For you true gear heads...question on A/F...
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MBWorld Fanatic!
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From: Tampa, Florida
06 SL65 / 97 993tt /11 Suburban/ 2012 GTR (AMG è la mia Famiglia la Bestia è la mia protezione)
For you true gear heads...question on A/F...
Tell me if I have this right:
Running too rich a mixture will mean that all the fuel won't burn during detonation leaving power in the cylinder. Too lean and your engine runs hot, and can cause damage to the internals (pistons) and also leaves power in the cylinder.
If my 55 is running too rich, which I'll find out when I get my pre-dyno run next week prior to the VRP cams/heads...what should be done to get a correct A/F ratio? I know Chris @ C2 Design knows and will get it right for me, but I'd like to educate myself on what are the steps to get a proper A/F ratio? An ECU adjustment? My mind is a sponge...bring on the knowledge.
Jon
Running too rich a mixture will mean that all the fuel won't burn during detonation leaving power in the cylinder. Too lean and your engine runs hot, and can cause damage to the internals (pistons) and also leaves power in the cylinder.
If my 55 is running too rich, which I'll find out when I get my pre-dyno run next week prior to the VRP cams/heads...what should be done to get a correct A/F ratio? I know Chris @ C2 Design knows and will get it right for me, but I'd like to educate myself on what are the steps to get a proper A/F ratio? An ECU adjustment? My mind is a sponge...bring on the knowledge.
Jon
Super Member
Joined: Nov 2006
Posts: 952
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From: NJ/Greece
2006 CLS55 & 2002 SL55 (R129) Silver Arrow
80mm TB!
I've read all too many times that it does wonders for the AMG 55 motors. It leans it up to the right amount of Air/Fuel.
If you ask me, it should have come stock with the 80mm TB
I've read all too many times that it does wonders for the AMG 55 motors. It leans it up to the right amount of Air/Fuel.
If you ask me, it should have come stock with the 80mm TB
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MBWorld Fanatic!
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From: Tampa, Florida
06 SL65 / 97 993tt /11 Suburban/ 2012 GTR (AMG è la mia Famiglia la Bestia è la mia protezione)
I've got it already...just from reading up on other sites...it looks like I'd have to go back to Kleeman and get a "leaner" file for the ECU.
Out Of Control!!
Joined: Sep 2004
Posts: 13,394
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From: San Diego
2015 S212
Tis true. If your car is running rich, then a tune is what you can do since you've already done the 80mmTB.
These cars are really designed to run rich, out of protection for the motor. Add to that, the fact that it loves to dump fuel on any scenario that it doesn't like and you end up wasting a load of gas.
A TB is definitely in my future.
These cars are really designed to run rich, out of protection for the motor. Add to that, the fact that it loves to dump fuel on any scenario that it doesn't like and you end up wasting a load of gas.
A TB is definitely in my future.
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From: Caribbean/Florida/Colorado
E-ZGO 53hp., 1999 E 430 sport, 2004 E 55, 2008 Tahoe LTZ on 24"s
I see you painted your S/C red
I guess the up keep on all the polished parts under your hood got to be too much. It is like a love hate relationship love to have clean shiny engine compartment, hate to drive it and get it dirty. Drive and enjoy
AMGFan,
Basic, rich=good on S/C cars, I would not change the ecu tune until after your cams are changed out, they may lean out your mixture.
Detonation can ruin your day.
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From: Tampa, Florida
06 SL65 / 97 993tt /11 Suburban/ 2012 GTR (AMG è la mia Famiglia la Bestia è la mia protezione)
Hey Tech-Tune,
I see you painted your S/C red I guess the up keep on all the polished parts under your hood got to be too much. It is like a love hate relationship love to have clean shiny engine compartment, hate to drive it and get it dirty. Drive and enjoy
AMGFan,
Basic, rich=good on S/C cars, I would not change the ecu tune until after your cams are changed out, they may lean out your mixture.
Detonation can ruin your day.
I see you painted your S/C red
I guess the up keep on all the polished parts under your hood got to be too much. It is like a love hate relationship love to have clean shiny engine compartment, hate to drive it and get it dirty. Drive and enjoyAMGFan,
Basic, rich=good on S/C cars, I would not change the ecu tune until after your cams are changed out, they may lean out your mixture.
Detonation can ruin your day.
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Joined: Jul 2003
Posts: 2,123
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From: Chicago, IL
Real Cars
AMGFan,
I am not necessarily a fan of band-aid solutions for issues with cars - whether they be bad a/f ratios, cooling, or whatever. There is a cause and effect for any gremlin a car may have. In the case of a/f ratios - these cars run rich for a number of different reasons. Jangy pointed out that part of that reason is to protect the motor, which is true, but I'd like to also point out that running rich can also hard a motor - and it's not always a safe thing!
Unfortunately we don't have any AMG engineers on board that could elaborate more on their mentality behind the tuning, but my guess is that there's also an element of cooling that was inherently problematic with these engines that the rich a/f fuel also addresses. As you had said, lean mixtures tend to run hotter for a variety of reasons, and with our cars running rich already having heat issues, running lean can lead to problems if the cooling issue is not addressed.
That is not something you have addressed and by running a leaner mixture with what are I'm sure already high AITs (air intake temperatures). I think you need to be aware that there may be a bit of "carriage before the horse" going on here. There are areas of the 55k motors that I think need improvement before one goes down the route you are going down. No, I don't think you are going to blow your motor by leaning out the fuel mixture a bit without a cooling package, but what I am saying is that I personally would not take that route. I think it's more important to sort out your AIT before you start doing tuning mostly because you will be able to kill two birds with one stone if you do a tune after you do the cooling package - the first one being getting your A/F right the second being able to take advantage of a much needed mod that will have an affect on your AIT and ultimately your a/f ratios anyways. Also, if you are planning on further modifying your air intake tract (read: cams) - the extra "safety" a rich a/f ratio may prove beneficial because almost inevitably with a bigger cam that allows more air into a cylinder, you will obviously be altering your a/f ratio.
A/F ratio is something people can write books about - it can get very complex very quickly. I hope this answers your question somewhat but also makes you aware of some other factors you should be considering along with your tune!
-m
I am not necessarily a fan of band-aid solutions for issues with cars - whether they be bad a/f ratios, cooling, or whatever. There is a cause and effect for any gremlin a car may have. In the case of a/f ratios - these cars run rich for a number of different reasons. Jangy pointed out that part of that reason is to protect the motor, which is true, but I'd like to also point out that running rich can also hard a motor - and it's not always a safe thing!
Unfortunately we don't have any AMG engineers on board that could elaborate more on their mentality behind the tuning, but my guess is that there's also an element of cooling that was inherently problematic with these engines that the rich a/f fuel also addresses. As you had said, lean mixtures tend to run hotter for a variety of reasons, and with our cars running rich already having heat issues, running lean can lead to problems if the cooling issue is not addressed.
That is not something you have addressed and by running a leaner mixture with what are I'm sure already high AITs (air intake temperatures). I think you need to be aware that there may be a bit of "carriage before the horse" going on here. There are areas of the 55k motors that I think need improvement before one goes down the route you are going down. No, I don't think you are going to blow your motor by leaning out the fuel mixture a bit without a cooling package, but what I am saying is that I personally would not take that route. I think it's more important to sort out your AIT before you start doing tuning mostly because you will be able to kill two birds with one stone if you do a tune after you do the cooling package - the first one being getting your A/F right the second being able to take advantage of a much needed mod that will have an affect on your AIT and ultimately your a/f ratios anyways. Also, if you are planning on further modifying your air intake tract (read: cams) - the extra "safety" a rich a/f ratio may prove beneficial because almost inevitably with a bigger cam that allows more air into a cylinder, you will obviously be altering your a/f ratio.
A/F ratio is something people can write books about - it can get very complex very quickly. I hope this answers your question somewhat but also makes you aware of some other factors you should be considering along with your tune!
-m
Last edited by Marcus Frost; Jan 17, 2008 at 10:55 PM.
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MBWorld Fanatic!
Joined: Jul 2003
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From: Tampa, Florida
06 SL65 / 97 993tt /11 Suburban/ 2012 GTR (AMG è la mia Famiglia la Bestia è la mia protezione)
AMGFan,
I am not necessarily a fan of band-aid solutions for issues with cars - whether they be bad a/f ratios, cooling, or whatever. There is a cause and effect for any gremlin a car may have. In the case of a/f ratios - these cars run rich for a number of different reasons. Jangy pointed out that part of that reason is to protect the motor, which is true, but I'd like to also point out that running rich can also hard a motor - and it's not always a safe thing!
Unfortunately we don't have any AMG engineers on board that could elaborate more on their mentality behind the tuning, but my guess is that there's also an element of cooling that was inherently problematic with these engines that the rich a/f fuel also addresses. As you had said, lean mixtures tend to run hotter for a variety of reasons, and with our cars running rich already having heat issues, running lean can lead to problems if the cooling issue is not addressed.
That is not something you have addressed and by running a leaner mixture with what are I'm sure already high AITs (air intake temperatures). I think you need to be aware that there may be a bit of "carriage before the horse" going on here. There are areas of the 55k motors that I think need improvement before one goes down the route you are going down. No, I don't think you are going to blow your motor by leaning out the fuel mixture a bit without a cooling package, but what I am saying is that I personally would not take that route. I think it's more important to sort out your AIT before you start doing tuning mostly because you will be able to kill two birds with one stone if you do a tune after you do the cooling package - the first one being getting your A/F right the second being able to take advantage of a much needed mod that will have an affect on your AIT and ultimately your a/f ratios anyways. Also, if you are planning on further modifying your air intake tract (read: cams) - the extra "safety" a rich a/f ratio may prove beneficial because almost inevitably with a bigger cam that allows more air into a cylinder, you will obviously be altering your a/f ratio.
A/F ratio is something people can write books about - it can get very complex very quickly. I hope this answers your question somewhat but also makes you aware of some other factors you should be considering along with your tune!
-m
I am not necessarily a fan of band-aid solutions for issues with cars - whether they be bad a/f ratios, cooling, or whatever. There is a cause and effect for any gremlin a car may have. In the case of a/f ratios - these cars run rich for a number of different reasons. Jangy pointed out that part of that reason is to protect the motor, which is true, but I'd like to also point out that running rich can also hard a motor - and it's not always a safe thing!
Unfortunately we don't have any AMG engineers on board that could elaborate more on their mentality behind the tuning, but my guess is that there's also an element of cooling that was inherently problematic with these engines that the rich a/f fuel also addresses. As you had said, lean mixtures tend to run hotter for a variety of reasons, and with our cars running rich already having heat issues, running lean can lead to problems if the cooling issue is not addressed.
That is not something you have addressed and by running a leaner mixture with what are I'm sure already high AITs (air intake temperatures). I think you need to be aware that there may be a bit of "carriage before the horse" going on here. There are areas of the 55k motors that I think need improvement before one goes down the route you are going down. No, I don't think you are going to blow your motor by leaning out the fuel mixture a bit without a cooling package, but what I am saying is that I personally would not take that route. I think it's more important to sort out your AIT before you start doing tuning mostly because you will be able to kill two birds with one stone if you do a tune after you do the cooling package - the first one being getting your A/F right the second being able to take advantage of a much needed mod that will have an affect on your AIT and ultimately your a/f ratios anyways. Also, if you are planning on further modifying your air intake tract (read: cams) - the extra "safety" a rich a/f ratio may prove beneficial because almost inevitably with a bigger cam that allows more air into a cylinder, you will obviously be altering your a/f ratio.
A/F ratio is something people can write books about - it can get very complex very quickly. I hope this answers your question somewhat but also makes you aware of some other factors you should be considering along with your tune!
-m
This is a great learning experience with respect to not only modifications, but also the synergy of all the mods. No mod is an island...I think I have the right people working on it and the help on the board has been phenomenal.
I'm glad there are a bunch of guys going through the same thing which helps, because the shared information will really help in tapping as much potential in our 55 as we can.
Current Project: Baseline dyno/VRP cams/VRP modified heads/VRP I/C upgrade kit/-10C mod/Vorsteiner rear diffuser/ECU tune based on post-dyno
Next Project: EGS/TCU/Drivetrain Upgrade (pending on VRP development)
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but they change after I add another mod...our cars are so smart...
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From: PA
S600, GL450, GLC 43
Tell me if I have this right:
Running too rich a mixture will mean that all the fuel won't burn during detonation leaving power in the cylinder. Too lean and your engine runs hot, and can cause damage to the internals (pistons) and also leaves power in the cylinder.
If my 55 is running too rich, which I'll find out when I get my pre-dyno run next week prior to the VRP cams/heads...what should be done to get a correct A/F ratio? I know Chris @ C2 Design knows and will get it right for me, but I'd like to educate myself on what are the steps to get a proper A/F ratio? An ECU adjustment? My mind is a sponge...bring on the knowledge.
Jon
Running too rich a mixture will mean that all the fuel won't burn during detonation leaving power in the cylinder. Too lean and your engine runs hot, and can cause damage to the internals (pistons) and also leaves power in the cylinder.
If my 55 is running too rich, which I'll find out when I get my pre-dyno run next week prior to the VRP cams/heads...what should be done to get a correct A/F ratio? I know Chris @ C2 Design knows and will get it right for me, but I'd like to educate myself on what are the steps to get a proper A/F ratio? An ECU adjustment? My mind is a sponge...bring on the knowledge.
Jon
Having owned forced induction cars for almost two decades, I can tell you this with VERY good knowledge and expense, DON"T ever run a blown engine leaner than a 13/1 ratio. FI motors need a richer mixture for MANY reasons, and the addtional power you get from say a 13.5/1 AF ratio is only about 2% more power. What you don't get from this leaner mixture is 1. Cooling, 2. Detonation control espically with our lovely gas that is avaible todday.
FI motors really DO NOT loose HP from a fatter mixture. Now if you are down around 11/1 or even 10/1, you are loosing some power. B&M did some marvolous work back in the 80's/early 90's on air fuel ratios with blown engines and it was AMAZING that running richer, REALLY did not effect the power band that much, 2-4%. However they had EXTREMELY bad results, melted pistons, blown head gaskets, fried rings, etc, etc, when they tried to lean it out above 13.5/1.
Unless your mixture is down in the 11's or 10's you are really are not going to see much of a gain here.
On the down side, I have NO clue about MB electronics, but I am sure Victor, Jerry, ADAM, or some other GREAT people here will chime in to help.
Just remeber rich is safe, lean, above 13.5/1, is destructive to a motor.
See yeah
PS: I will scan in some documents from a few blower manufacturers over the weekend that back up this little paragraph. I think it will surprise MANY on this site.
