185 + tune+ race gas =
05-19-2009, 04:07 PM
#26
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i put some 100 in at the track and couldn't really tell any difference. I actually thought I lost power somehow, maybe its because I was thinking/anticipating that I would feel a huge difference when I put the 100 then didn't lol....maybe just my mind playing some tricks on me.
05-19-2009, 04:18 PM
#27
I thought the car would pull less timing with higher octane = more hp, regardless of tune. No?
Obviously, if the car was specifically tuned to run on 100 or 110 it should perform even better, but even the tuning gurus seem to think a normal 91/93 octane tune will perform better on race fuel. I have yet to try this personally as I'm not in a hurry to burn out my cats and have no need, but still curious.
I can assure you these colder temps down south the past couple days have made my car feel like she gained 100hp!! Wow, what a difference cooler temps and low humidity make!
Obviously, if the car was specifically tuned to run on 100 or 110 it should perform even better, but even the tuning gurus seem to think a normal 91/93 octane tune will perform better on race fuel. I have yet to try this personally as I'm not in a hurry to burn out my cats and have no need, but still curious.
I can assure you these colder temps down south the past couple days have made my car feel like she gained 100hp!! Wow, what a difference cooler temps and low humidity make!
Why would 100 Octane affect cats??? I can see running rich affecting cats but surely running 100 octane on a 93 tune would not?? Are you saying that 100 octane fuel will cause the car to run rich, tuned or not???
05-19-2009, 04:20 PM
#28
i put some 100 in at the track and couldn't really tell any difference. I actually thought I lost power somehow, maybe its because I was thinking/anticipating that I would feel a huge difference when I put the 100 then didn't lol....maybe just my mind playing some tricks on me.
05-19-2009, 04:30 PM
#29
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Eurocharged Performance ML63 and TT lambo
+1 , without the tune, the only thing 100 Octane would do it allow the ECM/ECU to NOT pull timing if it sensed detonation which is highly unlikely on 93 anyway??? I think that WITH a 100/110 octane tune, the timing would advance a bit for more HP. Again, thats WITH a 100 octane tune!!! Wayne, you know about this stuff, what do you think????
05-19-2009, 04:55 PM
#30
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C32 AMG
Sorry, that was a bit of a sarcastic remark. No, I am not implying that running 100/110 is going to burn out your cats...right away at least. If anything it would be harder on the O2 sensors than the cats I would imagine. From what I've been told it has to do with the lead....
05-19-2009, 05:11 PM
#31
Sorry, that was a bit of a sarcastic remark. No, I am not implying that running 100/110 is going to burn out your cats...right away at least. If anything it would be harder on the O2 sensors than the cats I would imagine. From what I've been told it has to do with the lead....
Theres no lead in the 100 we can run here in Illinois, its still 100 unleaded!!! see below:
Overview
Sunoco 260 GT™ 100, which has the highest octane rating of any street legal fuel, is now available at selected retail locations.
Sunoco 260 GT 100 is designed for high performance street cars, muscle cars, classics, street rods, motorcycles, karts and marine applications. Sunoco 260 GT 100 contains no metallic compounds to harm catalytic converters or oxygen sensors. It contains a comprehensive additive package for greater engine protection and reduced fuel system deposits. Sunoco 260 GT 100 is also compatible with virtually all two-stroke synthetic and mineral based motor oils.
Last edited by Newzchspy; 05-19-2009 at 05:18 PM.
05-20-2009, 09:43 AM
#32
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SLK55 AMG, E320 BlueTec, ML350, (formerly) C32 AMG, MR2 Turbo, HD-FLH-FSE, BMW R100RS, Ducati M900
High Octane
Generally, all things being equal if a car is tuned for 93 octane and is running well (i.e. no detonation) then putting 100 octane fuel in it will NOT increase the performance of the vehicle.
However, I used to race motorcycles and we did extensive testing of fuels and we found that some of the unleaded race fuels were oxygenated which meant that additives in the fuel contributed oxygen to the combustion process and thus did caused the engine to produce more power even when tuned for 93 octane street fuel. As far as I recall, this effect was mostly due to the race fuel burning more completely in the combustion chamber and thus was contributing more of its available heat energy to do work and less wasted out the exhaust. Keep in mind that the gains are relatively small and do vary with the fuel and vehicle. I think that a 120 hp sportbike was gaining something like 3-5 hp at most with this.
It is worth noting that the Sunoco 260 GT 100 is a oxygenated fuel, so this could possibley combine to provide a small performance gain. Only 0-60, 1/4 mi times and dyno numbers all taken with and without the fuel and on the same day would verify such claims.
Another item to consider is that while fuel injected, those sportbikes did not have closed loop engine management systems. They lacked the O2 sensor in the exhaust and thus did not vary mixture with changes in the oxygen levels of the exhaust. I have no idea what having the oxygenated fuel in a car would do? Probably it would do nothing bad. Another consideration is that if your AMG tune is right on the ragged edge and is detonating a little bit (and thus retarding the timing a little more) then having the higher octane fuel should make a real difference.
Irish
However, I used to race motorcycles and we did extensive testing of fuels and we found that some of the unleaded race fuels were oxygenated which meant that additives in the fuel contributed oxygen to the combustion process and thus did caused the engine to produce more power even when tuned for 93 octane street fuel. As far as I recall, this effect was mostly due to the race fuel burning more completely in the combustion chamber and thus was contributing more of its available heat energy to do work and less wasted out the exhaust. Keep in mind that the gains are relatively small and do vary with the fuel and vehicle. I think that a 120 hp sportbike was gaining something like 3-5 hp at most with this.
It is worth noting that the Sunoco 260 GT 100 is a oxygenated fuel, so this could possibley combine to provide a small performance gain. Only 0-60, 1/4 mi times and dyno numbers all taken with and without the fuel and on the same day would verify such claims.
Another item to consider is that while fuel injected, those sportbikes did not have closed loop engine management systems. They lacked the O2 sensor in the exhaust and thus did not vary mixture with changes in the oxygen levels of the exhaust. I have no idea what having the oxygenated fuel in a car would do? Probably it would do nothing bad. Another consideration is that if your AMG tune is right on the ragged edge and is detonating a little bit (and thus retarding the timing a little more) then having the higher octane fuel should make a real difference.
Irish
