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Denlasoul
06-11-2003, 08:44 PM
I read awhile ago about people having their cars tuned to the higher Octane gas using the Mercedes Star Diagnostic tool. Has anyone here done it? Any observations? I might have my local mechanic do it for me, if it's a positive gain.

DLS

Renn 208
06-11-2003, 08:47 PM
Originally posted by Denlasoul
I read awhile ago about people having their cars tuned to the higher Octane gas using the Mercedes Star Diagnostic tool. Has anyone here done it? Any observations? I might have my local mechanic do it for me, if it's a positive gain.

DLS

Nokia mentioned a while back that while he was able to set it to 93RON, he couldn't get it to stick.

You might be better off with some UD pullies...or any of speedybenz's mods

Denlasoul
06-11-2003, 08:50 PM
What do you mean by "Nokia couldnt get it to stick"? I am planning on doing the underdrive pulleys, just putting it off for now.

Speedybenz mods?!?!!? Light years ahead of me. :) Though I like the idea of shedding pounds, and better handling. I read shedding 6 pounds is like adding 1hp to the car.

Renn 208
06-11-2003, 08:54 PM
Originally posted by Denlasoul
What do you mean by "Nokia couldnt get it to stick"? I am planning on doing the underdrive pulleys, just putting it off for now.

Speedybenz mods?!?!!? Light years ahead of me. :) Though I like the idea of shedding pounds, and better handling. I read shedding 6 pounds is like adding 1hp to the car.

1. nokia would be the best to clarify, but my understanding was that the setting went back to 91 on its own.

2. light years? nah, Jeff's got all kinds of doable mods...and lucky you, it's the same car now!

jnolte
06-11-2003, 09:58 PM
what modz does speedybenz got??

Renn 208
06-12-2003, 08:38 AM
Originally posted by jnolte
what modz does speedybenz got??

use search

speedybenz
06-12-2003, 09:58 AM
I had this mod performed to my 1999, C280 V6. And it stuck to the ECU for as long as I owned it. I even went back to check it about 3 months after the change and the ECU still retained the new code.

It did make the V6 engine pull better of the bottom and through the middle of the powerband but no real gain on top. However the gain in the middle was great and I will change to this setting on my current car when I get a chance.

Jeff

kodiak
06-12-2003, 10:44 AM
Where are you getting 93 RON gas? And is it actually 93 RON or 93 pump gas (R+M/2) or in long from RON + MON /2?

Thanks,
~dnm

Brabus
06-12-2003, 01:21 PM
Originally posted by kodiak
Where are you getting 93 RON gas? And is it actually 93 RON or 93 pump gas (R+M/2) or in long from RON + MON /2?

Thanks,
~dnm

I don't think they're talking about switching the actual gas but actually tricking the computer that you have better gas so it uses it in a more performance oriented way. I hear this lowers mileage though??

dwang
06-13-2003, 11:45 AM
I believe the theory goes something like this...

The ignition is set to a certain retard for firing. Changing the setting to 93 retards the ignition even more, thus making some gains. Does this sound right???

Here are some snapshot pics of the computer screen during the change (this was for a 203 vehicle):

dwang
06-13-2003, 11:46 AM
2nd screen:

dwang
06-13-2003, 11:47 AM
3rd screen:

dwang
06-13-2003, 11:48 AM
4th screen:

dwang
06-13-2003, 11:49 AM
5th:

dwang
06-13-2003, 11:49 AM
Finally last screen:

speedybenz
06-13-2003, 04:04 PM
Changing to the 93 fuel setting alters the ignition timing. It advances the timing some which can help torque in the lower and middle ofthe powerband and may or may not help the top end.

I always ran 91 octane fuel in my V6 and did not have any detonation problems. But different cars will react differently. So if you make the change you need to listin for detonation or learn to read spark plugs to see detonation on the plug.

Jeff

Denlasoul
06-13-2003, 08:08 PM
What would detonation sound like?

speedybenz
06-13-2003, 09:09 PM
Detonation can be hard to hear, but the pinging that you hear in some engines is sort of typical. Although the pinging noise is more of preignition and not as destructive.

You you suspect detonation you can check your spark plugs. You want to look at the ceramic around the electrode for little specks of black or balls of black to purple deposits. These are indication of aluminum being blown off the piston and then deposited on your plugs.

You may also notice the water temps go up substanially, but not always.

If I were to change the ECU to the 93 fuel setting I would run cooler plugs. probably one heat range cooler.

Jeff

Denlasoul
06-14-2003, 07:38 PM
How much of a difference is 92 and 93 Octane? I think my local gas station has 92, and was wondering how much of a difference there is between the two.

speedybenz
06-16-2003, 09:36 AM
Difference between 93 and 92 octane? Not enough to worry about. Ther is very little difference between 91 and 93 octane.

Jeff

kodiak
06-19-2003, 03:19 PM
I might have to give this one a shot. Anyone have the software to do it? Suppose I could just go with a PowerChip 93 octane and be done with it....

~dnm

Alps
06-19-2003, 11:26 PM
UK has 95 RON in the garages, thats what i run my C36 on all the time!

Deepchord
06-23-2003, 10:54 PM
sounds "retarded" when you mess with the stock timing..

har har har

98c43amg
06-27-2003, 03:41 PM
Hello all,

I'm new to this board. Nice to meet you all.

I've been running it [RON93] for years on and off. Among many things "just not right" w/my less than perfect C43 is it has absolutely no peddle response with ignition set to "default". I have to have it set to RON93 else I want to drive the car in a lake.

When I'm not running in RON93 mode is always becuase a service tech reset my configuration and/or reset the adaptations. Otherwise it stays set.

Additionally, I understood it =retartds= the timing, not advances it. The result is much more low and mid RPM torque. Though I find it to perhaps be at the expense of high RPM torque [though that may just be unique to my less than perfect car].

Additionally, the "93" in "RON93" is the european 93 octane. That equates to US 91 octane. Thus it's actually setting the car to operate on "cheaper" gas, not better gas. It limits the amount of advancement the ignition will operate at through the RPM range [higher octane allows for more advancement]. As an example, if you run the ignition in "default" mode with Sunoco 95 octane [US], the car will advance its timing quite a bit more vs how much it would if running with that gas and ignition set to RON93.

...at least as I understand it...
;)

Denlasoul
06-27-2003, 07:38 PM
Hello and welcome!

You said having your car set to RON93 had better low and midrange torque, and that high end might be comprimised. Do you know for sure, or are you going by seat of the pants? I'm curious b/c I want a little more at the lower end, but definitely do not want to sacrifice my top end. I guess I should just go out and find out for myself.

Thanks

98c43amg
07-09-2003, 05:21 PM
Though I have Dyno'ed my car, and do have a product that can make measurements and convert that to a torque curve, I'm speaking "seat of the pants" here.

However I didn't really notice any top end loss when I first had it done several years ago. I'll know what's wrong [hopefully] after Monday when I bring my car to a mechanic specializing in performance tuning Mercedes.

BTW, there's a person in Westchester who just took my urgings and did it to his C43 and he states he now finds no reason to chip his car [he was thinking about the Powerchip.] He's extremely happy with the results.

I too am happy -- and it's possibly my loss in hi-rpm torque is just a result of my car being "tired". Maybe time for a head porting and displacement bore to a 5Liter or more. :)

speedybenz
07-14-2003, 08:38 AM
I took my C43 in and had the ignition timing changed to 93RON.

I then had to drive it home, 3 miles to give it back to my wife, so I can't really tell if it made a noticable change yet.

Well I do think it performed better with a little more snap, but I need to drive it more.

Jeff

98c43amg
07-29-2003, 06:56 AM
Originally posted by speedybenz
I took my C43 in and had the ignition timing changed to 93RON.
I then had to drive it home, 3 miles to give it back to my wife, so I can't really tell if it made a noticable change yet.
Well I do think it performed better with a little more snap, but I need to drive it more.


So what do you think now? One guy who did this after corresponding with me said he now sees no reason to upgrade to the PowerChip after doing this.

BTW, I've discovered the reasonS for my hi-rmp power loss, and it's not associated with the RON93 setting. I can't wait to get them resolved and get the car back that I so know and once loved.

best regards

speedybenz
07-29-2003, 09:03 AM
98c43amg,

So what did your mechcanic find was the reason for the high rpm power loss. Please tell.

Also after driving my C43 with the ignition changed to RON93 I have to say that I am pretty sure I am getting either some misfires or detonation. It's enough to feel the engine pull back a little, which sort of feels like the car hesitates in 3 or 4 spots on the way through the powerband to redline.

It's a very odd feeling sort of like when the ESP kicks in, but not quite that noticable.

I may try some different spark plugs and see if that gets rid of the problem, but if not, then I will have to go back to the RON91 setting.

On a separate issue do any of you with c43 feel that some days your car is a rocket with good power all the way through the power band and other days the car can barely get out of its own way? Very fustrating. My c43 does this quite a bit and it drives me nuts.

Jeff

Denlasoul
07-29-2003, 09:24 AM
Originally posted by speedybenz
On a separate issue do any of you with c43 feel that some days your car is a rocket with good power all the way through the power band and other days the car can barely get out of its own way? Very fustrating. My c43 does this quite a bit and it drives me nuts.

Jeff

Jeff:

I noticed something like that too, but here is my take on it. Since I dont drive my car much anymore (I commute using a bus), the only time I take it out is on the weekends. On weekends I am usually with my wife, so I dont get crazy with the car.

It's weird, when I am with my wife the car is tame and kinda sluggish. When I am alone, it becomes really aggressive after a few miles of driving (>5). Kinda like it has two types of transmission settings, and no my wife is not overweight ;)

Sadly, I dont drive my car enough to see if there is really a problem. Maybe tomorrw and this weekend, I can check it out more. I have a few days off to play with my car. :)

98c43amg
07-29-2003, 10:33 AM
Originally posted by Denlasoul
It's weird, when I am with my wife the car is tame and kinda sluggish. When I am alone, it becomes really aggressive after a few miles of driving (>5). Kinda like it has two types of transmission settings, and no my wife is not overweight ;)


The dreaded "Automatic Transmission Adaption" of Mercedes -- the one thing to dispise [despise?] about modern Mercedes cars. Oh I know this all to well. I describe it as "the car goes to sleep". It plays a role in the reduced performance both you and speedybenz see. Remember, we have an electronic trottle, and the trani plays a role in how responsive the throttle will be to our input, as the car is constanly adapting both its engine and transmission "behaviour" based on how agressive we are being with the throttle pedal.

It's why I've called several tuners to find out if a) I can get a manual trani installed [yes, for $20K], or b) they have a way to disable the transmission adaption in the trani's ECU and lock it in "hot-rod mode".

Negative on both accounts.

I've taken to rowing the shifter as a rule; usually not down to 1st, but between 2nd to 4th. My car spends most of its time in third actually as I don't do too much highway driving.

[speedybenz, I will reply in a moment]

98c43amg
07-29-2003, 12:32 PM
Long Multi-Part Reply ... please read through.


Originally posted by speedybenz
98c43amg,
So what did your mechcanic find was the reason for the high rpm power loss. Please tell.


Actually, I discovered most of these things. [he'll probably find more] Now that the car's out of warranty, I'm getting my hands dirty again. I shouldn't have waited, as the local MB dealership threw their hands in the air more than a year ago and said they couldn't figure out what was wrong. [the dealership in NYC could [factory store actually], but they never could/did relay all the info back to me, and the one guy who could have, left before I got to get it out of him! :) Plus it's a pain for me to go there, so I'm trying someone out here on LI who's touted as a Mercedes Performance God by everyone who knows him. ]

I'll pass what I discovered [mainly #3 below] along to him Monday when I can finally get into his shop, as I'll need him to perform some corrective measures.

More than high RPM loss also. My car lost the ability to spin its tires on launch after it got warmed up, and barely when it was cold!

1) Probably need new plugs [47K miles]. This one the mechanic did say when he test drove the car before making an appointment for me. I also believed this for a reason some may not consider. My car spends a lot of its time between 3K and 6K RPM. Probably reduces the life of the plugs having sparked so many more times than the average driver within the same set of miles. :) Plus, my car was stalling [or nearly stalling] after cold start, and sometimes even back-firing in the first few minutes of use. Kind of all made me believe the spark wasn't as hot as what it once was.

2) Air Filter and Air Box became filthy in less than one year!

This was a real surprise while I was intalling K&N's. I'm new to Long Island, where they use a lot of sand on the roads in the Winter. This winter was bad. I was concerned about it building up in the air box. I shouldn't have waited checking it out! Sand, Dirt, Leaves, you mention it. I was expecting to see mice living in there as it looked like a nest. And I had a new air filter installed less than a year before! I'll have to keep a close eye on the K&N's.

3) Gunk coming from the driver's side value cover through the hose that goes into the MAF sensor housing before the Intake Manifold, just under the MAF sensor. Is it happening on the other side where what its gunking up is less visible? could be.

...this one... This has serious implications, as the intake manifold and heads may be gunked up too! [I'm going to ask my mechanic to take off the intake manifold to inspect and clean]. Last time I had it in the shop in NYC they said the dual-stage manifold wasn't working correctly [it should change position twice, not once] and had to de-gunk some things. They gave it back to me and I was all smiles. Then in a few thousand miles, frowns. The dual stage manifold may not be working correctly again and why my car's such a dog to 2500 rpm.

Now, what exactly am I talking about. If you take a look on your car at the hose connecting from the back of the driver's side valve cover to the side of the MAF Sensor housing, you'll see there's no valve [PCV?] in that connection. Assuming it is PCV, I'm assuming it has to be inside the valve cover. Hope so, because if there's no valve, that whole arraingement is definitely not right. Oil gunk is being injected or sucked right into the intake manifold! That's also why I probably see loss of a quart of oil every 5K miles or so.



Also after driving my C43 with the ignition changed to RON93 I have to say that I am pretty sure I am getting either some misfires or detonation. It's enough to feel the engine pull back a little, which sort of feels like the car hesitates in 3 or 4 spots on the way through the powerband to redline.

It's a very odd feeling sort of like when the ESP kicks in, but not quite that noticable.

I may try some different spark plugs and see if that gets rid of the problem, but if not, then I will have to go back to the RON91 setting.


Your tukis (sic) is sensitive! I agree, I feel the same thing.

I believe what you're feeling though is a "power-band" like effect in the mid-rpm range being caused by use of a different fuel and ignition map in the ECU when operating in RON93 mode. I discussed this very thing with my mechanic. He seemed to think the "check engine" light would be going on if there was continued detonation.

I hope so. If it's detonation, I'm going to need new pistons or heads and a bore job running this way!

There's also another reason I'm on the RON93 setting below.



On a separate issue do any of you with c43 feel that some days your car is a rocket with good power all the way through the power band and other days the car can barely get out of its own way? Very fustrating. My c43 does this quite a bit and it drives me nuts.


I concur. Have to floor the car and go agressively between trottle to brake to trottle to brake a few times to "wake it up". It's the frigg'n "adaption". Try rowing the shifter to third and second instead of letting the tranni do what it wants. I'm much happier that way.

Aside from what I replied in the previous message regarding the trani adaption, and how it supresses performance ... Another thing =requiring= me to run at RON93. Peddle response. Even when my car's running right and cleaned [after I get it back from NYC working it over] with ignition set to default, my trottle is either on or off. As I move the trottle from 1/3 to 2/3, there's very little change in response. And the car goes no where from 0 to 1/3 throttle. However on RON 93, when the car's running right, 0 to 1/3 throttle nearly spins the tires. 0 to 2/3 smokes 'em.

As a final note, I had all this done under warranty:
- I've had three tranni rebuilds [it's great now after the last NYC rebuild]
- On my third exhaust replacement due to the others failing and rattling [you'd think it was made in america]
- had the seats worked on at least a dozen times [I hate those bladdered seats]
- had misc electric switch problems with windows and sun-roof [all ok for years now]
- right front steering knuckle went, which took out the wheel bearing, which failied and took out the breaks and rotor!
- oodles and oodles of other little things.

However, it's all been fixed, and if the engine performance can be brought back to where it should be, I'll be lov'n the ride again.

best regards, and sorry for the lengthy message, but there's a lot to say!
;)

speedybenz
07-29-2003, 01:33 PM
98c43amg,

Thanks for the information. It was not too long.

I took off my intake manifold a month ago or so and it was contaminated with lots of crap from the engine vent tibe that runs to the 90 degree elbow just below the MAS.

I wish ther was a way to hook the throttle up to the pedal, so that damn throttle plate would open up inrelation to how far I pushed the pedal down.

I think the Knock Sensors are located right below the intake manifold, bolted to the block. I should have just removed them.

I have a plan to put an air/oil separtor inline with that tube that connects to the MAS and intake manifold.

I also want to measure the pressure coming out of that tube to see how much blow by I am getting past the piston rings.

Jeff

BenzMeister
07-29-2003, 03:31 PM
Originally posted by speedybenz
I had this mod performed to my 1999, C280 V6. And it stuck to the ECU for as long as I owned it. I even went back to check it about 3 months after the change and the ECU still retained the new code.

It did make the V6 engine pull better of the bottom and through the middle of the powerband but no real gain on top. However the gain in the middle was great and I will change to this setting on my current car when I get a chance.

Jeff Where can you get this mod for 93 octane done? at the dealer? did they charge you? 93 octane is plentiful here in Mass, RI and VT.

Thanks

98c43amg
07-29-2003, 06:28 PM
Originally posted by BenzMeister
Where can you get this mod for 93 octane done? at the dealer? did they charge you? 93 octane is plentiful here in Mass, RI and VT.


The setting can only be done via the "Star Diagnosis Computer" [Mercedes monopoly]. I find you need to have a good relationship with a senior tech at the MB dealership [and having a history of greasing some palms sure doesn't hurt :) ]. I've never been charged for it because they're not supposed to do it [i.e., why I take care of them]

You mis-understand regarding the octane. RON93 is a European octane reference. Here in the US we use the (RON+MON)/2 method. MON = 89 for all US gas; no exceptions. Thus "RON93" = (93+89)/2 = 91 octane in the United States. Thus, it's setting the engine up to operate at lower octane gas. [another reason why I believe thinking it leads to detonation is mistaken.] Furthermore, I actually believe my car runs better on Getty 92 octane, than any other 93 octane gas.

98c43amg
07-29-2003, 06:35 PM
Originally posted by speedybenz

I took off my intake manifold a month ago or so and it was contaminated with lots of crap from the engine vent tibe that runs to the 90 degree elbow just below the MAS.
[snip]
I have a plan to put an air/oil separtor inline with that tube that connects to the MAS and intake manifold.

I also want to measure the pressure coming out of that tube to see how much blow by I am getting past the piston rings.



So that's the way it's supposed to work? No valve, with gunk flowing into the intake system the norm?

That blows, or sux, which ever it is ;) . I don't have the experience with this sutff [computers and audio, that's different]. If you can, please let me know what to do if you're successful in finding a way to "filter" that flow of air.

speedybenz
07-29-2003, 08:52 PM
The change to RON93 changes the ignition timing of the ECU. It advances the ignition timing to take advantage of a slightly higher octane gas that is more resistant to detonation.

The advanced ignition timing will usually increase power in the the lower to middle part of the powerband and at part throttle.

Advanced ignition timing at full throttle at high rpm is uaually not the best thing for the engine because as the rpm increases the air/fuel mixture is subject to more turbulance in the combustion chamber thus it tends to burn faster and does not need the earlier ignition timing/ advanced setting.

Hopefully we can all gather info and come to some fixes to help all our MBs run stronger by getting the ECU set up better using the Star Diagnosing computer.

Jeff

98c43amg
07-29-2003, 09:47 PM
Originally posted by speedybenz
The change to RON93 changes the ignition timing of the ECU. It advances the ignition timing to take advantage of a slightly higher octane gas that is more resistant to detonation.


See, that's the one place what I've learned from the MB techs, and looking over their shoulder while they use the Star Diagnosis Computer, and other places that what I know differs from what I've been reading on these boards.

I came to learn setting this value will adjust the amount the ignition will get retarded. [As a side note, I've also learned that the timing is not "advanced" per say, except for special cases on certain cars; it starts at some maximum possible advance amount programmed in, and it is retarded based on numerous engine dynamics of rpm, load, throttle angle, air-flow, air-temperature, etc..] And setting ignition to RON93 [or anything under the ignition timing setting] reduces ignition from some possible max in all cases.

Here's the supporting material....
I've seen and worked with this in person, but here's a series of images provided by Renntech to help all of us:
http://www.infopages.net/renntech/fuel_settings/index.htm

Click on the 6th, right most image. The text is a little blurry, but it reads "the correction is used to retard timing in order to prevent the engine [something to the effect of "from experiencing detonation if"] fuel is poor.

It says it right there in the Mercedes Star Diagnosis Computer. Setting anything here, even RON93 [B]retards ignition from a possible maximum, allowing one to operate with lower octane fuel than the car is made to operate with when ignition is set to "default".

Thus the line of reasoning follows:
- if the car does not experience detonation when ignition is set to "default" using high octane fuel [let's say octane 93 US, which would equal RON97 if it was available on this ignition timing menu in the computer].
- and setting it to RON93 *retards* the timing from the max so it could operate without detonation at lower octane fuel
- how then can detonation occur with the ignition timing set at RON93, and still using US octane 92 - 94 fuel?
:Ponder:

At least that's the way I see it based on the info stated in the MB Star Diagnosis Computer [and what the MB techs and a Service Manager told me]. So what is the supporting material you're using that says RON93 *advances* the timing beyond what the engine would otherwise operate at if ignition is set to "default"?

Now additionally, I'm also coming at this from the standpoint of an AMG car, which requires premium fuel. I'm not sure, but a C180?, 230?, 280? may be programmed to operate at RON89 from the factory [equals US Octane 89 as well, since MON always equals 89 here]. That would completely change everything, and yes setting to RON93 would then retard the timing less than the car would otherwise operate at if ignition is set to "default". Put anothyer way, retarding the timing less for all intents and purposes equals advancing it beyond where it would have operated at if ignition was set to "default".

Lemme know if that's the difference in our take on all this. It's been an enjoyable discussion.

Best Regards.

speedybenz
08-01-2003, 09:31 AM
98c43amg,

I have been looking into the RON93 functions a little closer and this is what I have learned from my dealer, Kleemann and Evosport.

The RON93 setting does advance the ignition curve or allows a differnet timing map in the ECU to operate. Using the RON93 setting you have told the ECU that you have higher octane fuel in the engine so there is less chance of detonation.

With fuel of a higher octane (less detonation prone) you can advance or fire the ignition sooner hopfully making more power. But only if the engine reaches the peak cylinder pressures after top dead center, around 10 degrees ATDC. If peak cylinder pressure is reached sooner than that then the engine loses power as the piston as to fight through the higherr cylinder pressures to reach TDC. And if the spark fires too late then the peak pressure will be lower and will happen to after too many degrees of crankshaft rotation have occured.

As for the screen pic, it sort of looks like a dual screen snapshot and maybe the statement is left on screen from a previuos computer command.

Jeff

98c43amg
08-01-2003, 10:51 AM
Thank You. It all certainly all sheds a new light on things; still leaves me with questions though.


Originally posted by speedybenz
The RON93 setting does advance the ignition curve or allows a differnet timing map in the ECU to operate. Using the RON93 setting you have told the ECU that you have higher octane fuel in the engine so there is less chance of detonation.


Hmmm ... I was thinking change in timing map. Otherwise something I don't get then.

My car C43 is made for "Premium Fuel Only"; guessing that's also assumed when ignition timing is set to "default" in the Star Diagnosis Computer.

I guess that begs the question, what Octane level does Mercedes consider to be "Premium Fuel" then?... See maybe I'm incorrect in believing that to be about 92-93 Octane US [95-97 Octane European, or RON95 - RON97 if it were to exist in the Star Diagnosis Computer]. And by setting my ignition timing to "RON93", I'm telling the engine I'm running with at least 91 Octane US (R+M/2); retarding? the maximum advance it would ever use?

I wish I knew how to measure this and graph it.



With fuel of a higher octane (less detonation prone) you can advance or fire the ignition sooner hopfully making more power. But only if the engine reaches the peak cylinder pressures after top dead center, around 10 degrees ATDC. If peak cylinder pressure is reached sooner than that then the engine loses power as the piston as to fight through the higherr cylinder pressures to reach TDC. And if the spark fires too late then the peak pressure will be lower and will happen to after too many degrees of crankshaft rotation have occured.


Well put. How does that relate to the increase in torque between 1K to 3K rpm though, i.e. low rpm power?[power, meaning torque at a rate, i.e. RPM] Another reason I believed the RON93 setting retarded timing was the car acts as the way my firsts cars acted if I had turned the distributor cap back; as you may have in your Pontiac or Chevy [or whatever] in the 70s [if you're that old :) ] That always resulted in better low-end torque at the expense of high end torque.



As for the screen pic, it sort of looks like a dual screen snapshot and maybe the statement is left on screen from a previuos computer command.


Don't know what picture you're referring to. It's no dual screen shot or any image aberration. I've worked with this very page with two different techs and it looks 100% like you see it in the pic. The screen pic is of the person making the actual RON level selection, thus the image is displaying a few of the RON pull-down entries, with the selected pull-down value of RON93 highlighted.

Just to dispel any mis-understanding of what I'm talking about, the URL to the actual image is below. It is clear the Star Diagnosis Computer does say "retard the ignition timing". This is no "left-over" from a previous screen.

http://www.infopages.net/renntech/fuel_settings/DSC00105.jpg

[ EDIT: oh, silly me. this is also on the 1st page of this thread, posted by 'dwang']

...I'm so torn -- do I believe the experts in tuning my automobile or the manufacturer of my automobile!
:crossid:

I will point out the two additional advantages I've observed running on RON93 any why I continue to do it.

1) The car immediately jumps when I touch the peddle. With ignition on "default" I have to go to about 1/2 throttle just to start moving off the line faster than a Pinto. Then further in "default" mode , once moving I can go to 1/3 throttle, 1/2 throttle, 3/4 throttle and it hardly makes a difference. The car hardly moves until it kicks down to a lower gear. (I want to drive the car into a wall when it does this). With RON93 I have more noticable difference in pull w/the move of the peddle.

[ EDIT: speedybenz, is your C43 on "default" now? I know you tried RON93 but got the sense you wouldn't keep it that way. Just wondering if your car acts this way at all when on "default"? ]

2) No Stinky Smell! Your car may do this too. If I'm driving with the windows closed, fan off, but sun-roof open, the aerodynamics of the car allows for the exhaust to "seep" back in through the sun-roof.

- As just one example ... If I'm driving with ignition in "default" and take an especially windy up-hill on-ramp by my house that requires about 40mph entry speed and about 80mph exit speed, sharp right then long left sweep up a hill, and sharp right to enter the highway, by the time I hit the hi-way, I have a strong pungent rotten-egg/sulfer smell filling the car regardless of the gas brand I use [gotta open those windows!]. (there's never anyone in front of me when I'm able to really drive it, and it's the start of the hiway so there's no other cars infront that I'm picking up the smell from) I understand that smell to be caused by unburned fuel reacting in the catalytic converter.

- With the car on RON93, no other smell other than cleanly burned exhaust.

speedybenz
08-20-2003, 11:18 AM
Well it has been awhile since I switched my fuel setting to 93RON and it feels as if the car just sudenly figured out what to do.

The engine is now very responsive and peppy. I am very happy with the mod and would suggest it to others now.

I would not have said that 3 weeks ago. For some reason now the car just flat rips.

Jeff

Denlasoul
08-20-2003, 11:41 AM
Wow! Thanks for the tutorial. I think I have a general grasp on it. :)

I'll be doing this mod also. I will keep a good eye out for anything I observe.

1SIKBNZ
08-24-2003, 06:25 PM
Hello, im new to this forum and posting. Ive been following for awhile though. I have been looking for ways to improve the low end on my 99'c280 and this sounds like i would like to give it a shot. Im near the sf area anyone knows of a place that would do this modification? or how i should go about asking a tech if its is somthing they are not supposed to do? Thanks for any info.

speedybenz
09-03-2003, 09:48 AM
I posted earlier about a slight mis or hesitation in the engine while WFO. Well I am pretty sure what I am feeling is the intake manifold crossover point.

I also noticed that this same thing can be seen on the HPS dyno graph of the C43.

So anyhow I do not think this mis is detonation related but due to the intake changing the runner length.

I do like the acceleration of the car with the ignition set at 93RON, it's quite a bit quicker.

Jeff

1SIKBNZ
09-03-2003, 09:56 AM
Hey guys so any help on where i might be able to get this done? I cruised by the MB stealership the other day just to inquire and not a single tech in the joint had any idea of the even existence of this setting! LOL. They looked at me like i was just some punk kid tryin to sound smart. well its obovious that i am smarter than them but only thanks to this board!!!:D help me out i wanna try this. thanks guys!

Denlasoul
09-03-2003, 10:26 AM
you can either go to a Stealership and find a guy WILLING to do the change or go to an Indy shop. They should know what this is, but are never allowed to tinker with it...something to do about emmissions and such. So basically, it's "frowned" upon from Stealerships, but you can always find that one guy willing to do it for you.

DLS

BenzMeister
09-03-2003, 11:38 AM
Where I first got the C280, it was a bit sluggish and the tranny was slow shifting. I went back to the dealer and he reset the tranny back to default, he told me the previous owner probably wasn't as aggressive as I. He also said to use 93 or 94 Octane gasoline and in a while you will feel the difference. I also added a K&N air filter and to tell you the truth the car is much more responsive, when I kick down the pedal I feel the forward surge and even when I start from a full stop at a light and I accelerate briskly I can feel the difference. Maybe that all I neede to do on my C280. I also asked a dealer about the 93 RON and they didn't have a clue about it.:)

BenzMeister
09-03-2003, 11:48 AM
When I first got my 99 C280 last year, I noticed it was kind of sluggish and the automatic shifted very slowly. I took it back to the dealer and they reset the tranny back to default and said the tranny would adapt to my driving style, which it did, took about two weeks of agressive driving. I only use 93 or 94 octane. The last time I went to the dealer I asked him to reset the engine codes and the tranny codes back to default. After a couple of weeks I have a very brisk moving C280, when you kick down the pedal you can feel the car jump ahead and accelerate. Also I drive in D4 around town and on 45 mph roads, it makes a big difference in performance from D5, IMHO:)

98c43amg
09-03-2003, 04:19 PM
While getting my car aligned and windshield replaced at the MB dealership I decided to have my car inspected there too. ...Car didn't pass, with CO levels too high. Sure hope it isn't RON93!!! I'll keep you posted.

1SIKBNZ
09-03-2003, 04:25 PM
as far as setting the trany back to default, is that all you need to tell them? just set the tranny back to default? also how much did they charge u to do that? thanks.

Denlasoul
09-03-2003, 06:08 PM
Originally posted by 98c43amg
While getting my car aligned and windshield replaced at the MB dealership I decided to have my car inspected there too. ...Car didn't pass, with CO levels too high. Sure hope it isn't RON93!!! I'll keep you posted.

Did they check it using the OBD II method or tailpipes? When I got my inspected for emmissions they just plugged my car in and said ok you're good. My car isnt set to 93RON though, keep me posted b/c this would be useless if I have to keep changing it back to stock. Unless......I get a Star Diagnosis System...hmmmm.

BenzMeister
09-04-2003, 05:57 AM
Originally posted by 1SIKBNZ
as far as setting the trany back to default, is that all you need to tell them? just set the tranny back to default? also how much did they charge u to do that? thanks.

Yes, I told them what the problem was and asked them if they could reset the tranny back to it default or factory settings, no charge, my car is under warranty.

Alps
09-04-2003, 06:01 AM
Denlasoul,

star diagnosis system inc cradel and cables costs a dealer over $50k, the will not sell to anyone else but a francaise!


otherwise all the backstreet garages may invest! and put the dealers outa business! or in my opinion provide the dealers with some healthy competition!

Denlasoul
09-04-2003, 07:33 AM
Looks like I have to resort to bribery. :)

98c43amg
09-04-2003, 03:57 PM
Originally posted by Denlasoul
Did they check it using the OBD II method or tailpipes? When I got my inspected for emmissions they just plugged my car in and said ok you're good. My car isnt set to 93RON though, keep me posted b/c this would be useless if I have to keep changing it back to stock.

In NY, it's via the Tailpipe on a dyno ... varying speed through all the gears for about 10 minutes (I wonder how they do it on a 4wd car?!) ... and the whole aquired data package has to get uploaded to the State, with pictures of the back of the car for the plate ... I believe. (someone from NY correct me if I'm wrong) Pretty sick, and way too much work for a small shop for just the $35 they get for it.

Anyway, I was told by my service advisor they reset the settings to default, ran the inspection, then put everything back as found again [i.e. RON93]. What the...? I had the car inspected last year and this wasn't needed!

Personally, I think there's another answer. I think I'll replace some O2 sensors before next year's inspection. I bought an OBD-II scanner and code reader, and read two codes for "slow" O2 sensors.

I guess they didn't want to get into that because my bill was already $1000 and they were doing me a favor. <big grin>

(and yes, I always leave about a C-note for the workers, give or take ... ;) ...bribery is likely to get you everywhere)

BenzMeister
09-04-2003, 04:58 PM
Originally posted by 98c43amg
In NY, it's via the Tailpipe on a dyno ... varying speed through all the gears for about 10 minutes (I wonder how they do it on a 4wd car?!) ... and the whole aquired data package has to get uploaded to the State, with pictures of the back of the car for the plate ... I believe. (someone from NY correct me if I'm wrong) Pretty sick, and way too much work for a small shop for just the $35 they get for it.

Anyway, I was told by my service advisor they reset the settings to default, ran the inspection, then put everything back as found again [i.e. RON93]. What the...? I had the car inspected last year and this wasn't needed!

Personally, I think there's another answer. I think I'll replace some O2 sensors before next year's inspection. I bought an OBD-II scanner and code reader, and read two codes for "slow" O2 sensors.

I guess they didn't want to get into that because my bill was already $1000 and they were doing me a favor. <big grin>

(and yes, I always leave about a C-note for the workers, give or take ... ;) ...bribery is likely to get you everywhere)

I would say that the 94 RON is not the culprit, in fact it should keep everything cleaner. Your idea about the O2 sensors is good, aren't O2 sensor covered on the extended polution stuff warranty? By the way Mass also has the same procedure, the tech drives the car alway performs the inspection and brings it back, mostly service stations do it, and some dealers, but I understand I local service station guy paid about $100K for all the new equipment, analyser, dyno, computers, broadband hookup to the state. Before Mass went to CAFE the owner would drive the car up to and stay in the car for the lights horn and all that stuff, it was easy, if you had a clunker to throw the service guy a fews buck to pass you, now I understand it is almost impossible and if you get caughtb, big fine the first time, the second time fine, loose your license and perhaps spend some time in the slammer.

speedybenz
09-18-2003, 09:31 PM
98c43amg,

On the topic of RON93, I still am not sure if the setting retards or advances the timing from the defalt setting. But I think I have to agree with your data that it appears to retard the timing.

Is there anyway to check this out for certain, ie timing light or other device.

These damn Mercedes are a pain in the ass to figure out.

Oh, and I still have my car set to RON93.

Jeff

BenzMeister
09-19-2003, 05:23 AM
I really believe these cars, especially later models OBD2 will adjust to the higher octane, as my transmission has adjusted to my driver style. We could disconnect the battery for 15 minutes, this is suppose to reset everthing back to default, you'll have to play around with the power windows, moon roof and electric door locks to get them to work correctly again, but that info is in the owners maunal. From the reset point drive the car and see how it performs.:)

98c43amg
09-20-2003, 07:48 AM
Originally posted by BenzMeister
We could disconnect the battery for 15 minutes, this is suppose to reset everthing back to default, you'll have to play around with the power windows, moon roof and electric door locks to get them to work correctly again,

...and Radio if you haven't been "touched" by Steve MBenzNL ;). You can get it from MB if you don't have it.

To my dismay, before my local MB dealership got to know me, I'd end up having them reset everything just to trying to "fix" things; and I've changed my battery. Car's always dull with really no mid-peddle throttle response afterwards, with the peddle response instead either "on" or "off". It remains so until I have the RON93 thing done. ...RON93 wins hands down.

BenzMeister
09-20-2003, 11:49 AM
Originally posted by 98c43amg
...and Radio if you haven't been "touched" by Steve MBenzNL ;). You can get it from MB if you don't have it.

To my dismay, before my local MB dealership got to know me, I'd end up having them reset everything just to trying to "fix" things; and I've changed my battery. Car's always dull with really no mid-peddle throttle response afterwards, with the peddle response instead either "on" or "off". It remains so until I have the RON93 thing done. ...RON93 wins hands down.

I guess I'm going to have to try the RON93 thing done. You said the dealer can do it. Are they willing to do it and did they charge you?

Renn 208
09-20-2003, 12:35 PM
A question:

93 RON fuel is equivilant to 89 octane at a US pump, correct? So by changing the setting from baseline to 93 RON, you're basically telling the car that it will be running on 89. If this is not correct, I would like to know.

BenzMeister
09-20-2003, 03:34 PM
Originally posted by Renn 208
A question:

93 RON fuel is equivilant to 89 octane at a US pump, correct? So by changing the setting from baseline to 93 RON, you're basically telling the car that it will be running on 89. If this is not correct, I would like to know.


Good ? anyone know the answer?

98c43amg
09-21-2003, 06:57 AM
Originally posted by Renn 208
A question:

93 RON fuel is equivilant to 89 octane at a US pump, correct?

No, 93RON = 91 Octane US

United States calculation uses the RON+MON/2 method. MON = 89 for all US fuels.

Thus 93RON (Euro) = 93+89/2 = 91

BTW, if I could recommend ... Make sure to read through this whole thread (especially thread segment link "3"). I give a lot of background on this setting (and RON93).

98c43amg
09-21-2003, 07:00 AM
Originally posted by BenzMeister
I guess I'm going to have to try the RON93 thing done. You said the dealer can do it. Are they willing to do it and did they charge you?

Yes, at the MB dealership. Bribery will get you everywhere.:eek:

BenzMeister
09-21-2003, 07:14 AM
Originally posted by 98c43amg
Yes, at the MB dealership. Bribery will get you everywhere.:eek: Yes, bribery will get you everywhere,:)

Renn 208
09-21-2003, 08:10 AM
Originally posted by 98c43amg
No, 93RON = 91 Octane US

United States calculation uses the RON+MON/2 method. MON = 89 for all US fuels.



How is it possible for all US fuel to have MON 89 when I can buy 87 pump octane at the gas station?

Regardless, I think that your initial explanation of how the setting works is the one to go with at this point. "Default" allows for more advance than the 93 RON setting.

98c43amg
09-21-2003, 11:36 AM
Originally posted by Renn 208
How is it possible for all US fuel to have MON 89 when I can buy 87 pump octane at the gas station?


US Octane 87 would equal RON85 in Europe. Don't know if it exists, but that's what designation is would get according to that formula.

Search the Internet on it. A statement of "MON is 89 for all fuel in the US" is one of the statements I read on this subject a few months back.

To tell you the truth, given the advent of re-formulated and oxygenated fuels making the scene, I'm not so sure about it anymore.

want your head to spin?

http://www.faqs.org/faqs/autos/gasoline-faq/part1/

Though I haven't found the clearcut statement of "MON is 89 in the US" in that FAQ, I have found other statements that assume it, as in secton 10.2: "...Standard 102 RON gasoline would be about 96 (R+M)/2 if sold as a pump gasoline...". If MON's 89, RON102 calculates to 95.5, which is "about 96" as stated. There's most likely something in there that states "MON is 89 for standard US pump fuel" ; haven't deciphered the techno-babble yet though.

98c43amg
09-21-2003, 01:13 PM
Originally posted by 98c43amg
US Octane 87 would equal RON85 in Europe. Don't know if it exists, but that's what designation is would get according to that formula.


I stand corrected. Given what's stated at the site below (and I've seen the same stated at others), that MON is usually less than RON, MON is probably not 89 if the US Octane rating (Anitknock Index) is 87.

http://www.fueltechinc.com/antiknock.htm

It probably stand then that MON is only 89 for fuels in the "premium" category. Less for mid and standard grade fuels.

http://www.energy.ca.gov/gasoline/types_of_gasoline.html

BenzMeister
09-21-2003, 01:40 PM
Anybody live in a state where they mix etahnol with gas? How does it work, I've heard this fuel will rot rubber and all sorts of I think "urban legend" type stuff. :)

98c43amg
09-21-2003, 07:32 PM
Originally posted by BenzMeister
Anybody live in a state where they mix etahnol with gas? How does it work, I've heard this fuel will rot rubber and all sorts of I think "urban legend" type stuff. :)

I know it doesn't answer the question you asked, but this is somewhat related so thought you might be interested (as it's a 'negative' on use of methanol)...

Section 7.5 of the Gasoline FAQ does state: "The use of fuels with alcohols such as methanol can confuse the engine management system as they generate more hydrogen which can fool the oxygen sensor [76] ."

BTW, I recommend anyone reading this thread to read sections 4 thru 8 of the Gasoline FAQ. Really interesting stuff; progressively more interesting and peaking at sections 6&7 for me at least.

BenzMeister
09-22-2003, 04:22 AM
Originally posted by 98c43amg
I know it doesn't answer the question you asked, but this is somewhat related so thought you might be interested (as it's a 'negative' on use of methanol)...

Section 7.5 of the Gasoline FAQ does state: "The use of fuels with alcohols such as methanol can confuse the engine management system as they generate more hydrogen which can fool the oxygen sensor [76] ."

BTW, I recommend anyone reading this thread to read sections 4 thru 8 of the Gasoline FAQ. Really interesting stuff; progressively more interesting and peaking at sections 6&7 for me at least.

Correct me if I am wrong about this, don't the car manufacuerer's "set up" cars that are sold in states that us alcohols mixed with gasoline? I have read the EMS can get "confused", great choice of words by the way, with these fuels, so there could be a problem for example, if I drove from Mass out west and stopped in say Iowa, and gas with with ethanol mixed fuel. I picked Iowa only for the reason there's a lot of corn there.


:) :) :) :) :)

Denlasoul
11-07-2003, 09:49 PM
Bump. I was wondering if something like a Unichip could assist in setting the RON. Also, if we could get a hold of the Euro spec ECU information, is it possible to have a Unichip set to the same parameters?

98c43amg
11-29-2003, 12:55 PM
Originally posted by Denlasoul
Bump. I was wondering if something like a Unichip could assist in setting the RON.

Sorry. Been gone a =while=.

Setting the RON (ignition max advance) to any of the three programmed values [maps?] requires the MB Star Diagnosis computer. ...a MB monopoly that's what that is. I've checked with every manufacturer of diagnosis and coding tools. None do the RON setting.
:(

l8r,
-steve

speedybenz
11-29-2003, 03:57 PM
The Unichip will allow you to adjust the timing of the ignition at various levels of engine load and rpm. So the base RON setting becomes less important with a Unichip. So at say an engine load of 50% and 4000 rpm you could advance the timing 8 degrees or to best power making setting as dictated by the engine on the dyno.

Jeff

BenzMeister
11-30-2003, 08:33 AM
you need to fuel with the engine computer on OBD 2 cars especially. These cars will adjust engine values according to what RON fuel you are using. From day 1 I've used 93 or 94 octane Sonoco gas in my car and within a couple of week of using the gas I noticed quite a difference in performance to the plus side. I added a K&N filter and the same think happened. However, if you want to start from scratch I've been told if you disconnect you battery for 10 min plus and reconnect all parameter and values for the on board computer will be set back to factory specs and has you change to higher octane the car will adjust and run much better. In the case of German cars, I had a Bimmer before the my Mercedes, in the owners manual it told you the use of higher octane gas would be benefical to the engine. Off course when you do the battery thing you have to manual reset your, windows, sunroof, esp, radio and some other things.

moebiusgold
11-30-2003, 09:21 AM
Originally posted by BenzMeister
However, if you want to start from scratch I've been told if you disconnect you battery for 10 min plus and reconnect

When I first got my car and hadn't figured out everything tht was wrong I found that just disconnecting the battery for a couple of seconds would accomplish this. I would have performance relief for a day or 2 than things would slowly drift in the direction of degraded performance. Eventually the CEL would come on. All I ever had to do was put in the radio code. I know my C is older. I think that I read that '95 C36s were the only MB that had OBD-II that year, all others had OBD-I.

jnolte
11-30-2003, 11:21 AM
Originally posted by moebiusgold
When I first got my car and hadn't figured out everything tht was wrong I found that just disconnecting the battery for a couple of seconds would accomplish this. I would have performance relief for a day or 2 than things would slowly drift in the direction of degraded performance. Eventually the CEL would come on. All I ever had to do was put in the radio code. I know my C is older. I think that I read that '95 C36s were the only MB that had OBD-II that year, all others had OBD-I.


I also used to do this!!! It drove good for like a day then back to shit. I heard that doing this to much can mess up your ECU

moebiusgold
11-30-2003, 12:29 PM
Originally posted by jnolte
I also used to do this!!! It drove good for like a day then back to shit. I heard that doing this to much can mess up your ECU
Anmy time you turn a computor on and off there is a risk. I think that they are pretty well isolated. I'm more nervoooous about welding on it. I've had bizzar things happen on cars not as nice.

My guess to what is happening is the long term fuel trim gets set back to 0 from where ever it was. Then it starts learning. Every key start from that point on it makes a little adj. to its starting point using what the O2's were saying last time. There's lots of other things I'm glossing over but what I'm sayhing is cuz something isn't right, its not going to be able to zero in on the right settings, instead it gets further away. m At some point it has has enough and CEL and or limp.