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Don't you just love the top end on the highway now? The car feels so much more responsive and even partial throttle around town the car feels more composed. I know that's subjective but the tune does make a noticeable improvement. I'm keen to hear your comments.
Update from last nights track day... it was mixed results.
I did three runs.
The first one I did using race start and it was "meh", my 60 ft was 1.97 and my time was 11.4 @ 127.4mph.
The second and third runs were faster, but there was bad to go with the good...
At first glance this run looks okay, but notice the speed trace and the G load trace... they both fall off before the end of the run.
The cause? Apparently the car was experiencing "low fuel pressure" according to the CEL that accompanied the total loss of power as the car coasted over the quarter mile beams. The car did not go into limp mode, and the power cut was only temporary. Once I turned off teh track and drove back to the timing station the car drove fine.
What's odd is that the power cut happened at almost the same part of the track on two separate runs.
Here's the CEL log...
So, what's the good?
Well a bunch of things actually...
a. The car protected itself.
b. I was logging with HP Tuner on all the runs when the issues happened, and I've sent those files back to Jerry to decipher. We will figured out the issue and a way to resolve it.
c. I was there with friends and we did a roll race on a Mexican highway before getting to the track and I'm proud to say I hung with a tuned Huracan, with neither car giving an inch. That is a new one for me and I'm proud of that fact
d. I launched the car with traction control off and brake boosting and managed my best 60ft and 0-60 time at the track to date. That appears to be the best way to launch these cars.
Here's a side shot of the car at prestage...
and my friends... both these guys get out of the hole much better than me, so while we make comparable power, I'm not competitive in the quarter. Its hard to beat a 1.6 60 ft with a 1.8 60 ft. when making similar traps speeds. The street is a different matter though..
And yes, it seems we are partial to white and black..
I still managed an 11.2, with a 2046 DA in high 80's temps and stupid humidity, albeit coasting over the beams, and was still the fastest E63 of the night.
We plan on going back to the track next weekend.
Hopefully Jerry will have a new tune for me to try by then.
Having the myGenius allows us to swap tunes back and forth with relative ease.
I've driven the car all over Houston today in a spirited fashion and with the same fuel in the tank with zero issues.
I'm hoping its a quick fix. Fortunately we have the fuel trims and injector pressures logged to see where the issue is.
For those of you with draggy, I'm Brutus_Tx on the site and I posted all my videos there if you'd like to see them.
As mentioned I was able to log all the runs and send the data back to Jerry for review and analysis.
The run above looked PERFECT (until fuel cut) with the exception of two things.
The throttle closes a tiny bit in the lower rpm of 4th gear.
Fuel rail pressure drops 1000 PSI from 1st gear to top of 4th.
Jerry has provided me with a new tune that does the following in response to my logs...
The rail pressure was raised slightly and the low pressure pump turned up about 5%.
Fingers are crossed that this fixes it.
As an additional safety measure I've lowered the ethanol ration to ~1:1 (or E50) to help reduce the demand on the fueling system and to allow the car to run a little richer at WOT.
If the AFR looks rich enough at WOT with this new tune I'll bump it back up to E60 at that point.
Bear in mind, up until last Friday night, the car did, and still does, run fine. We just took it to the edge of safety on Friday night.
Those of you who have a version of this tune, I recommend dropping the ethanol to E50 for the time being as an added level of Safety.
Below is the ratio I am using for the time being...10 gallons E85 to 9 gallons 93 Octane
The plan is to rerun this Friday night with the new tune.
Great update and post Brutus! Really the most transparent collection of data on the M157 to date.. Dynos, 1/4 miles slips, and now Datalogs to go with it.
This platform is moving forward light years compared to the last few years. Datalogs to see how the car is reacting and whats its doing is amazing. And now to have the chance to log, save and send to tuners for questions, answers, adjustments is what it is all about, and of course sharing with the community.
Reaching the limit of the factory fuel system as setup oem is already great to see, esp logged as above.
The small throttle closures on most modern turbo engines is common, most ecu's use it to control boost and such. As long as its small and not consistent or for long duration of time.
In the 94+F ambient weather, those times and how the car is performing is pretty bad ***!
Great update and post Brutus! Really the most transparent collection of data on the M157 to date.. Dynos, 1/4 miles slips, and now Datalogs to go with it.
This platform is moving forward light years compared to the last few years. Datalogs to see how the car is reacting and whats its doing is amazing. And now to have the chance to log, save and send to tuners for questions, answers, adjustments is what it is all about, and of course sharing with the community.
Reaching the limit of the factory fuel system as setup oem is already great to see, esp logged as above.
The small throttle closures on most modern turbo engines is common, most ecu's use it to control boost and such. As long as its small and not consistent or for long duration of time.
In the 94+F ambient weather, those times and how the car is performing is pretty bad ***!
Now, lets take these W123's out and race! haha
Thank you for the kind words, however I have to give kuddos to Jerry at Eurocharged for being so committed to advancing this platform.
Without his involvement, the recent advances in this platform wouldn't have occurred otherwise.
I'm just the enthusiast who wants all his fellow enthusiasts to be exposed to the same knowledge pool I'm being exposed too.
Maybe I missed it but have you logged lpfp pressure?
Appears to cut throttle resulting in a short 1-2 shift. Assuming that is tcu torque management?
Great info
We are logging EVERYTHING... lol
It just isn't displayed on the screen shot above.
TCU torque management is painfully apparent when reviewing the logs.
Maximum boost in first gear is 7psi.
Second gear max boost is 13 psi.
Third gear is 15 psi, and 4th is 17/18psi and wide open throttle.
The ECU is requesting max boost across all gears, but the TCU isn't having any part in the party...
Image having 15 psi available in first gear what that hole shot would look like? Of course we'd all be looking for new transmissions, clutch packs and axles then.
I just wish we could manipulate the TCU such that we could closer approach the performance these cars can ultimately deliver.
Our cars would be 10 second cars with very little effort.
I'm so close now its maddening. If I could tweak my TCU and get a 1.7 60ft, I'd be in the 10's already.
I wish there was a thread specific to the Renntech TCU tune that was unbiased and transparent, but I can't seem to find anything.
Perhaps people who have/had the TCU tune would start a new thread and post their impressions/experiences? we can hope....
Last edited by brutus_tx; 10-09-2019 at 02:13 PM.
Reason: typo
It's possible there is not enough time in 1st and 2nd to reach max boost.
While I'm flat footing it at 100%, the car is only brake boosting to 7psi before moving off the line, and its flat through first and slowly increases as I move through the gears.
I'm confident the TCU is holding it back...
For the data nuts, see this graph of the run showing the data points starting with brake boosting, pressure build, brake release and roll out..
Data shown below consists of...
Engine RPM
Intake manifold pressure (subtract 14.6psi)
Throttle Position (% open)
Accelerator Position
Vehicle Speed
While the gas peddle is at 100%, note the commanded throttle position. Just because I want 100% throttle doesn't mean I'm getting it.
Additionally, the throttle position has a direct correlation on boost being made.
Hopefully you guys can make sense of the graph above and the information displayed is of benefit.
Last edited by brutus_tx; 10-09-2019 at 03:23 PM.
Reason: added graph
While I'm flat footing it at 100%, the car is only brake boosting to 7psi before moving off the line, and its flat through first and slowly increases as I move through the gears.
I'm confident the TCU is holding it back...
For the data nuts, see this graph of the run showing the data points starting with brake boosting, pressure build, brake release and roll out..
Data shown below consists of...
Engine RPM
Intake manifold pressure (subtract 14.6psi)
Throttle Position (% open)
Accelerator Position
Vehicle Speed
While the gas peddle is at 100%, note the commanded throttle position. Just because I want 100% throttle doesn't mean I'm getting it.
Additionally, the throttle position has a direct correlation on boost being made.
Hopefully you guys can make sense of the graph above and the information displayed is of benefit.
Me and Brutus have talked and looked over data for a few days offline here, and these conclusions are solid ones...
As mentioned, there is major throttle closure happening to control load or torque in first gear, that the tcu is requesting to cut. If lowering boost targets cant get the load request the car is looking for, it of course goes for the next best thing, throttle closure. Both happen in first and a bit in second.
No matter what boost anyone is gonna request in 1/2 gear from any tune on the market, our cars wont allow that tq load to be met.
Brutus brake boosting maxed out at about 7psi, and never got any higher in first gear once out of the hole.
I have datalogged numerous cars on the forum, and its all the same story really...
Renntech is the only company to offer a tcu tune, and how much of the tq limiters it removes is yet to be seen and or if they remove them all. Those launches would be bad *** but i would expect something to go. But a MCT with full M157 unchained from a dig has to be fun with 4matic
We are logging EVERYTHING... lol
It just isn't displayed on the screen shot above.
TCU torque management is painfully apparent when reviewing the logs.
Maximum boost in first gear is 7psi.
Second gear max boost is 13 psi.
Third gear is 15 psi, and 4th is 17/18psi and wide open throttle.
The ECU is requesting max boost across all gears, but the TCU isn't having any part in the party...
Image having 15 psi available in first gear what that hole shot would look like? Of course we'd all be looking for new transmissions, clutch packs and axles then.
I just wish we could manipulate the TCU such that we could closer approach the performance these cars can ultimately deliver.
Our cars would be 10 second cars with very little effort.
I'm so close now its maddening. If I could tweak my TCU and get a 1.7 60ft, I'd be in the 10's already.
I wish there was a thread specific to the Renntech TCU tune that was unbiased and transparent, but I can't seem to find anything.
Perhaps people who have/had the TCU tune would start a new thread and post their impressions/experiences? we can hope....
Agreed. TCU access would be great. HP tuners said they have no immediate plans but may in the future. I've offered to leave my car with them if they could do it but probably a ways out if at all.
Only other way around it is to skew things to make everything believe it's a lower torque output but it risks the trans if you are delivering a few hundred ft/lbs more than it thinks you are.
I do think there's a lot on the table as far as bringing in the power quicker (but still smoothly)..... so as to not destroy components.
I get blips in throttle position during gear shifts, but otherwise I don't think my car is pulling boost/throttle in the lower gears.
Under the log file tab, export the log in .csv format, then upload it on datazap.me very cool website to graph your log with all parameters, this way it can be shares more clearly.
I get blips in throttle position during gear shifts, but otherwise I don't think my car is pulling boost/throttle in the lower gears.
At some point in first gear from your data log image above, can you check the following?
Accelerator Position.. if you are flat footing it, I expect this will be 90-100%
Throttle Position... we saw a max of 50% in my logs in first gear
Intake Manifold absolute pressure... remember to deduct 14.7psi from reading... I saw ~ 22psi max in first.
I suspect your's will be very similar, at least in first gear where the TCU is overriding any boost requests from the ECU.
TCU torque management is painfully apparent when reviewing the logs.
Maximum boost in first gear is 7psi.
Second gear max boost is 13 psi.
Third gear is 15 psi, and 4th is 17/18psi and wide open throttle.
thank you for letting me know that my Torque app isnt broken and neither is my car. i could never get about 7 or 8 psi of boost to show on the app when i would hammer it from a dead stop. i never stayed in much into 2nd as i thought 1st gear should show me what i needed. now, thanks to you, i know why it was reading so low. i really really appreciate it!!!
At some point in first gear from your data log image above, can you check the following?
Accelerator Position.. if you are flat footing it, I expect this will be 90-100%
Throttle Position... we saw a max of 50% in my logs in first gear
Intake Manifold absolute pressure... remember to deduct 14.7psi from reading... I saw ~ 22psi max in first.
I suspect your's will be very similar, at least in first gear where the TCU is overriding any boost requests from the ECU.
In 1st gear, accel position is 100% even before the start of the run, probably the launch control
Throttle position sensor 85.9% until 49mph, then it blips down briefly.
MAP maxed 34 PSI at 28mph. dips down then back up to 36psi at 43 mph. Then it fluctuates from 32-37psi until 130mph. After 130mph, i.e.5th gear, MAP is rock steady at 37psi. TCU is tuned. See updated screenshot
In 1st gear, accel position is 100% even before the start of the run, probably the launch control
Throttle position sensor 85.9% until 49mph, then it blips down briefly.
MAP maxed 34 PSI at 28mph. dips down then back up to 36psi at 43 mph. Then it fluctuates from 32-37psi until 130mph. After 130mph, i.e.5th gear, MAP is rock steady at 37psi. TCU is tuned. See updated screenshot
In 1st gear, accel position is 100% even before the start of the run, probably the launch control
Throttle position sensor 85.9% until 49mph, then it blips down briefly.
MAP maxed 34 PSI at 28mph. dips down then back up to 36psi at 43 mph. Then it fluctuates from 32-37psi until 130mph. After 130mph, i.e.5th gear, MAP is rock steady at 37psi. TCU is tuned. See updated screenshot
Subtract 14.7psi (atmospheric pressure) from your boost readings to get actual readings.
Your TCU tune is obviously letting you access to the majority of the power out of the hole.
Can I ask where you got it? How is overall driveability?
Additionally, do you have any quarter mile slips and/or data logs you can share? I'd really like to see your 60ft and 330 ft times to compare to mine.
If I can shave 2/10ths off my launch I'd have a 10 second car now with only a tune...
I now am running a slightly modified tune.
As mentioned further up in the thread, it has been modified to account for the fuel rail pressure drop experienced at E60 WOT..
I am also now running E50 to reduce the demand on the injectors, but will slowly bring the ratio up after I get a couple of runs in.
On the drive in to work this morning I logged the drive and was able to get a couple of 3rd gear pulls in.
For the drive ,Traction Control was off, and I was in manual mode. Both were selected to eliminate any step down or traction interference.
While it wasn't a quarter mile run it did allow me to log fuel pressure etc.
The great news is that the fuel pressure went to ~2900 psi and stayed there through the brief run up in 3rd.
Hopefully the weather holds and I'll be able to get to the track again tonight to log some more runs..
All this sounds like the tuned M157 and M177 are equal. W212 is lighter than the W213 so W213 makes more power to match the W212 tune vs tune
The only difference is stock vs stock
Subtract 14.7psi (atmospheric pressure) from your boost readings to get actual readings.
Your TCU tune is obviously letting you access to the majority of the power out of the hole.
Can I ask where you got it? How is overall driveability?
Additionally, do you have any quarter mile slips and/or data logs you can share? I'd really like to see your 60ft and 330 ft times to compare to mine.
If I can shave 2/10ths off my launch I'd have a 10 second car now with only a tune...
Ecu and TCU tuned by GAD Motors. I recorded a few runs in order to monitor my IATs and to see what happens with increasing methanol injection. Also to check for slipping clutch. I have lots of 1/4 slips.
There was no change to 60' using launch control. 1.8x typical. 1.7s could be had using brake torque but I was afraid to brake torque it too hard. 330' 4.6-4.7s with Launch control. A lot more variable with brake torque. Car has a stroked motor and was running 3071 turbos, so not apples to apples comparison. Trap speeds 137-141mph, lot of pull up top. TCU frees up the power but it also makes it easier to slip clutch in 1st and 2nd, sometimes higher gears also, when transmission is hot. Brake torque heats things up a lot, so does waiting in line in staging lane.
Driveability is excellent, like stock.
We are at 2000+ feet elevation. Atmospheric pressure is often 13.5psi during summer.
10-04-2019, 09:06 PM
