FridgeFreezer Posted September 20, 2006 Share Posted September 20, 2006 I have been building a MS for a forumer who wants it as a drop-in replacement for a Lucas 14CU unit - playing round with the case I found that if you really wanted you could fit two MegaSquirts into one Lucas box: You'd need straight-up D connectors and mount the MAP sensor differently, but it's doable. Easy to make them switchable too, so if one suffers a problem the other can be switched in. Perhaps a tad pointless though as they don't seem to break like Lucas ones Quote Link to comment Share on other sites More sharing options...
imspanners Posted September 21, 2006 Share Posted September 21, 2006 Ah, but could you not run 2 seperate maps then? Say, one for power and the other for emissions (in case VOSA stop you)? Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted September 21, 2006 Author Share Posted September 21, 2006 No - you could run FOUR separate maps as each MS will do dual table anyway B) The real trick comes when you stick the MS-II CPU upgrade in and the two can talk to each other over the CAN bus, the possibilties are endless. Quote Link to comment Share on other sites More sharing options...
dollythelw Posted September 21, 2006 Share Posted September 21, 2006 diese.. ok ok.. it does look like a little city for tiny people though if you ran two in one casing John are they both powered up and the output is switched or is the output common and the input juice is switched? Quote Link to comment Share on other sites More sharing options...
reads90 Posted September 21, 2006 Share Posted September 21, 2006 Jon as you know i am a diesel man so bit simple on petrols. But i am getting on so should get into it. Does this mean you can run one for speed and one for torque. and switch between the two. If so how quickly can you switch over, and can it be done on the go, as such Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted September 21, 2006 Author Share Posted September 21, 2006 diese.. ok ok..Fuc... oh, never mind... Jez - you switch the +12v feed so only one wire needed, theoretically one MS could switch the other on using a spare output, then that MS could switch the first one off the same way. Not sure how that would ever be useful though Ali - table switching can be done on the move, it's instant. Switching ECU's may give a bit of a stumble but the MS does come on instantly so it would really be the delay in the time it takes for the switch contacts to move. In both cases I'd say it's probably a good idea not to switch tables or ECU's while you have your foot welded to the floor redlining it as sudden jump in timing/fuelling under high load could be undesirable. Does this mean you can run one for speed and one for torque. A good fuel map you should have both anyway - the real difference would be one map for economy/emissions, towards the weaker end of the mixture, and one for performance where everything is bang on 12.5:1 mixture. Quote Link to comment Share on other sites More sharing options...
geoffbeaumont Posted September 21, 2006 Share Posted September 21, 2006 I have been building a MS for a forumer who wants it as a drop-in replacement for a Lucas 14CU unit - playing round with the case I found that if you really wanted you could fit two MegaSquirts into one Lucas box: You'd need straight-up D connectors and mount the MAP sensor differently, but it's doable. Easy to make them switchable too, so if one suffers a problem the other can be switched in. Perhaps a tad pointless though as they don't seem to break like Lucas ones We've got similar plans for my Megasquirt in the near future - it's going in a smaller 14CUX case, though, which might be a little trickier. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted September 21, 2006 Author Share Posted September 21, 2006 Still plenty room I reckon Geoff, I didn't cut any of the weird internal lugs to make it fit in there (although fitting TWO in may prove harder ) If you can, use straight-up DB9 and DB37 connectors as they make a neater job / closer fit, if I did this again (and something tells me I will) I would solder the wires onto the AMP plug from underneath as it would've been neater. Worked out well enough though IMHO: Quote Link to comment Share on other sites More sharing options...
geoffbeaumont Posted September 21, 2006 Share Posted September 21, 2006 Still plenty room I reckon Geoff, I didn't cut any of the weird internal lugs to make it fit in there (although fitting TWO in may prove harder )If you can, use straight-up DB9 and DB37 connectors as they make a neater job / closer fit, if I did this again (and something tells me I will) I would solder the wires onto the AMP plug from underneath as it would've been neater. I'm leaving that project in the capable hands of my mate Jonathan, who's a lot handier with a soldering iron than me (he's an avionics tech). I think we'll have to lose the current case completely, rather than keep half of it as a mount as you've done, and also to rebuild the dual ego and table switching input in there too. Additional connectors will probably be military spec waterproof jobbies, with the whole case properly potted against the unlikely event of a door seal leaking Guaranteed to be a lot tidier than the current solution, which is the megasquirt sat in a tangle of wires and excess vacuum tube in front of the driving seat Veering slightly off topic, we've been toying with our crazy ideas of dropping fuelling to half the cylinders at low loads again, and we reckon it'd probably work... The thinking is that we rejig the injector looms so that one 'bank' serves cylinders 1-3-5-7 and the other 2-4-6-8. Cutting fuelling to one bank should then turn a 45deg V8 into a 90deg V4. Obviously, a bit of coding will be required to actually do anything useful with this, but I think we'll wire it up so we can try the theory when we put the engine back together Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted September 21, 2006 Author Share Posted September 21, 2006 Geoff - be careful with the potting compound, the MAP sensor will not enjoy being potted as it needs ambient pressure to the hole to compare the manifold pressure with. You could have it set to slow alternating squirts, so each bank fires once every two cycles rather than using one bank all the time. Not convinced this will be as easy as the theory sounds - interesting to see though. Quote Link to comment Share on other sites More sharing options...
geoffbeaumont Posted September 22, 2006 Share Posted September 22, 2006 Geoff - be careful with the potting compound, the MAP sensor will not enjoy being potted as it needs ambient pressure to the hole to compare the manifold pressure with. Thanks for the warning. You could have it set to slow alternating squirts, so each bank fires once every two cycles rather than using one bank all the time. Interesting...will have to look into this. Not convinced this will be as easy as the theory sounds - interesting to see though. No, neither am I, but there's only one way to find out One downside is that there's no practical way to keep the valves open on the unused cylinders so they'll still be compressing and therefore causing a fair bit of drag but not contributing any power. It might turn out that even if it does work there's no practical benefit, and in my case it'll only work for petrol not LPG anyway, but it'll be an interesting project. Seems like a good idea to experiment on the 3.5 before I get round to rebuilding the other engine. Breaking it won't make me cry as much! Quote Link to comment Share on other sites More sharing options...
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