MAF Amplifier - home brew = Leccy projects for the so inclined....

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Joe_H

Joe_H

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If anyone likes playing leccy - here is a MAF amplifier (should work with more or less anything) - ie TD4 - Pierburg etc etc) - It is purely an exercise in design - if you want to build one test it on the bench first. If you are unsure about basic electronics it is best left to someone else.
However, feel free to experiment - add / discuss ideas ? - - whatever. It is good fun and cheap.

Dirt cheap to make, less than a fiver with a box. - can be turned off :) - gain anywhere from 1:1 - 1.47:1
The pot sets the gain, for a Pierburg use about 1.1 : 1 gain (ie - variable resistor (pot) set to about 10K) it isn't that critical really - you can just turn it till it smokes a bit (the EXHAUST - not the amp :rolleyes: :)) then back off a tad :D

For info -
You can always calculate the gain of the dc amplifier here (a non inverting op amp DC amplifier) by the formula 1 + (R(feedback) / Rin))
Where, in the 'crappy drawing', Rfeedback is the 47K variable pot' and Rin is the Fixed value 100K resistor . As the 47K is variable from 0 ohms to 47K ohms, it can be seen that the gain is variable from 1:1 to 1.47:1,
1:1 (Rfeedback turned to 0 ohms) is effectively OFF - where output = input.

You can calculate the above range of gain by using the formula above and replacing Rfeedback for any value between 0 and 47K ohms. If the variable resistor (Rfeedback) is set to 10K then the gain = 1 + (10000/100000) = 1.1 : 1 .

Tweak your existing MAF or use it to replace the existing MAF with another model with more or less correct size pipework and for similar engine size and fuel type.. (preferably very slightly larger capacity)
back of fag packet again, ain't got my Schematic Design prog loaded on this lappy.
Just an example to show you how cheap things can be made yet do the job just as well as anything bought

Op Amp here is a an OPA350PA (single supply 5v capable rail to rail unit - cheap as chips from RS components who offer free next day delivery.
You only need to attach into the 5v and gnd feed to the MAF and then cut the maf signal wire and put maf side to in and ecu side to out - sorted. - sell the car just join the maf sensor wire back together. You could probably build it small enough if you wanted to fit under the MAF plug sleeve. Whatever.
Joe ;)

mafamplifier.JPG


that's about it...... :rolleyes:
 
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Hi Jim,
The 'gain' is the amplification factor of the DC feedback signal to the ECU -
If your MAF is down on performance then a slight gain will improve things no end.
A gain of 1.1:1 would, for example - give a DC input to output value of the input x 1.1

Hence 2v in would be 2.2 out, 3v in would be 3.3V out and 4v in would be 4.4v out - so it follows a progressively higher output feed as airflow increases. It effectively shifts the output curve of the MAF slightly higher (depending on gain). the ecu sees this as higher airflow into the engine and increases the fuelling to compensate hence providing more power (obviously there is a limit) - so if your existing MAF is a tad down, or you replace the MAF with a cheaper but slightly different (lower) output it can be corrected and in many ways improved and matched to your engines needs.
The higher the gain setting, the greater the shift in the curve plot of the MAF output is.
So, it is a simple method to increase power on a diesel !, it is capable of compensating for MAFs that are slightly contaminated and not working at their best (typical on TD4 units) (It increases the signal to the ecu proportionally ), or it can also compensate for a different type of MAF like the Pierburg units which are often cheaper than the equivalent Bosch ones.
Joe
 
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I take it the decoupling caps go in series with the inputs, or do they go to ground?

Suggestions: Build this up into a resin-potted package that will piggy-back into the existing MAF connector. Have the pot labelled 'less power -> more power' and have a shunt feature to bypass the unit for baseline testing. Fix up an OLED screen displaying in/out voltage, gain, time, date and weather. Sell the units on eBay for £29.99. Cut me in at 33%.

Oh, and you're welcome...
 
guineafowl21 said:
I take it the decoupling caps go in series with the inputs, or do they go to ground?

Suggestions: Build this up into a resin-potted package that will piggy-back into the existing MAF connector. Have the pot labelled 'less power -> more power' and have a shunt feature to bypass the unit for baseline testing. Fix up an OLED screen displaying in/out voltage, gain, time, date and weather. Sell the units on eBay for £29.99. Cut me in at 33%.

Oh, and you're welcome...
Click to expand...
Lol ::) no the caps would go to ground. Caps in series would block DC. - caps on the inputs and outputs to ground are only to pass any hf crap to deck. They probably would not be needed. but hey, they are only pence.
Across the power supply ( 5v and ground )- that is for the op amp supply, that is best decoupled - from 5v to ground - by a 4.7 microfarad (anywhere from 1uF to 10 uF would be fine - whatever is in the junk box ) electrolytic cap and a 0.1 microfarad ceramic. the values of Rf and Rin can be substituted depending what you have lying around - the gain can be calculated from the equations in the first post. Dont see any point going over 1.5:1 at all. (probably no more than 1.3 is needed but you can always turn it down .....)
You don't need to bypass it for baseline testing, turning the 47k pot to 0 ohms gives a 1:1 gain so it is effectively not there. input = output.
The op amp is mil spec rated so no worries there on temps etc.
As for manufacture and selling - errr nope.... :eek: - I retired 13 years ago and don't intend to work again... anyone else can if they want - it is for anyone to use as far as I am concerned. If copied, I would just appreciate a mention in the credits. ;)
Joe
 
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Joe_H said:
If anyone likes playing leccy - here is a MAF amplifier (should work with more or less anything) - ie TD4 - Pierburg etc etc) - It is purely an exercise in design - if you want to build one test it on the bench first. If you are unsure about basic electronics it is best left to someone else.
However, feel free to experiment - add / discuss ideas ? - - whatever. It is good fun and cheap.

Dirt cheap to make, less than a fiver with a box. - can be turned off :) - gain anywhere from 1:1 - 1.47:1
The pot sets the gain, for a Pierburg use about 1.1 : 1 gain (ie - variable resistor (pot) set to about 10K) it isn't that critical really - you can just turn it till it smokes a bit (the EXHAUST - not the amp :rolleyes: :)) then back off a tad :D

For info -
You can always calculate the gain of the dc amplifier here (a non inverting op amp DC amplifier) by the formula 1 + (R(feedback) / Rin))
Where, in the 'crappy drawing', Rfeedback is the 47K variable pot' and Rin is the Fixed value 100K resistor . As the 47K is variable from 0 ohms to 47K ohms, it can be seen that the gain is variable from 1:1 to 1.47:1,
1:1 (Rfeedback turned to 0 ohms) is effectively OFF - where output = input.

You can calculate the above range of gain by using the formula above and replacing Rfeedback for any value between 0 and 47K ohms. If the variable resistor (Rfeedback) is set to 10K then the gain = 1 + (10000/100000) = 1.1 : 1 .

Tweak your existing MAF or use it to replace the existing MAF with another model with more or less correct size pipework and for similar engine size and fuel type.. (preferably very slightly larger capacity)
back of fag packet again, ain't got my Schematic Design prog loaded on this lappy.
Just an example to show you how cheap things can be made yet do the job just as well as anything bought

Op Amp here is a an OPA350PA (single supply 5v capable rail to rail unit - cheap as chips from RS components who offer free next day delivery.
You only need to attach into the 5v and gnd feed to the MAF and then cut the maf signal wire and put maf side to in and ecu side to out - sorted. - sell the car just join the maf sensor wire back together. You could probably build it small enough if you wanted to fit under the MAF plug sleeve. Whatever.
Joe ;)

View attachment 105364

that's about it...... :rolleyes:
Click to expand...
Joe great post:).
But can you put it all into English so that an electronics numpty like me can have a go at making one with any sort of confidence.
I know you say "If you are unsure about basic electronics it is best left to someone else". but I would love to have a go at making and testing one.
 
Tim4x4 said:
Joe great post:).
But can you put it all into English so that an electronics numpty like me can have a go at making one with any sort of confidence.
I know you say "If you are unsure about basic electronics it is best left to someone else". but I would love to have a go at making and testing one.
Click to expand...
Hello Tim,
I won't be able to give a detailed reply today as I have limited time. Tomorrow I will have more time.
Many people have some knowledge of electronics and a lot have been brought into the hobby with Arduino / Pic micro etc. Also Amateur Radio. Still, It would be useful to know your level of experience and what equipment you have ?
For instance - have you a reasonable knowledge of basic electronics ? ohm law etc.. do you know what an OP-AMP is ? - have you got a variable power supply ? - preferred but not absolutely necessary as you can use a usb charger if needed. Have you ever used vero-board ?. Do you have a reasonable level of competence with soldering ?. Can you read a circuit diagram and a car wiring diagram ?.
Cheers Tim
Joe
 
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Hi Joe
Very interested in this thread. As you know I just bought a TD4 which I plan to use off road so looking as much boost in power/torque as possible but don't fancy spending £200 on a Ronbox. If I thought the Synergy was significantly better than any other tuning box on the market or anything I could make myself I would order one straight away but is it????
I have a basic but very rusty knowledge of electronics (did my HNC 30 years ago) so happy to give it a go.
 
Alibro said:
Hi Joe
Very interested in this thread. As you know I just bought a TD4 which I plan to use off road so looking as much boost in power/torque as possible but don't fancy spending £200 on a Ronbox. If I thought the Synergy was significantly better than any other tuning box on the market or anything I could make myself I would order one straight away but is it????
I have a basic but very rusty knowledge of electronics (did my HNC 30 years ago) so happy to give it a go.
Click to expand...
Hello Alibro mate
That circuit is not better than a full synergy, but is more than likely as good as the MAF unit part of it :) - and the separate MAF amp units. It would be easy to add the other parts needed to boost fuel to the system (which is all these units are doing!) . ALL first generation 'sensor tricking' (which is still what happens today!) started off with tricking the CTS, then the MAF sensor of the K Jetronic by altering the spring load (it was a 'flap' type regulator in those days :) ).. these worked well ! - very well - but were a bit of a scatter gun approach. Even today with JUST a MAF amp unit there are decent performance gains to be had !. Some companies that sell both an AMP and a Fuel pressure trick unit push the more expensive sensor pressure unit and play down the improvements obtainable with JUST maf adjustments.
However, JUST a maf adjustment for more power is still fairly simple - but quite acceptable for most people ! (you might be happy with just this, same as most people are perfectly happy with the EVRY mod to the VP37 on the L series)
The synergy and similar type unit 'thingies' also trick the ecu into thinking that the fuel pressure (signal from the Rail pressure sensor) is different to what it actually is - hence if you take the voltage out from the sensor (fuel rail pressure), and reduce it, the ecu thinks the pressure is lower than it has requested so controls the pump regulator to increase the pressure. Now we have a situation where the injector opening time is the same, however the fuel is injected at higher pressure (more fuel).
At the moment, my understanding of the TD4 pump is that the rail pressure will increase as engine rpm increases to allow shorter injection times otherwise we would have timing / fuel burn issues.
So, by changing the output voltage of the sensor with a 'box of tricks' is fairly easy to do. It can be either linear or non linear. A basic unit could be made in a similar way to the above circuit - but by reducing the voltage output, negative gain in effect and would work fairly well. There are certain things to look out for though - Idle should take care of itself with speed monitoring backing off the injector pulse width or pressure (we shouldn't have to do anything at idle).. then ideally, we want to limit fuel pressure raise above a certain rpm otherwise we can possibly get an abnormally low injector opening period at higher rpm. I would imagine that rpm could be monitored from the pressure sensor by looking for a minute variation in pressure as an injector opens.(that would be a digital unit though as opposed to analogue. )
This is getting to the point though where it really needs to go digital. In some ways THAT actually becomes easier. !
There is a little product called an Arduino embedded microprocessor board (don't let that put you off :) ) - it is really easy to use - all the development tools (programs) are absolutely free, there is an immense amount of data out there on the unit - it is a standard unit - it only needs a usb connection to power and program it and test it. Then it can be powered in the vehicle when you are happy. Changes can be made whilst the unit is in circuit without disconnecting it (via usb and a laptop)
One unit could do far more than any synergy type box. They are dirt cheap as there are many millions in use. They come in tiny sizes for final use and a larger version for design use.
Here is a small unit that is a complete computer and could do anything and far more than any available tuning 'box' (Check the price!)
http://www.ebay.co.uk/itm/1PCS-MIni...520211?hash=item2ca9465693:g:W20AAOSwoBtW2CRy
Here is a normal unit for designing and testing
http://www.ebay.co.uk/itm/Version-U...283852?hash=item2a6a22ad0c:g:P-4AAOSwbYZXXmzi
Again, check the price. That is almost all the hardware you need apart from a few components costing pence. ALL the development programs are free and excellent as said. SO MUCH info is available also.
The programs needed (the coding) for the type of thing we are looking for is absolutely simple - nothing complex at all.
We can use non liner 'pseudo' maps simply (sounds high tech but is really simple)
So, I would suggest you build the map amplifier first and play, then look at arduino basic programming -it really is NOT that complex - and of course I can help (although my main expertise and experience is in PIC micro units in commercial projects) - The arduino has so much info and help it is superb. There is an on board led and you could have a program up and running in a few minutes to flash the led and then alter the rate it flashed it .. this is a good way to quickly learn and the code is there for you to download with full explanations. All the compiling of the code and the programming of the unit is done automatically by a single click in the IDE (development program) - Integrated development environment.
It all sound incredibly complicated, but it is actually easier than building electronic circuits from scratch. Most people can pick up the basic coding in an hour or two as all the hard work is done for you.
https://www.arduino.cc/
Have a look here - the board I linked to will work perfectly and are a Chinese copy of the unit (which is ok as it is open source hardware and software) and the chink units are excellent.

With one of those we could do anything :)

The reason things like the synergy are so popular is that they are plug and pray... this is what the vast majority of users want and will still want, - simply unplug one or two connectors and plug the unit in !. However, for anyone wanting to play leccy / programming etc, and doesnt mind cutting a few wires and connecting to a few others there is no issue. It can still all be removed if needed and any cut wires rejoined.
It is also far more flexible that commercial units as you have FULL control over what you do with it. Adding things like turbo VNT controllers would not be all that difficult - often the hardest thing is getting the base data to work from ! - for that you need some careful use of a multimeter or diagnostics, or indeed you can build a data logging unit from an arduino and hook up a couple of wires to log what is happening at the area you want to 'tweak' :) :)
The world is your crab.. (or was that Oyster ? I always forget)
Have a nose around at the arduino site... we can look at developing code for one later if you want. First off build the maf amplifier and play. Any help I can give I will. I just dont want to be doing ALL the work lol. ;) your HNC etc will mean it will be simplicity for you -like riding a bike
Joe
 
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Joe_H said:
Hello Tim,
I won't be able to give a detailed reply today as I have limited time. Tomorrow I will have more time.
Many people have some knowledge of electronics and a lot have been brought into the hobby with Arduino / Pic micro etc. Also Amateur Radio. Still, It would be useful to know your level of experience and what equipment you have ?
For instance - have you a reasonable knowledge of basic electronics ? ohm law etc.. do you know what an OP-AMP is ? - have you got a variable power supply ? - preferred but not absolutely necessary as you can use a usb charger if needed. Have you ever used vero-board ?. Do you have a reasonable level of competence with soldering ?. Can you read a circuit diagram and a car wiring diagram ?.
Cheers Tim
Joe
Click to expand...
Joe thank you for your reply to answer your questions it goes like this.
My knowledge of the black art you and others call electronics is less than school boy level
I do understand ohm's law and how it is applied
I know what an Op-Amp is and what it will do but understanding how it works is above my level of knowledge
I do have a variable power supply (it is a dual tracking DC power supply TPS 4000 topward electronics)
Not used vero-board (I have used pre-made boards previously but not vero-board)
A good level of competence with soldering (I have previously constructed electronic circuits onto pre-made boards)
I can read an electrical diagram with confidence and use it to construct circuits and fault find.
I am able to follow an electronic circuit diagram but understanding the interaction of each component we are back to this witchcraft you and others practice
 
Tim4x4 said:
Joe thank you for your reply to answer your questions it goes like this.
My knowledge of the black art you and others call electronics is less than school boy level
I do understand ohm's law and how it is applied
I know what an Op-Amp is and what it will do but understanding how it works is above my level of knowledge
I do have a variable power supply (it is a dual tracking DC power supply TPS 4000 topward electronics)
Not used vero-board (I have used pre-made boards previously but not vero-board)
A good level of competence with soldering (I have previously constructed electronic circuits onto pre-made boards)
I can read an electrical diagram with confidence and use it to construct circuits and fault find.
I am able to follow an electronic circuit diagram but understanding the interaction of each component we are back to this witchcraft you and others practice
Click to expand...
Hi Tim, you shouldn't have ANY issues - that is a good background and probably all you need.

I would build the unit on veroboard for testing. (it could even be left on vero)
You dont need to know how an op amp works - just an idea of what it does and the types of basic circuits that can be built - as here for example - anon inverting dc amp.

The IC pinout (for the opamp) is in the PDF attached (page 3 - top left - OPA350 8pin PDIP )- which is the 'normal' size and fits veroboard hole spacing - it can also be fitted into an 8 pin DIL socket which is a good way of doing it. (nothing much else of note in the datasheet but peruse at leisure);)
You will see the connections as in my scribble - pin 7 and 4 are the 5v supply (you can fit a 1uF to 10uF (any value around that range) across the supply allowing for polarity of the electrolytic cap. Also in parallel with that cap fit a 0.1 uF capacitor. If you assemble it on veroboard (use a small preset pot for the 47K - tiny little thing that you adjust with a small screwdriver)
Hook it up to your PSU (which sounds excellent) 5v fixed supply to the opamp - then a variable supply to Vin.. Measure V out with a multimeter or a scope of you have one - it should correspond to the input * the calculated gain. (you can check the gain both by the Vin to Vout and also the set value of the 47 variable in relation to the fixed 100K.)
Just ask if you need more info.
Joe :)
http://www.ti.com/lit/ds/sbos099d/sbos099d.pdf
 
Joe_H said:
Hi Tim, you shouldn't have ANY issues - that is a good background and probably all you need.

I would build the unit on veroboard for testing. (it could even be left on vero)
You dont need to know how an op amp works - just an idea of what it does and the types of basic circuits that can be built - as here for example - anon inverting dc amp.

The IC pinout (for the opamp) is in the PDF attached (page 3 - top left - OPA350 8pin PDIP )- which is the 'normal' size and fits veroboard hole spacing - it can also be fitted into an 8 pin DIL socket which is a good way of doing it. (nothing much else of note in the datasheet but peruse at leisure);)
You will see the connections as in my scribble - pin 7 and 4 are the 5v supply (you can fit a 1uF to 10uF (any value around that range) across the supply allowing for polarity of the electrolytic cap. Also in parallel with that cap fit a 0.1 uF capacitor. If you assemble it on veroboard (use a small preset pot for the 47K - tiny little thing that you adjust with a small screwdriver)
Hook it up to your PSU (which sounds excellent) 5v fixed supply to the opamp - then a variable supply to Vin.. Measure V out with a multimeter or a scope of you have one - it should correspond to the input * the calculated gain. (you can check the gain both by the Vin to Vout and also the set value of the 47 variable in relation to the fixed 100K.)
Just ask if you need more info.
Joe :)
http://www.ti.com/lit/ds/sbos099d/sbos099d.pdf
Click to expand...
Joe thank you again for your time and information.
Let me explain why I am interested in the MAF amp and if you can say yay or nay to its use.
I have been having running issues with my vehicle and have used an Hawkeye diagnostic unit to help find the problem.
The issue was leaky seals on the fuel injectors or a breakdown on the insulation from the crank position sensor, not sure which because I made repairs to both prior to testing after which all as OK.
On the journey to finding the fault the diagnostic reader indicated low airflow through the MAF (MAF less than 12 months old and genuine LR).
I exchanged it with the main dealer but new one also gave lower than expected airflow readings and a max voltage of 3.8 volts.
As I understand from RAVE the correct max voltage should be 5 Volts.
So can I use the MAF amplifier to trim the correct settings (max 5 Volts) or would this have a detrimental effect at lower RPM?
I am not looking to boost performance just to make adjustments to the normal levels.
 
Joe_H said:
Hello Alibro mate
That circuit is not better than a full synergy, but is more than likely as good as the MAF unit part of it :) - and the separate MAF amp units. It would be easy to add the other parts needed to boost fuel to the system (which is all these units are doing!) . ALL first generation 'sensor tricking' (which is still what happens today!) started off with tricking the CTS, then the MAF sensor of the K Jetronic by altering the spring load (it was a 'flap' type regulator in those days :) ).. these worked well ! - very well - but were a bit of a scatter gun approach. Even today with JUST a MAF amp unit there are decent performance gains to be had !. Some companies that sell both an AMP and a Fuel pressure trick unit push the more expensive sensor pressure unit and play down the improvements obtainable with JUST maf adjustments.
However, JUST a maf adjustment for more power is still fairly simple - but quite acceptable for most people ! (you might be happy with just this, same as most people are perfectly happy with the EVRY mod to the VP37 on the L series)
The synergy and similar type unit 'thingies' also trick the ecu into thinking that the fuel pressure (signal from the Rail pressure sensor) is different to what it actually is - hence if you take the voltage out from the sensor (fuel rail pressure), and reduce it, the ecu thinks the pressure is lower than it has requested so controls the pump regulator to increase the pressure. Now we have a situation where the injector opening time is the same, however the fuel is injected at higher pressure (more fuel).
At the moment, my understanding of the TD4 pump is that the rail pressure will increase as engine rpm increases to allow shorter injection times otherwise we would have timing / fuel burn issues.
So, by changing the output voltage of the sensor with a 'box of tricks' is fairly easy to do. It can be either linear or non linear. A basic unit could be made in a similar way to the above circuit - but by reducing the voltage output, negative gain in effect and would work fairly well. There are certain things to look out for though - Idle should take care of itself with speed monitoring backing off the injector pulse width or pressure (we shouldn't have to do anything at idle).. then ideally, we want to limit fuel pressure raise above a certain rpm otherwise we can possibly get an abnormally low injector opening period at higher rpm. I would imagine that rpm could be monitored from the pressure sensor by looking for a minute variation in pressure as an injector opens.(that would be a digital unit though as opposed to analogue. )
This is getting to the point though where it really needs to go digital. In some ways THAT actually becomes easier. !
There is a little product called an Arduino embedded microprocessor board (don't let that put you off :) ) - it is really easy to use - all the development tools (programs) are absolutely free, there is an immense amount of data out there on the unit - it is a standard unit - it only needs a usb connection to power and program it and test it. Then it can be powered in the vehicle when you are happy. Changes can be made whilst the unit is in circuit without disconnecting it (via usb and a laptop)
One unit could do far more than any synergy type box. They are dirt cheap as there are many millions in use. They come in tiny sizes for final use and a larger version for design use.
Here is a small unit that is a complete computer and could do anything and far more than any available tuning 'box' (Check the price!)
http://www.ebay.co.uk/itm/1PCS-MIni...520211?hash=item2ca9465693:g:W20AAOSwoBtW2CRy
Here is a normal unit for designing and testing
http://www.ebay.co.uk/itm/Version-U...283852?hash=item2a6a22ad0c:g:P-4AAOSwbYZXXmzi
Again, check the price. That is almost all the hardware you need apart from a few components costing pence. ALL the development programs are free and excellent as said. SO MUCH info is available also.
The programs needed (the coding) for the type of thing we are looking for is absolutely simple - nothing complex at all.
We can use non liner 'pseudo' maps simply (sounds high tech but is really simple)
So, I would suggest you build the map amplifier first and play, then look at arduino basic programming -it really is NOT that complex - and of course I can help (although my main expertise and experience is in PIC micro units in commercial projects) - The arduino has so much info and help it is superb. There is an on board led and you could have a program up and running in a few minutes to flash the led and then alter the rate it flashed it .. this is a good way to quickly learn and the code is there for you to download with full explanations. All the compiling of the code and the programming of the unit is done automatically by a single click in the IDE (development program) - Integrated development environment.
It all sound incredibly complicated, but it is actually easier than building electronic circuits from scratch. Most people can pick up the basic coding in an hour or two as all the hard work is done for you.
https://www.arduino.cc/
Have a look here - the board I linked to will work perfectly and are a Chinese copy of the unit (which is ok as it is open source hardware and software) and the chink units are excellent.

With one of those we could do anything :)

The reason things like the synergy are so popular is that they are plug and pray... this is what the vast majority of users want and will still want, - simply unplug one or two connectors and plug the unit in !. However, for anyone wanting to play leccy / programming etc, and doesnt mind cutting a few wires and connecting to a few others there is no issue. It can still all be removed if needed and any cut wires rejoined.
It is also far more flexible that commercial units as you have FULL control over what you do with it. Adding things like turbo VNT controllers would not be all that difficult - often the hardest thing is getting the base data to work from ! - for that you need some careful use of a multimeter or diagnostics, or indeed you can build a data logging unit from an arduino and hook up a couple of wires to log what is happening at the area you want to 'tweak' :) :)
The world is your crab.. (or was that Oyster ? I always forget)
Have a nose around at the arduino site... we can look at developing code for one later if you want. First off build the maf amplifier and play. Any help I can give I will. I just dont want to be doing ALL the work lol. ;) your HNC etc will mean it will be simplicity for you -like riding a bike
Joe
Click to expand...
Now your getting me very interested. :)
I didn't realise the synergy had two separate functions as this is all new to me but will defo have a go at doing the MAF amp. I'm a computer engineer so happy playing with them and fixing them but never got into programming I've heard of the arduino but never used one but I already have a rasberry pi. Do you think it would be suitable or is the Arduino better suited for this type of application?
You are talking to the type of eejit you would rather cut open and recondition a VCU myself than pay someone to do it, so DIY power boost is right up my street. Like you say, most people are scared of doing things themselves (often with good reason) and would rather pay for something tried and trusted. I'm too stupid to go that way. :confused:
Bertie is my project car so is perfect for this kind of experimentation, or at least will be once I've sorted the EGR and associated build up of crap in the inlet manifold and fitted new hoses etc. That means I'll be busy spannering for a few weeks but will then get the soldering iron out.
If I have picked you up correctly the list of components required is
Op Amp..........................OPA350PA
Voltage regulator ...........78L05 (only needed if taking power from 12V)
Electrolytic cap x 2.........4.7 to 10uF
Ceramic cap....................0.1uF
47k variable resistor (log or linear, does it matter?)
 
Tim4x4 said:
Joe thank you again for your time and information.
Let me explain why I am interested in the MAF amp and if you can say yay or nay to its use.
I have been having running issues with my vehicle and have used an Hawkeye diagnostic unit to help find the problem.
The issue was leaky seals on the fuel injectors or a breakdown on the insulation from the crank position sensor, not sure which because I made repairs to both prior to testing after which all as OK.
On the journey to finding the fault the diagnostic reader indicated low airflow through the MAF (MAF less than 12 months old and genuine LR).
I exchanged it with the main dealer but new one also gave lower than expected airflow readings and a max voltage of 3.8 volts.
As I understand from RAVE the correct max voltage should be 5 Volts.
So can I use the MAF amplifier to trim the correct settings (max 5 Volts) or would this have a detrimental effect at lower RPM?
I am not looking to boost performance just to make adjustments to the normal levels.
Click to expand...
Hi Tim
What do you mean by -
Tim4x4 said:
the diagnostic reader indicated low airflow through the MAF
Click to expand...
In what way ?

Also, max is usually around 4.5 on most units
If it is the maf that is low then yes, certainly the unit should work ok. If you look at a typical sort of maf curve. (below) you will see output non linearity (the graph is only for a guide !.
But, if you consider the gain factor of the opamp against the maf output curve, then the increase in actual voltage is far lower at the bottom end (the low airflow) and increases as the airflow increases.
I must confess I am baffled as to why you are having issues with two maf unit??? - are you sure getting full boost ? - also the peak airflow (hence high reading) will be difficult to measure.
Are they definitely the correct part ?
Also how does it drive ?
Joe
 

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Joe_H said:
Hi Tim
What do you mean by -

In what way ?

Also, max is usually around 4.5 on most units
If it is the maf that is low then yes, certainly the unit should work ok. If you look at a typical sort of maf curve. (below) you will see output non linearity (the graph is only for a guide !.
But, if you consider the gain factor of the opamp against the maf output curve, then the increase in actual voltage is far lower at the bottom end (the low airflow) and increases as the airflow increases.
I must confess I am baffled as to why you are having issues with two maf unit??? - are you sure getting full boost ? - also the peak airflow (hence high reading) will be difficult to measure.
Are they definitely the correct part ?
Also how does it drive ?
Joe
Click to expand...
Joe using diagnostic reader on live data and looking at airflow under full turbo boost ( traveling uphill near max revs) it should be reading around 600 but mine is reading 480 switch from airflow to MAF voltage it is reading 3.8Volts under the same conditions.
The boost pressure is well within the manufacturers guidelines @ 215-220
The parts are correct
It drives now as well as it always has but I do not know anything different only ever driven this one.
 
Alibro said:
Now your getting me very interested. :)
I didn't realise the synergy had two separate functions as this is all new to me but will defo have a go at doing the MAF amp. I'm a computer engineer so happy playing with them and fixing them but never got into programming I've heard of the arduino but never used one but I already have a rasberry pi. Do you think it would be suitable or is the Arduino better suited for this type of application?
You are talking to the type of eejit you would rather cut open and recondition a VCU myself than pay someone to do it, so DIY power boost is right up my street. Like you say, most people are scared of doing things themselves (often with good reason) and would rather pay for something tried and trusted. I'm too stupid to go that way. :confused:
Bertie is my project car so is perfect for this kind of experimentation, or at least will be once I've sorted the EGR and associated build up of crap in the inlet manifold and fitted new hoses etc. That means I'll be busy spannering for a few weeks but will then get the soldering iron out.
If I have picked you up correctly the list of components required is
Op Amp..........................OPA350PA
Voltage regulator ...........78L05 (only needed if taking power from 12V)
Electrolytic cap x 2.........4.7 to 10uF
Ceramic cap....................0.1uF
47k variable resistor (log or linear, does it matter?)
Click to expand...
Hi Mate ;)
I think it is only the 2A synergy that does the MAF as well - not sure -.. it is the one with the maf compensate switch on lol :)
On the list, yes that is ok - ref the Vreg, - we will probably need it - and it will need a couple of caps - but thats for later.
Only 1 Electrolytic cap for the op amp - anywhere from 1 to 10uF (we are better with smaller for space as well) - however if we are using a 78L05, then we need 2 - they can be both 1uF or 2.2uF - or whatever :)
two 0.1uF caps.
the 47k should be linear and you could use a miniature preset as opposed to one with a knob on - lot smaller.
100K ohm 1/8th watt resistor (1% to 5%) not really critical.

Build on a bit of veroboard and test. You can put 5v for the op amp supply (you could use a usb charger if you havent got a bench psu - and then use a pot across the 5v supply to control the input to the Vin terminal (if you see what I mean) - measure the output with a multimeter.
As for the ras Pi, forget that- it is way way overkill and to be honest i know Jack about them - I have a couple but never fired them up.
The arduino is much much much easier to use and better supported with a HUGE library of ready made code to cut and paste and also a superb free IDE to use (the main program for the PC to do all the magic with it.
All programming done over USB.
Playing around with analogue is great and may well be all one needs - however - moving on to digital is far better and gives us loads more options. You could have a fuel pressure tweak, a maf tweak and a VNT controller all on the same board - you could even drive a small lcd in the cockpit to display info.. all from one unit..
And they only cost a few quid... the hard work is in the programming and data gathering, but yes, anything is possible - most definitely.
Joe
 
Tim4x4 said:
Joe using diagnostic reader on live data and looking at airflow under full turbo boost ( traveling uphill near max revs) it should be reading around 600 but mine is reading 480 switch from airflow to MAF voltage it is reading 3.8Volts under the same conditions.
The boost pressure is well within the manufacturers guidelines @ 215-220
The parts are correct
It drives now as well as it always has but I do not know anything different only ever driven this one.
Click to expand...
Interesting, it would be useful to compare someone else's results..... (unfortunately (well - fortunately :) :) mine is an L series)
But no worries - it is worth experimenting -

With most of this, the real key is getting baseline data. In the absence of that it is a bit of trial and error which can be good fun. Keep all adjustments small and record data as you go in a notebook to refer back to.
Having the diagnostics is a huge help as well.
Joe
 
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