I read that most EMS's control a 20B the same way they control a V6 engine. I know the Haltech e6K does it this way.
The wolf3d can control a 20B. Does it control it this way as well?

What are the benefits/downsides of this? I heard that power will not change but controling it V6 style will result in poorer fuel mileage and less smooth operating. Is that true?

 

well with a 20b running a leading and trailing timing split you need 6 ignition outputs. since no easily obtainable ems has 6 outputs, you fire the leading and trailing together, wastesparked. this only takes 3 outputs, just like a v6. also like a v6 it needs to fire 120degrees. this is why the 20b is a 6 cylinder piston engine. i know it looks like a rotary but, its not.

mike

 

well this may sound over simplified but how about treating it like a V12 to get the 6 sparks. Or am I just not seeing the whole picture.

 

So what's the disadvantage then to running it like a V6?

 

this is the only way the haltech will run it (i tried everything else), the disadvantage is that you cant have a leading and trailing split. and you can't run the e6k like a v12 because a v12 would fire every 60degrees and not 120 like you need.

mike

 

Yes, the Wolf3D also runs the 20B like a V-6, and so do the Motec EMS units which run the world-famous Mazda-sponsored GT race cars. FYI, the 4-rotor race cars also fire the plugs together, but they have 3 plugs per rotor.

Advantage of firing leading & trailing together: more power

Disadvantage of firing leading & trailing together: will not pass emissions testing

The new Electromotive TEC3 and soon to be released AEM Race EMS units claim to run a 20B with split timing, but these claims have not yet been proven.

 

im not 100% on this but i think the lemans engines fire l and t together but the late trailing does vary.

mike

 

So as far as I'm concerned, it's a benefit and there is no real disadvantage Thank you, that is what I thought were the advantages/disadvantages initially.

 

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? I've had wonderful results running my pre '86 13Bs in wasted spark mode. Heh, they even sound like '86+ RX-7s

Too bad no ECUs currently support this.

Hmm, what would a 20B sound like with Leading wasted sparks and maybe a 15º Trailing split? I'm doing a 20B conversion mainly for that wonderful sound; well, at least 50% anyway. Heheh!

 

you could run a E6K + IG5 to get the split trailing. but if you got a 20B in your most likly your not going to have emissions on your car.

firing L + T will give more power.

 

Microtech MTX12 has 6 ingnation out puts (no waste spark) and leading/trailing split, Its the Only ECU on the market that can do this.

 

it would be nice but the 20b is 120degrees, not 180.
i tried it (unintentionally) when i was setting up the haltech, it doesn't work

mike

 

You can use 2 TEC2s, which is what is on my car and the other PFS conversions.

Russ Turner, former PFS employee and current Electromotive employee, told me that I should sell my twin TEC2s on ebay and upgrade to the TEC3. To the best of my knowledge, you're right about not having been proven. However, I have great faith in Russ and would not hesitate to do the upgrade based on his assurance.

According to Jim Hagerty, at Mariah Motorsports, he used a TEC1 which had been specially programmed for him by Electromotive for his 20B-in-an-'87 project.

 

Has anyone used a Megasquirt DYI ems on a 20b?

 

I've been hearing that the motec m800 runs split timing on the 20b. They claim it on their website.

If thats the case, the Haltech is going in the DSM and an m800 is going in the FC.

 

High boost DSM + 20B FC = OMFG!

 

i dont think the m800 can run the split, ill try and find out for you

 

Cool man, that's all the encouragement I needed! I'm building my own now for sure. I've sorta been dinking around with the idea since late '99, but now I've got enough info and will soon have enough raw material to finally finish it. Don't you just love it when things sorta 'click'?

 

I like toys

I didn't mention my 1979 3/4 ton Chevy 4x4 with a 468 and over 500 ft/lbs of torque, or the Modified WS6 But I don't usually post about domestics on this board

 

clicking is good

mike

 

How can you run a 20B in waste spark mode? I don't understand. When one rotor is at TDC, it doesn't coincide with the end of any other rotor's combustion cycle.

 

you wastespark the leading and trailing.

mike

 

I believe this split is only RPM dependent - not the nicest way of handling the split.&nbsp I don't consider this as a true independent split trailing ignition since stock 20B is 3D versus RPM and load.


-Ted

 

Do you have any ideas on how to duplicate that w/o the stock ECU?

 

Unless it's something on your left front wheel that keeps clicking.
That's true. In order to understand it, you've got to stop thinking two dimensionaly, or is it two rotaraly? That's the secret