMW E46 DSP car.