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Ignition timing; Selector switch thingy
Topic Started: Sun Nov 5, 2006 11:01 pm (5,323 Views)
Conrad
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Therapy Needed
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Clarkie's thread just made me have a thought - what are the settings?
For 95 RON fuel, Big Ben said use S. I always assumed S was for super unleaded i.e. 98 RON, and N was for normal fuel - 95RON.
If I have this the wrong way round it may explain a lot about my idle!
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Ukmerctechie
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All our cars should be run on s.
The n setting is for 91 ron fuel.
All our fuel is above the n setting.
Stick it on s and forget about it.
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Conrad
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Therapy Needed
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Thanks! I'll change it in the morning. :)
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pentoman
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Ukmerctechie
Nov 5 2006, 10:27 PM
All our cars should be run on s.
The n setting is for 91 ron fuel.
All our fuel is above the n setting.
Stick it on s and forget about it.

Are you aware of the differences between different countries and their octane ratings?

So if S is for both normal unleaded and super unleaded, that means a 16v cannot get any power advantage using super unleaded over normal?
As the timing is the same?
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Ukmerctechie
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pentoman
Nov 6 2006, 01:39 PM
Ukmerctechie
Nov 5 2006, 10:27 PM
All our cars should be run on s.
The n setting is for 91 ron fuel.
All our fuel is above the n setting.
Stick it on s and forget about it.

Are you aware of the differences between different countries and their octane ratings?

So if S is for both normal unleaded and super unleaded, that means a 16v cannot get any power advantage using super unleaded over normal?
As the timing is the same?

Sorry i made the mistake of not taking into account people from others countries.
I was only talking about the uk cars.
I apologise to our overseas neighbours.
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pentoman
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By differences in different countries I was referring to how like 91 Octane in the US is something like 95 Octane over here. So although it seems like the US have crap quality fuel at 91 Octane, it's not quite like that because their ratings are different.


I am still wondering about what you've said because I would have thought S mode was for 97/98 (UK) RON and N for 95 (UK) RON. I assume this would be the case for all Euro models, if I assume they all have the same quality Normal and Super unleaded fuels.


If S covers both normal and super unleaded, then there is almost no point in using super unleaded 98 octane because the timing is not taking advantage of it.
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Cosmo2.5-16
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Part of things
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S is for Premium Fuel
N is for Regular Fuel

Its very important to have the ezl at the right point accoring to the fuel you are using, so that the ignition timing is right.

on lunch at the moment dont have much time now, will post more info on this later on
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Big Ben
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Posted Image

This is a page out of the red cars handbook. Intrestingly the black cars handbook does not have this info in!!
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Big Ben
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Posted Image

This is the other page quoted in the first! Note the Ron No's.
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Cosmo2.5-16
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If you are going to have the EZL plug at point S i would recomend that you use the best fuel on the market, Shell V-Power is a very good quality petrol, which if you were to use this the whole time well then have the EZL plug at point S if not have it at N.

Having the EZL at the S point while using crap fuel will cause all sort of problems, ie. poor acceleration, pinking, engine damage.

There is also a check you can do with a multimeter at the EZL pulg to check to see if its still working. The plug is made up of resistors, different ratings of resistors for the different settings.

I know that over here in ireland the fuel quailty is pretty crap although its ment to be 95 unleaded :angry: CRAP
If i was using the 95 unleaded i would have the EZL plug at N
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Ukmerctechie
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Cosmo2.5-16
Nov 8 2006, 12:29 AM
If you are going to have the EZL plug at point S i would recomend that you use the best fuel on the market, Shell V-Power is a very good quality petrol, which if you were to use this the whole time well then have the EZL plug at point S if not have it at N.

Having the EZL at the S point while using crap fuel will cause all sort of problems, ie. poor acceleration, pinking, engine damage.

There is also a check you can do with a multimeter at the EZL pulg to check to see if its still working. The plug is made up of resistors, different ratings of resistors for the different settings.

I know that over here in ireland the fuel quailty is pretty crap although its ment to be 95 unleaded  :angry:  CRAP
If i was using the 95 unleaded i would have the EZL plug at N

N is for 91minimum!
S for all british fuel.
Read your manual.
Put the resistor at n at your own risk.
What is so hard to understand about this?
The s/n plug is for adjusting the timing to poor quality fuels in an emergency,not for power hikes or tuning purposes.
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pentoman
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Thanks BB - that clears that up! S sets ignition timing for "premium" OR "super" unleaded.

But my point remains:

A 16v will not take advantage of super unleaded fuel and will make NO more power running on super unleaded (97/98/102 RON) versus your everyday premium unleaded.

How can we rectify this?
Sounds like free BHP time for 16v owners if there's a way to.

For example, in a BMW 330i the owner's manual says it makes 231bhp on 97/98 RON, but 221bhp on 95 RON. Presumably a similar power difference would be possible on a 16v.
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cossie connoisseur
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there can be only one ;-)
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My car runs better on super than normal and feels quicker. Even other people driving the car notice it.

My setting is always on S
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Neil
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cossie connoisseur
Nov 8 2006, 11:15 AM
My car runs better on super than normal and feels quicker.
My setting is always on S

mine too (on both counts).
i use BP Ultimate most of the time.
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Chris Martens
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hi,

I've learned in this forum that no British 2.3-16 has a catalytic converter, right?

So these engines produce 185hp with 98 RON, because 98 RON (leaded) fuel was the usual juice at the time, this engine was designed.

Mercedes always was conservative with the settings, so you can use 95 RON with the same EZL settings, if your engine is clean internally, that means no excessive oil consumption and no London traffic only. :)

If you set the EZL knob to lower values, you retard the ignition and you'll loose some power...

The 2.5-16 has a lower compression rate and was designed to use 95 RON, so that's a different thing.

I use 98 RON (or higher) for my 1984 2.3-16 but have driven her with 95 RON without any problems. But she's a fun car only and I don't use her in the city. I didn't notice any difference in power when using different fuel, EZL setting remains the same.
I use 95 RON for the M103 in my 1989 300TE with the EZL knob is set to "1" since some years...

regards,
Christian
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pentoman
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Interesting stuff Chris :). So it seems it's just a 2.5-16 that does not adjust timing for super unleaded fuel (and therefore has potential for a power increase there?).

Did anyone read Evo magazine's huge fuel test recently? They had a Mk V Golf GTi (2.0 turbo) and it was interesting to see the results. I think one "bad" super unleaded's power curve was not much better than good premium unleaded's. They did Tesco 102 octane, which gave the best low down torque but actually the best for top end power was BP Ultimate if I recall correctly.

Difference was I think around 15bhp maximum difference between the least powerful and most powerful fuel. Was done with multiple batches of fuel and very well controlled.
The Golf has a knock sensor and adjusts to the limit of timing for the best power curve.
But I think they did say that if your car did not have a knock sensor (or you did not do manual adjustment) there would be no difference in power, although there would still be differences in how the engine runs/starts etc.

That is what my thinking comes from about the 2.5-16 not taking advantage of super unleaded.

This was kind of proven by their testing of the fuels in a new M5. It turned out to be useless for the test - It had a damn near identical trace for every single fuel it was run with. I guess it's not running at the limits of its timing ;).
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Big Ben
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What is the increment of advance for each setting on the adjuster? It should be possible to advance the ignition a tad more when using a higher octane. Remember if you have a cat you don't have the higher compression of engines that used leaded fuels!

It was so much easier in the old days. You could listen to the engine and make small adjustments!!
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Cosmo2.5-16
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Part of things
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Adapting firing point to available fuel

16 vavlers

These engines achieve optimum performance and consumption figures when operated on premium grade fuel.
As they are performance cars.

The firing point is retarded by 2 degrees for each detent of the plug.
(ascending numbers)

EZL point S

Firing point for premium grade Fuel

EZL point N

Firing point for regular grade Fuel

Difference between point S and point N =

Engine 4000 rpm =
Point S = 18 - 22 degrees BTDC
Point N = 13 - 17 degrees BTDC
Engine idling =
Point S = 14 - 18 degrees BTDC
Point N = 14 - 18 degrees BTDC
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pentoman
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So what we need is a new point that is something like (guessing here!):

Engine 4000 rpm =
Point SUPERMEGA = 16 - 20 degress BTDC
Point S = 18 - 22 degrees BTDC
Point N = 13 - 17 degrees BTDC
Engine idling =
Point SUPERMEGA = 14-18 degrees BTDC
Point S = 14 - 18 degrees BTDC
Point N = 14 - 18 degrees BTDC


I'll see if I can get my car on the diagnostic computer and measure the timing, and see what faking some new switch values does. And then hopefully run the car with data logger and get a trace to see if it's any quicker :). Perhaps this goes some of the way to the 35bhp improvement mentioned for fitting aftermarket management, which of course would take better advantage of super unleaded fuel!
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GEZIJ
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theres no S or N markinkgs on mine, just numbered from 1 to 7.
its set at 5, never tried to alter it but have often wondered if its at the right setting?
looking at past posts on this thread it looks like 1 would be the S setting.
not sure whether to change it.
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Matt
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Administrator - Hawk Eye

Bloody EZL plugs thats what I say, they cause nothing but confusion :lol: :rolleyes:
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cosworth2.3owner
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Hi,

On my 16v, it just says EZL (no KAT or ECE wriiten on it) and its numbered from 1 to 7. Is Setting 1 for S ?

Thanks
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Matt
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cosworth2.3owner
Feb 11 2007, 12:20 AM
Hi,

On my 16v, it just says EZL (no KAT or ECE wriiten on it) and its numbered from 1 to 7. Is Setting 1 for S ?

Thanks

Yes
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Cossie 2.5
Part of things
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Mines got the S and the N but what are the numbers for??
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pentoman
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Cossie 2.5
Feb 11 2007, 08:00 PM
Mines got the S and the N but what are the numbers for??

Other, in-between positions no doubt!
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