Renntech Stage 4 Dyno - With A/F Reading
Thread Starter
MBWorld Fanatic!
Joined: Nov 2005
Posts: 1,463
Likes: 0
E55
Renntech Stage 4 Dyno - With A/F Reading
Round 2. Took the car back to the dyno shop this weekend in order to get the A/F ratio on the chart. Dynoed at 460.65rwhp. A little better than the 449rwhp. NO MODS WERE DONE TO THE CAR IN THE INTERIM. Suprisingly gained a little over 10hp.
In a few weeks, I will be getting green air filters and thermo wrapping my air intakes. Hopefully that will get me closer to 470rwhp. (we shall see).
Thanks to everyone who commented on my last dyno run. Last week my beast peaked out around 5.2K RPMS. It seems to be pulling all the way up to 5750 RPMS now before leveling out. In my opinion, I think I have a heat problem. Any thoughts?
Last week's dyno...
https://mbworld.org/forums/w211-amg/155468-renntech-stage-4-dyno.html
In a few weeks, I will be getting green air filters and thermo wrapping my air intakes. Hopefully that will get me closer to 470rwhp. (we shall see).
Thanks to everyone who commented on my last dyno run. Last week my beast peaked out around 5.2K RPMS. It seems to be pulling all the way up to 5750 RPMS now before leveling out. In my opinion, I think I have a heat problem. Any thoughts?
Last week's dyno...
https://mbworld.org/forums/w211-amg/155468-renntech-stage-4-dyno.html
Super Member
Joined: Aug 2005
Posts: 665
Likes: 0
On your previous dyno run, the HP curves flattened out after 5000 RPM. On the chart above, the curves start to flatten out at about 5300 RPM. However, the A/F chart is giving us a good clue as to what is going on. See how the A/F curves are divirging at 5300 RPM, as they head for the bottom of the chart? If this rich condition were due to programming, the curves wouldn't divirge - they would overlay each other. Heat probably wouldn't cause this much curve divirgence, either. This is due to different airflow conditions, which is probably due to different boost levels. I would say that we're seeing the effects of the bypass valve being utilized on your plots.
Prior to about 4500 RPM, your A/F ratio is a little lean. You may want to get a little fuel added to the fuel maps to bring the ratio closer to 12.5:1 in this range.
You may still have a heat issue. The peak torque for your mods should be higher - probably about 20-30 lb-ft higher. Can you data log during a run?
Please ask the dyno operator to plot RPM on the X-axis in future plots.
Prior to about 4500 RPM, your A/F ratio is a little lean. You may want to get a little fuel added to the fuel maps to bring the ratio closer to 12.5:1 in this range.
You may still have a heat issue. The peak torque for your mods should be higher - probably about 20-30 lb-ft higher. Can you data log during a run?
Please ask the dyno operator to plot RPM on the X-axis in future plots.
Thread Starter
MBWorld Fanatic!
Joined: Nov 2005
Posts: 1,463
Likes: 0
E55
Originally Posted by Grumpy666
Please ask the dyno operator to plot RPM on the X-axis in future plots.
MBWorld Fanatic!
Joined: Mar 2002
Posts: 1,662
Likes: 1
From: South Florida
STS,FGT,12C,P85D,M4
just have him email you the runfile (the data file) , and you can do all the graphing with the dynojet software that you can download from their site.... RPM's would help....
Trending Topics
Thread Starter
MBWorld Fanatic!
Joined: Nov 2005
Posts: 1,463
Likes: 0
E55
Originally Posted by Fikse
just have him email you the runfile (the data file) , and you can do all the graphing with the dynojet software that you can download from their site.... RPM's would help....
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
MBWorld Fanatic!
Joined: Jun 2006
Posts: 6,649
Likes: 207
'03 E55, Range Rover Sport Supercharged, Ducati 748R
Originally Posted by Grumpy666
On your previous dyno run, the HP curves flattened out after 5000 RPM. On the chart above, the curves start to flatten out at about 5300 RPM. However, the A/F chart is giving us a good clue as to what is going on. See how the A/F curves are divirging at 5300 RPM, as they head for the bottom of the chart? If this rich condition were due to programming, the curves wouldn't divirge - they would overlay each other. Heat probably wouldn't cause this much curve divirgence, either. This is due to different airflow conditions, which is probably due to different boost levels. I would say that we're seeing the effects of the bypass valve being utilized on your plots.
Prior to about 4500 RPM, your A/F ratio is a little lean. You may want to get a little fuel added to the fuel maps to bring the ratio closer to 12.5:1 in this range.
You may still have a heat issue. The peak torque for your mods should be higher - probably about 20-30 lb-ft higher. Can you data log during a run?
Please ask the dyno operator to plot RPM on the X-axis in future plots.
Prior to about 4500 RPM, your A/F ratio is a little lean. You may want to get a little fuel added to the fuel maps to bring the ratio closer to 12.5:1 in this range.
You may still have a heat issue. The peak torque for your mods should be higher - probably about 20-30 lb-ft higher. Can you data log during a run?
Please ask the dyno operator to plot RPM on the X-axis in future plots.
i'm seeing a trend here in your posts/thoughts and it makes a lot of sense. do you think part of the recalled ecu problem is a remapped control of the bypass valve? if so, shouldn't this be an easy fix for tuners (if they knew this was part of the problem)?
Thread Starter
MBWorld Fanatic!
Joined: Nov 2005
Posts: 1,463
Likes: 0
E55
Originally Posted by eclou
Your AFR is so lean under the torque peak that I would advise not running it at WOT until you get it improved. You will lose a head gasket running it that way, or worse.
MBWorld Fanatic!
Joined: Dec 2001
Posts: 3,436
Likes: 6
300ce
Originally Posted by MB_Steve
Could my A/F be off the chart because it is reading below 10?
...............Has your car undergone the secondary air injection pump recall? If so, then you have your answer. There is a load limit in the ECu's that have undergone the recall. At high boost, the ECU pulls timming and you run very rich to protect the engine. I have been saying this and probably sound like a nag by now.
Ted
Senior Member
Joined: Jun 2003
Posts: 280
Likes: 0
From: Houston, TX
Originally Posted by MB_Steve
Please explain....
supercharged motors are tuned to an AFR no leaner than 12.5:1 under wide open throttle to maintain a margin of safety of preventing detonation. Usually the most likely area on the rpm scale for that to occur would in the vicinity of the peak torque curve. That is usually when the motor will be experiencing the peak cylinder pressures during combustion. Your motor is so incredibly lean there - dangerously lean even for a non-supercharged motor - that I promise you that damage will occur if you keep pushing the motor hard. Such damage would include a blown headgasket, burned valves and pistons, to actually throwing a connecting rod and blowing a hole in the side of the block itself.
Turbo motors also are tuned with the same safety margins in mind, however tuners will purposely calibrate it to run leaner (in the 13.5:1 range) prior to peak torque in order to purposely increase exhaust gas temps and velocity for the sake of helping spool up the turbo.
Thread Starter
MBWorld Fanatic!
Joined: Nov 2005
Posts: 1,463
Likes: 0
E55
Originally Posted by eclou
Steve,
supercharged motors are tuned to an AFR no leaner than 12.5:1 under wide open throttle to maintain a margin of safety of preventing detonation. Usually the most likely area on the rpm scale for that to occur would in the vicinity of the peak torque curve. That is usually when the motor will be experiencing the peak cylinder pressures during combustion. Your motor is so incredibly lean there - dangerously lean even for a non-supercharged motor - that I promise you that damage will occur if you keep pushing the motor hard. Such damage would include a blown headgasket, burned valves and pistons, to actually throwing a connecting rod and blowing a hole in the side of the block itself.
Turbo motors also are tuned with the same safety margins in mind, however tuners will purposely calibrate it to run leaner (in the 13.5:1 range) prior to peak torque in order to purposely increase exhaust gas temps and velocity for the sake of helping spool up the turbo.
supercharged motors are tuned to an AFR no leaner than 12.5:1 under wide open throttle to maintain a margin of safety of preventing detonation. Usually the most likely area on the rpm scale for that to occur would in the vicinity of the peak torque curve. That is usually when the motor will be experiencing the peak cylinder pressures during combustion. Your motor is so incredibly lean there - dangerously lean even for a non-supercharged motor - that I promise you that damage will occur if you keep pushing the motor hard. Such damage would include a blown headgasket, burned valves and pistons, to actually throwing a connecting rod and blowing a hole in the side of the block itself.
Turbo motors also are tuned with the same safety margins in mind, however tuners will purposely calibrate it to run leaner (in the 13.5:1 range) prior to peak torque in order to purposely increase exhaust gas temps and velocity for the sake of helping spool up the turbo.
Senior Member
Joined: Jun 2003
Posts: 280
Likes: 0
From: Houston, TX
Originally Posted by MB_Steve
Pardon my ignorance, but are you saying that I should be running closer to 12.5 A/F in the low RPMS which I believe is now reading around 13.5 to 14?
Thread Starter
MBWorld Fanatic!
Joined: Nov 2005
Posts: 1,463
Likes: 0
E55
Originally Posted by eclou
The other possibility would be that the wideband is not accurate because of calibration or because it is not a pre-cat sample. Remember the catalytic converters will alter the exhaust gas sampling and not give you the "real" condition in the combustion chamber where it counts.
Super Member
Joined: Aug 2005
Posts: 665
Likes: 0
Originally Posted by eclou
Remember the catalytic converters will alter the exhaust gas sampling and not give you the "real" condition in the combustion chamber where it counts.
Senior Member
Joined: Jun 2003
Posts: 280
Likes: 0
From: Houston, TX
Yes, it should mean that the real AFR may be not as bad, depending on where they put the wideband oxygen sensor. If it is the tailpipe, it is not very useful. If measuring from the exhaust upstream from the cats (I don't know what your system has) then it is highly accurate. From experiences with multiple blown headgaskets and burned valves, I would seriously ease off the car until you know what is really going on with the AFR, and correct it as needed. These blocks are not exactly cheap or widely available.
