Race Fuel at Track Days.

Folks,

Question for you's. Say your car is mapped for E5 only ok and runs grand. But one day you go to a track day (drag racing only) and the option arose to use race fuel (102ron). Can anyone speculate if there would be any performance gains to be achieved by doing this?

Cheers
Paddy

No performance gains but it will give you extra safety from detonation. On the track, oil vapours could get into the cylinders, reducing the octane level of the petrol

Yeah I was thinking that alright. I no of a starlet turbo which is road mapped for race fuel only and he runs it on drag strip and its very quick but has alot of work carried out on it! But again its mapped for it, just wanted to see would it have real performance benefits for a car thats not mapped for it.

not unless your ecu can adjust for 102 which it still can if ecutek'd afaik..the map provides optimal settings for the fuel you mapped for but can still adjust timming in case of knock so I dont see why it couldn't advance timing if the right fuel is in there..would need an ectuk person to answer that but a standard jdm subaru ecu would be mapped for 100 ron so you woudlnt gain anything..I dont know of any jap cars that are factory mapped for 102 but they do sell it at the pumps

[quote author=Dagnut link=topic=16053.msg197598#msg197598 date=1246011819]
not unless your ecu can adjust for 102 which it still can if ecutek'd afaik..the map provides optimal settings for the fuel you mapped for but can still adjust timming in case of knock so I dont see why it couldn't advance timing if the right fuel is in there..would need an ectuk person to answer that but a standard jdm subaru ecu would be mapped for 100 ron so you woudlnt gain anything..I dont know of any jap cars that are factory mapped for 102 but they do sell it at the pumps
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Didnt know that. The standard ECU can adjust 3 degrees of timing afaik so would that mean that cars in the UK that are mapped for 98 octane can run on 95 with no issue whatsoever because it can still adjust the 3 degrees?

[quote author=Sweetcakes link=topic=16053.msg197614#msg197614 date=1246015312]
[quote author=Dagnut link=topic=16053.msg197598#msg197598 date=1246011819]
not unless your ecu can adjust for 102 which it still can if ecutek'd afaik..the map provides optimal settings for the fuel you mapped for but can still adjust timming in case of knock so I dont see why it couldn't advance timing if the right fuel is in there..would need an ectuk person to answer that but a standard jdm subaru ecu would be mapped for 100 ron so you woudlnt gain anything..I dont know of any jap cars that are factory mapped for 102 but they do sell it at the pumps
[/quote]

Didnt know that. The standard ECU can adjust 3 degrees of timing afaik so would that mean that cars in the UK that are mapped for 98 octane can run on 95 with no issue whatsoever because it can still adjust the 3 degrees?
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I think so yes I'm not sure its directly related to the value of ron..ie 3 ron equals 3 degrees of timing.. but even after ecutek your ecu still has the ability to put you into "safemode".
I dont think a uk car can advance timing but when you use 99 shell or even bp 102..Im not sure why but I think AF ratios and boost are more important when advancing where as you can just retard timing to reduce knock(various so called mappers used to do this and claim they where mapping for 95)...all just afaik but

Cool, but why then, would i have been told to be very careful when running E5 without booster (after mapping for E5 + booster) and not to take it above 1bar of boost? If the ignition retards itself to the the slightly lower octane, then it should be alright to run full boost surely?

if your mapped for e5 + booster you could be mapped for 100 ron? possibly..anyway the ecu can retard for knock but in a lot of cases the damage is already done so any time running lower octane fuel your at risk...I'm sure the risk increases and the amount of ron redcution allowance > timing to be pulled(can't phrase that properly) decreases as your boost and fueling increases..if you know what I mean..
For example with a standard b4 factory mapped 100 ron running e5 (lets says it 98 for now) from the pumps @ .8 bar of boost would probably be safer than our cars mapped for E5 @ 1.2 bar of boost but running 95..i think
In any case the ecu retards ingintion after it detects knock so the damage can be done

ah, makes sense now, bigger boost will see the engine sh*t itself before it has a chance to retard the timing. Thanks man

Glad you understood what I was trying to say..basically as with anything the margin of error decreases as you push the boundaries