Porsche 911 Turbo with more… well, just more!
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Hello, my name is Alex and I have a modification problem. It's been 2 weeks since my last modification. Well at least admitting I have a problem is the first step. I am told that sharing with others is also a large part of the healing process. So let me dive straight in and welcome you to another geeky report about tinkering with your Porsche. Today's subject; the dark and forbidden arts of aftermarket tuning!
Many would say enhancing a Porsche 997 Turbo is overkill. In a lot of ways those people would be right. For those of you lucky enough to have been to one of Porsche’s experience days in a 997 Turbo you will know that the car’s factory power and handling almost defy belief. So why would anyone want more from a car that Porsche labelled a 'Masterpiece' on release?
The answer lies in all that massive latent potential the Turbo has. Potential virtually untapped by the factory supplied car. Firstly you have the massively over-engineered 'Metzger' GT1 based engine. So should you have the desire, even increasing the power to over 700BHP is well within tolerances. Secondly, Porsche markets the Turbo as primarily a GT car. They say that if you want a more track focused model then there are the GT3/RS and GT3 variants to satisfy that need. This means those of us who want both a GT and a track car must choose between the two. However, with a few suspension upgrades you can truly have the best of both worlds from a Turbo.
The personal motivators to enhance my Turbo were more due to a series of smaller events than one master plan. I knew from day one that for me Porsche lacked three key factory options for the Turbo. In order of personal importance; alternate wheel options, a sports exhaust option, and a sports suspension option.
So my enhancements began on day 1 of collecting my new Turbo in the form of a shiny set of 19" HRE P40 wheels.
The curves I feel suite the lines of the car much better than the angular stock wheels, and the bonus of an un-sprung weight saving of 5kg to boot.
Instantly the car felt lighter on its feet.
Powerkit (incl. Sports Exhaust)
Next was the Sports Exhaust. After completing much research I narrowed my best options down to Cargraphic (medium or loud versions) or Tubi Style. In comparison Cargraphic is a deeper note, has the best release of back-pressure (more power), but does have some resonance between 2 and 3 thousand revs (which dissipates after a few thousand miles of driving). Tubi on the other hand is a little cheaper, good quality though, higher pitched and has no resonance. The deciding factor was that the Cargraphic exhaust was also part of a packaged power-kit developed by RS-Tuning. By all accounts, the best three Porsche tuners in Europe are Ruf, RS-Tuning and Manthey. Also, the Cargraphic power-kit is TUV certified so German approved to a very high level of standards.
So I took the car down to Parr based near Gatwick to fit a Cargraphic Stage II 544PS/798Nm kit consisting of a sports exhaust (medium loudness), ECU remap and a BMC sports air filter. The results were frankly startling. The noise heavenly, turbo lag now almost non-existent, and the power delivery so much smoother. All with face warping acceleration due to around 100 extra BHP throughout the rev range and almost a third more torque. SportAuto magazine tested a CG544 car and recorded a 100-200kph time of only 7.1s. Compare that to the official 8.6s of the stock Turbo and 7.4s of a 997 GT2 and you start to realize the hidden potential of the Turbo even from a Stage II kit.
Next up, suspension. This has been the most heavily criticized area of the Turbo by the motoring press. Even a heavier Nissan GT-R with the same power makes it around the legendary NBR track almost 30 seconds faster than a Turbo does. Critics say the handling is far too unpredictable on the limit with lots of under-steer followed by snap over-steer. Add that to a back-end that likes to 'hop' in sport PASM mode when going around corners and you end up with a car mainly suited to straight autobahns.
After a simple geometry re-alignment you can make the car feel much lighter on its feet. If you then go to the next level and start upgrading suspension components to GT3/RS and GT2 specifications then you can really start improving things. After much research I decided to upgrade my dampeners to the Bilstein B16 Damptronic kit, the same kit they fit to the Aston Martin DB9 and the new Nissan GT-R. Bilstein are the only after-market dampeners which work with PASM (given the OEM ones are bottom of the range Bilstein anyway). That means the sport button still switches between soft and hard options.
Throw in a GMG sway-bar set, a GMG rear toe-steer kit, a GMG dog-bone kit, lowered ride height, a corner weight adjust, and a geometry adjust…and you get a car that can almost match a GT2 on a track, with all the practicality and usability of 4wd and back seats for public streets.
After all the fantastic feedback on the Porsche Club forums about Chris Franklin at Center Gravity near Birmingham I decided to take the project to him. Chris is a Bilstein partner and is incredibly knowledgeable and experienced in tuning Porsche suspensions.
The first incarnation of the suspension tuning we decided to go with -20mm ride height drop along with medium stiffness front and back roll bars. This resulted in the car that was very stiff, cornered like it was on wheels on flat surfaces but on bumpy b-roads (where my car spends most of its time playing) it was not at all compliant. Rather jittery when you planted your right foot shall we say, and teeth chattering when going slow over really poor road surfaces. Sport mode PASM was even more severe.
Three thousand miles later and I brought the car back to Chris to see if we could improve things based on my feedback. Most notably the suspension had sagged significantly during this period. My stock dampeners dropped at least 10mm during the first 7500 miles from the factory. The new Bilstein kit followed suit but not to the same degree; sagging 7mm at the front and 4mm at the rear. This meant though I could then raise the suspension back up to where it was before, plus the extra 5mm I want to go to make the -15mm target. This had a massive, and I mean massive, effect on the ride quality and suspension compliance. Combine that with changing the front sways to full soft (still stiffer than OEM), and the car now feels like it's glued to bumpy roads with a ride like silk velvet. Truly staggering was the difference, even the wife subsequently given her full endorsement. After working on the car all day, Chris came back from his quick test drive, rolled down the window and said "boy do I love my job sometimes!"
Suffice to say, I am pleased as punch with my car now. A real 'keeper' that amazes me now each and every time I turn the ignition key. To me, it's the car that Porsche should have released from the factory.
I would say I am finished enhancing but I have to admit that since writing this report I have already fitted some Rennline pedals to help with heal & toe, and I am now eyeing up aftermarket iPod integration solutions. Where does it all end? Probably more Modifications-Anonymous meetings. I look forward to seeing you there!
Aftermarket car mods - good or bad?
Are you for or against modifying cars? Pluses include: not having to wait 5 years for manufacturer to catch up. Negatives include: void factory warranty
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