Already boasting significant power from its 3.0 V6 CRD engine, one owner of a Chrysler 300 recently approached leading UK aftermarket tuner, Celtic Tuning, to squeeze significantly more horses out and create a truly powerful charger. With the new large front mounted intercooler installed lower temperatures are ensured when the engine is operating at higher boost pressures and thus maintained reliability. The compressor housing has been machined and a larger compressor wheel with uprated 360 degree bearings has been installed along with other blueprinting modifications to enable the pressures to be achieved with complete reliability. Photo: Comparison between the original and replacement unit. All the development was tested, monitored and measured using Celtic Tunings Dastek 750 dynamometer. The rear wheel drive 300c stood up extremely well to over 40 hours development on the rolling road, putting out a final figure of 314bhp. The standard setup has a very narrow, low volume intercooler while the replacement fitted by Celtic Tuning’s engineering team is a much larger high volume front facing intercooler with silicone hoses. See comparison of intercoolers in top photo. The standard Garrett GT2056V turbo has been modified and converted to a hybrid format in order to be able to achieve pressures of up to 1.9 bar. Photo: Modified unit fitted back on the engine.

The alliance between Fiat and Chrysler is rapidly creating a scenario where the two carmaker’s future fortunes will be interlocked in all areas from distribution and market positioning to technology and platform sharing. Fiat has in recent weeks revealed that the Chrysler brand will be tied up closely with its own Lancia unit, the two divisions pursuing an upmarket, luxury brief in different global markets. In this respect Chrysler’s flagship sedan, the 300 series, already hits the mark with its powerful yet refined Mercedes 3.0 V6 diesel engine.  Chrysler therefore has a high performance luxury sedan that is as distinctive as it is powerful.

The 300 has already carved a niche in many European countries and built its status as an upmarket, prestigious offering. In the UK the 300 has been well received by consumers and its distinct, muscular looks always ensure it stands out from the crowd in its category. Already boasting significant power from its 3.0 V6 CRD engine, one owner recently approached leading UK aftermarket tuner, Celtic Tuning, to squeeze significantly more horses out and create a truly powerful charger.

The brief was to make the car as fast and responsive as possible without compromise to reliability or affecting the standard appearance of the vehicle. The option for the turbo upgrade was to obtain extra power but more so to ensure ultimate reliability meaning that it operates comfortably under tolerance for maximum boost psi. The integrated intercooler keeps chamber temperatures down and provides for better/cleaner atomisation. The customer wished to retain OEM brake rotors so visually the car’s appearance remains as standard, leaving only brake pad upgrades as an option.

Gearbox

The 300C gearbox has a 600 Nm torque limiter inside its control unit which equates to 442 lb/ft of torque. With the front mounted intercooler and turbo upgrade it was necessary to delimit the gearbox in order to achieve the higher bhp figures; without this modification the torque limiter would hold back peak power across the entire rev range. The 300C’s engine puts out 376 lb/ft at around 1600-1800 rpm as standard but as the gearbox in fourth kicks down at anything below 2,700 rpm it was impossible to test the actual peak torque of the engine on a chassis dynamometer. The gearbox controller was modified to allow a new limit of up to 760 Nm to be achieved, which equates to 560lbft, thus allowing the maximum power to be smoothly achieved.

Front Mounted Intercooler

The standard setup has a very narrow, low volume intercooler which, with the higher boost pressures now being used, would become inefficient. The replacement fitted by Celtic Tuning’s engineering team is a much larger high volume front facing intercooler with silicone hoses. Installation required the cross member located behind the bumper to be adapted slightly in order to fit. No physical cosmetic changes were necessary from the outside. With the new large front mounted intercooler installed lower temperatures are ensured when the engine is operating at higher boost pressures and thus maintained reliability.

Turbo

The standard Garrett GT2056V turbo has been modified and converted to a hybrid format in order to be able to achieve pressures of up to 1.9 bar. The compressor housing has been machined and a larger compressor wheel with uprated 360 degree bearings has been installed along with other blueprinting modifications to enable the pressures to be achieved with complete reliability. The well-proven standard unit was chosen for the upgrade due to minimal space available at the rear of the engine bay and limited amount of resources available for this engine.

Engine

The 3.0 V6 CRD engine is a Mercedes Benz family unit sourced by Chrysler during the German brand’s ownership of the now Fiat-controlled U.S. carmaker. Utilising commonrail 2 injection technology and with peak running pressures of up to 1600 bar, this engine is a very good base for tuning as well as being a reliable and well-proven unit. The Bosch EDC16 ECU is a flexible control unit and enables high power outputs to be achieved whilst finely controlling emissions to ensure the AFR’s are as clean as they are standard.

Braking

The braking was mildly upgraded with EBC Yellow Stuff brake pads, while the ventilated rotors, due to their production size at 345 mm, are retained in their standard format. The stopping power provided is vastly improved whilst maintaining the silent operation of the standard discs.

Performance Times

The performance times tested were taken using the production turbo with front mounted intercooler, delimited gearbox software and upgraded ECU software. The engine was putting out 293 bhp and 402 lbft of torque. Naturally the times at the optimised 314 bhp and 416 lbft will be slightly quicker. Celtic tuning will have this data available shortly. At a kerb weight of 1910 kg the 300C is a relatively heavy car making every second achieved a test for the engineers.

> Performance Times Table (All)

Results

Three levels of performance upgrades are now available for this engine from Celtic Tuning through this rigorous project. These compare with the stock power, which is 215 bhp according to manufacturer. The first option is a software only upgrade to the standard ECU taking power from 215 bhp and 315 lb/ft up to 270 bhp and 369 lb/ft. The second option is an ECU software upgrade along with delimiting the gearbox controller and fitting an optimised large front mounted intercooler, taking power with this option from 215 bhp and 315 lb/ft up to 293 bhp and 402 lb/ft. The final tuning level is as with the second option but with an uprated turbo for additional boost and reliability, power climbs to 314 bhp and 416 lb/ft (with scope to go even higher).

Technical Data

Power/Torque Graph (Stage 1) / Power/Torque Graph (Stage 2) / Power/Torque Graph (Stage 3) / Performance Times Graph (Stage 2) / Performance Times Table (All)

About Celtic Tuning

Celtic Tuning are specialists in the performance tuning of the vehicles engine management system. We develop all our own software in house which gives us endless flexibility to tune an engine to the customers’ requirements. As well many years in automotive software development we have 22 years experience in full engine reconditioning, performance tuning and engine race preparation. The mechanical knowledge is fundamental in the precision tuning of the engine management system which gives us a distinct advantage over many others. We work on a wide variety of vehicles ranging from cars, vans (commercials), 4X4s, trucks, agricultural vehicles, track/race cars and marine engines. We pride ourselves on customer satisfaction and is at the forefront of our operations. With reliability, drivability and satisfaction being our target we are sure you will be delighted with the service we offer. For more information on Celtic Tuning visit: www.celtictuning.co.uk