John Speake

Ah ! Sorry, misunderstood your Q.

The safest short term option for LH2.2/EZF woukld be to use a MAF restrictor, like Tim Murphy's. This has the advantage that it increases the range available on the LH map, but also automatically scales down the load signal sent to the EZF , thus effectively extending that load axis as well.

The loss of resolution resulting from this wasn't a problem when Louie tuned Jim's car. The load axis was increased on a 2:1 ratio.

Rick Carter

That's what I suspected but didn't know; especially scaling down the load signal sent to the EZF. Thanks again.

Tony

Great stuff, Louie! Thats a keeper. !

Louie928

I have to have a difference of opinion with John on the knock detection system. The knocklite may work, and Ken has figured a way to have it dial in some retard. Probably ok if you don't have too much advance to start with, and don't mind the power hit. I was surprised to see how poorly the TS open type manifold handles mixture distribution. You have some cylinders merrily knocking away and others without a trace of knock. S4s are not immune to that either so it isn't all the fault of poor TS manifold design. On my ITB intake some cylinders come in sooner than others on knock and you'd think they would all be the same. A system that generates background noise map for each cylinder, monitors knock on each cylinder, and retards only those that are knocking is going to do the best job. That's why my vote goes to the J&S Electronics knock control unit.

However, for the '85/'86 boosted folks, it probably isn't as bad as all that because those engines have the stock timing quite retarded from optimum and as Ken has found there are several ways to retard even more. If you are running 6 to 8 psi boost, then don't worry a lot about it, and you can probably get by with what Ken has done. If you have boost in the 10psi range or higher, or just like to have all the performance the engine can produce, go with the J&S unit. It's interesting to see what Ken has found is that most of the increased performance of the S4 is in the better timing (knock) control offered by the EZ-K.

Louie

John Speake

Hey ! :-) I was suggesting to use the Knocklite's indication of knock to help remap the EZF and then use it for some extra knock retard in "normal" use.... I know it's not in the same league as the J & S though....

Do you think that approach is too risky ?

Tony

Would opening up the throttle switch and adjusting the WOT activation point work also? I like the boost switch idea though.

Louie928

Hi John,
I think that would work without a problem as long as you understand the limitations of fixed timing. I got so spooked after getting my GT on the road after timing it as best as I could; very near the edge. The fuel we get here varies with location quite a bit and also altitude where you buy it. I'm probably more paranoid about it than most. With fixed timing, you have to time for the worst possible situation and end up with timing similar to the US '85/'86. That is really conservative. I wasn't satisfied to leave 20 hp just so I'd not inadvertently cause damage so went a different route. If you live where it's flat, don't plan on going to high elevations where fuel grade is worse, then go for it.

Y'know John, what would be really handy would be to have a Sharktuner LH/EZ setup where you could load in different maps without grubbing around getting the LH/EZ out and covers off to swap chips. Then, have to put it all together again. Guess you could sorta do that using the different coding plug options, but not with closed loop on both maps. Just a thought.

Louie

Louie928

Tony,
There is no need for the WOT switch for the EZ at all. Tune timing using the main map. The only functional need for the WOT switch in the LH is to ensure open loop operation so you can acurately set the mixture. You can split the cover off of the throttle switch and bend contacts so the WOT switch would activate at about 40 - 50 % throttle. That should work. Put zeros in the WOT LH map and tune all mixture using the main map.

Louie

PorKen

What happens to the EZ-F mapping under boost? It just maxes out at 0 hg in the cruise map?

EZ-K gets a MAF based load reference from the LH, whereas EZ-F uses it's own, internal, MAP (vacuum) sensor.

Here's a thought - use the warmup/air temp maps (5 cells each) with a boost sensitive MAP sensor, to add/subtract from the cruise map map in steps as boost decreases/increases?

Louie928

Ken,
Good idea. The resolution would be a little coarse, but a whole lot better than what's available now. Will the warm up map take nevative numbers?

Louie

PorKen

I should have split that thought up. The warmup (coolant) map is advance only, the airtemp is retard only.

The warmup map wouldn't work, because you're off the cruise map, or on the last row. (I was thinking to retard the whole map, and advance it with the warmup map in a negative relationship with boost.)

Using the airtemp map, you'd retard from the cruise map as boost increased. Maybe save one cell for the octane loop (knock retard).

You'd need a circuit to convert the boost MAP sensor range into the range of the airtemp values (-37,-26,28,105,127°F).

PorKen

With EZ-F and boost, it seems to me that you're always going to be stuck in a flat, rpm dependent map, either the bottom of the cruise, or the WOT map. (Then retard from there.)

I guess this is OT, as it's not SuperMAF related...

Louie928

You'd have to do some sleuthing to get the voltage across the sensor at various temps. Figure the MAP senspr output at various pressures and see how the correlations went. Use a voltage divider to get the MAP output within the required range. Last resort could be a programmable controller to change the MAP output to the voltage you need for the temp input. The spread between the temp cells is way non linear, but there is probably interpolation happening too so maybe not a big deal. Good idea, Ken. tune the EZ-F up to atmospheric on the main map, then add retard as boost comes up. Then use a J&S Vampire to control individual cylinder timing when you go South and get crappy gas. Heh, heh.

PorKen

The warmup and airtemp maps are additive, not exclusive...

You could have 10 retard steps, for example, 1-5 in the warmup map (in reverse adding to 6), and 6-10 in the airtemp.

You could even have 25ish (5 x 5) steps by splitting the retard into big jumps, and filling with decreasing advance between each step.

John Speake

I was thinking of a base mapping "near the edge" and a fairly fail safe knock retard value, but yes it would be a compromise compared to a system like J &S.

Reprogrammable EPROMs in the LH and EZK ? - that would be a really useful idea !