rusty_wingnut Posted April 13, 2012 Share Posted April 13, 2012 Chaps bit of advice required - I have got one of Nigels V8 megasquirt kits that was installed and ran a RV8. I wish to now use this system for an MGB engine, the 4cyl B series. (I don't want another V8 - don't go there!) My question is what do I need to change to make this work? I know I need an EDIS 4 and to rework the injector loom to a new setup. Obviously it will need a specific MG map on the ECU. But is there anything I've missed? Quote Link to comment Share on other sites More sharing options...
zoltan Posted April 13, 2012 Share Posted April 13, 2012 New crank sensor missing tooth position but this is friggable when you mount it on the B series Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted April 15, 2012 Share Posted April 15, 2012 If you're going from EDIS to EDIS then you don't need to change anything with the ECU other than settings for your engine. Depending what coolant temperature sensor you use you may need to re-flash the ECU firmware as the V8 versions from Nigel will have the V8 sensor data in them. Use "Easytherm" to calibrate it, or just use Rover sensors and stick with the V8 firmware, or use GM sensors and use the original firmware. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted April 16, 2012 Share Posted April 16, 2012 IIRC, the V8 EDIS units are wired upside-down compared to the EDIS4's, so you are likely to have to re-do all this wiring. Quote Link to comment Share on other sites More sharing options...
rusty_wingnut Posted April 17, 2012 Author Share Posted April 17, 2012 I think I also need to tell Megatune that the car has 4 cylinders now rather than 8. Reading around it seems vehicles with Siamese ports are more tricky to 'squirt, so I may run the sparks side first and move on to the fuel side later. Quote Link to comment Share on other sites More sharing options...
zoltan Posted April 17, 2012 Share Posted April 17, 2012 5 port A Series Minis are a right bitch because you get charge robbing occurring on the centre two cylinders unless you throw fuel at it. Rover got round this with some clever firing on the standard MEMS systems on the multi point MPI Minis. Not sure of the exact details of what they did because we take the 5 port heads off and put a cross flow 16 valve head on with none of that aggro The single point injection behaved like a carb so this wasn't such an issue but that ran out of time on it's emissions ticket so they had to go MPI Quote Link to comment Share on other sites More sharing options...
rusty_wingnut Posted June 8, 2012 Author Share Posted June 8, 2012 Seems like a single throttle body is the way to go for this - for ease of install, and let's face it - a single throttle body and controlled sparks will be a big improvement over two out of balance SUs and a 40yr old distributor! (I have fitted a hairy cam, better exhaust and a big valve head for reference) Has anybody experience of mounting throttle bodies? Should I pick one from a similar size engine and BHP then work it onto a manifold, and then how does one go about getting a single injector to work? Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted June 8, 2012 Share Posted June 8, 2012 Similar BHP is the key as I understand it, erring slightly on the high side. If you go too far you'll have rubbish idle as the injector can't be opened-and-shut quickly enough for fine control of the fuelling. There's quite a lot of leeway though, I'd expect anything that's within 50% of your rough BHP to be more than good enough. Beware of weird injector impedances and fuel pressure requirements with some TBI's, I have *no* clue on the state of things these days but I remember there being some wacky ones out there back in the day - issues like trying to find a fuel pump that is half way between a carb one (~6psi) and an EFI one (~100psi) can be a right pain. I'd have a look on the MSEFI / MSEXTRA forums to see who's using what and with how much success - you might find there's a favourite TBI that gets bolted to everything. Also well worth remembering what you got the TBI from, and even robbing other parts like the fuel pump if you can (a complete donor scrapper which you then flog the remains of could be worth a punt if one can be found cheap). Another option is one or more motorbike TBI's. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted June 8, 2012 Share Posted June 8, 2012 I seem to remember VW (Bosch) throttle bodies being a favourite... Quote Link to comment Share on other sites More sharing options...
rusty_wingnut Posted June 21, 2012 Author Share Posted June 21, 2012 I guess I should update - initially I have gone for sparks only. EDIS 4 is wired in with a really simple loom for a single coil. The trigger wheel went on a diet as did the front pulley and with cyl1 at TDC the missing tooth is 9 ahead of the sensor. I've found a suitable spark map and uploaded that. Yet to try it yet as the engine is out of the shell Quote Link to comment Share on other sites More sharing options...
rusty_wingnut Posted October 28, 2012 Author Share Posted October 28, 2012 Well I have an update and a question. I tried to start the car today and was not successful, well sort of! With the Saw wire connected nothing Was happening bar a few backfires, but with Saw disconnected and running in Edis limp mode it fired straight away and ran lovely! So I can deduce I am missing something inside megasquirt. I have changed the spark map for one a little more specific for the MG, I have set MS for 4 cylinders. As said I have the trigger wheel set 90 degrees behind the missing tooth. So can anyone suggest any settings I may have missed? I've read some of the megamanual but not found anything apart from discussion on trigger angles, however these settings cannot be changed in my MS for some reason? Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 29, 2012 Share Posted October 29, 2012 You don't change trigger angles with EDIS, the only thing that has a bearing is the trim value as this adds or subtracts from the ignition table. I suspect your trim value needs changing to bring the timing correct. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 29, 2012 Share Posted October 29, 2012 Timing light time..... Quote Link to comment Share on other sites More sharing options...
rusty_wingnut Posted November 1, 2012 Author Share Posted November 1, 2012 Indeed it was, I found the timing to far advanced, so adjusted the trim angle by a guess to start with and it started. A few more adjustments and I have the timing as er the manual and rock steady. Very pleasing. Now to try a map similar to the distributor curve specified for BMC special tune. Quote Link to comment Share on other sites More sharing options...
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