Hi,
OK, before I start I will state that I am a professional tuner, however, I am not touting for business, I may never tune a VR4 again! However, before taking on this car, I did a fair bit of research and found this site very useful, so thought I would take the time to share the results.
So first a bit of background: A friend with a garage asked me to take a look at a car that came in with a knocking engine; the customer was supplying another engine; but they wanted my opinion on what had caused the failure and would it be possible to remap the car if needed. Upon removing the engine it became obvious that the car had been running lean, had been detting and that the turbos were quite 'tired'. Replacement turbos were acquired and after discussion with the customer we removed the Unichip and fitted an uprated fuel pump in readiness for remapping. The car already had a 2.5" decat and k&n panel filter.
After some tentative checking out on the road and with a few miles on the replacement engine I headed for the dyno to see where we were, not a great 264bhp at around 0.6bar, fuelling was off the scale rich!
After a little fettling we got to 329bhp and 368lbft, boost was now 1.05bar at peak torque tailing to 0.9bar at peak power, fuelling at 0.76-0.77 lambda. I was convinced that there was more to be had but I had to pull 2 degrees of timing and charge temps were now rising 15C in a single run, the graphs really show that there was a restriction somewhere, experience with early Evos pointed me towards the intercooler.
After a call to the customer and letting him have a drive he was impressed enough to agree to trying a better intercooler, a week later I picked the car up again and had another play, the result was 359bhp and 382lbft at 1.15bar peak tailing to 1.05, boost control could be better but not bad for the standard setup and flying blind with no 2byte load on the 7201 ECU. Fuelling at a safe 0.76 lambda and this time a healthy increase in ignition timing to smooth things out.
Graphs below, first is the real reason for the post and all the waffling - the comparison of power and torque with the standard intercooler and the 600x300mm core.
Hope this may be of some use to someone.
Andrew...