JZM History: Manthey Racing 3.9-litre Porsche 996 conversion

Here’s a copy of a feature by Chris Knapman of GT Porsche magazine from ten years ago – December 2007 – detailing a Manthey Racing conversion carried out on our friend Didier’s LHD 996 GT3 to bring it to 3.9-litres with 455bhp on tap. This was a very special car at the time and we have built many more since! Email steve@jzm.south.co.uk to discuss modifying and tuning your 911 for fast road or track use using the many high quality components supplied by JZM.

What’s in your garage? Manthey-tuned Porsche 996 GT3

It takes something special to stand out at a track day where there are 964, 996 and 997 generations of Cup car, a Carrera GT, and any number of modified RSs. But stand out is precisely what Didier Denat’s black 996 GT3 does, both in the paddock and out on the track which, as you’ve no doubt spotted in this case, is the Nürburgring Nordschleife.

At first glance you might mistake this modified Mk2 GT3 for a repainted RS. After all, it has a genuine RS front bumper, a carbon rear wing and italicised script running down the base of the doors. Look a little closer, though and that script doesn’t read GT3 RS, but rather ‘GT3 CS’, recalling the Carrera Club Sport of the late Eighties.

“The brief was to create a car that I could drive to the ‘Ring and still be relaxed when I arrive, and then that I will also be one of the quicker cars out on the track,” says Didier of his 996. Interpreting that brief, Manthey Motors and its UK distributor JZM Porsche created this GT3 M440 Club Sport.

“I did a bit of research and really wanted to go to the best guys in the business, and I wanted somebody that knows the ‘Ring inside out to do the setup. This was about two-and-a-half years ago. The first thing I did was the suspension with Manthey’s three-way adjustable coilovers built by KW Suspension, and then the brakes, for which I used JZM Porsche’s setup.”

The brakes in question are ceramic floating discs, which JZM says are 1.5kg lighter each than the standard GT3 steel discs. Measuring 360mm (original Mk2 discs are 350mm), the discs are built to JZM’s specifications and offer improved braking power and longevity over the standard items (note: we have now upgraded these items further with our custom carbon brakes from Surface Transforms). JZM Porsche also fitted the KW Suspension to Didier’s car, along with a Manthey K410 engine upgrade.

The K410 consists of a full Manthey sports exhaust that is 6.7kg lighter than the original, and a reprogramming of the GT3’s Motronic to yield more power from the flat-six engine. However, as is so often the case when it comes to modifying cars, Didier wasn’t quite finished: “Nine months after the first modifications I did a second batch with Manthey Motors. They exchanged the gearing, fitting 20 per cent shorter ratios, as well as a race clutch, single mass flywheel, race diff and uniball strut tops to improve turn-in, and set it up very nicely for the ‘Ring.

“Then at the beginning of this year I was thinking ‘what should I do next – keep that car or get a 997 GT3 RS?’, but because the RS was going to require a lot of extra money, I decided instead to put this towards improving my car further. Speaking to Steve McHale at JZM Porsche and Manthey’s engineers, I decided to go for Manthey’s 3.9-litre engine conversion: the ultimate step it offers for the GT3.

“Manthey was amazing because the first time after they did the engine conversion they put it on the dyno and it was doing 451bhp. Before, with the K410, it was pulling about 424bhp. So I said to Manthey that spending all that money on the 3.9-litre conversion for an extra 27bhp seemed like a lot. There was a lot more torque – about 332 lb ft – but, because I was hoping for more power, Manthey took the engine out of the car again and checked everything, but when they put it back in and back on the dyno it was the same. The guys then said they would do something a bit special so that my car would be beyond the normal 3.9-litre conversion figures.”

It is for this reason that a Cup filter resides under the engine cover of Didier’s car, combined with a carbon ram air intake system, which results in a naturally aspirated engine with 455 bhp and 347 lb ft of torque. “What is particularly impressive is the power from 180km/h,” explains Didier. “It now accelerates like it used to in third gear. You can get very easily to 280-290kmh, and I’ve hit the limiter at 8200 revs with 309km/h on the clock.”

Of course the GT3 philosophy isn’t only about maximising power. “I wanted to really lighten the car as well, so we put on BBS magnesium wheels, the carbon doors, carbon bonnet and took all the air bags out, as well as removing the regular seat belts and fitting plastic windows in place of the rear screen and rear side windows. Just this Cup steering wheel, believe it or not, is five kilos difference and the doors are 11 kilos lighter each. Then we fitted the rear wing, a proper RS front bumper with the air intake, and JZM canted the radiator back to improve the airflow.”

Given the car’s obvious focus toward track work, one wonders how usable it is on the road. “It’s amazing as a road car,” enthuses Didier. “I took the insulation between the engine and the cabin out but it’s actually no noisier than it was before, although it does pull slightly more revs because of the shorter gearing. And while it’s lighter, I have kept the radio and the air-con because removing these doesn’t make sense.”

And what about on the track? “Oh, it’s amazing. In a straight line it pulls away from Cup cars. I remember when I first bought this car I wasn’t that comfortable with it. It was a bit understeery and a bit jittery, but now it is superb – you just turn and it goes. Under heavy braking, the ceramic brakes are absolutely amazing and the car stays completely flat. With the original car I couldn’t trail brake into the corners because the back end would move around, but now it is really stable.”

So, the perfect GT3? “I certainly don’t think that there’s much left to do!” says Didier laughing. “I don’t think I’ll ever sell this car. It’s so special – you take a project and spend so much time thinking what you’ll do and all the research that by the end you don’t want to part with it. The next thing I want to do would be to buy a Cup car and race that. I would love to do this but I think I need to get a bit better first, so I’ve started racing at Caterham and after a couple of seasons I might be ready to move on. For track days it’s difficult to justify buying a Cup car though, because I think that my car at the moment is faster, plus you can get a lot of fun from driving it on the road.”

It won’t surprise you to hear that this isn’t the first Porsche Didier has owned, his relationship with the marque starting off with a 996 Carrera 4, which he swapped for a 996 Turbo. “I had the Turbo tuned to 540 horsepower by PSI Motorsport and kept it for two years, but on the track it wasn’t that great and I wanted to get to the next level, so that’s why I got a GT3.”

A couple of quick passenger laps on a deserted Nordschleife demonstrate that the next level is precisely what Didier has ended up with. With an abundance of torque and a surefootedness GT3 owners might well crave at the ‘Ring, it feels a phenomenal machine. We may not have found this Manthey GT3 M440 Club Sport at Didier’s garage, but it’s fair to say that the ‘Ring is its rightful second home.

Download the full feature on our Manthey JZM Porsche 996 GT3 3.9-litre conversion.

Porsche 991 GT2 RS sets new Nürburgring lap record

Porsche recently turned to local hero, Bedfordshire’s Nick Tandy, to help set a new road car lap record at the Nürburgring. Driving a brand new Porsche 991 GT2 RS, Tandy and colleague Lars Kern broke the established record of 6 minutes 52 seconds on their very first try and went on to set a series of five laps, all below 6 minutes and 50 seconds. As the day wore on, the atmospheric conditions reached perfection just after 7pm and it was VLN driver Kern who ultimately set the new record of 6 minutes 47.3 seconds.

“At the start of the development process, we set ourselves a lap time target for the GT2 RS of less than 7 minutes and 5 seconds,” said Frank-Steffen Walliser, Vice President Motorsport and GT Cars. “The credit for beating this target by 17.7 seconds goes to our development engineers, mechanics and drivers, who demonstrated an exceptionally strong team performance. This result makes it official: The GT2 RS is not only the most powerful, but also the fastest 911 ever built.”

“It’s not just the record time achieved by the GT2 RS that demonstrates the vehicle’s class, but also its consistent performance in every lap,” remarked Andreas Preuninger, Director GT Model Line. “We’re particularly proud of the fact that this was achieved with two different vehicles and two different drivers, as this underlines the GT2 RS’s ability to reproduce this record result over and over again.”

The twin-turbo flat six engine in the new 991 GT2 RS produces 700 horsepower and delivers its prodigious grunt through the rear wheels only. Weighing 1470 kilos with a full fuel tank, Porsche’s most powerful 911 accelerates from zero to 62 miles per hour in 2.8 seconds and on to a top speed of 211 mph. The new GT2 RS has 80 horsepower more than the last model and delivers 750 Newton metres of torque.

The order book for the new 911 GT2 RS has long since been filled and enquiries have already been received at JZM for the cars that will inevitably come to market soon after delivery. Email sales@jzm.south.co.uk if you are considering selling your new GT2 RS, or would like to discuss obtaining one some time in the future.


KW launches suspension kits for 718 Porsche Boxster/Cayman

Our friends at KW Suspension have just launched some exciting new damper kits for the latest Porsche Boxster and Cayman. The market leaders in high end aftermarket suspension upgrades, KW Automotive has unveiled a Height Assisted Spring kit, Variant 3 package and a range-topping 3-way Clubsport option.

While Porsche endowed its latest Boxster and Cayman models with divine chassis balance, there is room for improvement in the quality of standard suspension. However, this does not mean the cars must be substantially altered in ride height or appearance.  KW’s Height Adjustable Spring (HAS) kit is a great place to start when upgrading the standard 718 suspension.

KW’s HAS kit features an innovative spring perch, which allows for individual height adjustment while the springs are in situ. This is a great advantage over traditional spring kits, which force owners to choose a final ride height before the springs are fitted. KW’s clever engineering solution makes adjusting the ride height very straightforward, which gives Porsche owners substantial control over how their car looks and handles.

Porsche 718 Boxster and Cayman Variant V3 Suspension

Boxster and Cayman owners keen on a distinct lift in suspension performance should certainly look closely at the all-new Variant V3 kit for 718 models. Providing the perfect balance between fast road and regular track day use, KW Variant V3 suspension is a recommended upgrade here at JZM Porsche and our KW factory-trained technicians would be delighted to fit this to your 718, including a full geo alignment on our Hunter setup ramp.

KW’s patented valve technology is the secret behind the V3’s ability. The coilovers allow independent adjustment of both damper compression (bump) and rebound settings while the units are on the car. This again permits owners to make fine adjustments to key handling characteristics for a completely tailored ride quality. Adjusting the compression could not be easier: just click the the lower adjustment wheel through any of its 12 preset positions. Rebound rates are similarly adjustable, by using a similar cog with 16 preset points.

KW upgraded suspension for PASM-equipped Porsche 718 models

KW has developed two types of Variant 3 kit: one cars fitted with Porsche Active Suspension Management (PASM), one for those without. All 718-chassis owners can benefit from the upgraded KW suspension experience, safe in the knowledge that the kit is entirely compatible with the car’s electronics.

Clubsport Coilovers for Porsche Cayman/Boxster

The final product in the new KW Suspension range for 718 models is a Clubsport coilover kit, aimed at serious track day enthusiasts. While still providing a high-quality ride on the road, Clubsport dampers include a further step up in valving technology, allowing owners to adjust rebound through 16 positions, low speed compression through 6 settings and high speed compression through 14 preset positions. We have fitted many Clubsport kits and are always amazed at the performance they can unlock – highly recommended upgrade for any Porsche.

JZM is a preferred partner and recommended technical centre for all KW Suspension upgrades. We carry a full range of KW kits in stock and we can ship worldwide. Email parts@jzm.south.co.uk to discuss.

Don’t forget that our next Cars, Coffee and Croissants event takes place on October 1st. KW representatives will be on site to discuss all of the kits available for every Porsche model, including classic air-cooled 911s.

KW Suspension Summer Sale at JZM

Enthusiastic Porsche drivers can save up to £300 on the finest spring and damper packages from KW Suspension at JZM Porsche, thanks to KW’s summer sale.

Germany’s premier aftermarket suspension manufacturer has introduced a suspension specific voucher code, which is valid until September 30th, 2017 for all KW Suspension purchases made from JZM Porsche.

  • Variant 1 systems now have £100 off with voucher code KWSUSA2017V1UK
  • Variant 2 systems now have £200 off with voucher code KWSUSA2017V2UK
  • Variant 3 systems now have £300 off with voucher code KWSUSA2017V3UK

Contact us to discuss a KW upgrade with optional fitting and chassis alignment at JZM Porsche. We have fitted hundreds of KW systems and nothing beats the feel of decent suspension, properly set up on a great 911. Email service@jzm.south.co.uk to discuss.

Jagermeister Porsche 935 in for JZM chassis geometry setup

This stunning Jagermeister Porsche 935 recreation was a recent visitor to our Hunter laser alignment ramp, for perfect chassis geometry as part of race preparation setup.

We carry out hundreds of chassis setups every year and it’s always exciting to play with cool Porsches. Adjusting the 935’s suspension is easy: the car rides on coilovers and just about everything is rose-jointed, making the geometry tweakable down to the finest increments.

Unlike some neglected Porsche road cars, everything easily comes undone on a regularly adjusted race car, so there was no freeing-off to be done before the process got started. The whole job took less than two hours: a cost-effective trip to the JZM setup bench.

Some people pay thousands of pounds to have their Porsche set up elsewhere, only to find that it still does not handle right afterwards. Our chassis setups start at just a few hundred pounds and feedback is always extremely positive.

Email steve@jzm.south.co.uk to discuss how a JZM setup can bring your Porsche back to its best. There is no need to spend thousands of pounds on chassis alignment when you bring it to people with four decades of experience who know what they are doing!

Porsche Cayenne Engine Lights Troubleshooting

This smart Porsche Cayenne V6 TDI recently arrived at the JZM workshop in a state of some distress, or so the dashboard warning lights would have us believe. The owners were convinced the engine was in trouble and that the bills would be huge. Cayenne engines are generally reliable so we plugged it in to our official Porsche PIWIS 3 diagnostic set up and had a look at the fault codes being reported.

PIWIS 3 has a direct connection to the factory at Stuttgart and downloads technical updates daily. If Porsche know a model has an issue, bulletins are issued to PIWIS 3 users which explain how to solve it. JZM Porsche is one of only two specialists in the UK using Porsche PIWIS 3 – it is an expensive tool but absolutely essential to properly maintain the newer models.

Our first instinct with urban Cayennes – especially diesels – is that they are usually choked up from sitting in traffic most of their lives. This gives emission problems as the catalytic converters can only recycle and burn off pollutants when the car is on a long run at speed. PIWIS 3 checked every operating system on the Cayenne and pointed out a few faults: mainly emissions-related issues.

The owner confirmed the car was not solely used around town, so it had been going through its emissions cycles. We recycled the cats using PIWIS and, while it improved the situation, it did not solve it completely. We then checked other areas including the data being fed to the ECU – was this a sensor issue? While PIWIS had already shown its merit in manually cycling the catalytic converters, the process of finding faulty sensors is where it comes into its own.

PIWIS checks and reports on the condition of every part on the car in real time. With the car running for an extended period, we could see that a number of temperature sensors were not reading sufficiently high. Incorrect temp readings would obviously affect the ECU function, so we tracked these parts down and went through further checks to narrow it down to a single component.

After numerous emails and phone calls to Porsche, checking their opinions and knowledge of similar issues, we went with our best instinct on which sensor was likely causing the issue. Finally the Cayenne had a spring back in its step. It had been a long process to find the issue, but we would never have found it with the PIWIS system and a technical hotline to Porsche, just in case.

If you are running a late model Porsche – anything from a 981 or 718 Boxster/Cayman to a brand new 991 GT3 RS or 918 Spyder, only PIWIS 3 can correctly communicate with your vehicle and ensure it is functioning correctly. With our service workshop labour rate an average of £40 per hour cheaper than official Porsche dealers, why take it anywhere else? Email service@jzm.south.co.uk to discuss your next appointment.

Choked Porsche Panamera Intake: Get Some Nuts

This poor-running Porsche Panamera was the first service car to benefit from our latest investment in workshop equipment: a mobile Nederman dustless media blaster. Arriving in the JZM Porsche service workshop with terrible running and a string of fault lights showing, a PIWIS check directed our diagnosis towards the intake. Stripping the intake manifold from the engine, we soon found the valves to be clogged almost solid, following a life sitting mainly in London traffic.

The only way to fix this problem would normally be to strip and clean the heads and valve train – quite an expensive process. We could have used our high-power blast cabinet to great effect but would still have had to strip the heads off. Talking to our equipment suppliers, we came across the dustless Nederman system, using crushed walnut shells.

Turning the engine to top dead centre on one cylinder so the valves are closed, the machine blasts the backs of the valves with walnut shell media, simultaneously removing waste products. The shells are combustible, so any small fragment which manages to find its way into the combustion chamber will just be burned off without damaging the engine. The results were terrific and we will find many more uses for the new blaster!

Manthey Nurburgring Track Day: May 10, 2017

Our friends at Manthey Racing have asked us to share details of their upcoming track day at the Nürburgring next Wednesday May 10. This will be a very special track day, with a meet-and-greet and barbecue at Manthey workshops on the Tuesday evening, and a detailed briefing at the Ring on Wednesday morning, before just 80 road cars are allowed on track for the entire day.


  • Rental of Nürburgring-Nordschleife racetrack (max. 80 vehicles)
  • Manthey-Racing technology service
  • Michelin tyre service
  • Full-day corporate/product presentation by the Scherer Group, KW Automotive etc. (car park on Nordschleife approach road)
  • Racetrack safety package including breakdown vehicle
  • Manthey-Racing instructors (€150/hour)
  • Catering 10.05.2017: food and non-alcoholic beverages from 08.30h – 17.00h (Devil’s Diner restaurant; all other purchases at the entrant’s own expense)

Entry fee including all the above-mentioned services:

  • Per road vehicle including one driver + one passenger/accompanying person €999
  • Each additional driver €299
  • Each additional passenger/accompanying person €129

All prices including rate of VAT at 19%. Download the PDF with more details here.

JZM Porsche Tuning: Turbo Upgrades

We’re been steadily improving the Porsche service information available on our website. To add to our tuning and performance options, we have now added a section dealing with turbo power upgrades.

Our turbo power upgrades have been developed and extensively tested by the leading suppliers in Germany. All power figures stated are well within expected power improvements: we don’t make exaggerated power claims when quoting potential gains.

Porsche 996 Turbo tuning packages include:

Standard Turbo Stage 1 (+70bhp/130Nm) & Stage 2 (+88bhp/150Nm)

Turbo S, X50 and GT2 Stage 1 (+60bhp/120Nm) & Stage 2 (+78bhp/140Nm)

Porsche 997 Turbo tuning packages include:

Gen 1 997 Turbo: +55bhp/110Nm

Gen 2 997 Turbo: +70bhp/120Nm

997 GT2 power upgrade: +70bhp/100Nm

997 GT2 RS power upgrade: +70bhp/100Nm

Email JZM service to discuss the upgrade packages and prices.

Akrapovic upgrade exhaust for Porsche 991.2 Carrera (Turbo)

JZM is delighted to be the first UK supplier of the all-new Akrapovic exhaust system for Gen 2 991 Carrera models. Designed to replace the factory sports exhaust, the new Akrapovic system for the now turbocharged Carreras is manufactured from ultra-lightweight, heat-resistant titanium alloys, which have been coated for increased durability.

Part of Akrapovic’s highly regarded ‘Slip-On’ line, the system tops the scales at two-thirds the weight of a standard exhaust. Thanks to much improved gas flow through the exhaust’s central silencer and out through titanium tailpipes, performance is greatly enhanced over standard. Buyers also have the option of a stainless steel link pipe set, complete with sports catalytic converters and a stunning carbon-fibre diffuser.

Delivering less weight, more performance and increased visual impact, the new Akrapovic system is a perfect addition to our range of high end tuning products for Porsche models. Email Steve McHale to discuss any of our Porsche tuning products or visit the JZM Porsche tuning shop.

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