top end falls off (before and after) dyno tune. looking for suggestions...
 

hello everyone,

had my car re-tuned yesterday. 2012 cls63.

car was making peak power of 591 whp and 737 wtq before the retune (original file was kleemann)at a local event featuring Eurocharged.

after re-tuning and dyno Jerry was able to extract an additional ~60 whp and 80-90ish wtq. however the car stills feels and is losing acceleration up top. from 4800 - 6300 which is where you live in the 1/4 mile. it has resulted in lousy trap speeds.(118-121). basically stock trap speeds.

the drop off on the dyno confirms what i feel hen i run the car. unbelievably strong on kickdown at 90-110 km/h but then when it upshifts to 4th it drops right into the point in the rpm range where my power drops off - 4500-5000, and there's very little pull from then on.

looking for suggestions on what to check.

it was suggested to check the waste gate actuator.

or do i just need turbos?

car has catless downpipes and turbo pipes.
had NGK spark plugs and bmc air filters.

i attached a graph of couple of the runs from yesterday.

thanks!

Chad


http://img145.imagevenue.com/loc211/..._122_211lo.jpg

Log a 4th gear pull from about 2500-6000

Things to look at are Boost Pressure, Intake air temps, Timing, LT ST fuel trims, absolute TPS.

That should shed some light. From the looks of it your AFR looks good but that could a false reading depending on where they got them from. Could be getting hot and pulling timing, could have exhaust leaks, could be a leak in the vacuum lines controlling boost so its tapering off, could be misgapped spark plugs blowing through causing misfires up top, could be a bunch of things. Try and log those PIDS and report back then we can somewhat trouble shoot for you.

I don't think anything is wrong with the turbos as they are not damaged or anything.

I have the stage 2 EC file and car runs very strong all the way up to redline.

I would make sure the park plugs are gapped properly. Try a .021 gap

i should be able to get the the log data within a day. i will report back.

by needing turbos i didnt mean anything was wrong with mine. just that i might need a bigger turbo upgrade.

They do lose steam but not that bad. compare to most other dyno sheets of tuned cars, yours take a pretty substantial HP dive right before 5k rpms. Torque usually comes on early dies off about 5k but HP takes over and remains pretty flat till redline. Your HP Peaks before 5k then drops and levels out. That tells me something is up. Especially if you can see it in your trap speeds as that usually dictates a good estimated HP number of where you are at. My car with traps around 125-126 with gutted cats, No tune but does have a piggy back.

ya the car has about 31,000 miles on it.

mine also has kleemann turbo pipes.

Not at all. The stock turbos with tune and catless
dp are easily good for 125-130mph trap speeds. Larger turbos are needed if you want higher than 130mph traps.

Something is just not right with the setup and needs to
be sorted out.

here is what my EC dyno sheet looks like in comparison, and car is running strong on top end with this tune.

https://cimg9.ibsrv.net/gimg/www.mbw...6704b21214.jpg

in that graph the power falls off just like mine. ?

AAnd at the same rpm. You have the same problem as me? Lol

Ok so I'm beginning to think this drop off may be normal. Or at least common.. I just went on weistec's site and their tune and downpipes setup dyno looked the same .drops off about 100 HP from peak to the end of the pull.

What mods do you have? Just a tune?

And to your question yes I do want over 130 mph.

My goal is 135+ mph. I realize that will require at least turbo upgrades. And thats what I intend to do.

But as of now. With turbopipes and catless downpipes I'm stuck at 118 -121 mph.

it falls off but look at every dyno sheet for the m157. All m157s make huge mid range power and power falls off towards top end due to smaller turbo size.

At the the same time, most are still making strong enough top end to easily trap 125+.

The diffeence with yours is how much less power it's making vs mine and others at higher RPM.

Your drop off is more significant. Are you making 620whp by the time you get to 5k rpm? Are you at 590whp by 5.5k rpm?

the answer is your not close. Yes all m157 have huge midrange and then drop after midrange but not as much.

the mods are same as you, Eurocharged tune, catless dp, afe dry filters, and upgraded/regapped spark plugs to 0.21

not sure which brand of plugs but I'm sure they are good ordered through EC.

Something with the car needs to be sorted out and the tuner should be helping with this.

what are you talking about?


im right at 620 hp at 5000 rpm

at 5.5k rpm im at about 575 hp. according to the graph.

so yes you're a "whopping 15 hp" above me at 5500 rpm.

anyway. i did a couple of runs with a scangauge i borrowed from a friend.

the ambient temp was about 25 deg c. quite a warm day.

the intake temps rose to 62 deg. on the first pull.


then on a pull about a minute later they rose to 66 deg.

both runs were to about 210-240 km/h

i basically just floored it at 100km/h and the auto shifting took over. sport plus. traction control on.

before the pulls the intake temps were around 40 i believe.

im not to sure what this means but the intake temps definitely rose.

from what ive heard 30 deg above ambient is what they should be... ???

mine rose to about 41 deg above ambient.

unfortunately i didnt record the data. im still figuring out how to use the scan tool. so just reporting what i saw on the digital readout as i did the runs.

tomorrow i will buy a scangauge and i believe thees a performance data feature that allows you to record and export data.

from this initial testing im thinking cooling might be the issue. my car is a 2012 with the stock cooling system, correct me if im wrong, but i believe for the 2013 model year the intercooler was upgraded on these cars.

I believe the intercooler was the same. Only difference was split cooling. There is an extra coolant reservoir next to the ecu for 2013 and up.

You are making good power on the dyno, which is a good start. You've been given some good direction here; definitely log your data. Go back to post #2 and log those items. IATs do look a bit high after your pulls, and logging boost/iats/timing/etc, it'll paint a picture.

you mention mis gapped spark plugs

that reminds me. i am using non oem spark plugs that were gapped after i bought them. to .6 mm.


ngk 1555. SIZKBR8A8HS are the plugs

should i be using a different plug from oem? or are oem ok?

OEM would be fine but the gap doesn't sound right. EC has mine regaped after he tune to .021-22 right around there.

This could definitely be part of the problem.

Also the dyno pic you posted above for some reason is very blurry when trying to view it so it's not possible for us to see the exact power your making at specific rpms.

.021 what? Inches?

.022 inches is .56 mm. Mine were .6 mm. so pretty close To yours no?

yes sorry that's correct. So that's probably not the issue then.

The correct plug is oem is bosch ZR6SII3320 (0041598103)

Gapped at .021-.024

My car is untuned and I have them gapped down. It made a big difference up top. With my pigggy back racechip unit turned up it will make 19-20 lbs boost till 6k without falling off. Also what fuel are you filling up with brand wise? Fuel these days is loaded up with crap Ethanol which in that form is hurting octane. I've had the best luck with Shell V-Power 93. If I get gas at QT or others I can look at my Fuel Trims and see the difference.

The Stock plugs have been updated from the past plugs. They are a cooler plug than the old OEM so work perfect for tuned or untuned. Also make sure the plugs are torqued to spec so they have the proper indexing which also makes a decent difference when the tolerances are as close as they are.

I finally got around to looking this up on the Mercedes EPC as a response to a question on another thread. Mercedes split the intercooler coolant from the rest of the engine cooling system after a build date of 12/14/11. Engine numbers at or above 60008336 are split. Our 4/12 build definitely has the extra small coolant reservoir in front of the engine ECU. To check, just remove the engine top center cover. Either you have it or you don't. As stated else where, the older builds can be updated to split the system. Splitting the intercooler system should result in lower intake air temps, more power potential plus less likely to detonate.

http://img270.imagevenue.com/loc13/t...d_122_13lo.jpg


this is a crop from the same pic i posted.

you cant read those numbers? (you have to click on it)

i must have super vision, cause i can read them all.

hmm, i assumed all the 2012 models wouldn't have had it.

to upgrade to the split system, who offers this?

is this one of the cooling mods ams offers? i went to their site and they have several cooling mod offerings for this engine.

ok, so the tool i have doesnt have the ability to export data. you're limited to viewing it on the device itself.

and the logging feature is very archaic. you basically can only select one parameter at a time to save, and to view you have to scroll through the captured values which only refresh every second or so. so you could miss quiet a lot of data.

so i just filmed the screen of the tool with my phone.

if anyone knows of a better data logging tool for this purpose let me know. as long as its not 7-800 bucks.





4th gear pull

You have no timing advance up top, which is hurting you. I had similar mods and tune, and would see several degrees of timing (6-10) up top...you have zero or negative. Cooling doesn't look too bad, but of course could always be better. As mentioned before, check plugs and gap. Also, ensure you are running good gas.

That, my friend, is about as far I can help out. Still learning myself...