When I go for a remap, should the car be full of the specific type of fuel I want to use going forward?
It seems that you can get better power and economy from super particularly if the car is remapped for super fuel. But this would suggest that if you then run an ordinary fuel, the car will probably perform worse than before on ordinary. Does this follow?
Thats because super unleaded is less volatile, and will not pre-ignite all by itself. Which means you can advance the spark and burn it where it is more efficient to burn it. But if you have the car mapped for super and run ordinary fuel it will knock and pink, which will activate the knock sensor and automatically retard the timing - undoing the advancement of the remap and probably some more just to be on the safe side of things - this will make it inefficient and less powerful. However, you could probably get away with driving it at low loads and light throttle applications with ordinary fuel even with a map for 99, but I wouldn't bother as you couldn't SAFELY put your foot down.
So perhaps should I fill with super and then get it mapped and stick in super? Or equally stick it full of ordinary and keep using ordinary?
I'd stick with the super, get the most out of it you can.
Yup I have noticed since my initial remap, the car is much smoother and more powerful and seems to have better mileage on superU.
But the thing is the car had a mixed tank of unleaded and super during its re-mapping, will this have made a difference to the mapping? S
Depends on how much they advanced the timing when they remapped it. They probably just advanced it a tiny bit, maybe took it close to the limit of what 95 octane fuel will accept before it pre-ignites. You can go a whole lot further than that but it'd probably involve a good few hours on the dyno, being live mapped with lots of different throttle applications to get it bang on. Plenty of tuners just like to whack on a generic remap, rolling road it, tweek it if necessary and then pass go collect $200.
i was wondering, would an un-mapped car run ok on super unleaded (97/98/99 RON) rather than standard 95?
with regard to mapping, if you use 95 and have the car mapped for 95, you will get "x" increase. if you use, say, 98 and get the car mapped for 98, you will also get "x" increase.
whether or not you get, say, "x+5%" increase or anything else may depend, best to ring a tuner and ask them.
A car mapped for 95 (whether standard map or a remap) will run fine on 99 octane. However, the calorific value for the fuels is the same so technically if the car mapped for 95 is running on 95 fuel using maximum igniton advance that the standard ECU allows, you will see no benefit from 99 octane. However, many super unleaded fuels also have cleaning agents in them, so you may see some benefit due to the cleaning effect on the injectors and fuel system, giving a better spray pattern and therefore better air fuel mix. And you may just imagine the car feels better, sometimes my car feels great and sometimes it feels terrible but I'm sure 90% of it is all in my head.
With super you can get away with advancing the spark slightly more without risk of pre-detonation. Hence you burn more of the fuel where it is more thermodynamically efficient to do so, around TDC, and extract more work from the power stroke. Therefore a custom map for 99 RON V-Power or whatever will be able to liberate a few more bhp as well as a bit more economy on part load. If I were getting a map there is no way I would use anything other than super.