Controlling a 20B like a V6
07-26-02, 03:02 AM
#26
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Originally posted by j9fd3s
you wastespark the leading and trailing.
mike
you wastespark the leading and trailing.
mike
Waste spark is something different altogether - that involves firing two different cylinders/chambers at the same time - one spark is at TDC compression stroke and the other one is just "wasted".
07-26-02, 09:41 AM
#28
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peejay is right. It is not wastespark (one fires into exhaust cycle), it is parallel firing.
New Haltech does 3 and 4 rotor with full 3D trail control. Seq injection and oil metering pump control too.
Firing the Lead and Trail in parallel does not produce the best power in my experience. A few degrees of split generally have it running better under WOT depending on the motor, fuel and mods. At light throttle it does seem to run fractionally better when fired together, but HC emissions go up considerably. I also the split needs varying more with load than rpm.
New Haltech does 3 and 4 rotor with full 3D trail control. Seq injection and oil metering pump control too.
Firing the Lead and Trail in parallel does not produce the best power in my experience. A few degrees of split generally have it running better under WOT depending on the motor, fuel and mods. At light throttle it does seem to run fractionally better when fired together, but HC emissions go up considerably. I also the split needs varying more with load than rpm.
07-26-02, 10:55 AM
#29
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Originally posted by The_HITman
New Haltech does 3 and 4 rotor with full 3D trail control. Seq injection and oil metering pump control too.
Firing the Lead and Trail in parallel does not produce the best power in my experience. A few degrees of split generally have it running better under WOT depending on the motor, fuel and mods. At light throttle it does seem to run fractionally better when fired together, but HC emissions go up considerably. I also the split needs varying more with load than rpm.
New Haltech does 3 and 4 rotor with full 3D trail control. Seq injection and oil metering pump control too.
Firing the Lead and Trail in parallel does not produce the best power in my experience. A few degrees of split generally have it running better under WOT depending on the motor, fuel and mods. At light throttle it does seem to run fractionally better when fired together, but HC emissions go up considerably. I also the split needs varying more with load than rpm.
mike
Last edited by j9fd3s; 07-26-02 at 10:57 AM.
07-26-02, 08:44 PM
#30
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Originally posted by j9fd3s
im not 100% on this but i think the lemans engines fire l and t together but the late trailing does vary.
im not 100% on this but i think the lemans engines fire l and t together but the late trailing does vary.
Originally posted by Kurgan
I've been hearing that the motec m800 runs split timing on the 20b. They claim it on their website.
I've been hearing that the motec m800 runs split timing on the 20b. They claim it on their website.
Originally posted by 10sec rx7
i dont think the m800 can run the split, ill try and find out for you
i dont think the m800 can run the split, ill try and find out for you
07-26-02, 08:54 PM
#31
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the way that the m800 is wired it can't do the split the leading coil pack and trailing coil pack are wired together http://www.motec.com.au/drawings/m16.pdf
you can see the 3 ignition outputs are shared between l and t
mike
you can see the 3 ignition outputs are shared between l and t
mike
07-26-02, 10:30 PM
#32
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The new one is weeks away over here for a very small number of units, and only locally near Haltech so each install can be checked on for bugs. I have been playing with one on a 13B for a while and the ECU is getting there very rapidly. Just small stuff to sort.
You guys in the US should see it in couple of months.
You guys in the US should see it in couple of months.
07-27-02, 03:24 PM
#33
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cool thats fast, i was planning on 20b stage 2 next year (making things look good, polishing, paint etc) maybe i'll redo the ems too.
mike
mike
08-06-02, 09:15 PM
#34
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Originally posted by Jeff20B
If there was a cheap way to add a 180º wasted spark to each L plug (like '86+ 13Bs)
If there was a cheap way to add a 180º wasted spark to each L plug (like '86+ 13Bs)
...do you think it would help the power and emissions even more?
08-07-02, 01:42 AM
#35
I'm building a 20B ignition and the info here has been very helpful. On my old 2 rotor engine, adding wasted spark has helped power and reduced emissions (old '70s carb), so I was hoping it could be done on a 20B as well. Too bad. Simply prototyping a 20B ignition (without L/T split) has been rather challenging in its own way. Forget the split (for now); I'll be running it like a V6. 
Last edited by Jeff20B; 08-07-02 at 01:45 AM.
08-08-02, 12:36 AM
#36
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Originally posted by Jeff20B
I'm building a 20B ignition and the info here has been very helpful. On my old 2 rotor engine, adding wasted spark has helped power and reduced emissions (old '70s carb), so I was hoping it could be done on a 20B as well.
I'm building a 20B ignition and the info here has been very helpful. On my old 2 rotor engine, adding wasted spark has helped power and reduced emissions (old '70s carb), so I was hoping it could be done on a 20B as well.
Yes, the split timing was better for the carburated engines, as simultaneous firing could lead to the infamous colliding flame front problem. Modern EFI engines do not have this problem.
08-14-02, 04:29 AM
#38
Old [Sch|F]ool
Us 1st-genners (and pre-RX-7 folk) have been converting to waste spark with two different camps - one mindset uses an additional ignitor and factory coil, another uses a single MSD to drive two MSD coils... either way each leading plug has its own coil and they fire simultaneously.
Anyway, pending the finding of an intact early V6 model, I might have a way of making a CHEAP setup to convert a distributor to fire a 20B in non-split mode... and possibly also with factory-style fixed split if one is willing to make their own distributor cap.
Anyway, pending the finding of an intact early V6 model, I might have a way of making a CHEAP setup to convert a distributor to fire a 20B in non-split mode... and possibly also with factory-style fixed split if one is willing to make their own distributor cap.
08-14-02, 11:48 PM
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Originally posted by Node
Would you mind educating me of this problem?
Would you mind educating me of this problem?
I don't know why carb engines are more prone to detonation with simultaneous ignition, while EFI engines run just fine. Maybe one of our technical gurus can explain this?
08-15-02, 11:00 AM
#42
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i've been reading my rotary engine book, and of course
this isn't mentioned. they do show that when knock occurs it is right next to the trailing spark plug.
mike
this isn't mentioned. they do show that when knock occurs it is right next to the trailing spark plug.
mike
08-15-02, 02:41 PM
#45
Old [Sch|F]ool
The problem with the '80 was due to the fact that both ignitors were encased in one unit. I never had a problem... 
But I did find out that trailing ignition did NOT want to be more than 10 degrees BTDC under full advance, no matter WHAT. That may have had something to do with it. I seem to recall that later engines have altered spark plug locations.
But I did find out that trailing ignition did NOT want to be more than 10 degrees BTDC under full advance, no matter WHAT. That may have had something to do with it. I seem to recall that later engines have altered spark plug locations.
08-15-02, 03:35 PM
#46
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as the rotor moves the trailing side of the combustion chamber is getting smaller and the leading side is getting bigger. this means the flame front moves toward the leading side.
mike
mike
08-16-02, 06:27 PM
#48
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actually it may have something to do with the shape of the rotor recess. the 13b's have a squarish shape recess, and the 12a's have one that tapered on the trailing side. this taper raises the working gas pressure on the trailing side, that and a misfire could be the culprit, no?
mike
mike