These guys supposedly did a top speed test, and got to something like 175 MPH, I wonder because when they take off it doesn't seem like they are stepping on the gas pedal very hard, and secondly, Mario Andretti drove a 2003 SL55 AMG for a Motor Trend episode .... at 208 MPH. Something is wonky here.
I know that factory setting for the USA came with a speed limiter programmed into the ECU at 156MPH, but adding a different supercharger pulley and a ECU tune to go with that, removes that limiter. My former R230, a 2004 SL600 had a Renntech tune and the guy I sold that car to, lives in Montana where they have some highways where you can go super fast. He's used his phone with a GPS to track his speed and although the car's speedometer only goes to 160 (LOL) he's had the car up to 178 MPH and says the car still had a LOT of gas pedal left. He brings the car here every summer for a BBQ and pool fest. I haven't seen how fast my SL55 will go, but with an aftermarket supercharger pulley and an ECU tune to go with, I'm sure the 156MPH limiter is gone, and I bet the car will easily exceed 200 MPH.
The episode of Motor Trend where they bring the SL to Mario Andretti was on Youtube, but they had to block it due to Motor Trend copyright. If you use a TOR browser, which makes it appear that you aren't in the USA, you can view that video. Mario absolutely LOVES that SL55!!!!
These cars are so fast already that you don't have to do much at all to make them really stratospheric.
Motor Trend is big media. IMHO everything they do is to promote their brand, integrity be damned. I fully expect that they heavily modified this car even though they called it stock. I also suspect that Mario Andretti wouldn't drive an untested car.
Physics suggest that a stock SL55 cannot hit 200 MPH.
An average car needs about 300 HP to reach 150 MPH.
The HP need to reach a higher speed is the THIRD power of the speed difference. So (200/150)**3 is 2.37. Yes, more that double the power (HP) needed to reach 200 MPH than 150MPH.
300HP * 2.37 = 711HP.
A very aerodynamic car might need less, but generally the cars tested reaching 200 MPH all have 700+ HP.
I've had my '03 since new. I delimited the car shortly after I took delivery and on an un-named road in an un-named state quite a few years ago....... My SL55 did 202mph. It pinned the 200mph speedo and went a little bit more, before I ran out of road!
It was such a non event and so stable that I reached down and hit the seat massager....... just to say I did!
Taken shortly after said run on one of straightest, most desolate roads in the country...
I've had my '03 since new. I delimited the car shortly after I took delivery and on an un-named road in an un-named state quite a few years ago....... My SL55 did 202mph. It pinned the 200mph speedo and went a little bit more, before I ran out of road!
It was such a non event and so stable that I reached down and hit the seat massager....... just to say I did!
Taken shortly after said run on one of straightest, most desolate roads in the country...
With newer tires, I took my 2007 up to 175 mph. That’s faster than my airplane at cruise. The car felt pretty solid, but things were moving fast and I got nervous. The car is stock as far as I know. There was more left in the car.
Sounds like the R230 is more aerodynamic than an average car and therefore only needs 250HP (or less) at 150 MPH. Multiply by 2.37 and you get 592 HP.. With a 10-20 MPH tailwind, true 200 MPH might be possible.
I've been reading car magazines since the early 1970s. Companies like Ferrari or Lamborghini always claimed their next car would top 200 MPH, but for decades it didn't happen.
The Ferrari F40 is generally considered the first production car to reach 200 MPH in 1987, although Car and Driver "only" reached 197. Interestingly this car was only rated at 471 HP, but since it was only 44" tall and weighed 3018 lbs versus the SL55 51" tall and weighing 4319 lbs, the F40 was much more aerodynamic and had much lower rolling resistance.
From an AI Overview:
A typical, production-based car generally requires around 250 to 350+ horsepower to achieve a top speed of 150 mph, depending heavily on aerodynamics and gearing. While some lightweight or exceptionally aerodynamic cars can hit 150 mph with less (e.g., ~200 hp), most standard vehicles need higher output to overcome air resistance.
Fun stuff although I doubt I'll ever have a (reasonably) safe opportunity to try a top speed run.
I hope to get back into some 1/4 mile drag racing at the local track this year and get some times in my SL600/SL65. Goal is 11.5.
In the world of automotive engineering, aerodynamics plays a critical role in efficiency, stability and performance. Today, wind tunnel testing is standard practice across the industry, but decades ago it was still a developing science. Mercedes-Benz built one of the most advanced wind tunnels of its time and fundamentally changed the way cars were designed.
The Mercedes-Benz wind tunnel in Stuttgart-Untertürkheim became operational in the late 1960s. At the time, it was considered a major technological investment and was used primarily for internal research rather than public demonstration. Engineers used the facility to study how air moved around vehicles at different speeds, allowing them to refine body shapes with unprecedented precision.
Before wind tunnels came along, car design often relied heavily on styling intuition and basic road testing. While these methods produced attractive vehicles, they didn't always result in optimal aerodynamic efficiency. The Stuttgart wind tunnel allowed Mercedes engineers to develop scientifically optimised shapes that reduced drag and improved stability at high speeds.
One of the key outcomes of this research was the gradual reduction of drag coefficients across Mercedes model ranges. Engineers refined rooflines, smoothed body panels and integrated bumpers more seamlessly into the body structure. Small details such as mirror positioning, underbody airflow and window angles were also carefully studied and improved.
These developments had a significant impact on fuel efficiency and driving comfort. Lower aerodynamic drag meant that vehicles required less energy to maintain motorway speeds, reducing fuel consumption while also lowering wind noise inside the cabin. At the same time, improved airflow management enhanced high-speed stability, particularly important on Germany’s Autobahn.
By the 1980s, Mercedes-Benz had established itself as a leader in aerodynamic design. Many of the principles developed in that early wind tunnel research influenced the design of models throughout the decade and beyond. The knowledge gained there helped shape the sleek yet functional styling that still characterises Mercedes vehicles today.
The legacy of this aerodynamic research continues to benefit classic Mercedes owners. Vehicles developed with careful wind tunnel testing often deliver a refined driving experience even decades later. .
The Stuttgart wind tunnel was a turning point in automotive design history. By combining engineering discipline with careful aerodynamic research, Mercedes-Benz helped redefine how modern cars are shaped – proving that even invisible forces like airflow can transform the driving experience.
I love all the magazine (and now AI) racers. I've run my Indycar at over 200 and the way the scenery was going by, the SL55 will do 200. You can get your calculators and slide rules out and say this and that, but nothing replaces the actual experience in real life.
I love all the magazine (and now AI) racers. I've run my Indycar at over 200 and the way the scenery was going by, the SL55 will do 200. You can get your calculators and slide rules out and say this and that, but nothing replaces the actual experience in real life.
Wasn't that test done at Nardo? If so, there's a substantial difference between a looped track designed to measure top speed vs. a stretch of airstrip.
A mix of AI and paper napkin math, while entertaining, doesn't tell the story here.
Anyone who's explored the upper end of these cars knows better.
Here's a video of a Yamaha R1 pinned at 300 kph / 186 mph and still struggling to catch a R230 SL63:
I guarantee you my SL55 AMG will do 200 MPH verified by a GPS app on a cell phone. If it doesn't I'll give you the car provided you give me something in return that I can drive. LOL It does have an aftermarket pulley, throttle body and ECU tuned but there is no way I am gonna drive it that fast, I'm too afraid of a tire blowing up or something like that. LOL
I think the fastest I will "ever" drive the car is about 140-150 MPH and even that is a little fast for me. I like the car because when the light turns green, it has no qualms about getting up and going. Takes off better than all the other cars without even getting out of the ho-hum. And, passing other cars is a breeze... I love the M113K !!!!!!!!!
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
