Subaru - OEM ECU or Standalone aftermarket ECU?

[ttriebler]

Megasquirt just came out with a PNP system http://www.diyautotune.com/catalog/mega ... p-599.html. I'm not saying get that because making your own wiring harness is still going to look nicer, but you can see the additional features you get in the lower part of the advertisement.

So....why would you spend $1200 on a Megasquirt pro ECU that plugs into your Subaru harness to give you what you already have (arguably less than what you already have) with your standard Subaru ECU with a $45 Taxtrix cable and free Romraider software?

[volksbugly]

Megasquirt just came out with a PNP system http://www.diyautotune.com/catalog/mega ... p-599.html. I'm not saying get that because making your own wiring harness is still going to look nicer, but you can see the additional features you get in the lower part of the advertisement.

So....why would you spend $1200 on a Megasquirt pro ECU that plugs into your Subaru harness to give you what you already have (arguably less than what you already have) with your standard Subaru ECU with a $45 Taxtrix cable and free Romraider software?

Looking at the advertisement I mentioned...

Advanced Feature Set (Included!)

12x12 Air Fuel Ratio Target Tables for use with wide band O2 sensor for precise tuning and table trim.
AVCS (Variable valve timing) support for engine swaps (uses extra wires on the expansion connector)
Multiple traction control strategies
Built-in 3-step rev limiter / launch control with flat shift and burnout rev limiter
Real time barometric correction
Internal 4-bar MAP sensor reads up to 44PSI of boost
Overboost protection
Rally style anti lag
Water injection control - on/off or variable
Knock sensor input with adjustable sensitivity, crank angle windowing, and more
Table switching input. Change fuel and spark maps on the fly for different fuels, nitrous activation, etc.
Input for flex fuel sensor - switch between E85 and gasoline on the fly!
CANBus connector allows interconnection of other MegaSquirt-compatible devices for additional functions (EGT Input, Additional Sensors.....the possibilities are limitless

What less would you get???


Again I'm not saying get it, probably get a regular ms and build a harness which is 1/2 price.

[Piledriver]

That MS ecu is for those with a very highly modified engine the stock ECU simply cannot deal with...
on a stock engine I would absolutely not hesitate to use the stock subaru ECU.

You could do a std ms3v3.0 case ms3+ms3x + knock + RTC modules and harness for much less than $1200.

The pro just has everything built in and has a sealable case and automotive grade AMP connectors.
The same could be said of the factory ecu...

[panel]

with your standard Subaru ECU with a $45 Taxtrix cable and free Romraider software?

Just curious what years (Subaru) does this support ? (this only applies to me)

[56SemaRag]

But I'm at the bottom of my Subaru learning ladder, so please let me know if I'm barking up the wrong tree.
I'm after the most power possible from a standard engine and turbo, which I believe is around the 280bhp mark.

You are not barking up the wrong tree at all. The stock ECU will meet your requirement. A flashed ECU, with minimal hardware and a free open source program will exceed this easily and safely. Matter of fact you can double that and the stock ECU can handle it. It's already been proven that the Subaru and Mitsu ECUs can handle highly modified engines well past the 500HP range.

If the Subaru engine didn't have an ECU then MS would be an option, although an expensive one. I just don't think it is necessary considering how well the stock ECU works with the motor it was designed for and will probably come with your engine if you go the JDM route....which I recommend.

When it comes to the claim of utilizing MS and AVCS for a Subaru engine.....MS DOES NOT SUPPORT AVCS FUNCTIONS FOR SUBARU ENGINES so we can let that die here. From their site "Currently, the VVTuner is available for the 2001-2005 Mazda MX-5 Miata. Other VVTuner applications are likely to be added with firmware and/or hardware updates in the future." Even if it did work, you would have to spend another $200 for an external controller and $40 in two pigtail adapters. The current one already built into the ECUs are completely able to be edited.

It's nice to know that you can keep the majority of the engine sensors, have an OBDII port and disable any CEL you wish with the un-checking of a box. The tables within the stock ECU are extensive for example the open loop fueling is on the order of 16 x18. You can create a rally anti-lag feature for $10 (no kidding). Folks have developed launch control as well, all free through open source. I have never over boosted, or had boost spikes and I am pulling 20psi from 3,300 rpm to 7K with an aftermarket turbo on my DD. My daily car originally produced around 210HP I am now close to 375HP and will be pushing closer to 400 soon. The knock correction isn't a one-size-fits-all design, it was designed and improved by Subaru engineers to include fine knock correction, feedback knock correction, and ignition advance multipliers.

When it comes to Subarus, detonation (knock) will kill them in short order. What you can do is learn to tune in a safe affordable way starting with the stock map. Making minor changes on a stock map will yield results because they are not tuned for pure performance from the factory....they have warranties to back. I don't want to come off as an E-D!ck RomRaider fanboi MS basher...I just don't think it is worth the cost when the OP can can get a complete engine system with an excellent ECU and modify the firmware fairly cheap. I think MS is a great, innovative user developed system for cars that actually need it.

with your standard Subaru ECU with a $45 Taxtrix cable and free Romraider software?

Just curious what years (Subaru) does this support ? (this only applies to me)

A few , I just want to know where Todd got an original Tactrix for $45?, beware of fakes!!! The price point is around $170 and the knock offs are hit and miss with regards to reliability.
RomRaider Supported ECU's

[jrobe]

Lots of good info, thanks!!

[ryans88gt]

microsquirt costs less than $300 with the harness (wiring required).

For those of us like me that do not have a computer or complete harness, this has to be cheaper than trying to find good stock computer and harness.... and then a maf and getting all the stock sensors etc...

[Dan Dryden]

I'm planning to source a donor car, so using the stock ecu is the best option for me.
If I was to source just the engine, I have to agree that an aftermarket ecu would probably be the better option.
Thanks 56semarag for your response. It's exciting to know that I will have many tuning options and ecu functions to play with.

[ttriebler]

Some pretty awesome info and ideas there. 56semarag I'm completely on the same page as you.
Having said that, if you acquire an engine without an ECU then getting an MS or similar may well be the way to go if it's too hard to find the correct factory ECU for your engine.

I also want to whet your appetite a bit here. You may well have hear of CANbus engines (approx MY2007 build onwards) which have a local network built into them for all the components to talk together. Most CANbus engines also have AVCS (Subaru's Vtec) which is a very nice feature for low-down torque. These CANbus engines and ECU's don't work outside of the Subaru environment if they don't have everything still connected to them - e.g. ABS system, dash cluster etc so the only way late model engines have been used is with aftermarket ECU's. These aftermarket ECU's (as per 56semarag post above) have not managed to implement the AVCS function (or implement it well) up until now, diminishing the performance of the late model motors.

We will be launching a new website in the next few weeks which sells a box to plug into a CANbus wiring loom and allow late model CANbus engines to work outside of the Subaru environment. It removes the need for the ABS system and other systems to be connected and as an option, even removes the need for the Subaru dash cluster to be connected. This will allow those EZ30R, EZ36R, EE20 and new FB and FA20T motors to operate with full function. Dual AVCS, direct injection etc. Gonna be some crazy 6 cylinder speedster replicas appearing........

I will post more details when the website is up, and it's early days yet as we have only tested on AUDM engines but we will be testing in each market to ensure compatibility. We have the 2009 300hp WRX EJ25 turbo motor running perfectly.

[Piledriver]

When it comes to the claim of utilizing MS and AVCS for a Subaru engine.....MS DOES NOT SUPPORT AVCS FUNCTIONS FOR SUBARU ENGINES so we can let that die here.

No longer necessarily true, or at least not for long, the latest MS3 dev code supports 4 sensors/4 cams/8 solenoids, most (all?) Subaru wheels already have decoders, and is under heavy development, the only thing holding it back is folks to test it and work with the devs, as they don't have a late Subaru handy.

http://www.msextra.com/forums/viewtopic ... &start=480

pre-1.4 is in beta now, likely to become release code in a month or so.
It works quite nicely, I think I have run release code for about 20 minutes in the last 5 years, strictly for troubleshooting purposes.

I do not know what other hardware would be required, I don't (usually) swing watercooled.

...but I do agree that the stock ecu is a better choice for most uses if available.

[RonW]

Wow that sounds pretty sick!!! I'm really looking forward to seeing this. Nice to have options down the road.
Running stock JDM ECU with tactrix/RomRaider and tuned for US gas in my set up. since then i've just put the laptop away and been putting the miles on and going thru tires

http://iwolfe.com/ron/wp-content/upload ... 24x682.jpg

[ttriebler]

Nice pic Ron !!!

For those of you interested in looking at our CANbus emulator, head on over to Subatronics by Subarugears for a peek.
http://www.subatronics.com

[RonW]

Thanks todd.

That is pretty sick. I was wondering if/when i kill my motor how to run a CANbus. looking forward to some development news and you know it doesnt exist till we see video btw EDIT: nm, just saw the vid on FB. not sure how to embed the link here

[ttriebler]

[56SemaRag]

It is so cool to have all these ECU options.