RENNTech's Mercedes-McLaren SLR 722 with... 722HP

[blue8]

When Mercedes decided it was time to give the SLR supercar a boost, it created the SLR 722 edition. But don’t for a second think that number has anything to do with the car’s output. In fact, the supercharged 5.5L V8 engine puts out 650hp, a significantly lower figure than its 722 labeling suggests. The odd title comes from the 1955 Mille Miglia, where Stirling Moss and Denis Jenkinson beat out favorites from Porsche and Ferrari to take victory in a Mercedes-Benz 300SLR. The car was wearing the number “722,” which indicated the 7.22am starting time of the race.

At least for the original, the number 722 had some significance, but as RENNtech’s Hartmut Feyhl puts it, “for most people, six-fifty is probably enough but you see that ‘722’ on the car and you start to want seven-hundred and twenty-two horsepower.” Feyhl is a former AMG staffer with over 12 years experience at the famous Mercedes tuner and has since started his own tuning shop, RENNtech performance.

For the extra power, engineers upgraded the stock intercoolers and replaced the intercooler pump with a RENNtech-specific unit that has close to double the capacity of the standard version. Intake temperatures are now 10 degrees Celsius cooler, which meant that boost pressure could be increased and thus the 722hp mark could be achieved. Pity the original propeller-style wheels were swapped with these much more ordinary 20 inchers.

-- I love that this car is so powerful and looks like a stock SLR. Tuners should learn from this one! Wheels are a little dull though... but it could have been worse

[TopGearNL]

This should have been the SLR 722! On a technical basis that is, not the looks.. I prefer the normal 722 looks. So Badass

[yg60m]

As always with tuners I wonder about reliability. I suppose that if Mercedes engineers could have put 722 bhp they would have ...

[HeilSvenska]

but you see that ‘722’ on the car and you start to want seven-hundred and twenty-two horsepower.”

Exactly something that a poseur would say. A real connoisseur of automobiles would recognize that red 722 anywhere. Sheesh. And it looks worse with those bland wheels.

[Mattk]

Ah, the idea was good. A pity it doesn't look as good as the regular SLR 722.

[novass]

Originally Posted by blue8 Pity the original propeller-style wheels were swapped with these much more ordinary 20 inchers.

I don't like the wheels RENNtech put on, but I like them a whole shit load better than those turbine/propeller things.

This looks much better IMO

[bmwdriver]

^+1
looks much better, they should have placed the 722hp engine in here as others mentioned already
black rims are to die for

[Svensson]

I'm sure it's fast as hell, but ugh... that Renntech thing looks ugly, especially in the 2nd pic with the doors open

[saadie]

i never was a fan of the slr .... this one is even uglier

[Bernardo]

i dont like those slr 722 rims..they dont fit the car well IMHO the perfect rim for the slr its the one they use for it in brabus..so hooot!

[Kaz]

HERE IN FLORIDA, 722 MEANS WHAT YOU THINK IT MEANS
Lake Park, FL, 10 April 2007

At the 1955 Mille Miglia, at 7:22am, British racing drivers Stirling Moss and Denis Jenkinson set out on what was to be a historic run. Moss’ Mercedes-Benz 300SLR, though visually similar to the road-going 300SL “gull wing” car, was based heavily on Mercedes’ W196 Grand Prix car… despite this; the Italian teams were the heavy favorites to win, with a strong showing expected from the Porsche 550 team. The SLR, wearing the number “722” (indicating the 7:22 start time) won the race, and turned Stirling Moss into a legend.

Some 50 years later, very little seemed to have changed. Mercedes McLaren’s 626hp SLR had barely seen the light of day before Ferrari’s Enzo stole the headlines. To make matters worse, Porsche’s flyweight Carrera GT arrived – with the Bugatti Veyron hot on its heels. All of a sudden, the SLR was washed out in a wave of new supercar headlines.

Mercedes decided the best response to this dilemma would be to invoke the spirit of Moss and the original Mille Miglia number 722, and released, in the summer of 2006, a special edition Mercedes-McLaren SLR 722… with 650hp.

“For most people, six-fifty is probably enough” says RENNtech’s Hartmut Feyhl “but you see that ‘722’ on the car and you start to want seven-hundred and twenty-two horsepower.”

Such comments might be easily dismissed – but not when they come from Feyhl. No stranger to high-performance, Feyhl followed up his 12 year run at AMG by forming RENNtech – a tuning house generally regarded as the nation’s foremost authority on Mercedes-Benz performance.

The RENNtech crew began with a comprehensive review of the SLR’s stock components, when attention quickly focused on the car’s intercooler. “The stock intercooler wasn’t doing the job,” Feyhl explains, “it needed an upgrade”.

That “upgrade” took the form of a virtual redesign of the SLR’s intercoolers. The stock intercooler pump was replaced with a RENNtech-specific pump with almost double the capacity of outgoing unit. A dedicated radiator was installed, and the new pieces were integrated into the engine bay almost invisibly. As Feyhl points out, “It looks like it’s supposed to be there.”

The new intercooler dropped intake temperatures an average of 10 degrees Celsius across the operating range, and the time it took to get the engine’s temperatures back to “normal” after a dyno run was greatly reduced. “We used to have to wait almost 2 minutes between dyno runs to the get the temperatures back down, even with big fans blowing,” says Feyhl. “Now it takes about 20 seconds.”

The improved cooling meant that RENNtech could shift their attention to the supercharger and pulley – a RENNtech pulley kit, enhanced by RENNtech’s own SLR specific software tuning, increased boost to the SLR’s 5.5 liter V8 and produced an astonishing, albeit coincidental, result: 722hp – which might mean a lot more to McLaren customers than 7:22am.

Copyright © 2007, Renntech