PrecisionBoost wrote:Given the 1.6L uses an external ring it should be possible to mount the 1.6L crank pulley onto the 2.0L and make an adjustable mount for the pickup.
That is to say that you could design it such that the crank pickup is moveable.... so that you can advance or retard the ignition by a few degrees.
Yes... that is what I was talking about on the last post..... making the crank pickup moveable on a bracket
Oh ya.... pontiacjeff.... he was the LT3 guy I was thinking of.... he has a Grand Am right?
If I remember correctly.... wasn't he the one that ran the distributor off an accessory belt?
I remember commenting something about "aren't you worry the belt will slip" or something like that.... but he said he had no problems
Personally.... I think it should go onto a toothed belt like your standard timing belt.... I suppose one could take a timing gear off the crank and turn it into a separate pulley just for the distributor.
If you search around the relocation of a distributor to run off a belt is something many guys have done..... quite often it's needed when someone shoves a big V8 into something that was designed for a 4 or 6cyl..... the Chev V8 distributor sticks up pretty high and get's in the way even on truck.
Lots of V8 guys buy reluctor wheels that can be added on for better accuracy (compared to the standard distributor setup )....... I'm pretty sure MSD and Accel both make reluctor wheel add on kits..... I'm also pretty sure that the programable MSD ignition systems give an option for using an external reluctor instead of using the factory distributor or ECU as the spark reference.
Basicly with a reluctor system your pluging in true firing angle for advance/retard..... where as if you use the stock ECU as reference it's X number of degrees advanced or retarded from the stock ignition timing.
The second option is the easiest because the ECU takes care of moving the ignition point based upon factors like engine temp and map signal......... where as a direct reluctor system is pretty much static.... you dial in 22 degrees of advance at 3750 RPM and that's what you get all the time.... it won't change with the engine temp or map signal.
For all out race systems the direct reluctor wheel timing is better because you can dial in exactly how many degrees you want and that is exactly what you will get.... so you can be very agressive with your timing.
With an ECU reference you have to be more conservative.... if you dial in 11 degrees of advance and at 12 degrees you get spark knock..... then you might run into trouble if the ECU decides to advance timing a degree or two.
In a direct system you will get 11 degrees no matter what..... but with the ECU... it may be 11 or it may be 8 or it may be 14 degrees of advance depending on what the ECU decides based upon a number of factors.
Separating the injector and ignition would be next to impossible..... it sure would be cool if you could have two pickups.... one in stock location and one "adjustable" unit 180 degrees away..... basicly when the first pickup is timing for 1&4 the second would be timing for 2&3.
Problem is that the crank pickup goes to one input if I remember correctly.... so that signal is split off inside the ECU's circuit board.
If however the crank pickup had split off into two different inputs.... one for ignition timing reference and one for ignition timing reference then it would be possible to use two pickups.
All that would be required is to exchange the spark plug wire sets ( since there is a 180 offset it would try to fire 2&3 when the ECU wanted to fire 1&4 )
I still don't think it would make that much difference to the injectors if they were off by a few degrees.... the correct amount of fuel would be added no matter what.
That is to say for example.... if it was off by a bit and the intake valve closed 90% of the way through the injector squirt.... then 10% would be left over in the intake manifold for the next time the valve opens...... so you'd get 10% from the previous injector cycle and 90% from the current.... which still adds up to 100%
Given the RPM levels the difference in duty cycle from pulse to pulse really doesn't change that quickly.
That is to say I doubt there is more than a 10% increase or decrease in duty cycle per firing sequence.
Even on let off at 5000 RPM you have an injector firing 42 times per second..... so if it takes even a half second to go from say 80% duty cycle down to 10% then it has 21 injector firing sequences to reduce the fuel duty cycle by 70%.... which works out to be about 3.33% per injector firing cycle.
So...... I still don't see any real negatives for changing the timing of the injectors by a few degrees..... I mean were not talking huge numbers.... perhaps timing might be adjusted as much as 10 degrees.... which is only a 2.8% change in the big scheme of things.
So....... I personally think an external reluctor with an adjustable crankshaft pickup is a great idea..... you could integrate it into an underdrive pulley and balance the whole unit as one piece.
You could even buy the Lanos pullies and cut the factory reluctor off the pulley via a lathe.... then simply attach the outer ring to a new aluminum pulley.
, kidding.
