WR1 Bro wrote:The replacement ECU's (Motec,link,Hydra,Gems,Apexi) compared to the standard ECU just have a little more control and can react quicker to different circumstances. Motec appears to be the daddy really. They should give you a bit more BHP and torque (maybe 10-15 of each). Some of them have features like dual boost maps, Anti lag, Launch control etc..Because of the quicker reactions of them you can map a little closer to the edge of detonation etc.
They're all quite different in their own way.
We don't use GEMS as our preferred ECU by accident. (We can do Motec and Apexi as well), but GEMS is the best all rounder available and does pretty much all the others do, and more than most, often for less.
It's (Markedly) cheaper than Motec, doesn't need a custom loom or wire chopping to fit. (GEMS drops straight into the factory ECU case, as does Sigma). Last I heard, Motec still hadn't sussed the AVCS control either?
Hydra needs its own complete loom/rewire from what I've seen of it, (but admittedly we've not looked at it in depth as we've not needed to).
Apexi doesn't have the range of control (particularly over boost) as GEMS, that's why you have to buy a secondary boost controller as well, making it more expensive than it might first appear. They also don't do past 99MY (IIRC) either.
WR1 Bro wrote:Also a MAF based system like o.e will only be good for maybe 450 BHP. After this you need a better ECU.
You can re-scale a MAF, but it's not so straight forward, and by the time you get to that sort of reliable power, as you so rightly say, you would be wanting something more "up to the task" than any of the MAF based units are. Also, the main contender in this area is SO long winded by the way it gets mapped, to get a satisfactory job from it, you would need to spend like 20 times longer (at least) mapping as it is VERY long winded to get alterations into the ECU and even that is limited by the amount of re-flashes the eeprom can take
WR1 Bro wrote:The downside of them is that some of the competition based ECU's like Gems and Link can make the car a bit obnoxious at tickover and low RPM.
Well, maybe 2 or so years ago, that would be accurate, but GEMS, have worked A LOT on these areas and still do, this is generated by the "road" market demanding better performance in this area; as motorsport units, they rarely see tickover (jacked open throttles & ALS). There are regular updates to GEMS ECU eeproms, each (usually) bringing software improvements to "operability". Cold start has been one of the most complex areas to master; there are (at least) 5 seperate fuel relative control maps, all interacting with each other at start-up, and you only usually get 1 go at setting up the cold start as well.
Huge subject in itself of course, and difficult to sum up so briefly. I'm sure it will generate further discussion.