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Home Made ECU

Old 07 December 2015, 12:36 PM
  #1  
Ruptor
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Default Home Made ECU

I am designing my own ECU for my Impreza non turbo for the following reasons
1) The ECU is dead and it used too much petrol anyway.
2) The car is restricted to be significantly slow so it doesn't embarrass the turbo.
3) Because I want total control over all parameters to experiment and see how economical I can make it run.
As a basic system to get the car running I just want to use two inputs and two outputs to control things. The crankshaft and camshaft sensors are the inputs and the injectors and ignition are the outputs. I don't need the throttle position to get things up and running but I will probably need it to start getting fancy and make the car drivable.
Looking at the subaru sensor information the crankshaft data is straight forward but the camshaft sensor data doesn't say which blip is for what cylinder. It says there are 1, 2, 1, 3 blips at each of the 90 degrees but can someone tell me which blip sequence identifies number one cylinder? I can't be asked to go out in the cold and take things apart or stick a scope on the sensor although I will do that when I get some hardware in place to test before I switch it on so I don't blow up the engine.
I wonder how fast the non turbo could go because I had a Dolomite Sprint that had a 0 to 60 mph time of 8.5 seconds as standard and just by changing the air intake I made it do it in 7.5 seconds. The Sprint was really heavy compared to the Impreza so maybe 7 seconds could be achieved or with some fancy ignition and injection settings mabybe faster.
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Old 07 December 2015, 12:37 PM
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lmao
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Old 07 December 2015, 12:42 PM
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I think subaru did a pretty good job of designing an ecu so why not just buy a 2nd hand one and remap it yourself?
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Old 07 December 2015, 12:49 PM
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Originally Posted by Ruptor View Post
I am designing my own ECU for my Impreza non turbo for the following reasons
1) The ECU is dead and it used too much petrol anyway.
2) The car is restricted to be significantly slow so it doesn't embarrass the turbo.
3) Because I want total control over all parameters to experiment and see how economical I can make it run.
As a basic system to get the car running I just want to use two inputs and two outputs to control things. The crankshaft and camshaft sensors are the inputs and the injectors and ignition are the outputs. I don't need the throttle position to get things up and running but I will probably need it to start getting fancy and make the car drivable.
Looking at the subaru sensor information the crankshaft data is straight forward but the camshaft sensor data doesn't say which blip is for what cylinder. It says there are 1, 2, 1, 3 blips at each of the 90 degrees but can someone tell me which blip sequence identifies number one cylinder? I can't be asked to go out in the cold and take things apart or stick a scope on the sensor although I will do that when I get some hardware in place to test before I switch it on so I don't blow up the engine.
I wonder how fast the non turbo could go because I had a Dolomite Sprint that had a 0 to 60 mph time of 8.5 seconds as standard and just by changing the air intake I made it do it in 7.5 seconds. The Sprint was really heavy compared to the Impreza so maybe 7 seconds could be achieved or with some fancy ignition and injection settings mabybe faster.

Drugs must be good in London lol
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Old 07 December 2015, 12:51 PM
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Wait, what?!?
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Old 07 December 2015, 12:53 PM
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very few folks i know who have the capability to actualy create there is ecu. Only one i know who actualy has lol
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Old 07 December 2015, 01:00 PM
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No techinical help here then.
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Old 07 December 2015, 01:12 PM
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1. The ecu doesn't use the petrol,your right foot controls it.
2. WTF!
3. remap and control the perameters.
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Old 07 December 2015, 01:26 PM
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Why do you think the latest cars are quoting figures like 100 mpg it isn't a change of map. It is OK you can stick to what you know I shall look at something new. Its a free world.
I am a Chartered electronics design engineer that is quite capable of solving any problems myself but I thought I would come here and see if anybody would help or take an interest.
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Old 07 December 2015, 01:35 PM
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Who is quoting 100mpg on an impreza new or old?
we all know whats quoted by the car company's isn't in the real world!

Rs Matt has some great fuel saving tips from a flat 4 boxer engine,i'm sure he will be along to help in the re-design of a non-turbo impreza ECU which will beat the STI in every way whilst getting 100 mpg+
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Old 07 December 2015, 02:04 PM
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Originally Posted by Ruptor View Post
Why do you think the latest cars are quoting figures like 100 mpg it isn't a change of map. It is OK you can stick to what you know I shall look at something new. Its a free world.
I am a Chartered electronics design engineer that is quite capable of solving any problems myself but I thought I would come here and see if anybody would help or take an interest.

Even the modern subaru's only get mid 30's at best, i know cos me dads got one less than 6 months old.

Your not gonna achieve anything a map wouldn't do, other than remove a whole heap of things you want to keep such as Knock control etc

No one buys a subaru for economy, they just arn't because of the engines design
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Old 07 December 2015, 09:11 PM
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Originally Posted by Ruptor View Post
Why do you think the latest cars are quoting figures like 100 mpg it isn't a change of map. It is OK you can stick to what you know I shall look at something new. Its a free world.
I am a Chartered electronics design engineer that is quite capable of solving any problems myself but I thought I would come here and see if anybody would help or take an interest.

100mpg really? u must wrk for vw :
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Old 07 December 2015, 09:52 PM
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Originally Posted by ossett2k2 View Post

Rs Matt has some great fuel saving tips from a flat 4 boxer engine,i'm sure he will be along to help in the re-design of a non-turbo impreza ECU which will beat the STI in every way whilst getting 100 mpg+
Now that made me laugh.SJ.
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Old 07 December 2015, 09:56 PM
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Mock at your peril as this person might be onto something.
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Old 08 December 2015, 12:45 PM
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you don't mention which car you have, is it a 2.0 or a 2.5? You might get somewhere by going super lean with LPG or E85 if you can find it - but I wouldn't be expecting vast differences in the overall power output unless your going to redesign the headers/intake manifold etc.

There's a few threads on the romraider forum with folk trying to increase MPG using E85, super lean, massive advance etc. might be worth searching into.
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Old 08 December 2015, 01:08 PM
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As an electronics design engineer, I would also love to make my own ECU. However I can assure you your time is MUCH better spent invested in the art of mapping and not in designing an ECU from scratch.

I don't know much about the non-turbos, presumably there is no off-the-shelf flashing solution, but honestly you are better working on a reliable well-proven platform than engineering everything from scratch. Therefore if you can't/don't want to reverse engineer the flash method for non-turbo ecus (someone would be able to tell you if its possible if you list your ecu) then start with a proven design - even mega-squirt would be better than starting from the beginning. Otherwise plenty of off the shelf alternatives. Alternatively replace your ECU (circa 20 on ebay) and then get a piggyback ecu to make any mapping changes (again cheap second hand).

Entire system design in electrically noisy environments is not something I'd entertain for a couple of horsepower and mpg. It would be man-years worth of development which only makes sense if you can sell you design 1000 times over afterwards.

With respect to fuel economy. Its an all-time driven 4WD system that is never going to be very efficient. Is there even variable valve timing on your engine? I am quite into fuel efficiency and would like to see what can be done, but you're up against a lot including poor aerodynamics, AWD, not the best exhaust manifold, and possibly not the best cylinder head design for lean burn.

I'd like to see any progress, but I honestly think that building and testing an ECU from scratch would be too time consuming.
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Old 08 December 2015, 01:23 PM
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Originally Posted by johned View Post
Mock at your peril as this person might be onto something.
+1

We might all be raving about 'Ruptor' ECU's in the next few years
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Old 09 December 2015, 05:00 PM
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I'm not what sure what goal your trying to achieve as your talking about fuel economy and power increases in the same post. I've done plenty of research into n/a imprezas mine being specific to the bugeye. Now as far as I'm led to believe their is no reflash available nor is it compatible with rom raider. As mentioned by tymatt I agree fit a replacement Ecu so at least have the basis of it starting and the diagnostics capability of reading the Ecu then fit a piggyback Ecu to then tune/modify as I did. Il be honest fuel economy is never going to be great due to the awd, you can lean out the parameters with a piggyback but your talking about minimal results and you must be careful.
Now as for power, there's not much gain to be had without spending big in n/a form, now forced induction is the only way to get good gains and this is still not cheap. I'm driving a supercharged n/a bugeye so it can be done and all fuel and ignition is controlled by piggyback Ecu working along side the standard Ecu
Which Impreza are you using ?
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Old 10 December 2015, 05:13 PM
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Originally Posted by Nismoboy View Post
100mpg really? u must wrk for vw :
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Old 02 April 2016, 11:08 PM
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Having looked at using Lazarus and the embedded code system of development I found it too complicated to get off the ground for now given the time I have available to spend on this project so I decided to use a PIC 18. I wasn't sure if it would have enough inputs for the sensors but I have managed to come up with a solution that fits. Of course once the PIC version is working it can be ported to any processor if more fancy calculation or complex processes are required and the PIC can't do but when all is said and done there isn't a lot required to control a car anyway. Having collected all the information about my Impreza Subaru signals, designed the hardware and 70% of the software to collect and distribute the I/O it is now just a question of finishing the first stage of software then testing by simulation to make sure all the signals come out at the right time before I go anywhere near the car so I make sure I don't fire a piston on an up stroke and blow it up.
I have always thought the existing car ECUs were not much good and now having designed one myself I think they are even worse than I thought. I would compare existing systems to a car with a fixed axal and no differential. They work but they could have been designed a lot better. It begs the question if I can implement an ECU on a PIC 18 running at 40 MHz with a prototype board measuring 2"x3" what are they doing with their 100 MHz + processors and massive realestate?
I have spent about three days on it so far. A day on building the relatively simple circuit. A day on collecting and understanding the signals to design the algorithm and a day coding but nothing has reached the testing stage yet.
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Old 02 April 2016, 11:19 PM
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What is scoobynet coming to?
We have latent genius aRSe_Matt with the wonders of ARB defined fuel efficiency.
Another guy trying to convince anyone who'll listen that the world is flat.
And now, with all due respect to our learned colleague, we have a Blue Peter style ECU.

It's got to be a conspiracy I tell ya!
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Old 03 April 2016, 07:40 AM
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April fools day has past now.
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Old 03 April 2016, 10:42 AM
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Originally Posted by Blue by You View Post
What is scoobynet coming to?
We have latent genius aRSe_Matt with the wonders of ARB defined fuel efficiency.
Another guy trying to convince anyone who'll listen that the world is flat.
And now, with all due respect to our learned colleague, we have a Blue Peter style ECU.

It's got to be a conspiracy I tell ya!
I think this forum is under used these days:
https://www.scoobynet.com/the-muppet-room-8/
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Old 03 April 2016, 01:32 PM
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Originally Posted by Blue by You View Post
What is scoobynet coming to?
We have latent genius aRSe_Matt with the wonders of ARB defined fuel efficiency.
Another guy trying to convince anyone who'll listen that the world is flat.
And now, with all due respect to our learned colleague, we have a Blue Peter style ECU.

It's got to be a conspiracy I tell ya!

You've forgotten PSL and his magic Honda diesel!
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Old 04 April 2016, 10:18 PM
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Why not do what esl have done and make a daughter board? I'm sure if its well priced you will get many sales, from young lads wanting to upgrade there sports.

What Impreza do you have?
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Old 05 April 2016, 03:38 PM
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All the best ideas start from crazy people that think outside the box. Its science and documented in history!

Good luck with the project!
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Old 05 April 2016, 05:24 PM
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Originally Posted by Khandaris View Post
All the best ideas start from crazy people that think outside the box. Its science and documented in history!

Good luck with the project!
Agree 100 percent.
I love hearing people's mad ideas... I have a few of my own.

Good luck with your project mate
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