In this article Marco Alsterfalk of the Swedish tuning company www.MTE.se explains issues such as the fuel enrichment effect on high load operating points, definition of knock, the fundamentals of knock, what the optimum lambda is and how the knock limit and indicated mean effective pressure (imep) are affected by variations in lambda. [ More... ]

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In-Depth Race Car Performance Analysis
June 2009
 

A Porsche 911 GT3 Cup race car has undergone a world unique performance analysis to show its competitiveness in the global Carrera Cup series. Information that every race car driver must know.


Report Summary:

A Powertrain Performance Assessment, PPA, has been made on a Porsche 911 GT3 on behalf of Flash Engineering. The car is a 2009 model and recently delivered from Porsche. Tests were performed at 30 March 2009 on a ROTOTEST VPA-RX8 2WD chassis dynamometer which is of a hub-connected type. Compared to an engine dynamometer the engine performance is reduced with drivetrain losses. It is of course important to have a powerful engine but from the drivers' point of view, it is the power available to the wheels that the driver can make use of.

All tests have been run in 5th gear and started with a Steady State test at every 500 rpm beginning from 2000 rpm. Maximum performance numbers are 386.4 Nm of torque and 410.2 PS of power. Compared to the stated factory numbers of 410 Nm and 420 PS there is a difference of 5.8% and 2.3% respectively. The torque difference is in the expected range whereas the power difference indicates slightly more engine power than stated.

The car has also been subjected to tests at Steady Rate. This means measurements during controlled accelerations. 4 rates have been tested; 300, 500, 700 and 1000 rpm/s. During accelerations some of the engine power is used solely to accelerate the inertia of the powertrain. This loss is increasing with the rate of acceleration. An estimation of the Powertrain Inertia shows a value of 0.16 kgm2 which equals having an extra weight of 222 kg in 1st gear. The actual value of Powertrain Inertia is relatively low considering the size of the engine.

Compensating for the estimated inertia show that the engine is producing approximately 10 Nm and 5 PS more during acceleration compared to Steady State. This may be related to less tendency to knock during acceleration. In any case it clearly shows a performance potential that would have been missed if the mapping had only included static conditions. Especially for a race car the improvements can be considered to be large. From the drivers standpoint it can very well be the difference between winning or loosing.


Driver

H.R.H. Prince Carl Philip Bernadotte
More info at:
www.royalcourt.se
www.carreracup.se


The full report Powertrain Performance Assessment, PPA, Porsche GT3 Cup 2009 is free to download for non-commercial purposes.

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Tuning theory, Part 5
January 2009
 

This is the fifth and last feature article in an feature article series about tuning a VW Passat 1.8 turbo. The unique educational feature article series, with its 30 000 EUR budget, was made possible through a cooperation between Rototest Research Institute and the Swedish auto magazine Bilsport.

Rototest Research Institute whishes to thank Bilsport (www.bilsport.se) with staff for its capable cooperation for more car tuning knowledge.

Passing examination in the family car tuning school
Includes: Power or torque, constant speed, change gear at crossing, power accelerates, tops 245, fit or slack, changes character, change gear whenever and optimal gear ratio.

Graphs: Tractive effort, acceleration improvement, Powertrain Performance Toyota Corolla and VW Golf GTI, acceleration potential Toyota Corolla and VW Golf GTI.

Reader questions and comments:
Please write to tuning-theory@rri.se, open to december 2009.

The article is free to download for non-commercial purposes.

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Tuning theory, Part 4
January 2009
 

This is the fourth feature article out of a total five in an feature article series about tuning a VW Passat 1.8 turbo. The unique educational feature article series, with its 30 000 EUR budget, was made possible through a cooperation between Rototest Research Institute and the Swedish auto magazine Bilsport.

Rototest Research Institute whishes to thank Bilsport (www.bilsport.se) with staff for its capable cooperation for more car tuning knowledge.

Mapping - the final touch
Includes: Tough adjustments, original system preferred, difficult torque curve, retain the margins, volumetric efficiency, knocking, the three elements of combustion, lambda value and 200 with environmental conscience.

Graphs: Mass flow and Diff temp, cooling efficiency, cooling power, engine speed and temp. after turbine, pressure loss exhaust with and without catalyst, powertrain performance, wheel torque and inlet pressure standard, with new exhaust, with new intercooler, and with a new engine calibration, engine speed and injector duty cycle, throttle, lambda, inlet pressure, engine speed and volumetric efficiency relative total, lambda.

Reader questions and comments:
Please write to tuning-theory@rri.se, open to december 2009.

The article is free to download for non-commercial purposes.

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Tuning theory, Part 3
September 2008
 

This is the third feature article out of a total five in an feature article series about tuning a VW Passat 1.8 turbo. The unique educational feature article series, with its 30 000 EUR budget, was made possible through a cooperation between Rototest Research Institute and the Swedish auto magazine Bilsport.

Rototest Research Institute whishes to thank Bilsport (www.bilsport.se) with staff for its capable cooperation for more car tuning knowledge.

The intercooler´s to be - or not to be?
Includes: Higher density, efficiency increases with the flow, theory can be destroyed, standard elements, perceived as gain, double cooling capacity, chassis dynamometer - that´s how it works, a tolerance of one percent, different measuring methods, forget the 25 percent losses and counting the horses.

Graphs: Pressure drop over the intercooler, powertrain performance with standard and new exhaust system and with new intercooler, air mass flow and pressure drop, air mass flow and cooling power and diff temperature and cooling efficiency.

Reader questions and comments:
Please write to tuning-theory@rri.se, open to december 2009.

The article is free to download for non-commercial purposes.

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Tuning theory, Part 2
August 2008
 

This is the second feature article out of a total five in an feature article series about tuning a VW Passat 1.8 turbo. The unique educational feature article series, with its 30 000 EUR budget, was made possible through a cooperation between Rototest Research Institute and the Swedish auto magazine Bilsport.

Rototest Research Institute whishes to thank Bilsport (www.bilsport.se) with staff for its capable cooperation for more car tuning knowledge.

Big exhaust system - benefit or pleasure?
Includes: Disadvantage or advantage, pre-condition for more power, half the gain, the surge line, measurements and results, more air in, specific fuel consumption, conclusions, volumetric efficiency, total volumetric efficiency and counting of molecules.

Graphs: Performance during an acceleration at 500 rpm/s, power and torque with new exhaust, exhaust performance, breathing capacity and efficient use of fuel and air.

Reader questions and comments:
Please write to tuning-theory@rri.se, open to december 2009.

The article is free to download for non-commercial purposes.

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Tuning theory, Part 1
August 2008
 

This is the first feature article out of a total five in a feature article series about tuning a VW Passat 1.8 turbo. The unique educational feature article series, with its 30 000 EUR budget, was made possible through a cooperation between Rototest Research Institute and the Swedish auto magazine Bilsport.

Rototest Research Institute whishes to thank Bilsport (www.bilsport.se) with staff for its capable cooperation for more car tuning knowledge.

Family car tuning under the magnifying glass at Rototest Research Institute
Includes: Background, test object, steady state and sweep, theoretical interpretations, measurements and results, turbo life and pressure, injector limit, exhaust temperatures, low exhaust noise-back pressure, still clean at 190 km/h and the compressor map.

Graphs: Power and torque - the original, information at max performance, intercooler performance, exhaust performance, speed related performance and the compressor map.

Reader questions and comments:
Please write to tuning-theory@rri.se, open to december 2009.

The article is free to download for non-commercial purposes.

[ Download ] (13 pages, 2505 kb)

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May 31, 2010 - Disruption of Service


Due to heavy thunderstorms, resulting in an unplanned outage of Internet service, the rri.se website was inaccessible between Sunday, May 30 and Monday, May 31, 2010. The issue was rectified on Monday evening at 18.04 CET and the website is now globally accessible again. We apologise for any inconvenience caused by this disruption, and we are undertaking necessary measures to ensure an uninterrupted service.