I recently purchased and SL600 and will be adding the Renntech upgrade next week. I decided to baseline the car prior to the upgrade. Using Dent auto in Norwood Mass the stock car produced 455hp and 480 ftlb of torque. This is more than expected at the rear wheels for this car, as a rule of thumb I use a 10% hp loss through the drive train when using manual transmission, I think that automatics have a greater loss (anyone got an estimate) you have to wonder why Mercedes are publishing a conservative number of 500hp at the flywheel. If you decide to check this for yourself make sure you know how to put the car into dyno mode. My car has the AMG package so I can shift with the paddles. The dyno was a dyno dynamics and we did the pulls in 4th gear. Even though I have paddle shifters this car is kind of fool proof so even through you can shift yourself if you go outside the safe operationing range the car will make its own decisions. This makes the dyno pull difficult because it will want to downshift during the pull. I will post my post Renntech results when available

 

What year is your SL?

What RennTech upgrades are you having done?

 

My car is an SL600 with the AMG sports package. I just got the ECU, TCU airbox and intercooler upgrade. I took the car to the DYNO before and after the upgrade. The resultant performance was not close to what I expected, I am in the process of working with Renntech on understanding why. The input air temp is to high which means that the intercooling is not working correctly. The intercooler is a water cooled system that has a radiator an electric pump and the intercoolers. The pump upgrade is supposed to increase the water flow and therefore improve the cooling of the incoming air. The system is a closed system with its own coolant. The system has been filled a bled twice but the input air is still to high. The car is back at the Mercedes dealer I am now suspecting that the the pump was wired backwards. Renntech and Mercedes dealer are working the issue. I will keep you posted

 

Sorry I forgot to say it is a 2008