95ron vs 98ron
Discussion
Hi guys upgraded my e36 m3 to an e46, now what i want to know is, the car is mapped for 98 ron petrol to give it the stated economy and performance figures, however it has been running nicly on 95 as it says in the manual it will do, my questions are as follows... how much econony and perfomance will be lost on lower grade fuel and when the tank runs out and i start using 98 or 99 ron, will i have to reset the ECU like i used to have to do on my imported impreza to take the ECU back to factory setting to get the benifit from the higher grade, or will it adjust on its own? thanks guys. Its a great car by the way,glad I done it :-)
E30M3SE said:
99Ron Shell VPower or similar.
End of thread.
Mines an e36 evo so not the same engine, but similar. I run it on tesco 98 or shell stuff pretty much all the time. If i get caught short ive put the lesser high performance stuff in from bp etc, and it usually feels ok to begin with but a little less responsive. Whenever ive managed to put higher back in again it's usually pretty noticeable.End of thread.
Congrats on the car. Had mine about 4 months now and only use V Power. Might just be me dreaming but I am sure the throttle response feels more crisp with the higher grade fuel. I have noticed this on other performance cars I have owned as well. As for fuel economy, not sure it makes that much difference. Would be good to know what people think of Tesco 99 RON.
my tvr never ran on anything less than 98, so as it was cheaper, i used tesco 99 ron, i believe its high in sulpher apparently? So used to blow through some injector cleaner now and again cos I heard it clogged things up a bit so the garage told me, I'll certainly use tesco as its local to me and much cheaper than shell. it does seem to be running sweet on 95 though, but I'll fill up with 99 and see if i notice much difference
You might see a difference on boosted engines where a knock sensor is used, but 95 octane fuel actually has a higher calorific value than 98 (it's marginal), so the only issue would be whether the faster burn time of the 95 octane fuel will give a problem with pre-ignition. If not then the power output will be much the same. On a boosted engine the ECU can run with more advance and marginally higher boost on higher octane fuels since their knock resistance is higher, then it will make a difference.
Dave
Dave
The calorific value is debateful, it depends on the mix used to generate the higher octane rating. Tesco for instance use a 5% mix of ethanol. Certainly on older cars I would run on super unleaded due to the lower ethanol content and especially if I was running direct injection.
But when it comes to power it isn't really noticeable. Lots of comparison tests etc with only a few hp increase which is never going to be really noticed. Bit like when people spend thousands on an exhaust for an extra 5bhp, consider it a noise upgrade and your money is wisely spent.
I've ran many hours logging 95 vs 98 with very aggressive timing maps and on 95 saw no increased knock so tuned the map on 95.
For the ECU learning on fuel type, it takes a % number of knock triggers for the spark map to be retarded, on older cars this was done by dropping down to a lower spark map for ignition. It would take quite a few tanks to relearn. Modern cars use adaptive maps much more real time but once a trigger is met it goes back to basics.
If you want to have a play, fill up on whatever fuel you normally fill up on and then go and unplug the battery for 30 minutes to ensure the memory is clear, on some cars you may need to remove the ECU fuse. Feel the difference? That's the car running on its default map with no adaptive changes... a trick some off the shelf tuners use - they force the map to remain static.
Fuel qualities these days are vastly improved over 20 or 30 years ago but having said all that, I stick Super in the M every time because its pennys different. Each tank costs maybe a quid or so more, its man maths at its best.
But when it comes to power it isn't really noticeable. Lots of comparison tests etc with only a few hp increase which is never going to be really noticed. Bit like when people spend thousands on an exhaust for an extra 5bhp, consider it a noise upgrade and your money is wisely spent.
I've ran many hours logging 95 vs 98 with very aggressive timing maps and on 95 saw no increased knock so tuned the map on 95.
For the ECU learning on fuel type, it takes a % number of knock triggers for the spark map to be retarded, on older cars this was done by dropping down to a lower spark map for ignition. It would take quite a few tanks to relearn. Modern cars use adaptive maps much more real time but once a trigger is met it goes back to basics.
If you want to have a play, fill up on whatever fuel you normally fill up on and then go and unplug the battery for 30 minutes to ensure the memory is clear, on some cars you may need to remove the ECU fuse. Feel the difference? That's the car running on its default map with no adaptive changes... a trick some off the shelf tuners use - they force the map to remain static.
Fuel qualities these days are vastly improved over 20 or 30 years ago but having said all that, I stick Super in the M every time because its pennys different. Each tank costs maybe a quid or so more, its man maths at its best.
Hair Flick said:
The calorific value is debateful, it depends on the mix used to generate the higher octane rating. Tesco for instance use a 5% mix of ethanol. Certainly on older cars I would run on super unleaded due to the lower ethanol content and especially if I was running direct injection.
But when it comes to power it isn't really noticeable. Lots of comparison tests etc with only a few hp increase which is never going to be really noticed. Bit like when people spend thousands on an exhaust for an extra 5bhp, consider it a noise upgrade and your money is wisely spent.
I've ran many hours logging 95 vs 98 with very aggressive timing maps and on 95 saw no increased knock so tuned the map on 95.
For the ECU learning on fuel type, it takes a % number of knock triggers for the spark map to be retarded, on older cars this was done by dropping down to a lower spark map for ignition. It would take quite a few tanks to relearn. Modern cars use adaptive maps much more real time but once a trigger is met it goes back to basics.
If you want to have a play, fill up on whatever fuel you normally fill up on and then go and unplug the battery for 30 minutes to ensure the memory is clear, on some cars you may need to remove the ECU fuse. Feel the difference? That's the car running on its default map with no adaptive changes... a trick some off the shelf tuners use - they force the map to remain static.
Fuel qualities these days are vastly improved over 20 or 30 years ago but having said all that, I stick Super in the M every time because its pennys different. Each tank costs maybe a quid or so more, its man maths at its best.
Ive heard of people forcing a dme/behaviour reset by disconnecting the battery on the m3 before but always assumed it was bBut when it comes to power it isn't really noticeable. Lots of comparison tests etc with only a few hp increase which is never going to be really noticed. Bit like when people spend thousands on an exhaust for an extra 5bhp, consider it a noise upgrade and your money is wisely spent.
I've ran many hours logging 95 vs 98 with very aggressive timing maps and on 95 saw no increased knock so tuned the map on 95.
For the ECU learning on fuel type, it takes a % number of knock triggers for the spark map to be retarded, on older cars this was done by dropping down to a lower spark map for ignition. It would take quite a few tanks to relearn. Modern cars use adaptive maps much more real time but once a trigger is met it goes back to basics.
If you want to have a play, fill up on whatever fuel you normally fill up on and then go and unplug the battery for 30 minutes to ensure the memory is clear, on some cars you may need to remove the ECU fuse. Feel the difference? That's the car running on its default map with no adaptive changes... a trick some off the shelf tuners use - they force the map to remain static.
Fuel qualities these days are vastly improved over 20 or 30 years ago but having said all that, I stick Super in the M every time because its pennys different. Each tank costs maybe a quid or so more, its man maths at its best.
ks. Is there anything to this?thanks guys, that has helped me a lot, i'll generally use higher grade stuff, but if im shopping at asda and need a bit of juice, as they only do 95 at my asda store, i wont feel too bad about chucking in 20 quid or so while im there :-) We are quite lucky around here as petrol is generally on the cheaper side of the national average I think, supermarket 95 here is running at £1.34 at the mo
We use 95 in our Karts as its a faster more aggressive burn. We have fixed timing and squish (compression ) is tightly regulated.
I too did loads of testing a few years ago on my Remapped Audi S4 2.7 Twin turbo and found I could run more ignition advance on Optimax (it was called at the time) than normal 95. Wheather it made more power or not never rolling roaded it to see.
I too did loads of testing a few years ago on my Remapped Audi S4 2.7 Twin turbo and found I could run more ignition advance on Optimax (it was called at the time) than normal 95. Wheather it made more power or not never rolling roaded it to see.
carreauchompeur said:
Andy70 said:
upgraded my e36 m3 to an e46,
Upgraded? Wash your mouth out paulmc said:
We use 95 in our Karts as its a faster more aggressive burn. We have fixed timing and squish (compression ) is tightly regulated.
I too did loads of testing a few years ago on my Remapped Audi S4 2.7 Twin turbo and found I could run more ignition advance on Optimax (it was called at the time) than normal 95. Wheather it made more power or not never rolling roaded it to see.
thats interesting, I have seen tests on 5th gear and other motoring shows and they have used 95, 97 and 98 ron, doing it properly like draining the tank before using different fuel etc and dyno tested them all, everything from something like a polo, then a golf gti and then an impreza, it seemed the more powerful the car was to begin with, the better the gains from the higher fuel grade, so it must make a difference in certain circumstances, i was just curious as to how much crap fuel would affect the running of a car thats mapped for better grade fuel, it seems to run sweet on 95, so as soon as its empty, i'll fill up with 99ron and see what happens..... watch this space lolI too did loads of testing a few years ago on my Remapped Audi S4 2.7 Twin turbo and found I could run more ignition advance on Optimax (it was called at the time) than normal 95. Wheather it made more power or not never rolling roaded it to see.
Andy70 said:
carreauchompeur said:
Andy70 said:
upgraded my e36 m3 to an e46,
Upgraded? Wash your mouth out That's SUCH an e46 thing to do.
VinceFox said:
Andy70 said:
carreauchompeur said:
Andy70 said:
upgraded my e36 m3 to an e46,
Upgraded? Wash your mouth out That's SUCH an e46 thing to do.
Andy70 said:
VinceFox said:
Andy70 said:
carreauchompeur said:
Andy70 said:
upgraded my e36 m3 to an e46,
Upgraded? Wash your mouth out That's SUCH an e46 thing to do.
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