Ignition systems with standalone
09-16-2005, 05:40 PM
#19
Three Wheelin'
Pauerman, how many teeth is that? It looks like it might be only ~24? What system are you running?
Dark, thedge, joseph imports, and I are all going to be testing out a "Divide by N" counter circuit, set to divide the 132 stock flywheel teeth by 3 to get 44 evenly spaced pulses per crank rotation. Then you feed the same chip the reference signal and it will "-1" for you. So for $5 per person (much cheaper if we ordered more than just the first 5 at a time, its only $1 in actual parts), we'll get a 44-1 signal from the stock sensors. In theory at least, it will take some additional work to implement.
More info here:
http://www.darklightning.com/motroni...opic.php?t=107
Check out the whole Motronic forum, lots of good technical info:
http://www.motroniccode.com/
About the coils, Pauerman was right on with the LS1 recommendation. If I don't go with COP units from the start, I'll probably use those. And if you're fouling plugs, either your ignition system isn't working properly, your fuel tuning is off, or you're ingesting a lot of oil. So unless your problem is the first of those, switching ignition systems isn't necessarily going to fix it.
Dark, thedge, joseph imports, and I are all going to be testing out a "Divide by N" counter circuit, set to divide the 132 stock flywheel teeth by 3 to get 44 evenly spaced pulses per crank rotation. Then you feed the same chip the reference signal and it will "-1" for you. So for $5 per person (much cheaper if we ordered more than just the first 5 at a time, its only $1 in actual parts), we'll get a 44-1 signal from the stock sensors. In theory at least, it will take some additional work to implement.
More info here:
http://www.darklightning.com/motroni...opic.php?t=107
Check out the whole Motronic forum, lots of good technical info:
http://www.motroniccode.com/
About the coils, Pauerman was right on with the LS1 recommendation. If I don't go with COP units from the start, I'll probably use those. And if you're fouling plugs, either your ignition system isn't working properly, your fuel tuning is off, or you're ingesting a lot of oil. So unless your problem is the first of those, switching ignition systems isn't necessarily going to fix it.
09-16-2005, 05:54 PM
#21
Racer
Thread Starter
Hey Vic; pleased to see the same triggering setup used - useful M10 thread in the front of the block, isn't it?
DanG I suspect I get fouling (only after prolonged idling or running in traffic, not like it's horrific or anything) entirely because the ignition system is not working properly. By that I mean it is not a strong enough spark or I could benefit from changing the plug grade by 1. It's also possible the fuelling at low load/speed isn't perfect as we decided not to spend a lot of time on it when I'll be increasing the pressure ASAP anyway. I doubt it's oil as I'm not recirculating from the breather.
DanG I suspect I get fouling (only after prolonged idling or running in traffic, not like it's horrific or anything) entirely because the ignition system is not working properly. By that I mean it is not a strong enough spark or I could benefit from changing the plug grade by 1. It's also possible the fuelling at low load/speed isn't perfect as we decided not to spend a lot of time on it when I'll be increasing the pressure ASAP anyway. I doubt it's oil as I'm not recirculating from the breather.
09-16-2005, 07:17 PM
#24
Race Director
Several problems, most of which you probably have already heard, oil fumes in the cabin, no vacuum on the crankcase... There are only negatives to the ATM vented design, and only positives to the recirculating. You still "catch" the oil in a recirculating design... but dont ave the other issues.
09-16-2005, 09:01 PM
#25
Addict
Rennlist Member
Rennlist Member
Originally Posted by DanG
Pauerman, how many teeth is that? It looks like it might be only ~24? What system are you running?
Originally Posted by DanG
About the coils, Pauerman was right on with the LS1 recommendation. If I don't go with COP units from the start, I'll probably use those. And if you're fouling plugs, either your ignition system isn't working properly, your fuel tuning is off, or you're ingesting a lot of oil. So unless your problem is the first of those, switching ignition systems isn't necessarily going to fix it.
Vic
09-17-2005, 01:13 AM
#26
Three Wheelin'
How much?
BTW, I got my chips for that divider circuit up above from John G today. Hopefully I'll be able to test them out very soon. Keep your fingers crossed!
BTW, I got my chips for that divider circuit up above from John G today. Hopefully I'll be able to test them out very soon. Keep your fingers crossed!
09-17-2005, 05:58 AM
#27
Racer
Thread Starter
The divider sounds interesting, though I am more than happy with my triggering now we have built it. Like Vic I used what the Autronic wanted and the easiest of those options (it was also happy with 2 missing tooth options).
I think I'll bear the LS1 coils in mind but I suspect it is very similar to the Nissan SR20DET setup NZ suggested and that would be much easier to get my hands on in the UK. I'd like to investigate CoP first anyway, especially the Peugeot set I have in my garage.
Andrew - I don't get fumes in the cabin. What am I losing by not having vacuum in the crank case? I understood it was just to get the oil vapour out but it's doing that anyway as I have a very small amount of oil in the catch tank.
I think I'll bear the LS1 coils in mind but I suspect it is very similar to the Nissan SR20DET setup NZ suggested and that would be much easier to get my hands on in the UK. I'd like to investigate CoP first anyway, especially the Peugeot set I have in my garage.
Andrew - I don't get fumes in the cabin. What am I losing by not having vacuum in the crank case? I understood it was just to get the oil vapour out but it's doing that anyway as I have a very small amount of oil in the catch tank.
09-17-2005, 11:26 AM
#28
Three Wheelin'
Fen it draws the fuel vapor from blowby out of your oil as well, it also helps prevent oil leaks, including pulling oil through the turbo's compressor shaft seal.
09-17-2005, 08:47 PM
#30
Racer
Thread Starter
Does it really though? I mean when would it help, during the induction stroke? On a forced induction engine that doesn't sound all that important. As soon as the compression stroke starts the pressure in the cylinder above the rings rises so much that I can't see a few pounds of vacuum below the rings making any significant difference and once the plug fires there is no way that the change in differential across the rings between an atmospheric and vacuumed crankcase can be significant. If anything I'd have thought vacuum below the rings would encourage blow-by.
All of that is just me thinking about it out loud, not based on experience or even anything I've read so I'm happy to be proved wrong.
In terms of removing fuel vapour I can see that, but won't vapour by its nature make its way out the breather anyway? I can see helping the oil through the turbo but then I've heard of excess oil usage with the same turbo I have on a car with stock breather and I'm not seeing that. Lastly I guess it would help with leaks but really it's a bandaid at best if you have that problem.
I guess I'm still not persuaded to route it back to the intake yet.
All of that is just me thinking about it out loud, not based on experience or even anything I've read so I'm happy to be proved wrong.
In terms of removing fuel vapour I can see that, but won't vapour by its nature make its way out the breather anyway? I can see helping the oil through the turbo but then I've heard of excess oil usage with the same turbo I have on a car with stock breather and I'm not seeing that. Lastly I guess it would help with leaks but really it's a bandaid at best if you have that problem.
I guess I'm still not persuaded to route it back to the intake yet.