| Author |
Message |
Bill Sebestyen (Bill308)
| | Posted on Tuesday, October 30, 2001 - 9:13 pm: | |
Tim,
High octane rated gas does not need to be hotter to burn, it just burns more controllably under the influence of a high compression ratio and heat. Bill |
Herbert Edward Gault (Irfgt)
| | Posted on Tuesday, October 30, 2001 - 9:08 pm: | |
High octane fuel will not harm a car that is designed to run on regular, in fact the combustion temps will go down and it will be less likely to vapor lock if your car has that tendency. |
Tim N (Timn88)
| | Posted on Tuesday, October 30, 2001 - 6:03 pm: | |
I knew higher octane gas needs to be hotter to burn, but i remeber one of my mechanic friends telling me it was a bad idea to put it in a regualr car because there will be no benefits over the 93 or 94 i usually put in. He also said it would mess something up, i forgot what though. |
Bill Sebestyen (Bill308)
| | Posted on Monday, October 29, 2001 - 9:08 pm: | |
Tim,
I think you've got it wrong.
Higher octane gas, in itself, will not burn valves. High octane is a measure of a fuel's abilility to resist detonation or knock. There is no more power in it and it does not burn hotter. Quit the contrary. As the fuel charge/air mixture burns in the cylinder, the end gas is heated and if the gas is of low octane rating and the chamber pressures are high enough, the end gas will explode. High octane gas minimizes the tendancy of the end gas to explode or knock. High octane gas enabless the use of high compression ratios, which promotes high efficiency and increased power.
The down side of high octane gas is that it costs more and if the high octane rating is the result of the presence of tetraethyl lead, any catalytic converter fitted, will be damaged. Tetraethyl lead is known to protect valve seats but the incorporation of hardened valve seats in modern cars makes its use unnecessary.
If you have experience with burned valves, something else is causing it.
Bill |
Tim N (Timn88)
| | Posted on Monday, October 29, 2001 - 8:37 pm: | |
dont put 100 in a regular non-ferrari. You will burn valves and mess up alot of stuff. I dont know if 100 will cause this, but 110 sure as hell will. |
BretM (Bretm)
| | Posted on Monday, October 29, 2001 - 12:08 pm: | |
Good article in Car and Driver this month about this topic. They do a whole test using 4 different types of cars. |
Richard Stephens (Dino2400)
| | Posted on Monday, October 29, 2001 - 2:14 am: | |
Well, sure, modern cars designed to run on 93 octane will run on 87 octane. But they accomplish this by retarding the timing (and possibly other changes depending on the car). So, yeah, you can drive it fine, but you are losing performance.
Anyway, no such fancy fuel/ignition management systems on my car and since I'm running 10.4:1 and we are down to 91 octane here in California, I need some booster. Does anyone know where I can buy Toulene or Xylene in 5 gallon cans in the San Francisco area?
Thanks,
Rich |
Steve Magnusson (91tr)
| | Posted on Thursday, October 25, 2001 - 10:50 am: | |
Ben -- do a search (on one of the outside search engines, not here) using "RON MON gasoline" and you'll get buried with info. From what I can see, most references say the "sensitivity" (RON-MON) of modern fuels is around 10 -- consequently, 91 RON would be about 86 AKI on the pump at the station. |
Frank Parker (Parkerfe)
| | Posted on Thursday, October 25, 2001 - 10:28 am: | |
U.S. fuel companies use an average octane rating between the Research(RON) and Motors(MON) ratings. Some countries just use one or the other. |
Ben Lobenstein 90 TR (Benjet)
| | Posted on Thursday, October 25, 2001 - 10:22 am: | |
OK now I have a question! (Raising my hand)!
I think my Manual states that I should be using 91 or higher RON.
The local pumps don't show RON. They show a magic formula "(RON + MON)/2 =" then you can take your pick of 87, 89, or 91 (down from 92 in CA).
While I can see now what RON and MON mean from the posts below, what does my 91 RON equal in the magical formula?
-Ben
P.S. Only newer high perfomance engines need higher octane, doesn't that also include Ferrari engines? I know they are probably talking about super high compression engines.... |
Paul Sloan (Sloan83qv)
| | Posted on Thursday, October 25, 2001 - 8:28 am: | |
RON octane is not what is posted on pumps.
READ BELOW>
octane number,
figure of merit representing the resistance of gasoline to premature detonation when exposed to heat and pressure in the combustion chamber of an internal-combustion engine. Such detonation is wasteful of the energy in the fuel and potentially damaging to the engine; premature detonation is indicated by knocking or pinging noises that occur as the engine operates. If an engine running on a particular gasoline makes such noises, they can be lessened or eliminated by using a gasoline with a higher octane number. The octane number of a sample of fuel is determined by burning the gasoline in an engine under controlled conditions, e.g., of spark timing, compression, engine speed, and load, until a standard level of knock occurs. The engine is next operated on a fuel blended from a form of isooctane that is very resistant to knocking and a form of heptane that knocks very easily. When a blend is found that duplicates the knocking intensity of the sample under test, the percentage of isooctane by volume in the blended sample is taken as the octane number of the fuel. Octane numbers higher than 100 are found by measuring the amount of tetraethyl lead that must be added to pure isooctane to duplicate the knocking of a sample fuel. At present three systems of octane rating are used in the United States. Two of these, the research octane and motor octane numbers, are determined by burning the gasoline in an engine under different, but specified, conditions. Usually the motor octane number is lower than the research octane. The third octane rating, which federal regulations require on commercial gasoline pumps, is an average of research octane and motor octane. Under this system a regular grade gasoline has an octane number of about 87 and a premium grade of about 93. Most American-made cars that were built in the 1971 model year or later can use regular gasoline. To prevent knocking, premium grade gasoline must be used in many cars built before 1971 and in some new cars that have high-performance engines. |
Paul Sloan (Sloan83qv)
| | Posted on Thursday, October 25, 2001 - 8:22 am: | |
As of August you can longer get 92 octane premium fuel in the state of Calif. premium is now 91.
The senior engineer for Porsche who cars gas caps state 93 0ctane only says that it's cars will run just fine on 91. (Guess what: they will also run fine on 87 too).
premimum fuel is a marketing gimick for profits.*
*With the exception of High Compression muscle cars. |
'75 308 GT4 (Peter)
| | Posted on Thursday, October 25, 2001 - 3:01 am: | |
True, my manual says to use either 96 or 91 RON (Research Octane Number). Since the max we have in Canada is 91 (some places have ethanol blends at 94+), that's what I put in. |
Nick Scianna (Nick)
| | Posted on Thursday, October 25, 2001 - 2:32 am: | |
Ferrari owners should always read their owners manuals first and then decide if they want to use a lower grade of fuel than specified.That decision is up to the individual. |
Paul Sloan (Sloan83qv)
| | Posted on Wednesday, October 24, 2001 - 7:10 am: | |
On this one I agree with Herb (and magoo) that 87 octane is just fine. Premium gas is not required in the 308, however running techron or a similar additive every 10 tankfuls is not a bad idea.
There are very few unmodified cars that require premium gas and using it when not needed is like throwing your money down the drain (or in this case the tank).
The oil companies have been very sucessful in marketing premium gas to a public that on a whole does not need it, guess which product they make the most profit on. |
Nick Scianna (Nick)
| | Posted on Tuesday, October 23, 2001 - 11:32 pm: | |
With respect to higher octane fuel,in a production Ferrari engine with the factory safe advance curves premium fuel is all that you really need.For K jetronic injected cars I actually recommend Chevron fuel as it has the correct additives in it to keep K jetronic systems clean & happy.I run premium fuel in my daily driver Ferrari's.. 92 octane.Anything above and beyond premium fuel is a waste of money unless your car has been modified.Then thats a whole diffent ball game!Nick Scianna.. |
magoo (Magoo)
| | Posted on Tuesday, October 23, 2001 - 11:32 pm: | |
Fred, I use it, Chevron, but I gotta tell ya that I don't think it gives any better performance than the 87 octane fuel. I've tried both. |
Frederick Thomas (Fred)
| | Posted on Tuesday, October 23, 2001 - 10:46 pm: | |
I always use shell 93. Do you guys think this is a waste? |
magoo (Magoo)
| | Posted on Tuesday, October 23, 2001 - 9:49 pm: | |
If our cars were higher compression then you probably would see the difference. Otherwise in my opinion you are wasting your money. |
'75 308 GT4 (Peter)
| | Posted on Tuesday, October 23, 2001 - 3:19 am: | |
This fuel is designed for aircraft which run at a constant, low RPM (>4500) and for high altitude (low oxygen levels). It burns fast, but with no punch. I used 105 once in my car, not straight, but cut into a tank of premium (91 oct). It smoothed it out, but no performance gain. |
magoo (Magoo)
| | Posted on Monday, October 22, 2001 - 10:06 pm: | |
I find Herbs comment to be correct in that I used 100+ octane in my 308 a couple of times to test. No difference than 87 octane fuel. I think it is a waste of money using 100+ octane fuels in these cars. |
Herbert Edward Gault (Irfgt)
| | Posted on Monday, October 22, 2001 - 4:13 pm: | |
Computer systems that adjust the timing do not have the ability to compensate for too much octane. They can retard the spark if it detects a spark knock but will not advance it further than what is programmed into it. Unless you are having a problem with a spark knock situation then higher octane fuel is a waste of money and any performance increase is probably psychological. High octane fuel is HARDER to burn than regular grade fuel. High octane is for high compression and turbocharged engines. My 308 runs just fine on 87 octane. |
Mitchel DeFrancis (4re308)
| | Posted on Monday, October 22, 2001 - 2:36 pm: | |
Franklin, I too put some 100 octane in both my Ferrari and my VW GTI VR6. I noticed the most in the GTI. WOW it was hilarious, just tapping teh gas and the car lunged forward. The GTI is one fast little car, and with the 100 in it, it FLEW. Did not notice too much difference in the Ferrari, just had some nice throttle response! |
Steve Magnusson (91tr)
| | Posted on Monday, October 22, 2001 - 2:20 pm: | |
Frank P. -- good article on this very subject in the latest FORZA. |
Frank Parker (Parkerfe)
| | Posted on Monday, October 22, 2001 - 2:00 pm: | |
If it is unleaded I don't see how it would affect any emissions components. That would happen if you used "leaded" high octane fuel. The car was made to run on fuel as low as 93 but will compensate for even lower via the ECU retarding the timing. I am wondering if the ECU will likewise adjust the car to run on higher octane fuel ? |
Rob Lay (Rob328gts)
| | Posted on Monday, October 22, 2001 - 1:21 pm: | |
downside is you loose your emissions components and it will cost several thousand dollars to replace. this may only be the 110+ stuff. i don't think 100 would hurt too bad. the cars are made to run on 93, I think higher oct just costs more and can potentially hurt your car. Nick? |
Frank Parker (Parkerfe)
| | Posted on Monday, October 22, 2001 - 12:39 pm: | |
Has any one tried using high octane fuel in their car ? I tried a tank full of 100 Octane unleaded racing fuel in my 348 Spider from a station near Road Atlanta. It cost $3.50 per gallon. I think I have noticed a slight power increase and a smoother running engine but that may be all in my head since I paid so much for it. Any one know of the upside or downside in using such fuel ? |