Octane level?
#27
skookum
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People take out their pumps on S4's alot because of being paranoid of failure. Also because you will be using clean oil instead of dirty oil from your engine. I have a TII s4 with a large street port that i premix and run 93 octane in, i have a TII s5 that i dont premix and run 93 in. its kinda preference only the s5 is hard to do since its an electric pump not a mechanical and the ecu will notice no oil and put you in fail safe mode
#28
Former Moderator. RIP Icemark.
#31
Sleeper but still slow
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Someone told me that turbocharged cars need premium, so my first fill up was on premium. After joining this site, my 2nd fill up was 87 per a thread almost exactly like this, the car got peppier, and seemed less like it was going to die at any moment like it did on the premium.
#35
Former Moderator. RIP Icemark.
Octane has absolutely nothing to do with increasing HP, so you were imagining things if you think that octane booster helped a FC engine in anyway.
See the octane rating is a measure of the autoignition resistance of gasoline and other fuels used in spark-ignition internal combustion engines. It is a measure of anti-detonation of a gasoline or fuel.
Or in layman's terms:
The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites.
So extra octane in no way will give you extra power. In fact on a FC chances are that high octane levels will result in less power, as it takes more to burn.
The power output of an engine depends on the energy content of its fuel, and this bears no simple relationship to the octane rating. A common understanding that may apply in only limited circumstances amongst gasoline consumers is that adding a higher octane fuel to a vehicle's engine will increase its performance and/or lessen its fuel consumption; this is false under most conditions — while engines perform best when using fuel with the octane rating for which they were designed and any increase in performance by using a fuel with a higher octane rating is minimal or imaginary.
#37
The Silent but Deadly Mod
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So to make this clear for everyone:
Premix will necessarily noticeably decrease the octane rating of fuel when used in at least a 100:1 ratio, but the engine content of said fuel will not necessarily increase, thus the car will not be anymore powerful even though its fuel has a lower octane.
True or False?
Premix will necessarily noticeably decrease the octane rating of fuel when used in at least a 100:1 ratio, but the engine content of said fuel will not necessarily increase, thus the car will not be anymore powerful even though its fuel has a lower octane.
True or False?
#42
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OK, you get one brownie point for being correct about jet engines generally having a higher compression ratio, and you get another brownie point just for relating the discussion to aviation. ....
However
1. You can't really compare an internal-combustion rotary engine with an external-combustion turbine engine with respect to octane ratings.
2. Jet A does not have an octane rating, but it would probably be around 15-25 octane if it did. Jet A is basically high-grade kerosene, similar to diesel fuel.
3. There is no 120-140 AVGAS that I am aware of. I think you mean 100/130 or 115/145, neither of which were designed for jet engines.
However
1. You can't really compare an internal-combustion rotary engine with an external-combustion turbine engine with respect to octane ratings.
2. Jet A does not have an octane rating, but it would probably be around 15-25 octane if it did. Jet A is basically high-grade kerosene, similar to diesel fuel.
3. There is no 120-140 AVGAS that I am aware of. I think you mean 100/130 or 115/145, neither of which were designed for jet engines.
#46
Boost ahoy!
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I guess next fill up, I'm knocking my car back down to 87....maybe that would explain why my car seems like it keeps getting slower and slower...hmm, probably in my head, but who knows
Last edited by CyberPitz; 01-24-08 at 06:07 PM.
#47
octane ratings are based upon the temperature at which the fuel ignites. as an engine compresses fuel it gains pressure and temperature. a knock occurs when the fuel ignites too soon because it reached its combution temperature BEFORE reaching the point of spark plug ignition. adding octane(as i'll call it) or detergents and additives to the fuel, effectively raises the temperature at which it combusts in order to prevent knocking. a rotary engine uses lower octane fuel because the temperatures and pressures in the engine before spark plug ignition are not high enough to ignite low octane fuel.
#49
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So to make this clear for everyone:
Premix will necessarily noticeably decrease the octane rating of fuel when used in at least a 100:1 ratio, but the engine content of said fuel will not necessarily increase, thus the car will not be anymore powerful even though its fuel has a lower octane.
True or False?
Premix will necessarily noticeably decrease the octane rating of fuel when used in at least a 100:1 ratio, but the engine content of said fuel will not necessarily increase, thus the car will not be anymore powerful even though its fuel has a lower octane.
True or False?
well if the octane rating is lower wouldn't that mean the fuel ignites and burns more readily? would this be enough to increase the power even slightly?
#50
Former Moderator. RIP Icemark.
But if the seals are tight, then it won't matter