by MFaulks » Wed Sep 08, 2010 5:47 pm
Dave with the greatest respect that sounds good in theory, but you will find this is not bourne out in practical reality. Firstly, let’s start with your motivation to move away from the Renix, as you say it’s plug and play in it’s OE state, but again tuned this can be a very different matter, and I speak from the experience of doing it. So firstly we agree you are looking to tweak an engine setup taking it away from the setup that Renault and Berex spent a large amount of $ sorting. It also has a large safety margin in terms of limit to detonation etc – to account bad fuel, poor maintenance, and a host of other issues. Further it has not been setup to achieve best power. I don’t imagine for one minute you spent your $ on the Adapt to only achieve the same power levels as the standard Renix offers, that would be pointless. So you wanted more power and to remove the safety margins, and take that responsibility yourself. If you are prepared to accept more compromise in terms of performance i.e. less, then plug and play as you say becomes increasingly possible.
The Renix does not rely on the knock sensor, and in fact is only sensitive within narrow rpm bands, tuned to the original engine parameters, that unless altered to match modified engine specs becomes inappropriate – depends where your engine makes the highest BMEP.
Suitably tuned, and using the same octane index fuel, you won’t need the knock sensors. If you are prone to putting in cheap fuel having setup up on premium then knock sensors will be the least of your worries. Running on the limit of knock is not the best way to achieve peak torque at any engine set point, and the small but not time sustained performance increase will increase your EGT and cause accelerated degradation of your engine if not failure. I actually had this discussion with the head of Ford UK engineering many years ago admittedly, and he was firmly against it. Engine dyno test results clearly show the knock limit is not a sustained place to be, nor necessarily give best torque. The only scientific way to know this is to have the engine on a dyno test stand and measure all the parameters, and we individually simply do not have that luxury, time or money in most cases.
When you employ a professional tuners resource, he will tune the engine to a compromise he feels is best fit, cognisant of the age, type, use, owner competence etc, and this will always be a judgement. I have no doubt Scoff has taken yours to the fine limit.
What more are you really looking to achieve, I guess that’s really the question?