What actually are you after if I may ask?

Even if you would know the answer to the question I am not sure if you get what you are looking for. Each engine will get slightly different results again (especially during its life), and it is not uncommon that engines give different hp levels provided by manufacturers, being it higher or lower. If you want to know what your engine does then there is just one way, you need to put it on an engine dyno.

 

AVOS, it is really just a curiosity. In the US we call it "Bench Racing"... or bragging rights. What had sparked my interest was the articles in the Modern Sporting Icon book concerning Paramount Performance tuning. They said the "flywheel" horsepower for a 4.0NA they tested was only 248hp (Jaguar csays its 290hp). Well first off they show a picture of them testing on a Chassis Dyno, so how can they measure "flywheel" hp? Is this a nomenclature difference between the Brits and the Yanks? Did they mean RWHP? Secondly the article says that Paramount "Remapped" the ECU and boosted output to 277 at the flywheel. They must mean RWHP. Plus are you aware of any performance tuning companies that truly can remap and give those kinds of gains. If so, there has to be someone in the US doing that also. I ask because I read in this forum no one makes a "Chip" that really works. Plus you said you have never changed the software on your car. Can you state what you've learned about reprogramming/remapping claims.

 

PP only has a chassis dyno, so any engine HP numbers they provide are estimates as the figures are calculated. Also their specific type of dyno is a dual drum per wheel one , and these types don’t give a good whp (rwhp) as there is more drag from the drums that you would experience on the road. You can find many debates about what sort of calculations you can do, but without true figures from an engine dyno, it stays just an estimate.
Here is a nice list of what the results from a chassis dyno can influence.
http://www.kennebell.net/techinfo/general-info/DynoTestVariables.pdf

For myself I try to stick to single drum units (and prefferably with eddy current to give some resistance) and only look at rwhp, but even then it will be hard to compare figures, you always need to take your time, and try to create similar circumstances if you want to compare runs.

Tuning the ECU should always be the last mod you do to your engine so you can set it as optimal as possible (especially when you start altering boost levels, as might even have to retard ignition). On a stock R engine I would guess you could gain about 20 rwhp, but it will depend a little on how sharp you go. The disadvantage is that the sharper you set the tune, the greater the risk on possible issues (i.e. detonation), as your margins get smaller. Things could change over time, for example 1 injector could spray less fuel then the others, and although for 1 bank the ECU will adjust the fuel ratio, there will still be one which will be leaner and be at risk.

I haven’t tuned mine, as the rich fuel mixture gives me some insurance, and the little bit of gains to be had would not outweigh the risk imho, and it would be hardly noticable anyway.

 

Hi super_jag,
Thanks for your useful post. It really helped me a lot as i was searching for same.