Tuning with CIS
 

All,
I'd like to state that I've found some success in changing the running of a 1990 190 16v by fooling the management system to control the EHA as per my wishes.

If you're interested in this then read on.

At its launch the 16v was criticised in the British media of the period of 'lifeless low rev performance' and in the strongest examples I even read something akin to 'the worst throttle response I have ever experienced'. I can only agree. People who have fitted EFi (electronic injection) and done a custom fuel map have reported big improvements.

I wanted therefore to have a rudimentary attempt at seeing what effects the fuel system's componenets have.

Air mass sensor position signal (or the throttle potentiometer)
http://i284.photobucket.com/albums/l...20tech/tps.jpg

Well, so K(E) jet CIS Mercedes have real no throttle position sensor. Instead there's a signal for the position of the air flap. When the air flap moves down the ECU knows it should supply more fuel using the EHA. Why, I am not sure because the movement of the air flap itself injects more fuel anyway. I guess this is what they call 'acceleration enrichment'.

I tried disconnecting mine to see what effect it has. This made the throttle response really bad. There was an even bigger delay before pushing the throttle and getting the engine to do work. However if you get jerky acceleration then disconnecting this seems to fix it.

Wide open/closed throttle switch
http://i284.photobucket.com/albums/l...20tech/wot.jpg
All it does actually is signal WOT and Idle positions. It makes no difference to the throttle response in all the in-between scenarios (i.e. 99% of driving) so I have ignored it apart from testing that it is working correctly.




Coolant temperature sensor
http://i284.photobucket.com/albums/l...20tech/cts.jpg

This important sensor signals engine temperature to the ECU, and the engine will run richer if the engine is cold (and raise its idle rpm). But you can abuse this by faking a signal at this sensor to fool the ECU to run the car richer. This is what I tried. I got the engine nice and warm but fitted a resistor to make it think it's only 60 degrees C. At low revs the car responds really well. At high revs... well... it was really jerky. Really horrible. I am not sure why. All over the place whenever you moved the throttle position. But then I had an idea, I disconnected the air flow sensor position potentiometer. Wow, the jerkiness went away and I was left with a great performing car that had staggeringly much better throttle response low down.

So I am convenced there is some basic tuning that could be done by changing the fuelling to improve the low-down response. However it would be important to understand what other effects doing this would have, just for example of fuel consumption. It's possibly the factory set up sacrifices response for fuel economy (all the Mercedes brochures boast about the economy of the 16v engine). If true then this would mean that there is room to retain the stock Jetronic CIS system but also to change its behaviour to the benefit of response and performance. My vision is of finding an effective way to force the ECU to richen or lean the mixture. Then it is necessary to apply some tuning work so as to translate that ability into the desired improvements. The ideal solution would be a mappable system such as Megasquirt used in conjunction with the stock ECU system to adjust the fuel map as desired. This would allow mapping on a rolling road.

The EHA:
http://i284.photobucket.com/albums/l...20tech/eha.jpg

I fitted a spare EHA and changed the hex screw adjustment on it - nothing good could come of it :(. Therefore I ruled out EHA adjustment as a sensible tuning method for performance gains.

My car has been returned to standard after this experiment but it has given me food for thought.

hey, i have never tried disconnecting the voltage out of the sensor plate, but disconnecting the wot switch does 2 things, first it stops the function of the over run fuel cut which might be why u felt the car respond better.
second, it stops the full throt enrichment.

as for the fooling of the temp sensor, well it will help lots more if u fool the timing box too. thats where the real power is, and its strange that ur car was not smooth on the enrichment for i have driven a 2.5-16 modded that way and the diff was stunning. i could tell cause that car had 2 switches which put it in stock factory mode.

my guess is on a proper tune and no cats you should be at abt 220hp,
as for beter low down feel , if after the fuel enrichment by foolin the temp still not as good as u want, try shorting pins 2 and 3 on the WOT switch u disconnected before. but keep it connected as well this time that way you will still have fuel cut on over run which helps ur MPGs.

hope you try those and tell us what you think.

i wish i have one of those cars, am trying to push a guy here to sell me his EVO2, would be a dream to own that car. the car is super clean but have been told it doesn't have the EVO2 engine, a stock 2.5 in place. still i'll take it and push the price down.

The 2.5 is pretty good, just has the torquey to be okay daily, but when you rev it it's great.

I went out to clarify what I'd said here just in case. I couldn't repeat the improvement :(. So it looks like it's back to the drawing board.

Why do you say you think there's more improvement possible from the ignition timing? My car has a 7 position switch for the ignition timing.

cause when u set it at say the s position or plug out and then do the mod i did it will pull more timing more than u can think. Just keep a notch down from where it pings
Try it man wont take more than an hour of fiddling. I swear it should make alot of difference. Check the other thread where i posted some
Values as a start point.
Hope u try them

Hmm I couldn't find them. I do remember seeing the figures once a long time ago (I think) - can you point me to it? Will let me do some research before having to go and take the switch apart to get the values.

I meant regarding the fooling of the temp sensor, sorry, here is the post but u can try higher values than those:



there are a few tricks to fool the ecu into some good timing advance and a bit more fuel as well.
IIRC find the engine temp sensor that has 4 wires into it, this one feeds temp input into 2 ecus, the ignition and injection. usually it should have 2 grounds and 2 live wires. the one that feed the injection should terminate at pin 21 in the ecu just do a connectivity test. once located cut it and fit a variable resistor. now the second one terminates in one of the wires going to the ignition ecu located on the left fender. also cut this and reconnect with a variable resistor.

Good values to start with should be abt:

450 ohms for the injection
and 750 ohms for the timing
and then adjust as u like.
let us know how it goes, it should give u a good power increase.
to see the diff just wire 2 switches the would bypass the variable resistors (short them no need to cut the connection to the resistors since electricity takes the shortest least resistant route)

The biggest problem I see with fooling the ecu's temp signals is that the feedback from the O2 sensor that will cause the ecu to pull that enrichment back out. That's pretty much the reason I put the effort into building my Lambda controller. Modifying the input signals may show small improvemnts but the feedback is constantly trying to undo them. Gain control of the feedback and the world is your oyster.:cool:

Very true, and thats the reason i had it removed on my 300, but it only does that in closed loop, open loop and full throtle will be running like intended by the fooling.
if u dont care much abt the closed loop running response u can leave the o2 on. i know u have it there to pass the emissions, here in lebanon the test is not that strict for the time being at least.

Great thread everybody. Jay, could you please post that link again? Thanks.

As soon as i find it my self man, if it is the link to the post where the values for the 7 position switch are listed!!!

anyway here they are as i have them on my phone :P just dont ask y :):


7. -No resistor = no retard
1. -1.4Kohm resistor = 2 degree retard
2. -1.3Kohm resistor = 4 degree retard
3. -750 ohm resistor = 6 degree retard (standard in US car)
4(S)-470 ohm resistor = 8 degree retard
5. -220 ohm resistor = 10 degree retard
6(N)-0 ohm resistor = 12 degree retard

PS: everything is on that phone :D

Haha ha ha
Well at least this post is thru my phone :) lol

I've always been curious about this device devopled for VW KE-Jetronic.
Theory sounds workable.
Should be adaptable to the Merc CIS-E

http://www.autotech.com/prod_engine_pwrmod.htm

well in theory it should, just need to tap into the correct wiring. but the diff is in the autotech the device reads the plate voltage and thus determines when to activate.

but don't think its doin anything to the timing side of things. more timing will really give good mid range pull.

The only thing the Autotech does is increase fuel delivery at wide open throttle position via the EHA.
It does so without tampering with any stock settings which is important.

I know of no single device that controls timing and fuel as these are in essence two discrete systems on the KE-Jetronic III equipped vehicles.


To modify fuel delivery at a point other then WOT on a stock engine would really not accomplish much.

Pulling more timing advance would give a better low end response.

i know timing is another ECU the way to work with it is to fool its temp based mapping and timing will be altered enough to feel the diff. i mean more timing than pulling the resistor could do alone

I have an 88 M-103, an 89 M-103, and a 93 M-119. I believe the M-119 would benefit from this mod as well and stated so at the end of last year in post #39 of this thread: http://www.peachparts.com/shopforum/mercedes-benz-performance-paddock/239201-e500-w124-performance-mods-3.html
In that post I stated, in part: "Also have done the Jim F "Cool Harness" mod but that had zero effect on my better runs cuz you've got to be at 80 degrees C or less to get a good time and the Jim F mod doesn't kick the fans on till well after that temperature. I guess a guy could run a higher value resistor to get the fans to keep the temp at 80C but I would rather run a second resistor at the other temp sensor to fool the ECU and EZL into thinking it's 80C all the time so that they will allow full "Party Time" mode all the time."
I think even 80c may be too high. There may be more to be gained by going for 40c or 60c. So today I picked up three 4 pin temp sensors at the local U-pull-it and I'm going back to the track this Sat. Since the sensor is grounded through it's wires and not it's case, I can just plug in a "dummy" sensor, wrap it in a bag, and leave it on top of the eng. Since the business end won't be submerged in water, it will automatically read lower---just what we want. And the gauge will be telling me what temp. the sensor is telling the EZL and LH ECU. I can move the sensor around a little to fine tune the final temp. I will report here, at that other thread, and on a new thread the results. Regards, Eric

Eric,
Try and have the engine think its at 40c, on your car it will fool both injection and ignition together, but i suppose you will be running too rich. and thats what makes this modd better on the W124, since u can fool timing and injection seperatly.

Any way we tried this on a C36 and did give that car better response, thou i really didn't get to try that car enough to have more accurate data.
The limit was that it would start running too rich and thus loosing the gained performance way before reaching the timing limits.

any way just fit a variable resistor and look for that sweet spot.

looking forward to your update.

Opps, does the 400E control timing thru a similar EZL like w124s!!!! or is it like the C36 M104?? would be gr8 if its an ezl i guess.

If you meant similar to the M-103 EZL then yes, it is. (All 3 of my Benzes are W-124s.) I'm not worried about going too rich as I've done breathing improvements that need to be compensated for anyway and both of the LH ECUs I'm running are 93s and therefore lack WOT fuel enrichment. If it gets too rich I can always up the temp. back to 60c or 80c. I saw an over 3 tenths improvement in the quarter mile just from dropping the eng. temp. from approx. 90c to 80c. I also have a traction problem at 80c that I don't have at 90c. (This is a non-ASR car.) Regards, Eric

Thanx for the proof that this somewhat free HP trick does work.

Well what can I say--- the car needs bigger tires now.http://www.peachparts.com/shopforum/...cons/icon6.gif 14.72@95.51 vs. previous best of 14.959@93.81. (14.44@97.405 MPH vs. 14.593@96.219 corrected) This day was 9 degrees F. cooler so I corrected the times http://www.dragtimes.com/da-density-altitude-calculator.php?elevationcorrect=1696&et=14.72&mph=95.51&correctetmph=Correct+ET+and+MPH and as you can see, there still is a nice gain. The gain could have been even more but when I drop the temp below aprox. 70c the car makes so much low-end torque that I lose traction, have to feather the throttle, and wind up running 15s (if I'm lucky). I have a hard enough time hooking up at 80c! I'm not going to start a new M-119 based thread on this mod like I planned until I can upgrade my rims and tires so that the full benefit of this mod can be properly documented. (I'm going to wear out my current tires first). I am going to try to get a friend to scan the timeslip and post it. Regards, Eric

so erric, i bet with no cats, the car should be close to abt 300 hp all in all. dunno just throwing a number here. but would be nice if you drop the temp more and dyno run the car.


Cool thing is that on a g-tech i clocked 1/4 mile in 14sec @102mph. but that was before i upped the boost and installed the meth kit.
Last time i timed my car 0 to 100 mph it clocked 12.1 sec

I figure I'm at 305hp even with the stock cats. Remember, I'm running a uncorrected 14.72 vs. the corrected 15.3 Car and Driver got from a stock 93 like mine back in 93 and it is rated at 275hp stock. And I'm still running those rotten 2.24 gears in the back! The commonly accepted rule of thumb is 10hp for every .10th reduction in ET. That should equate to a three tenths reduction and I'm already at twice that. Regards, Eric

impressive man, btw u think cams from the e500 would fit on your engine and still give you some more power?

Only the intake cam is different I think and yeah, it would probably gain me a bit but I'm not going to bother with it cause my long term plans involve swapping in a whole 5.0 eng. from a S class--- there really is nothing unique about the 5.0 in the 500E/E500 you know. GSXR and I have already talked about swapping S-class 5.0s in place of our 4.2s at that thread I linked earlier in this thread. But you know, I'd like to turbo one of my I-6s like you have done too! Regards, Eric

ERIC,
If you ask me, i would never turbo charge another of my cars again :( its just too much trouble, maybe its cause my car has so many miles on it, but every time i stressed my car out on a long run i would be thinking if somethin has went bad with the engine.

yesterday i took my car on 100mile trip in hot temps, and thou the car never overheated nor did it ping once it developed a small miss fire on idle and the breather is smoking more than usuall. now my plugs are way over due for a change and since i have no oil cooler on the m103 it could be cooked oil. any way tomorrow ill compression test the car, if anythin is off, ill be rebuilding the engine.

not that i dont love the way it delivers the power, its just that maybe my car has too much miles on it to take all this abuse. :/

Eric, that's a great idea, adding a "dummy" coolant temp sensor that's loose under the hood. One catch - the dash gauge reads from a totally different sensor. So you will never know what the "dummy" sensor is reading, without a digital scanner connected (which will show you the live data from the dummy sensor). That's good though, this way you know the exact engine temp based on the dash gauge.

Regardless, it should still work pretty well - and your tests back that up. I was going to try this myself, with a resistor pack, but I like your idea better since it's easier! Now I just need a 4-pin sensor...

:balloon2:

Eric, assuming you have stock wheels & tires mounted, what tire pressure were you running at the dragstrip? With traction problems, I would try lowering the pressure down to the low 20's (I wouldn't go below 20psi (cool/warm) on street tires though). That may help you hook it up. You may also need to start doing a burnout prior to launch, just in front of the waterbox (or are you already doing that?). You generally want to stay out of the waterbox with street tires since the tread will pick up some water and carry it up to the starting line.

:zorro:

Jay
These can't be right - the order should be either x,x,x,x,N,x,S -- N should be in the middle and S at the extreme end, if you look at the switch.

Not true, I believe Porsche or whoever fitted a a different injection system compared to the S class engine they started with (I believe it was LH instead of L which included hot wire intake air mass sensor?). It officially has 21 lbft more of torque from memory.

I think there are different switches. Mine is in the order i posted and with the same resistances. Just get a multimeter and read the resistances and follow same logic of the above list. Should help u narrow down ur advance and retard.

OKay, well it seems like your market cars are sent out with more safety for bad fuels over there.

my car is from switzerland so it could be on the safe side. Any way if ur going with the temp trick it should not be an issue.

So maybe it's a pain in the butt but it's still a cool car.

You know, it's a funny thing, I left the dummy sensor on today---just for grins---Went to church, also went to a couple of stores, and I keep wondering why the gauge was reading so high. So we have one sensor for the fans, one for the LH and EZL, and a third one too? Where is it? This means I didn't really know what temp. was being sent to the LH and EZL?

What I'd like to do on the street is let the LH see actual eng. temp. (for good fuel economy) and let the EZL see only what I want it to see via a resistor (which should help both fuel economy and power---the EZL is way too prone to pull ign. advance at the slightest little rise in temp). I just don't know which pins go where.

I can't wait till you start trying this stuff on your E420. Just make sure you've got plenty of rubber under that thing! Regards, Eric

205/60 15s at 35psi. As for the rest of your post, I already know those things and act accordingly---I used to race a lot back in the day at Carlsbad and OCIR---always on street tires---I always want to know what my cars run in the real world---on street tires with street gas, no ice on the intake etc. (I think we talked about that before.) In my experience, tire deflation isn't that effective on street tires---that is actually more for the slick running guys. Muscle Mustangs and Fast Fords did a story about 10 years ago that backs me on this.
The problem here is that these tires are just too small. Who else is running tires this small? Nobody at that dragstrip yesterday had tires this small. I actually already have the new tires--205/55 16s-- the Goodyears that won the C&D shoot-out not too long ago, But I need 2 more rims. I'm looking for 2 front S-class (W-140) rims---the ones that look like mine only they are 16s not 15s. Are these the rims the 500E/E500 got? And why the "Front only" "Rear only" thing? Do we have to adhere to that when using them on an E class? Regards, Eric

We didn't get the 500E till 92 and by then it shared it's eng./fuel injection/electronics/etc. with the new W-140 S-class. The 91 500E's set-up (KE Jetronic) came from the 500SL. 92 was the beginning of MB's long overdue phase-out of the KE jetronic system. 92 is also the first year of the new "low deck" 5.0 Regards, Eric

I am very surprised to hear this. This means the early R129 500SL came with KE Jetronic too? I have taken your information and tried to prove it for myself. I am surprised if when designing the M119 they bothered with KE at all, knowing they were moving away from it only 2-3 years later.
Wasn't the 600 from 1991 and it did not have KE Jetronic?

Googling some pics of the 1990 500 engine I found this pic
http://www.classiccarshop.co.uk/imag...gine-Large.jpg
Is that a fuel distributor at the back? Does that mean it's KE?

and this pic of a 1993
http://2phast.com/500e/engine-1.jpg which does not have that.

If it's true shouldn't this mean a 1990-1991 500 engine would have a lot worse power/torque curve than a 1992-? Which hopefully brings us close to topic..

I have measured mine. I think you have done yours wrong and I think I know why.
Yours:
7. -No resistor = no retard
1. -1.4Kohm resistor = 2 degree retard
2. -1.3Kohm resistor = 4 degree retard
3. -750 ohm resistor = 6 degree retard (standard in US car)
4(S)-470 ohm resistor = 8 degree retard
5. -220 ohm resistor = 10 degree retard
6(N)-0 ohm resistor = 12 degree retard

Mine:
1(S) - open no resistor (infinite resistance)
2 - 2.4 kohm
3(N) 1.3 Kohm
4 - 0.75
5 - 0.47
6 - 0.22
7 - measured 1 ohm resistance so it's just a piece of wire really.


Did you take the switch apart to measure? What I think you have done wrong is measured them at the wrong angle. Did you notice how when you set the switch the position marker is at the 7 o clock position, not 6 o clock position. BUT the connections inside are at the 6 o clock position. Therefore is you just measured the resistors directly its easy to think you are measuring the '7' position when you are in fact measuring the '1' position because they are offset.
What supports that is your number markings no sense - 7 should be for the position with most retard and 1 for the position with least. Why would 1-6 be increasing resistance and increasing retard, but then 7 to be no retard?? It would make '7' the most powerful/efficient position which is wrong.

I assume this is for the 'EZL ECE' switch on the fender(wing), not the 'EZL' switch under the windshield by the ECUs?

edit: this post confirms it
http://www.peachparts.com/shopforum/212692-post161.html

i have to check again, been ages since i read them, and i might have done it as u say. once i check ill let u know, p/n 015 545 08 28 / 9251 06

on a sad note i blew a piston ring on my TTm103 :(

I seriously doubt that USA-spec cars came delivered with 6° of retard. Do you have any documentation to prove that? AFAICT, US-spec cars came with zero retard (full power).

It's right next to the other sensors. 4-pin is for LH+EZL, 2-pin is for the fans, and the 1-pin connector is for the dash gauge.




Bingo! Only a digital scanner will show you that.




Can't do it. The LH injection systems have logic built in to compare the two values. If they are significantly different, the computers assume a faulty sensor, and will use the higher of the two values. This is mentioned in the factory documentation somewhere (I just read this within the last few weeks).

:(

It makes a real difference in traction, even on street tires. True DOT drag radials (or slicks) run on far lower pressures. Next time you're at the strip, and spinning the tires at 35psi, let 10psi out of the rears and try again. I'll be shocked if you report zero improvement in traction. I find the sweet spot on street tires is generally in the mid-20's.




No, they are different. The S-class wheels will have M14 bolt holes and ball seats. You'd need to use special M12 bolts with M14 seats to mount those up. The 500E wheels are specific to the 124 chassis. And they will be too wide, wrong offset, cause clearance issues, etc. You're better off sticking with 7.0 or 7.5 wheels on that car, around ET37-ET40. Tons of choices from the 202, 203, 208, 209, 210, and 170 chassis. Don't screw around with 124 or 129 wheels, that's asking for problems.




Front/rear only is for clearance, you can run a little wider out back (8.5 with 245's, with the proper offset, is the realistic maximum on a non-500E). Up front, 7.5 with 225's is fine, 8.0 with 235's is pushing it. All of these combos need rolled fender lips, fender spacers, and preferably the strut travel limiters too, as detailed in the AMG wheel install docs on my website.

Uh, btw, we should probably move this discussion into a new thread, don'tcha think? The CIS guys probably aren't interested, lol!




:boat:

simple proof is that usa spec cars came with fixed resistor value, so some retard was involved, i cant say how much thou.
as for:
"Originally Posted by 400Eric http://www.peachparts.com/shopforum/...s/viewpost.gif
What I'd like to do on the street is let the LH see actual eng. temp. (for good fuel economy) and let the EZL see only what I want it to see via a resistor (which should help both fuel economy and power---the EZL is way too prone to pull ign. advance at the slightest little rise in temp). I just don't know which pins go where.
Can't do it. The systems have logic built in to compare the two values. If they are significantly different, the computers assume a faulty sensor, and will use the higher of the two values.

:( "

well on my M103 thats what i did, one value for the timing and one for injection since i didn't much fuel i would run a small resistor value for the injection. dunno if its the same for ur v8.

as for finding the pin to the timing box its fairly easy. just do a connectivity test from the temp pin to one of the plugs in the EZL unit on the fender.

This isn't right (if we're talking about a KE sytem). There's 2 sensors because one goes to the injection and one goes to the ignition. You can fool them separately. But the ignition and injection do not communicate and compare values. What you are referring to is the comparison the injection ECU (and as far as I assume the ignition ECU?) does against the current value and the previous value from, say, a few moments earlier. If it varies wildly then the system knows the sensor has become shorted, disconnected, or is basically faulty. Because it knows a temp reading would never change so fast it knows the sensor is faulty. I'm not aware it compares the 2 coolant temperature sensor readings to diagnose a fault (though being Mercedes it would seem sensible)

I believe Jay is right about the standard 6 degrees retard - it's documented pretty well on the infamous 'free hp for w124/w201 owners' thread. What's also documented well though is mixed results (in terms of noticeability) when it comes to returning it to 0 retard.

Sorry, Eric and I were talking about LH injection - not the same as KE. My apologies for the confusion. I have edited that post to clarify things. :o



This is where I get highly skeptical. The presence of a resistor does not indicate there must be some retard. However the lack of a resistor does, I think, force maximum retard (minimum power). That "free HP" thread was a steaming pile of BS, IMNSHO, at least for USA-spec cars. I pulled the resistor on my '86 300E and watched my fuel economy drop 10% while gaining absolutely zero power. This trick may work in other countries which did have some amount of retard from the factory (so if you set it to less, or zero, retard there is a power increase). But for USA-spec vehicles, I still think we got zero retard (max power).

I also suspect the source of this myth is the difference in octane ratings between Europe and USA. People mistakenly think that because Europe has 96-100 octane premium pump gas, while the USA has 91-93 octane premium pump gas, that USA cars got "de-tuned" via a different EZL resistor setting, for our supposedly "low octane" gasoline. This is NOT TRUE... if you research RON and MON octane ratings, and the numbers displayed at the pumps on both sdes of the pond, you'll find that their gas and our gas is basically the same. One (or the other) does not have magically better pump gas.


:1eye:

gsxr is correct abt the fuel rating. I say usa has same grade fuel as the best in other countries. I might suspect that california cars might be slightly detuned, cant be sure as i live out of the usa.
Thats up to u guys to confirm. As for noticing more power, well u need to try and coax more timing to really feel it. Hence the temp trick. Dont forget a few degs of advance go a long way. But am sure u might hear some ping on top rpms if u really go crazy with the resistor values. I know i did.

Gr8 forum guys i love it. :)

If I recall the R16 resistor value in a USA spec car is 750 ohms.
This would equate to a 6 degree retard.

Agree that pulling the resistor on a stock vehicle really makes no noticeable difference in performance.

It does however make a difference on a turbo vehicle.

Pulling the resistor increases retard, right? Which I understand may reduce detonation under boost, but on a normally aspirated engine, it would actually cause a power LOSS instead of a power gain.

I'd still like to see factory documentation that shows 6° retard for a resistor value of 750 ohms (as well as for the other half-dozen values). The FSM (click here to view PDF file) doesn't seem to jive with those values, at least for CIS injection on the M103...

:drink:

Don't forget G-man, I'm a M-103 guy too!
I tested the 24 81 resistor and it gave me 749 ohms (within the tolerance I'm sure). Now I think it has been fairly well documented that when the 750 ohm spot is chosen on the cars that have those cool dials, the EZL retards the timing by 6 degrees. I think U.S. cars got the fixed 6 degree retard simply for emissions reasons. You and I briefly touched on the "resistor mod" topic before (in a PM I think) but I didn't really state my opinion because I didn't want to seem too argumentative cause I like and respect you too much but I have to say I'm a believer. I intend to back it with some back to back ETs in the future. It seems that the gain is mostly under part throttle conditions and low to mid-range RPM which make sense cause that is where the advance is needed the most and where these engines are kind of "soggy".
Lots of other posts to respond to but I'll have to do it later tonight. Regards, Eric