daedton

Hey all. Doing my first track day at High Plains Raceway here in Colorado. Was wondering what's the highest octance you can safely put in an 07 RS?

Thanks in advance.

07 RS
98 C2S
97 C4S
77 911S

GrantG

Hi - Hope to you there soon! No reason to put in more than 91 at altitude - maybe 93 if you can find it. High altitude needs less octane than sea level and using more octane than you need will just make you lose power (lower octane is more volatile). You only want to prevent detonation - not going to happen at altitude with pump premium. Try to get as little ethanol content as possible too (usually better with mid-grade).

roberga

you can put what ever (unleaded) you want and it will not hurt the car but it will not help. The tech guys will know more than me however my understanding is the ECU is programed to burn a range +/- the 92 in the book. Putting race gas will smell great but I do not think will help the performance. It will hurt your wallet as at least here in Seattle it runs > $6.00 a gallon

daedton

Thank you both! We're headed there this Sunday. $100 for the whole day. Not bad.

07 RS
98 C2S
97 C4S
77 911S

GrantG

I might see there. Come say hi if you see the car in my avatar.
-Grant

raspberryroadster

put in race gas (113 octane) if you want - can afford...higher octane never hurts (only means it prevents pre ignition- a good thing- by igniting at higher temp.). for economics run the octane your car is tuned for (i run 94...and when i cannot source that i add lucas octane enhancer).
likely you are tuned for 91/92....real issue usually only arise for turbo/supercharged engines where exceptional rapid power delivery causes extreme heat (in a normally aspirated engine pre-ignition from too low octane gas causes pinging/in a forced induction engine-supercharger/turbo pre ignitioncauses scored valve/damaged piston)

sharkster

As long as it's unleaded you can use MS109 if you like. Having said that with the tuning etc... that we've done the US cars on a _stock_ tune really don't take advantage of anything higher than 94 octane. They don't make any more power and with 94 the car utilizes the highest possible ignition map.

mooty

91 oct only.
if you got more than that, your cat will die.

GrantG

I don't think the car can even utilize 94 octane at 5,000 ft. elevation (air density is about 15% less). I think 91 is pretty close to max.

rcg412

this is not true at all. on the east coast it is 93 for premium. point is that higher than 94 it makes little to no difference in performance.

JR944

91 pump premium will work absolutely fine. That's what I ran all summer in my GT3 and the temp tomorrow will be low 50's at best. Detonation will not be an issue and 91 would be fine even if it was hotter. Fill up in Beyers on your way there as there is no non-race gas for sale at the track.

I'll be there coaching at least one other driver. PM if you'd like some help. 6 hours is a lot of track time, I could be convinced to drive my truck and pick up some extra gas on the way too.

Yours will be the 4th orange RS I've seen this year at HPR. Can't recall if I've seen any other colors....

Joe

sharkster

Ah yes there is the altitude factor so it'll still likely utilize a less aggressive ignition map

But the car is tuned for 93 octane from the factory so us California and other 91 users end up having the ECU run a less aggressive ignition map;(

GrantG

Also, the altitude acts as though the engine has a much lower static compression ratio, so detonation is not really a problem even with an aggressive ignition map.

Tacet-Conundrum

Can't we get 92 at shell gas stations? Not like I've bought the high octane stuff since I was in high school and we all drove around in 1985 honda civic s hatchbacks.

mooty

we have ran 100 oct unleaded race fuel.
over 8 cars, every cat died.
the remaining 12 cars on 91 are fine.
each car has 5k track miles min.

but CA is know to have "strange" fuel. so that may be the prob....