My car is a Smart Roadster Coupe.
Originally purchased in March 2004 from Euro Sportscars in Stoke Poges as No 02 of 100 of a special "Digi-tec" limited edition. This consisted of front spoiler, side skirts and rear spoiler, colour coded front and rear "grey plastic" areas, Digi-tec 16" graphite coloured alloy wheels, EBC drilled and grooved front brakes with EBC green-stuff brake pads, front wheels spaced out by 30mm per side, rear wheels spaced out by 25mm per side, Eibach performance springs, custom intake ducting, custom twin centre exit add-on to the standard exhaust and a Digi-tec re-map.
In December 2004 I changed the standard turbo for a Smart-R-Us Tsunami hybrid turbo together with an Evil-Twin dump valve. This appeared at the time to make the faster but I had no dyno or test data to back this up.
In January 2005 the Eibach springs and standard shock absorbers were upgraded to SW Greenline springs and Bilstein dampers. This lowered the ride height by a further 20mm and helped stiffen up the handling. Also at the same time the standard rear lights were changed for Michalak ones
Following a number of problems with the modified standard exhaust it was changed for a prototype Janspeed de-catted twin centre exit exhaust in October 2005. This can also be seen in the above photograph.
Before this minor engine modifications were undertaken. These consisted of Janspeed intercooler pipes, Brabus TIK pipe and a Viper induction system.
These modifications again appeared to make the car faster and more enjoyable to drive.
I attended my first dyno day in December 2005 in the hope that the car would be putting out a healthy amount of power. Bearing in mind the standard car puts out 80 bhp and the digi-tec press release and advertizing had the modified roadster putting out 112 bhp.
So, I was hugely disappointed to get a result of exactly 100 bhp and 76lb/ft of torque (according to the experts the car was "over-fueling").
This gave me the incentive to have a custom re-map as a lot of mods had been undertaken since the original re-map.
So, a few days later 2006 my first custom map was done which gave revised figures of 103.2 hp and 90lb/ft of torque (better but still not outstanding). They said that they had been quite conservative with the custom map so in february 2006 they had another go.Again this improved the figures slightly to give 105.5hp and 94.3lb/ft of torque - not bad for a 810kg car but still could be better.
Having driven a re-mapped Brabus Roadster in August 2006 that had been dyno tested at 133bhp my car felt very sluggish! Driving my car home from this meeting I noticed it was only boosting 1.25/1.3bar under full acceleration - the custom re-map previously had the boost maxing out at 1.5bar so I wondered whether it was an off day for the car (as it was very warm). I then decided to run some acceleration tests using a G-Tech Pro RR performance meter. These were done late at night (to ensure the lowest ambient temperature possible).
These runs were not scientifically controlled but were good enough to give a general indication of the performance of the car from a standing start. The results were somewhat worrying giving a 0-60 time between 11 and 11 1/2 seconds! Also apparent was that the turbo was still not boosting above 1.25bar and it was struggling to get there (normally the car would boost very quickly up to its maximum level!)
The next service was due August/September 2006 so I decided to spend some serious cash to try and get more performance out of the car and change the vehicles aesthetics. This also included diagnostic work to identify why the turbo boost was reduced.
The first item was to get the car on the dyno to see what it was putting out before doing any work. The result was a bit of a shock - the car was now putting out less than 92bhp and 89 lb/ft of torque (compared to 105.5hp and 94.3lb/ft of torque) - a loss of almost 15% power - it also confirmed the boost guage was accurate and maximum boost was only 1.25bar.
The car was stripped down and it was found that the Tsunami hybrid turbo was failing (lucky that it was caught in time!). Following specialist advice it was agreed to replace this unit with a standard roadster turbo (as it was found that the Tsunami was a modified 599cc turbo with an enlarged intake but a standard sized outlet which meant that more air was getting into the turbo but it couldn't get out any faster - a serious design flaw!). So, the standard turbo was added to the large list of things to do.
This work took close to six weeks in all to complete (most of which was due to delays at the paint shop). The work consisted of:
All wheels refurbished
Front brakes replaced with 308mm vented disks and AP Racing 4 pot calipers
Tillett Racing carbon fibre racing seats with suede pads and custom sub-frames
Michalak Bi-zenon front headlights and custom black vinyl surrounds to the front fog lights
Black side indicator lenses (replacing clear lenses)
Aluminium internal deocrative parts for main and secondary dash board instruments, door pulls, heating and ventilation controls, indicator stalks, dash top buttons and heating pods.
Aluminium and leather replacement gear knob and hand brake.
Aluminium starter button (replaces the key slot and ignition barrel)
Tinted side and rear windows
Brabus V6 style leather steering wheel with aluminium "ferrari style" gear change paddles
Aluminium and rubber pedals
Janspeed "stealth" exhaust with custom extension and twin centre exits (manufactured and fitted by Torque Exhausts)
Existing wheel spacers replaced with 40mm per side (80mm track widening) to the front wheels and 45mm per side (90mm track widening) to the rear wheels
Fully polished head fitted with Brabus cam and valve springs
4 bar fuel regulator
Mk 1 fuel rail
Mk 1 MAF sensor
Tsunami hybrid turbo replaced with standard roadster turbo (a Garrett GT12 unit)
A further custom map
Ventureshield custom clear protection to the front and sides of the car
The custom map results are getting there now - 121.0hp and 105.5lb/ft of torque. A much better result
I attended a "dyno" day four months after the latest set of modifications and put the car on the rolling road to see if the cars ecu had "learnt" the custom map parameters and improved performance accordingly. The results were pleasantly suprising - 127.5 bhp and 119.4 lb/ft of torque
We are now getting somewhere as these figures are similar to a mark 1 Lotus Elise (with the cars also having similar kerb weights).
There are a few ideas in the pipeline to further improve performance so - as they say "watch this space" for future developments.
Anyway, here's are few shots of the car as it is now