Twinspark conversion 2 simultaneous firing?

[paddy dougan]

Hi all,
has anyone here converted their twinspark to fire simultaneously??
If so, did you find any improvement?

Any info, thoughts, yes even outlandish!! much appreciated!!
Ta very much,
P

 

[MattW]

Hi all,
has anyone here converted their twinspark to fire simultaneously??
If so, did you find any improvement?

Any info, thoughts, yes even outlandish!! much appreciated!!
Ta very much,
P

Show's what I know - I assumed that both plugs in each cylinder fired simultaneously anyway.

As I understand, there's only one hall sensor for ignition (using a wasted spark on the non-firing cylinder) with the other hall sensor firing the injectors. So how's the lag on the second plug achieved? Via the ECU?

 

[ELIMINATOR]

My opinion is that BMW have made them fire at different times for a valid reason, even if this is just for emission reasons alone.

As the main plugs have the coils built into the plug caps, AKA coilpacks, and the secondary plugs have conventional leads. Somewhere there must be coils to fire these? How about changing these to a high performance coil? Dyna coils i think were the favoured "performance" bolt on coil of choice in some magazine featured bikes.

Trying to "split" the 12v signal from whence it came to another coil to get them to fire simutaneously might turn out crap.

there again someone who knows what he's talking about may be along soon

 

[paddy dougan]

Show's what I know - I assumed that both plugs in each cylinder fired simultaneously anyway.

As I understand, there's only one hall sensor for ignition (using a wasted spark on the non-firing cylinder) with the other hall sensor firing the injectors. So how's the lag on the second plug achieved? Via the ECU?

Yep, lag is carried out via ECU, through a conventional coil unit to both secondary plugs ATST.

 

[Paul Young]

Primaries fire just before TDC but secondaries fire at TDC, to ensure that exhaust gases being expelled are as clean as possible. So you can see that the secondary plugs are not intended to give any performance enhancement at all.

I've picked up a pair of R1100S t/s heads, another set of coils & all the gaskets to be able to swap them over. I just need the rocker assemblies & cams to avoid having to rip the existing ones apart. I wanted to try making a t/s where both plugs fire at the same time, so if anyone has any more info on this, I'd also be interested to hear it.

 

[paddy dougan]

Hope to get the engine back in this weekend,
twin spark conversion should be done by next weekend,
sooo will let you know how I get on.
P

 

[Mayhem]

Paddy
Not Hanging about then

it may be worth checking if there is any difference in the ignition timing & injection between a RT & GS, probably not make much difference but there are differences in compression ratio and cams between the 2 motors


Nice to meet you by the way

 

[paddy dougan]

Hi Keith,
nice to meet you too.
Engine now back in with new clutch,
rear end on and front back on also,
tomorrow time permitting front wheel on and tighten everything up.
Tank on and give it a whirl!!!!
Wiring for the Hall sensor is different so the original will have to be put back on. I've got a secondary spark unit coming this week so will then try out with both sparks at the same time.
But as Elininator wisely stated need to check that I dont lose current by piggy backing the coil units.
Will keep you up todate on progress!!!!

Keith, again many thanks. Top chap!!!!

cheers Paddy

Paddy
Not Hanging about then

it may be worth checking if there is any difference in the ignition timing & injection between a RT & GS, probably not make much difference but there are differences in compression ratio and cams between the 2 motors


Nice to meet you by the way

 

[alimey4u2]

If both plugs are fired at the "before the TDC point", the flame travel will be faster, therefore there would be a need to retard the ignition from the factory setting to realise any gains.... If any...