Wtf Is This? PnP Megasquirt ECU
Senior Member
Joined: Mar 2006
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Vehicle: 2000 Hyundai Elantra
The MegaSquirt fuel tuner is a build it yourself ECU. It takes some skill to do this, but look at the information below. You may find you CAN do this yourself.
Understanding how MegaSquirt controls the fuel injectors will help you to assemble, test, and tune your MegaSquirt for best performance. MegaSquirt works on a number of levels to inject the correct amount of fuel into your engine. Most tangible is the hardware. This consists of:
CPU (U1, the 68HC908) and clock section (Y1, the 32768 Hz crystal), that perform computations,
Serial communications section (most notably U6, the MAX232 chip) to enable tuning software to read and write parameters to MegaSquirt,
Power section (especially U5, the LM2937 voltage regulator) to provide a constant 5 volts for many of the other components,
Various input conditioning circuits (consisting mainly of capacitors, resistors, and diodes, but also including: U3, the MPX4250 MAP sensor, and U4, the opto-isolator for the ignition signal, and
A number of outputs to drive the injectors, relays, and LEDs. Significant components include U7, the 34151 FET injector driver, Q2 and Q7, the two IFRIZ34N FETs (field effect transistors) for the injector banks, Q1, the TIP32C flyback transistor, and a number of other transistor, capacitors, and resistors.
There are also a number of other associated parts, such as connectors, the case, cables, etc.
The MC68HC908 CPU is controlled by “embedded softwareâ€Â. This is “burned†into the non-volatile memory (remembers data even when the power is turned off) of the CPU. It is written in assembly language. The embedded code and its variants are freely available. Another part of the CPU memory is burned with the “bootloaderâ€Â, which tells the CPU how to interpret and store new versions of the embedded code sent through the serial communications port. The parameters that adjust the embedded code to your specific vehicle are configured using a laptop and tuning software, such as MegaTune. These are Windows9x/Me/XP applications. They can read information coming from the MegaSquirt, as well as send parameters to MegaSquirt for use and storage.
The amount of fuel injected by MegaSquirt depends on several factors:
The Ideal Gas Law that relates the amount of air to its pressure, volume and temperature, (this is a fundamental part of the embedded code).
Measured values: manifold pressure, engine and intake air temperature, rpm, etc. (these are taken from the sensor measurements).
Tuning parameters: REQ_FUEL, volumetric efficiency, injector open time, etc. (these are input and adjusted using the tuning software).
MegaSquirt uses all these factors to determine the fuel pulse width - longer pulse widths mean more fuel (richer), shorter pulse widths mean less fuel (leaner).
Understanding how MegaSquirt controls the fuel injectors will help you to assemble, test, and tune your MegaSquirt for best performance. MegaSquirt works on a number of levels to inject the correct amount of fuel into your engine. Most tangible is the hardware. This consists of:
CPU (U1, the 68HC908) and clock section (Y1, the 32768 Hz crystal), that perform computations,
Serial communications section (most notably U6, the MAX232 chip) to enable tuning software to read and write parameters to MegaSquirt,
Power section (especially U5, the LM2937 voltage regulator) to provide a constant 5 volts for many of the other components,
Various input conditioning circuits (consisting mainly of capacitors, resistors, and diodes, but also including: U3, the MPX4250 MAP sensor, and U4, the opto-isolator for the ignition signal, and
A number of outputs to drive the injectors, relays, and LEDs. Significant components include U7, the 34151 FET injector driver, Q2 and Q7, the two IFRIZ34N FETs (field effect transistors) for the injector banks, Q1, the TIP32C flyback transistor, and a number of other transistor, capacitors, and resistors.
There are also a number of other associated parts, such as connectors, the case, cables, etc.
The MC68HC908 CPU is controlled by “embedded softwareâ€Â. This is “burned†into the non-volatile memory (remembers data even when the power is turned off) of the CPU. It is written in assembly language. The embedded code and its variants are freely available. Another part of the CPU memory is burned with the “bootloaderâ€Â, which tells the CPU how to interpret and store new versions of the embedded code sent through the serial communications port. The parameters that adjust the embedded code to your specific vehicle are configured using a laptop and tuning software, such as MegaTune. These are Windows9x/Me/XP applications. They can read information coming from the MegaSquirt, as well as send parameters to MegaSquirt for use and storage.
The amount of fuel injected by MegaSquirt depends on several factors:
The Ideal Gas Law that relates the amount of air to its pressure, volume and temperature, (this is a fundamental part of the embedded code).
Measured values: manifold pressure, engine and intake air temperature, rpm, etc. (these are taken from the sensor measurements).
Tuning parameters: REQ_FUEL, volumetric efficiency, injector open time, etc. (these are input and adjusted using the tuning software).
MegaSquirt uses all these factors to determine the fuel pulse width - longer pulse widths mean more fuel (richer), shorter pulse widths mean less fuel (leaner).
Thread Starter
Senior Member
Joined: Mar 2002
Posts: 34,642
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From: Los Lunas, New Mexico, USA.
Vehicle: 2001 Hyundai Tiburon, 2004 Kia Sorento, 2010 Kia Soul
I knew you guys were smart, yup it's a MS.
Yes, you can build them yourself, but this is built, and totally ready, by a guy that does it for a living. He's done, if I remember correctly, 137 of these now. If you are interested in doing it yourself, post elsewhere, as this thread is not about that.
And about 8 for Kias and other Hyundai's.
Yes, it'll either have a core required, or you can pay $30 to $50 more to get one from us. I'll start building up a stock of used ecu's soon, they can be burnt out too, just need the connector really.
For a fully done, P&P system, that's a GREAT price.
Best part? Should only need a week of lead time, and the first ones will be for sale in about 2 weeks.
Yes, you can build them yourself, but this is built, and totally ready, by a guy that does it for a living. He's done, if I remember correctly, 137 of these now. If you are interested in doing it yourself, post elsewhere, as this thread is not about that.
And about 8 for Kias and other Hyundai's.
Yes, it'll either have a core required, or you can pay $30 to $50 more to get one from us. I'll start building up a stock of used ecu's soon, they can be burnt out too, just need the connector really.
For a fully done, P&P system, that's a GREAT price.
Best part? Should only need a week of lead time, and the first ones will be for sale in about 2 weeks.
Senior Member
Joined: Mar 2006
Posts: 7,799
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Vehicle: 2001 Hyundai Tiburon
Im down for one of Yamahas cores, LOL. I want one asap.
Couple questions:
Great to see this done for us. Looking forward to getting my damn car running!!!
Couple questions:
- No ignition ignitor or anything else needed, right?
- I have a map sensor with my turbo kit and do not have a maf. How will that be used? (Splice into the MAF wires and switch something inside perhaps)
Great to see this done for us. Looking forward to getting my damn car running!!!
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Joined: Jan 2008
Posts: 188
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Vehicle: 1999 Kia Sephia
Ok, sorry it took so long, I am at work, the other job!!!!
Anyway here goes.
Stage One
This is the megasquirt system using the latest technology they have available. Because we are using the latest version the price is going to be a little higher, but not much.
Stage one that is currently in Jeremy's car is indeed plug and play, it did idle at 4000 rpm until they turned it down. The next one should do everything his car does once it is tuned. We can then save the maps and include them in our new purchases. We have to spend a little time and come up with some instructions for this thing!!
Stage one assumes that you will be heading to the dyno shop to tune it as it does not include wideband O2 sensor. You can tune it with a narrow band that is the stock unit, but you will not be as accurate as you could be. You will need to purchase or supply a ecu as it will fit into the stock case and use the stock plug.
The price on Stage one is $500
Stage Two
The next step is what you get in stage one along with a wideband O2 sensor. My wording could be slightly incorrect on this, but my understanding is that this unit will be able to self tune itself within the guidelines of the parameters you set. Pretty cool stuff that even the OEM's we drive cannot do.
Price on Stage two is $700. Sorry, because of paypal fees and shipping to us, we need to be $25 more.
Add on Modules.
There is a bunch more that is and will be available, those including knock sensor and the ability to work with nitrous and of course our favorite BOOOST.
There will be price additions for these add ons that we will finalize once we get the initial testing out of the way.
Jeremy should have his in place this weekend, we will run it for a week and then move onward to having it in our catalog
Bill
Anyway here goes.
Stage One
This is the megasquirt system using the latest technology they have available. Because we are using the latest version the price is going to be a little higher, but not much.
Stage one that is currently in Jeremy's car is indeed plug and play, it did idle at 4000 rpm until they turned it down. The next one should do everything his car does once it is tuned. We can then save the maps and include them in our new purchases. We have to spend a little time and come up with some instructions for this thing!!
Stage one assumes that you will be heading to the dyno shop to tune it as it does not include wideband O2 sensor. You can tune it with a narrow band that is the stock unit, but you will not be as accurate as you could be. You will need to purchase or supply a ecu as it will fit into the stock case and use the stock plug.
The price on Stage one is $500
Stage Two
The next step is what you get in stage one along with a wideband O2 sensor. My wording could be slightly incorrect on this, but my understanding is that this unit will be able to self tune itself within the guidelines of the parameters you set. Pretty cool stuff that even the OEM's we drive cannot do.
Price on Stage two is $700. Sorry, because of paypal fees and shipping to us, we need to be $25 more.
Add on Modules.
There is a bunch more that is and will be available, those including knock sensor and the ability to work with nitrous and of course our favorite BOOOST.
There will be price additions for these add ons that we will finalize once we get the initial testing out of the way.
Jeremy should have his in place this weekend, we will run it for a week and then move onward to having it in our catalog
Bill
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Joined: Jan 2007
Posts: 316
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From: Marshfield, WI
Great news.
I have a few general questions:
1. How long do you think these will be available, or will they be ongoing as long as supply and demand are there?
2. If I'm understand this right, the prices listed are a base price for what you have so far said comes with it. Prices increase as we request additional things (features) with them, such as maps, or the ability to pre-heat your car for example.
3. Are the prices including an assembled unit, or an unassembled one?
I'm sure I will have more. I am super excited about this and very very grateful to everyone involved.
I have a few general questions:
1. How long do you think these will be available, or will they be ongoing as long as supply and demand are there?
2. If I'm understand this right, the prices listed are a base price for what you have so far said comes with it. Prices increase as we request additional things (features) with them, such as maps, or the ability to pre-heat your car for example.
3. Are the prices including an assembled unit, or an unassembled one?
I'm sure I will have more. I am super excited about this and very very grateful to everyone involved.
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Joined: Mar 2006
Posts: 7,799
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Vehicle: 2001 Hyundai Tiburon
Ill hit a couple of those I think Adam
1. The units are universal at first. He is just hooking them up to a stock ECU. That being said these can be made anytime I assume
2. The extras hes talking about are things like map sensors or other sensors to enable nitrous or other things. Not so much maps. It will come with a base map I understand but anything past that is really to different to do without a dyno. The preheating is all in the idle speed along with a timer.
3. Im going to say thats assembled.
As for me, I have a map sensor. The MS should be able to read that just like any other standalone and allow me to set fuel and spark at any given reading from the map sensor. I just need a way to wire it in.
I would like more info on what else can be built into these for extra. My PRS is sold and Im doing this asap. I need to have it wired for me to connect my map sensor and allow for nitrous later on. Please keep me (and others) updated so we can discuss further options with this unit.
1. The units are universal at first. He is just hooking them up to a stock ECU. That being said these can be made anytime I assume
2. The extras hes talking about are things like map sensors or other sensors to enable nitrous or other things. Not so much maps. It will come with a base map I understand but anything past that is really to different to do without a dyno. The preheating is all in the idle speed along with a timer.
3. Im going to say thats assembled.
As for me, I have a map sensor. The MS should be able to read that just like any other standalone and allow me to set fuel and spark at any given reading from the map sensor. I just need a way to wire it in.
I would like more info on what else can be built into these for extra. My PRS is sold and Im doing this asap. I need to have it wired for me to connect my map sensor and allow for nitrous later on. Please keep me (and others) updated so we can discuss further options with this unit.