Hazy1

Just got back from the dyno. Temp was 86 and humidity was a lovely 67%. Tried 3 pulls, with the 1st two basically back to back and about a 20-30 minute wait for the last pull. I have the graph saved as a jpeg if someone can tell me how to post it. All #'s SAE corrected.

1st pull - 387.92 HP / 424.57 Tq
2nd Pull - 369.61 HP / 433.08 Tq
3rd Pull - 381.06 HP / 448.30 Tq

The car was in dyno mode with manual shifting to 4th gear.

The #'s were about what I expected with the way the car feels lately. The car is stock and has been reflashed.

One theory that I have about the reflash conspiracy is that when the E55 cars were getting dyno #'s of 415-425, the cars were making similar crank power as the 493 HP SL/CL/S. By changing the computer settings and getting current dyno #'s in the 380-390 range, they simply put the cars back down to the 469 HP range that they had originally advertised them as having. They basically screwed us out of power, but if it is still within a legally acceptable range from an advertising vs. actual output standpoint, is there anything that we can really do about it other than get an aftermarket tune.

AMGfan

Hazy1,

I just called my tuner guy in Tampa because they did the pre-install dyno yesterday. I just got a verbal that the hp was at 387 rwhp, too. I have no details and he plans to email me the dyno sheet and other variables to look at...I'll try to post them after he gets them to me.

Normally, he stated that past E55's he has worked on have been around 400-405 rwhp...just wanted to let you know that you weren't the only one with the same questions.

Jon

higginsbeach

Just curious, did the car down shift when you did the stomp in 4th gear.

Hazy1

The guy behind the wheel brought the car slowly up to speed in gears 1-3 in manual mode. When he got to 4th, he dropped the hammer, the car stayed in 4th and he stopped when it hit the speed limiter.

And here's the graph:

MB_Forever

One of my friends' 2004 E55 used to dyno @ 418 whp (on average) until after the re-flash, his car started dynoing an average of 390 whp. But then again, he suspected IC pump issues and never dynoed after replacement of IC pump.

It is so hard to figure out whether this controversial flash really does decrease the car's performance or not? And if it does, was it designed intentionally to do that by Mercedes or was this nasty side effect just a coincidence I've read so many threads and so many pages upon pages of information without being able to come to a conclusion. And to make matters worse, there seems to be data that supports both sides of the argument

The 387 whp figure seems low. I would replace the IC pump and re-dyno the car before any mods. IC pump problems are very tricky: sometimes the pump doesn't just fail, sometimes it will continue degrading performance from time to time without any error codes or concrete symptoms. So I would just replace it anyways and re-dyno.

V12Godspeed

My car dynoed 410 RWHP, just a comparison, so something is definitely wrong. Obvious is the flash.

Hazy1

Thanks for the input. I've had the IC pump replaced, but it obviously could be in need of another. I am going to switch to the CM30 pump when I whittle the honey-do list down a little further (its currently about 546 single-spaced legal pages with a #2 font).

As far as the reflash, I have no idea if anything was changed on purpose, or if it was simply an unintended consequence of something else, but I can tell a definite difference in performace since it was done.

tigerlam92

Looking at the dyno graph, your A/F ratio is quite lean. From looking at many E55 dyno as well as other cars, the E55 is programmed tremendously richer than most cars. Your car to me is much leaner than most E55 I have seen and is somewhat dangerously lean. I would look into this first.

This could also happen, if he didn't quite floored the car. Could this be the case? Also did he ease into WOT or just slammed it down.

Vadim @ FD

Hazy1:

Check your air filters. If they are new, put in K&Ns or BMCs.

Hazy1

Vadim,

They are K&N with 25,000 mi +/-. I took them out and used my compressor to blow them clean 3-5,000 miles ago. I know that they need re-oiled at some point, but not sure if I'm maintaining them properly.

What are you seeing and what else do I need to do?

Thanks

BlownV8

I didn't do much better on that dyno when my CL600 when it was stock. I only got 398 RWHP before the Renntech mods.

Fikse

it looks like only the first run was pushed to redline..... the other runs he let off early..... on the full run, you can see where the HP curve drops at 5400 RPM, looks like the car was adjusting the timing and dropping power..... it could be the pump or just really bad heat soak..... I would hook up a monitor to look a the IAT's during the run and see what your getting as the RPM's increase.....

Vadim @ FD

Hazy: Call me tomorrow, let me see if can solve this mystery.

Hazy1

Hey Jim,

I asked them about your car and they had a file that said 414 or 424 RWHP before Renntech (I can't remember which), and about another 100 after. Maybe that was corrected??

Either way, thanks for the recommendation on the place.



Fiske,

When I scheduled the dyno run, I told them that I was most interested in tracking the IAT's and A/F ratio in addition to the HP & Tq and they told me no problem. When the car was all hooked up and ready to go, they informed me that they didn't have the equipment to datalog the IAT's on a Mercedes, just Ford & GM.

Jrocket

Was run #1 done in 3rd gear and the rest done in 4th?

The baro,heat and humidity didnt help you at all.You need to check IAT's and timing to see whats going on in there.

My car did 416 ona nice cool day with somewhat ideal weather conditions,usually it does 403-406 on noraml weather days.It drops off dramatically if not cooled down between runs though.The day I did 416,I ran 2 more back to back runs and ir dropped to 387ish or so.Pump was weak and the IATS were border line shut off,the car was pulling timing so badly you could physically hear the hp tone difference in the motor when making the 2nd and 3rd pull.You could almost pin point when the motor started to lay down on run 2 and it didnt even start to make decent power on run 3.You can tell to the ear,when the car is making a good clean pull and the best power.

BlownV8

I don't know if that was corrected or not but I'd imagine it was since it adjusts for altitude, temps, and humidity. The print-out of the before and after they gave me was 398 RWHP stock and almost 525 RWHP after the Renntech mods. Either way, the Renntech mods were worth the cost.

The shop owner, Brad, said my car accelerated the dyno faster than any street car he ran previously after the Renntech mods. I guess that's because the massive torque the engine makes way down low and the super flat hp curve. They were very impressed with the hp increase from the Renntech ECU/TCU.

The shop owner, Brad, is the brother of the guy with the 675 RWHP twin-turbo Cobra. Did he show you his supercharged Mustang LX. That thing making some serious power too but the LX is more of a street legal drag car while his brothers Cobra is a real street sleeper.

Happy2th

After the ECU flash my E55 went from 405 RWHP to 335 RWHP, then 10 minutes later it dynoed 355 RWHP. I'm ECSTATIC about it.

BlownV8

I would raise holy hell about the loss in power. That's a huge decrease!