I have a stock 03 E55 with around 50k on it. I had it on the dyno (dyno dynamics) last weekend to get some base numbers before doing any mods to the car. The car was recently serviced by my local MB dealer and I wasn't told of any issues at the last inspection.

As far as dynoing goes, we put it in dyno mode and just did 3 pulls. They were all about the same, but my car only made 350whp/365tq. From what I have seen on here, I was hoping to be around 400whp and 470tq or possibly slight higher.

Does anyone have any ideas on where I should go to look for the missing power? The guys at the tuning shop thought it could be something related to boost, but I have no idea where to start and my MB dealer didn't see anything out of the ordinary at the last visit either.

Any help will be greatly appreciated.

Have you replaced the spark plugs lately? I know MB recommends them to be replaced around 50k...

It could also be bad gas possibly?

Just my initial thoughts...

I would only dyno on a Mustang or Dynojet dyno. Dyno Dynamics are known to be all over the board and also give readings 10-15% lower which would put you spot on.

IC Pump?

I don't think that is really the issue on this one. As far as 2wd cars go, I don't think there is a huge difference in numbers between a dynojet and dyno dynamics. For example, my Viper put down 432hp on the same dyno stock and that is about what others have been getting on different dynos.

Are you referring to an issue in the wirinig? I was told from someone that people have had issues with the wiring being reversed on these cars causing a loss in power. Haven't had much time to research yet though.

Thanks for your help so far.

The intercooler pump is known to fall on A LOT of 55k motors. People usually upgrade the Heat exchanger and take care of the intercooler pump also. Look into the Johnson CM30. I'm not saying that is your problem but it could be.

buy a scan tool that shows intake air temps and log it,you probably have a dead pump.If you drive it on the street and do a few pulls does the car shutter and shut off the supercharger?

dynos can read low also,especially dynodynamics if it was run in shoot out mode.best way to know is with a scan tool and a time slip from the track.

I will try to get a scan tool and test it this weekend. I guess I haven't really did any back to back pulls with the car since I only drive it on the street.

Any idea what normal intake temps would be?

Thanks,
James

Not true. There can be a huge difference in these dynos on any car. The difference can come from many variables but I have personally seen dyno numbers vary in the neighborhood of 50whp when comparing dynojets and dynamics. They are not the same and the differences are seen in awd, fwd, and rwd cars.

My viper was in line with what it should have put down on a dynojet on the same dyno with the same operator (including using the same mode). The performance shop is one of the better shops in the area and agree that the power wasn't lost from the dyno.

Don't get me wrong, I'm not saying that your numbers aren't low, just commenting on the fact that those dynos read differently.

I would definitley data log your IAT. I didn't know it but my pump was dead and after datalogging for just a little while I could see that but I had no idea before. I suspected that maybe it was but I couldn't be certain. I have it fixed now and it pulls a good bit harder.

I understand and appreciate all feedback . I have had experience with that particular dyno so I am pretty sure it isn't that.

The car seems to pull pretty good on the road so I wouldn't be suprised if it would be something to do with dyno mode or not having enough air coming through the fan.

I will try to look into it a bit though. I wasn't there when it was on the dyno, but I was told that it didn't sound quite right either.

Like some others have mentioned, I would look into the IAT's as well as plugs and filters as well if the problem persists.