So I am “mildly modding” my S-class as it’s just about my favorite daily use car ever. I spend enough time in it that I wanted to upgrade a few things. The car is stunning to look at so all I did in the athstetics department was add a carbon front splitter. Next will be tuning.



1st off I can’t stand the speed limiter so I am defeating that – it’s stuck at 130. I should see 170+ once I program that out. Secondly the stock power is G R E A T but I luv more so… I am performing a RENNtech performance chip flash to go with the speed limiter delete.

I did a few performance runs "before" the mods. I used a G-tech performance timer that I have used for many years. I have compared the G-tech against actual drag strip times while at the drag strip & find it to be very accurate. It can be considered a fine tool for measuring details for both power & speed in this test. You can see device details at gtechpro.com.

Here are my average base-line G-tech runs today:




13.71 @ 106.7 mph in the standing 1/4 mile - 0-60 was 5.2 @ a 2000 RPM launch against the brake with traction control off & a ½ tank of gas. 40 degrees ambient.

I am looking to get into the 4’s 0-60. I will be completing the mods before Christmas.

Watch this space!

 

As stated I had the ECU reprogrammed with RENNtech software and went to get additional numbers. I drove the car conservatively up to the same test site and started to gather data. Immediately I found that again with the traction control off wheel spin was hard to control. I struggled with launches getting repeatable 5.2 zero to sixty most every attempt. Then once I could control myself and control my application of the throttle I produced a series of excellent runs with a zero-sixty of 5.02 seconds and a standing 1/4 mile in 13.45 @ 110.1 MPH best.



The car not only recorded better numbers but it's midrange punch around town when passing a slow truck or just moving into traffic feels much more aggressive. It actually surprises me.

I am pleased with the results. Next when I get a chance I will check the speed limiter.

 

 

You'll get to jail if you continue to drive like this.....

 

U go Man

 

You got it. Been driving "like this" since 1982 and can't seem to get it out of my system. Maybe someday.

 

Are you running your car at these speeds at the track? I ran my 750Li like that when I was stationed in Germany.

 

Very impressive (for 550)
Keep us posted

 

I thought so too. Thanks will do.

I do own several track cars but this land yacht isn't one of them - and it has no place on the race courses I frequent. However I am fortunate enough to have a very long driveway.

Its quite pleasing to be unrestricted in this car. The 130 MPH limiter was eating away at my psyche.

 

Cost for the upgrade?

 

RENNtech ECU programming = $1795 retail - plus shipping of unit.

 

Thanks for posting this detailed/concise data - I think I'm going w/ the ECU tuning now after seeing your numbers. Keep us posted. Are you going to do anything with exhaust system and the main pulley? I think you might see a good results if someone can make you custom headers (properly sized primary tubes into good collectors) and a better flowing muffler system. Not sure if X-pipes really do anything noticable. Also, I know folks can also put a large throttle body or bore yours maybe, you might see a big gain there - but you would have to change your ECU program to compensate for more air.

How's the air intake system looking now? Stock air filters or something less restrictive?

 

I have an appointment at my local custom muffler shop for a upgrade. We have looked at the system and mapped what others have done for sound, but we are not sure if there is any gain to be had for performance. However there must be a weight savings as the factory stuff is h e a v y. We are going to try the rear mufflers first (at the bumper) as the center resonators look pretty unrestricted. But the gains may be negligible.

Currently the intake system is perfectly stock. Benz had a TSB #2007010004MAR07 posted about a better intake (for driveabilty) but Mercedes has told me that I have the good one.

 

I'm told that the stock exhaust manifolds are the point where most improvement can be had. You're shooting for the venturi effect with properly sized primaries into correctly sized collectors - to help escape the exhaust gases and avoid problems like reversion of exhaust pulses. Google "Exhaust scavenging" and "volumetric efficiency of an engine"... We usually think of our motors as horse power producers at the crank, but if you think about the motor as an efficient air pump - then getting air in and escaping exhaust gases out become very important.

With my CL55, the cheap gains were removing restrictive plastic plates where the intake was, I guess those are for countries that have a lot of sand/dust in the air and letting air enter directly without hitting the hot radiator first - I have to look my S and see if something similar is there. Also, K&N air filters are much less restrictive than stock - cheap win there too.

 

Some headers as Serge stated would be the thing..great power to pickup especially with the midrange and top end. That should definitely help the OP get into his goals. Badass S550!

 

Maybe you can look into a Carbon Fiber Renntech airbox? I've got one on my W140 S and while performance may be negligible (what's 10hp really?), the exhaust note is deeper when the accelerator is pressed.

 

I will continue the research for sure. The factory airbox looked pretty good. Taking air from behind the grill and into a twin straight path to the filters. I was not sure how far I wanted to go with that bit but on my domestic tow rig (Hemi) I fabricated a ram-air kit from the bumper that helps above 50MPH. This car may benefit from that but I am not sure if I am willing to mock up something for a sedan (Badass or not ).

I added a Eaton style supercharger to one of my current cars not too long ago and found another that would fit up to this car. I am pretty pleased with the current gains but if I were to go as far as new exhaust manifolds (that is pretty extensive work) I would probably just bolt on the blower.

At say the current 400HP the car is wonderful, but you know how it is... Who doesn't want more? And to date its been relatively inexpensive mods to get it there to boot. If its gets pricey I will be expecting a serious punch toward 450 or more HP.

 

I think superchargers are a very risky way to go on our MB cars, unless they are factory units. Many horror stories with aftermarket supercharges, I almost went this way with my CL55. Eventually decided against it.

I agree that the stock airbox looks pretty nice and inlets to it as well (checked it out today), better than my Cl55 was. Though the stock air filters are more restrictive than the K&N ones - you may want to order a set, only about $100 for them and you can wash them out/re-use them. I think with headers, less restrictive mufflers, better air cleaners, main pulley changed to a lighted pulley, and your Renntech ECU programming you can see around 410-420 horses. About 390 to 400 without the headers with everything else above. The programming as you saw doesn't do dramatic horse power gains on a naturally aspirated car. To see 450+, the throttle body/intake would need lots of work or/and supercharger. Supercharger can get you to 500+ with enough boost, but very risky I think.

I'm going to be following your thread very closely, you're definitely doing cool stuff that most aren't and measuring precisely as you go along.

 

Thanks man. Yeah, by looking at your chop and your white S I think you & I are on the same page.

I will keep the fire burning and continue playing.