13.7 PSI Max boost is this normal
 

I purchased a 2005 e55 a few months back and just did some logging and saw that the car was making about 13.7psi of peak boost. I'm trying to figure out if the car was previously tuned or had a pulley installed and wanted to get some feedback to what you guys think the previous owner did to the car. I didn't want to buy something I didn't need like a new pulley if it already has one.

Thanks!

That's not stock boost

It has a pulley with that boost. The sc pulley is fairly easy to recognize. Google it for pics. The crank pulley you will have to measure in Mm's

https://cimg7.ibsrv.net/gimg/www.mbw...a5eb3c73e5.jpg

im assuming this is the OEM pulley that's on my car now

Yes it is. You probably have an aftermarket crank pulley

Stock SC pulley.

If you can read your belt number you maybe able to tell if you have a after market crank pulley.

Also the ribs will be different size

As Jerry explained to me, peak boost will not be seen until the top of 5th gear which I doubt anyone has done on the street. As I see it, for a given blower rpm, boost correlates to the back pressure the intake charge sees. The higher the load the slower the rpm build rate and thus higher back pressure resulting in higher boost. In the lower gears the rpm builds rapidly, back pressure is much less. My own SL55 with 77mm pulley, in 3rd gear runs to redline, only sees 12.7psi. I am confident it get to 15psi in 5th. Please correct if necessary people.

That's incorrect

please correct me...

Top of 3rd gear on the road is where you will see the true boost. Can't be 5th gear as that is essentially an overdrive gear

So why does my car only show 12.7psi max during this run with a 77mm pulley and all the other stage 3 bits? This is a 3rd gear pull. Cheers.

your boost looks about right. headers and tb? i only see 12.1 @1500 elevation

The log shows my boost drops off at higher rpm in 3rd gear which conflicts with what Hulk said that it happens at the top of 3rd gear. Eurocharged claim 15psi for the stage 3 kit with TB and headers and only an 83mm pulley and I have a 77mm pulley which Jerry tuned for. I asked Jerry all of this but still remain in the dark now. I have a V-box performance logger and from that I am very happy with how my car is performing. So what is the truth about boost levels in these cars?

Boost always drops off right before a shift. EC does not claim 15 psi with an 83mm pulley. The truth about boost levels is nobody actually sees the boost that is on the charts. In the real world it's always lower. What is your elevation?

based on Dawesville, Au.....he's basically at sea level.

Ok cool so that would explain why he has about .5 more boost than me.

kind of curious about your ignition timing.....anyone have insight on the 5630 rpm and 6379 rpm spots from his data log?



https://cimg2.ibsrv.net/gimg/www.mbw...a4f6be1637.png

As said boost is at top of 3rd period. Tb will close just before the shift to ease into the next gear.

He's also logging 6 parameters through the obd which is a very slow refresh rate.

I will reduce the parameters and check again. The timing issue is a concern. I will check my other logs to see if repeats.

The exact wording from Eurocharged on my package which first came with an 83mm pulley showing 15psi:

Eurocharged Performance Stage 3 Power Package

Make:
Mercedes Benz
Model:
55 Series AMG 5.5 V8
Series:
W211
Years:
2003-2006


Flash Type:
OBDII
Mygenius Compatible:
Yes
Dealer Flashable:
Yes



Stock Eurocharged
Peak Power (bhp) 469 642
Peak Torque (lb-ft) 516 696
Speed Limiter* (mph) 155 200
Rev Limiter* (rpm) 6300 6700
Boost (psi) 11.2 15.0



Package Includes

Eurocharged 55 Series Performance Engine Software

Eurocharged 55 Series Performance Transmission Software
Eurocharged Supercharger Pulley with a Eurocharged 180mm Crank Pulley Kit option to buy
Eurocharged Shorty Headers
82mm Throttle Body Kit
Injectors
55 Series Heat Exchanger
Johnson CM30 I/C Pump

That description is for the optional 180 mm crank pulley that adds 400 dollars to that package. I think they should make it more clear but I asked the questions when I was ordering things and that's what it means.

Eurocharged Supercharger Pulley with a Eurocharged 180mm Crank Pulley Kit option to buy

We were thinking the same lol