I flew down to Munich the summer of 2004 to meet up M5 Messageboard members KSA ///M5 and HIPAD, and also to celebrate that I got my driving license back after a four months unvolountary pause after a speeding incident.

This story of a week full of speeding is told on five pages:

Page 1

Visit to Porsche-tuner Koro.

Car we drove: Digi-Tec / Nowack BMW M3 3,2 Coupe (E36 1996).

Page 2

Visit to BMW-tuner Kelleners Sport and Digi-Tec.

Cars we drove: Kelleners Sport BMW M3 CSL (E46 2003) and Kelleners Sport BMW M3 (E46 2002)

Page 3

Visit to Alpina.

Cars we drove: Kelleners Sport BMW M3 CSL (E46 2003), Kelleners Sport BMW M3 (E46 2002), Ruf CTR (911 1987) and Alpina B8 4,6 Coupe (E36 1996).

I arrived at the airport in Munich and was greeted with the appropriate sign above. I was picked up by KSA ///M5, HIPAD and their friend in his VW Touareg with a V-10 diesel powered engine with 313 HP and 750 Nm of torque! It was interesting going 170 km/h on small country roads high up in a SUV. With 22' wheels it had surprisingly good road holding along with a three stage settings adjustable suspension.

First visit is Porsche-tuner Koro in Heilbronn. For the trip there we used a Dakaryellow M3 3.2 Coupe with 321 HP, that initially have been tuned by tuner Digitec. Digitec got the assignment to tune the engine as much as possible. The car had less than 40 000 km when they received it. Digi-Tec changed the camshafts, did head polishing, Group N ECU program etc. Digi-Tec claimed 56 HP but we have never received the dyno-papers. More on Digi-Tec later when we will visit them. Bottom line was that their M3 did not run 100% well when we had it. On the picture above you also see the KSA ///M5 Brilliantrot 850 CSi which have different cams, catalysts and exhausts from Nowack.

It is equipped with BBS Challenge wheels and AP-Racing brakes.

Checking oil...

Digitec's Alpha N program substitutes the mass airflowmeter sensors.

The airbox looks good but does it work?

Fueling up to go to to Koro. The M3 was equipped with aftermarket xenon from Hella that was very bright and good low-beam lights.

Traffic, traffic traffic. One Individual BMW 330Ci Convertible and one Ferrari 360 that did not want to race.

A 4,7 Alpina? That is not andI doubt is a 4,7 liter engine as well...

True xenon, but no bi-xenon.

You noticed that the cams were not adjusted with the engine software, or just to aggressive cams. The engien stalled sometimes under 2000 rpms and the power was all above 5000 rpms. Well over 5000 rpms it felt quite strong. We raced an Audi S8 and with 4 people in the BMW M3 and with only one person in the S8, it was surprisingly easy to overtake over 200 km/h.

The most popular colour of the E36 M3. Behind us is Johans race M3 E46 that he races on the VLN on Nürburgring.

After a couple of hours we arrived at Koro, which core competence in tuning is for Porsche normally aspirated engines. Additionally they are consulted by various automobile producers in R & D and construction. They also hold various patents for their technical solutions. Koro is the company who developed Audi's double-clutch Direct Shift Gearbox (DSG) system and the V10 powered diesel engine (in the Touareg for example) is partly developed by Koro. Koro AG is situated in Heilbronn.

For the last ten years Koro have worked for the automobile industry (Audi, Volkswagen and Toyota Racing) but in 1999 they started to work on Porsches, initially for their own development.

What founder Erich Korostenski did to the normally aspirated generation I Porsche 996 GT3 is very interesting. The normally aspirated 3,6 liter engine is increased to 4,6 liter (4566 cm^3) and has according to Koro 485 HP at 7500 rpm and a torque of 500 Nm. 0-100 km/h in acheived in 3,7 s and 0-200 km/h in 11,2 s according to Koro. Top speed is a claimed 331 km/h. This is over 103 HP/liter from a 4,6 liter engine.

Price for this engine conversion is €28 425 excluding tax.

The German magazine Auto Bild Test & Tuning acheived a remarkable laptime on the 3667 m long track motorpark Oschersleben near Magdeburg. It was not the cheapest, not the most comfortable nor the best compromise. Although it was the fastest. Koro holds patents for the technique of increasing the displacement as much as one liter.

Unfortunately we could not test drive the 4,6 liter 996 GT3, since it was partly disassembled. Good news was that we could get a closer look at it.

No compromises here, it is all out race for the Koro 996 4,6 S. It has BBS magnesium wheels as well as a special air-intakes on the Mk I rear spoiler for engine cooling.

Enlarged the cylinder sleeves fron 102 mm to 107 mm. Porsche always uses sleeves of aluminum which requires thicker cylinder walls than steele since aluminum is weaker. Aluminum has the good characteristics of be able to transfer the heat from the cylinder sleeve to the water faster than steel. Steel-sleeves has the advantage of larger strength which means you can bore it more than aluminum. Koro uses steel-sleeves with cooling ribs on them and thereby multiplying the surface area of heat-exchange, thereby avoiding the worser heat-exchange of aluminum in cylinder sleeves. Also the watercooling is more efficient since the water is forced through the ribs. This is a patent of Koro.

Koro is also involved with VLN race on the Nürburgring with a E46 M3 team. Interestingly they have plans for the upcoming M5 E60. Naturally a company like Koro have to work with the most advanced engines in order to make full use of their know-how and also for finding potential customers. The new M5 engine fits that category. An answer to a direct question why they won't work at Mercedes-AMG engines is that they are not as technically advanced as BMW M engines. Koro should know that, since one of their mechanics have worked for both BMW M and Mercedes-AMG. Koro also says that a V-10 engine is the best choise between 5 and 12-cylinder engines in regard to power and fuel-consumption.

The future goal for Koro is to have 60% of the company involved in engine tuning and 40% with consultancy for the automotive industry. Koro is planning to have the upgrades for the E60 M5 available in stages with first offerings is ECU and exhaust modifications and later on head polishing and more advanced engine developments. They think out of all BMW M5 E39 tuners Nowack is the one who put in most research into the engine tuning and therefore give the best result. Interestingly this is in line with what Kelleners Sport told us, that the most powerful M5 they dynoed was a Nowack N500, which after some engine management work by Kelleners had around 460-470 HP. Note that it might have had more or less before the engine management was changed with at Kelleners.

Our impression of Koro is that there is no question that they know how to work with Porsches normally aspirated engines. Their patents and their experience of working in the automotive industry for years which sounds very promising. Their patented technology to increase displacement surely makes the 996 GT3 a very fast and unique car with all the benefits of a normally aspirated car. Knowledge like this and with highly tuned engines (over 100 HP / liter) it will be very interesting for the upcoming BMW M engines.

Granted that it is a difficult market to be successful in and fewer and fewer companies are doing advanced engine tuning for the BMW M cars it is for enthusiasts interesting that they will work on the upcoming M5 engine. We know that the Koro Porsche-engines can perform but we have to wait and see what the future holds for Koro and the M5 E60.