Where to start... well I guess it was back in the Summer when I ditched the v-band for a full 5 stud 3" downpipe and lost just about all low down torque making off-boost driving less than urgent
So much so that it made my coupé very black and white i.e. it was either on or it was off! So back to the drawing board, I either revert back to my previous setup, change to a smaller turbo or really have a good think
Enter the magician, he needs no introduction, pure genius in a car... Barbz
So we started talking about what could be done and of course the obvious 2.4 conversion sprung up but while I am not a poor man lets just say I couldn't quite commit myself that far
Sooo, what to do? Well we both believed that the 2.4 had created a little bit of a chasm between its smaller 2.0 brother. There was no reason not to pursue the 2 litre with a vengeance, it simply required a bit of thought to create the right mix… so that’s what we did
Roll on 3 months and we arrive at the breaking point. The mechanical element had been masterfully put in place by Monsieur Barbz, all it needed now was an engine management up to the job. Going standalone was an option but I wanted to try and force the issue by keeping with the standard Bosch Motronic and Unichip combo which had thus far served me so well. Possible… well first off was running bigger injectors, 440cc the weapon of choice, so this immediately creates an issue with idle, throttle response, closed loop etc. Then we have the fabled MAF creating a restriction at the top end and therefore allowing enough air to flow and fuel accordingly.
At this point I should thank Suba for introducing FCCUKers to the new and undisputed heavyweight champions of Coupé mapping… Perfect Touch
The holy grail of Coupé mapping, live mapping, is now a reality! This was much more than a remap, this was a “new” map for a “new” engine going further into the Bosch Motronic than ever before. Rob is the mapping guru at Perfect Touch, a more dedicated or skilled mapper you will not find anywhere. In fact Rob is to mapping what Barbz is to engine building
So what could be done? Well the Unichip was tried but just wasn’t capable of such dynamic management. This is not surprising as while it is very effective for fine tuning the standard fuelling setup or even slightly greater, it is unfortunately out of range for more extreme requirements. So the only resource left was for Rob to truly get to grips with the Bosch Motronic… this was no easy task!
After 4 days of battling with bytes and code, relentless exhaust fumes, a multitude of never ending questions from myself, Rob created a brand new base map allowing for perfect idle, throttle response, lambda readings, ignition timing, rpm limiter and POWER
I now only have the Unichip controlling my water/methanol injection which works great
This is a complete first in coupe tuning (at least in the UK) where the Bosch Motronic has been successfully modified to accommodate such a highly tuned engine. Nice one!
So the results… if you haven’t already scrolled down to this bit
Wheel Power @ 1.5bar392bhp @ 7000rpm
Flywheel Power @ 1.5bar420bhp @ 7000rpm
355lbs/ft @ 5500rpm
Not too shabby for a 2 litre Fiat on pump fuel without any nitrous
There were so many runs conducted that is hard to recall and certainly most were not saved during the course of developing the new map. The best run from memory produced 398bhp @ the wheels
For some reason the fly power is a bit lower than normal due to very low transmission losses of 6%!!! Looking at Suba and TurboNick’s results at Perfect Touch they both had 15% losses, which is just about perfect for FWD, and Nigel and Highwayman had 10-11% which is a little on the low side… but 6%?!!
If we use the Puma racing FWD formula of wheel power +10bhp /0.9 (approximately 12-15% transmission losses) then this gives a fly power of 447bhp and 370lbs/ft… not that it matters as the business end is wheel power
On the road I have to admit that it’s borderline ridiculous… just perfect then
Off boost driving is now a pleasure with very good throttle response and super smooth cruising. Thankfully the Apexi can limit the boost in first and second so as to get maximum traction but when 3rd gear lets go I would not be lying to say that it feels quicker than first gear in a standard coupe and requires a strong arm to keep it in check. The top end is really quite something with a huge power band that just keeps holding all the way to redline at 7750rpm… and all at just 1.5bar
Yesterday driving back it was horribly wet which meant 4th gear was lighting up the wheels (proper wheel spin!) Just want some dry weather now… maybe at Silverstone
So there we go, another coupe tuning story
I like to think I played a small part in this tale (project manager me thinks
) but in reality it comes down to some seriously skilled people pushing the boundaries
Barbz is the man, nobody knows more about the coupé and quite simply nobody does it better. Coupled with our new friends Rob and Claudio at Perfect Touch, coupé tuning has just turned another page