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Wasted spark on LH2.4 with stock EZK

K

Karl Buchka

Active member
Joined
Mar 25, 2007
Location
Los Angeles
Update 08/19/11

Group buy is up. http://forums.turbobricks.com/showthread.php?p=3883351

Update 05/11/11

The circuit has successfully been tested on a 940 Turbo. The car fired up and ran cleanly with no apparent issues. I need to do some more testing of my own before I send out any boards. I'll keep this updated until that time.

I've also posted the first-cut source code here: http://forums.turbobricks.com/showpost.php?p=3760567&postcount=84

Original post:

There was a thread posted a few days ago talking about options for ditching the distributor on an otherwise stock LH2.4 equipped car which got me thinking. Alex and I have been playing with this for the last day or so and we've made some good progress.

photo.jpg


We got an EZK 146 box and tapped in to the VR conditioner circuit and the spark output. Those signals are sent to a microcontroller running a wheel decoder program that counts teeth and redirects the stock spark signal to two outputs. Here's what it looks like on the scope:

photo.jpg


Channel 1 is the output from the stock EZK VR conditioner being fed a 4kHz sinewave with two periods missing every 58 periods (this simulates a 60-2 trigger wheel running at 4000RPM), channel 2 is the stock trigger output signal, and the other two channels is the stock signal after being split.

We've tested the circuit on the bench from 100rpm to 10000rpm with no apparent faults.

What this essentially means is you can install this circuit in your otherwise bone stock LH2.4 car, wire up a wasted spark coil, and be up and running. The main catch here is that stock dwell is retained, meaning we need to find a wasted spark coil with similar dwell characteristics to what's stock. The Bosch Motorsport 4 cylinder wasted spark coil looks to be very close and is what we'll be testing this with first. A friend of ours has a 940 Turbo that we'll be testing this on in a few days.

Piping a cam sync to this chip for full sequential would be fairly trivial.

If this works and there's any interest I might have a run of circuit boards made up. Questions, comments?
 
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B-lennium said:
Haha, nice find. What made you guys think about this?

wy not go the megasquirt route?
Click to expand...

Don't get me wrong, I'll be the first person to ditch stock stuff, but some people don't want to deal with MS. I'm all for giving people options and this is potentially a simple way to upgrade your stock ignition system.
 
Karl Buchka said:
Don't get me wrong, I'll be the first person to ditch stock stuff, but some people don't want to deal with MS. I'm all for giving people options and this is potentially a simple way to upgrade your stock ignition system.
Click to expand...

thats a good outlook on things man!

you going to get some sort of kit together?
 
*subscribes*

Guess i'd better get cracking on making a dwell adjustment for the EZK.

I wonder how difficult it would be to modify the code in the EZK to use a second output, and toggle them in sequence? The CPU has a bunch of i/o pins, I don't think they ALL are used.

*paging ipdown to thread*

Either way, good work guys!
 
gear whine said:
thats a good outlook on things man!

you going to get some sort of kit together?
Click to expand...

Thanks. I haven't decided how to do it yet. I'll probably get some boards made up, but beyond that I'm not sure.

beepee said:
*subscribes*

Guess i'd better get cracking on making a dwell adjustment for the EZK.

I wonder how difficult it would be to modify the code in the EZK to use a second output, and toggle them in sequence? The CPU has a bunch of i/o pins, I don't think they ALL are used.

*paging ipdown to thread*

Either way, good work guys!
Click to expand...

Thanks, appreciate it.

If you find a spare output pin I don't imagine it would be terribly difficult to split the signal that way. This board might just be an interim solution, but so far I like the idea of not requiring any software mods at all.

Are you up on if there are any un-used pins on the EZK connector? Pin 25 looks promising, but I'd like one more. It would be nice not to have a bunch of wires coming out of the back of the box.
 
that is pretty damn baller. plenty of people with 2.4 who are pushing the stock stuff who would eat this up when you get it working. i'd be rocking 2.4 if i had a car that came with it in good shape/etc and didn't want to do too much destruction to it
 
Nice work guys!

I have a few Bosch 2x2 Motorsport/Alfa coils and the associated double powerstages, bought for exactly this purpose. I might have some spares, need anything?

A good spark is what really is lacking on a stock-ish ignition system. Every now and then I need to clean the corrosion of the contacts in the dizzy, there must be quite a bit of energy loss there.
 
JW240 said:
Nice work guys!

I have a few Bosch 2x2 Motorsport/Alfa coils and the associated double powerstages, bought for exactly this purpose. I might have some spares, need anything?

A good spark is what really is lacking on a stock-ish ignition system. Every now and then I need to clean the corrosion of the contacts in the dizzy, there must be quite a bit of energy loss there.
Click to expand...

Thanks for the offer, but I think I'm all set for the time being. I've got a Bosch 2x2 coil and a couple of ignition drivers I had left over from a VEMS install. If/when I get this working I might need help with some more long-term testing if you're interested.
 
man within the last few months lh2.4 went from crap to amazing potential. Im starting to get excited lol.
 
EZK is absolutely tunable. The software is unfortunately obtuse however. Know any 8051/8052 assembly experts? Will they take bribes?

I think the best shot is using an EZK with the EGR hardware (goldbox for example). Pin 15 could probably be adapted to drive a second ignition driver. Non-EGR EZKs are physically different; they lack a few components present on the EGR onces. At least the gold box that I have has a few extra transistors than my other 3 EZKs.

Ipdown and I have been going over the EZK and trying to piece together a rough idea of the actual pinout in relation to the CPU and onboard logic... but I might just try and write a test program to toggle all the outputs and check pin states.

Either way, I won't say that modifying the code onboard would be trivial, but so long as the EGR control output can be manipulated via CPU logic it is "possible".

I'd say that you guys have a much higher probability of successfully completing a piggyback controller before the EZK is software moddable to do wasted spark.

Just make sure you share you code so I can steal it and re-use it for fun and profit :-D
 
Karl Buchka said:
Thanks for the offer, but I think I'm all set for the time being. I've got a Bosch 2x2 coil and a couple of ignition drivers I had left over from a VEMS install. If/when I get this working I might need help with some more long-term testing if you're interested.
Click to expand...

Ok sounds like you have the parts covered, let me know if anything changes, it is yours for shipping. I'll gladly help with more testing of course!
 
Great work! I too believe that will not only bring lh 2.4 to almost modern age but also make it quite fun again. Let me know if there is anything I can do to help.
 
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