PorKen

According to the WSM, this tweak should also inhibit the 3° retard if the airbox temp is high.

If you had an external knock sensor box, it could ground the load switch input, if knocking. 20° would be overkill, but safe, especially with a single knock sensor?

Silverback66

I used to be pretty good at jetting Mikunis, plugs for the mains and **** accelerometer for the needles, could balance a pair of SU's by listening to the hiss with a short piece of garden hose, and was pretty fair at setting ignition timing with the cellophane from a pack of cigs, but as soon as I start swimming with the electrons I immediately get out of my depth. Pardon me if my questions reveal the depths of my ignorance.

The KnockSense site is hard to navigate, but it looks like it's primarily designed to give me a LED on the dash to tell me that I may already have holed a piston. Fifty bucks is plenty cheap enough, even with another $25 for the sensor, and the 3-pin connector hardware can be had, but what do you connect it to on an EZ-F?

Since the KnockSense, with the Bosch sensor, can take the sound of detonation and convert it to voltage to light an LED, would it be possible to feed that voltage into the WOT circuit that Ken is disabling in such a way to fool the EZ-F into retarding the timing only when there is detonation?

Does the EZ-F modulate between 40 and 20 degrees, or is it binary?

And since we've come this far, can John just harness an EZ-K with the LH for my 86.5?

John Speake

Yes, that is correct. But 20deg is brute force stuff.

Even a supercharged 928 engine rarely needs more than 9 degrees pulled back.

For the stock motors you are trying to warm up a bit, it would be good to use one of these boxes to determine if taking out that 20 deg WOT retard is likely to give you a problem or not. My guess is that under some combinations of load/rpm and temperature, not to mention fuel octane, you will get significant knock at some points.

But even when your proposed system kicks in you won't be worse than stock.

The proper solution will be to remap the EZ-F so you don't have to rely on the fixed steps that you can access at present.

John Speake

Yes, this is what Ken is thinking of.

Binary

??

PorKen

I think he means to swap in an EZK with the LH2.2.

From what I've gleaned from the WSM, the EZK + LH2.4 are much more symbiotic than the early brain boxes.

John Speake

OK, thanks Ken. To swap in an EZK to match up with a LH2.2 would require the use of the 60 tooth timing gear.

Another issue to solve would be that the EZK requires a load signal from the LH which the LH2.2 doesn't provide (which is why the EZ-F has the vacuum load sensor device (MAP)

In that sense EZK/LH2.3 are somewhat more interdependant

The clever trick would be to be able to interface a knock sensor into an EZ-F with more reasonable igntion retard steps when knock is detected. That might be possible once the code is cracked...

Silverback66

John's "clever trick" is exactly what I would have requested if only I possessed the vocabulary.

Since the sensor is in the middle of the V and the time between detonation events is nearly infinite as measured by electron travel, a single sensor located appropriately should be enough to identify which cylinder is hammering. Right?

I assume there are systems, probably using low-voltage stick-coils, that can retard the timing in steps on a per-cylinder basis until detonation stops only in that cylinder, and can measure detonation in that cylinder every other rotation of the crank. Right?

As John so sagely observed, the worst case scenario is the stock default, 85-86, which I understand from Ken cuts system ignition timing by 20 degrees whenever the throttle is 2/3 open. Since we are doomed to a binary, 8-cylinder, retard, can we use the KnockSense, or something like it, maybe wired in series with the position sensor, as a filter to retard system timing IFF there is both 2/3 throttle and knock?

If the filtered system cycles fast enough, our **** accelerometers wouldn't be able to tell the difference between disabling a single cylinder and cutting all 8 by half at the knees for a rotation of the crank. Right?

Don't say I didn't warn you about my questions.

John Speake

If you managed to fit an EZK with the two knock sensors, then you would have per cylinder knock retard.


It would be quite difficult to engineer such a system to interface with an EZ-F. The best compromise might be a "retard all" system with one sensor, a modified Knock Sense box that could kick back the timing by a smaller increment - say 10 degrees, with a fast recovery time.

The problem with this is that one cylinder usually knocks before the others..... from my observations with the EZK SharkTuner.

You won't get per cylinder retard with this simple system, because however fast the electrons travel, the knock has happened by the time the system knows about it :-)

The filtering required will also put a time delay into the system.

PorKen

If the EZF can't incorporate more programming in the chips, I would double the safety retard, from 3° to 6°, and use the input from the knock box to trigger that.

The knock box would need an adjustable threshold, adjustable retard time, and ideally, an adjustable rpm cutoff (high rpm noise).

I think the KnockSense already has the first two, it has a threshold for intensity, and the LED probably has a slight delay so you can see it.

PorKen

Here's the switch I made. I wired it to have Full Load/TempII tweaked, TII only, or factory. I drove around for about half an hour testing the different modes. Driving is much more pleasant with both tweaks on. Acceleration is much smoother/quieter with the FL, and pickup is improved with the TII.



I'm going to make a final version with thinner wire, and just a on/off switch, for simplicity.

BC

I'm not good with wiring, and I will need the extra kick on he 86. Can I have one of those?

SharkSkin

Nice gizmo, Ken!

Rick Carter

While my car is in for winter maintenance and upgrades I asked Rob to check my Temp sensors, Temp I is good but Temp II is not so I've ordered a new replacement and may try to implement Ken's upgrade. I'm still trying to understand if it will offer me something I can't get from the SMT-6 piggyback that lets me adjust timing.

Great Job Ken.

svp928

Damn! Guess I jumped the gun getting the Mark-1 Mod-0 version of Kens doodad... oh well, I like it anyway...

Steve

PorKen

Brendan - Sure!
...

Rick,

Note that the LH TempII has two sensors, so you have to measure each terminal to ground, not to each other.

I can't say how it will work with chips, piggyback, or boost, but I'm guessing taking out the full load switch may make for a smoother advance curve to program around?
...

Steve,

As soon as I get the smaller colored wire, I've got the parts for your 'upgrade'.