So I'm driving home from work today and I pass a Sunoco station. At this particular station I could get the GT Race Fuel rated at 100 Octane. Anyone ever run that gasoline in the TL?

100 octane would be harder to burn, and the timing would need adjusted, but the computer would take care of that right?

Just wondering.

JZ

 

Thats only for hot-rods.You prob blow your engine

 

no come on man. how could you blow it? The engine would be running a little hot and may not burn all of it. Maybe a little power and mpg. Depends on price but pretty sure it would not hurt it. ECU would take care of everything. Some people put in 93 in their 87 rated cars no bg deal

 

It's not going to hurt the engine, but isn't going to do anything except cost you more money. Don't expect racing fuel to give you more HP, Sunoco 93 or 94 is MORE octane than our engine needs, and spending extra money on racing fuel is just wasting money. I'd never use 89 octane in my car, but I'm sure not going to make the oil companies richer by buying racing fuel for a street car.

 

Shouldn't make a difference from 93 to 100 if our cars run well omn 91. Now if you were running 87 and went to 100 then I would expect some change. But not worth the premium if you ask me... consider how pricey 93 is I cannot imagine what 100 would be like.

If you are going to the strip, then see what (if any) the different might be.

 

in Europe average octane number is 95, standard is 98 and on some Shell, OMV stations you can refill with 100+, it will not burn your engine, makes it more powerfull only, I can not imagine how you in US have such a strange fuels (low octane 89, 91)
never heard about it, from time to time I but a 100liters canister of 110octane for street racing that is hot stuff

 

You're only wasting your money by putting this in your TL. Stick with 91 or 93.

 

Europe and the US calculate the octane rating differently. The US averages the research and motor octane numbers ((R + M) / 2) while Europe just goes by the research number (the higher of the two). 96 octane in Europe is roughly the equivalent of 92 octane in the US.

 

I'm not running 100 Octane, I would see it as a waste of cash. My question was if anyone has. I'm looking for the "Yea, I tried it and it didn't do squat." response. Or vice versa.

JZ

 

Higher octane fuels don't burn "hotter"...that's a misconception. The octane rating measures a fuel's ability to resist detonation or "knock". Lower octane fuels are more likely to cause spark knock...your knock sensor will pick it up and retard the engine's ignition timing to eliminate the knock. That's how you lose power running lower octane gas.

The benefits of running higher octane fuels can be seen if you have the ability to adjust the timing advance and lean out the mixture; both of these can increase power significantly (or melt your pistons, but that isn't because of the fuel). I don't know how far the TL's ECU can advance timing or change fuel trim, therefore I can't say at what point the ECU can no longer take advantage of the octane boost. It'd be interesting to test on a dyno, though.

 

This is 100% correct - but to add to JJ's articulate answer, most race fuels do not contain the additives street engines need, so long term use could indeed be detrimetal, as well as a waste of money.

 

thx 4 your explanation of differences between fuel in UE and US

 

This may be a stupid question but....isn't the Sonoco 100 a leaded fuel?

 

NO...as far as I know, leaded fuel is not sold in the USA. 100LL aviation gasoline contains lead, but it's not sold for automobiles and will actually damage today's gasoline engines which are designed for unleaded fuel. Stick with a good brand of premium gasoline and you'll be just fine...and so will your engine.

 

leaded fuel is sold in the states but i believe its anything over 104 octane.. 100 octane will not do anything for the tl because it is all computer controlled.. It doesnt need it.. I think it would actually be good for it to run some thru once in a while like a better version of an octane booster but really no need for it.. I would just use 93 and once a year get an injection cleaning at acura....

 

Well you would want to use it with the super charger right. With forced induction and a high compression ratio like that of the TL 11:1 you would want something less likely to knock. Am I right?

 

Higher octane will allow you to run higher compression ratios or high turbo boost. High compression makes more power, but requires more antiknock in your fuel. Since I am assuming you will not be changing your connecting rods or crankshaft or adding a turbo or supercharger, benefits from this gasoline will only be cosmetic.

 

Ok The higher the octane the more horse you get. All of those single turbo supras can only drive on race fuel which is over 100 octane. So please if you dont know what you are talking about, dont post it.



Edit by MOD cTLgo: Super large font size unneccesary, reduced font

 

Wow, you have no idea what you are talking about... go ahead and add yourself to that list. The overwhelming majority of cars on the road today do not need an extremely high-octane gas to run efficiently. Octane ratings are a measure of the ability of gas to resist engine knock. If your car is not "knocking" using a higher-octane fuel will do absolutely nothing for you, but waste your money. The real advantage of racing gasolines comes from the fact that they will tolerate higher compression ratios and thus indirectly will produce more power since you can now build an engine with a higher compression.

The bottom line here is that, in a given engine, a fuel that doesn't knock will produce the same power as most expensive racing gasolines.


Oh, and for the record?? When I had my Supra, I dynoed 620 rwhp at 22psi on a TO4R.....on Sunuco Ultra 94

 

NJ Aegean 03 It's amazing how many people still think this is true.

Sometimes the confusion comes with confusing gas mileage with power. Using a lower octane than required will give less power and mpg because the computer retards the engine when the knock sensor tells it to. But using a higher octane than required will neither increase mpg or power, but will decrease $$$ in your wallet.

 

And people willing to do this is proof that they are willing to spend like 3.00 a gallon for gasoline.... the oil companies love people who always believe the more it costs the better it is...

 

Where do we find these people?

High octane gasoline does not produce additional horsepower by itself. It is an enabler. The octane number is an index of antiknock additives in the gasoline. The higher the octane number, the more the fuel resists knock, or requires a higher combination of compression and spark to ignite.

According to Boyles law, a given molar quantity of gas will increase in temperature as you compress it or reduce its volume. In high compression or high boost engines if you use low octane fuel, the temperature during the compression cycle may exceed the ignition threshold of the fuel, causing the fuel to ignite at the wrong time- without needing a spark. The premature ignition is also called detonation or knock and can destroy and even melt your expensive high performance engine.

High compression and high boost engines provide higher power because they are able to cram more molecules of air and fuel into a small space, so that when the fuel burns, it expands with higher pressure, thereby giving your engine more power. High octane fuel is used with high performance engines to ensure that the fuel burns at the correct moment in time to avoid premature detonation and to ensure that the downstroke of the piston will turn the crank in the right direction.

So in those 'single turbo supras can only drive on race fuel which is over 100 octane' because if they use fuel with lower octane, the engine will blow up and spew all that expensive single turbo hardware all over the track, not so the 100 octane will make 'em so fast.

Modern vehicles with electronic ignition will adjust timing to make the most of available fuel quality, but will not make your car run higher than its rated horsepower. Unless you modify your vehicle for higher compression or add a turbo for boost, 100 octane gas won't do a thang for your horsepower.

Yes, I do know what I'm talking about.. You've just been schooled.

 

I recall an article in either CAR or EVO in which they dyno tested a car using regular high-octane unleaded fuel (96, IIRC) then the same car running Shell Optimax (98). The car put down a few more hp just by using the higher octane level fuel. The results surprised even the dyno guys and the editors. They evaluated the results and found that the engine programming did in fact compensate for the higher octane levels as much as it could, and this produced the extra few ponies.

If anyone has access to their library of past issues and can find it (I'm at work, so I won't be able to), that article will probably clear up a lot of the arguments going on in this thread.

 

If the car was turbo'ed, the turbo ECU should allow higher boost levels with higher octane gasoline... higher antiknock allows higher boost w/o detonation. And higher boost is more horsepower.

TLs do not come with a factory turbo.

 

This may not be entirely true, I recall Pat Goss from the PBS TV show Autoweek being asked a similar question concerning 93 or 89 octane fuel in engines only requiring 87.

He indicated that while it may not hurt the engine, higher octane fuels burn at a lower combustion chamber temperature than lower octane fuel (but burn longer in time hence more energy) in lower compression engines designed for lower octane. So they tend to leave more deposits on combustion chambers, pistons and exhaust valves. So over time a engine designed for 87 may build up enough deposits to make it necessary to require 89 or 93 octane fuel to prevent pre-detonation. I've seen similar writings on some motorcycle engine forums on the web.

Many people have already posted some excellent posts so essentially use the fuel that the engine was designed for and don't waste your money on high octane fuel the engine does not require.

 

I hear about the carbon buildup issue making it necessary to burn higher octane fuel later in the life of the engine. I had some experience with that on an 83 GM product. Yet in more recent years I haven't seen or heard that as a major issue with any car ... But then when your car has 140k miles on it you are more forgiving of its nature if it is not running like it did 6 years earlier...

 

Pat Goss...bwahahahahaha! Sorry, i could not resist, but I find something wrong in nearly every one of his shows, and I swear he reminds me of the wood shop guy in my high school. Notice that when he starts a sentence and cannot recall how to finish it, he says something like "and all that kind of good stuff". As for John Davis, I am just amazed he can keep finding l;arger khakis. When that show was just starting out on Maryland Public TV, I called them and offered to be a technical consultant, gratis, in order to help the show's credibility, because I thought they filled a valuable niche. Well, ol' JD did not seem to think he needed any help, even when I cited (politely I thought) 5 technical flaws in the last 2 episodes. Oh well, just goes to show, it is style over substance. I am just amazed they keep sending them cars - and I love the drag strip they use - it looks like it is running downhill, and my Mom could get better quarters than they turn.

Back on topic...this one has been beaten to death, but as I wrote already, racing fuels can hurt your car, since they are not formulated with deposit control additives. This is a Placebo Effect Web old wives tale for straight street cars with OE tunings - in cars like the supercharged SVT Cobras with pulley upgrades, timing advances, etc, racing fuel can put up some great dyno numbers, and are OK for use at the track

 

So to some up everything everybody has said " Dont waste your money, unless you have a turbo or a supercharger" IT wont do anything except waste your money.

 

Actually, to sum up, I asked if anyone has ever tried it....

Anyone?

JZ

 

The O2 sensor in modern cars will detect the unburnt gas that results in carbon build up as a rich a/f mix and lean out the injector metering and adjust ignition timing. The lean intake charge has a secondary effect of increasing combustion chamber temperature and burning out carbon deposits. The O2 sensor - injector feedback loop will constantly adjust until the correct a/f mix is detected according the the ECU fuel map.

Advances in timing control and fuel metering allow modern cars to run at higher compression with lower octane fuel. For example, the 3.1L (3.2) engine in Audi's 2005 models squeeze out 255 hp using a 12.5:1 compression ratio and no turbo. Fine control over timing and direct injection fuel metering allows Audi to use such high compression with street (although premium) gasoline.

 

There you go.

I feel qualified to comment since my other car uses high octane gas. My 98 Formula makes 754rwhp thru an unlocked T400, 28" slicks, and thru a 9". We have it tuned for 21 psi, max rpm of 7200, and are using C16. C16 is ~117 octane. It's about $8 per gallon. I can drive around using 93 but when I race we put in C16.

You can get 94-104 unleaded in the USA, usually around $4/gallon. Most of the leaded race gas at the pump is ~110L.

Disco, I have not tried it in my TL.

Now, if you were to go race at the track, in the hottest month of the year, and it was like 95F out, that 100UL might actually help a bit.

Most of the time it should not help our cars bonestock. Now if you could scan our cars and look at timing at WOT, you could see what the stock baseline is and then see if the pcm will add timing in with the 100UL. I have no idea if it can do that, but I would think there would be a max timing standard that comes stock in our cars like they do in all cars.

With our LS1 powered cars (www.ls1tech.com), I have seen folks increase their WOT timing using 100UL - 110L. I have a friend who added about 7 degrees of timing using 110L and a speed density tune.

Oh, and if you were to say spray a 100 shot of nitrous, I would probably run some 100UL mixed in with 93 because I would want more octane with the anticipated higher IAT's.

 

Perhaps they didn't believe in your oil filter bypass valve regulating oil pressure theory?

Glad to read your not bitter about being rejecting by Goss and Davis

Back to the original question, I asked a friend at my gym (what a place for fuel questions) who was a chemical engineer for Chevon for 12 years this question and the deposits being built-up on components due to over-octaning an engine. His answer....

Yes, no and maybe. He said my original answer of lower combustion chamber temperatures is overly simplistic and may not be true at all for some/many engines. The difference he said for higher octane fuels is the better uniformity and spread of the flame once it is ignited by the spark plug. The resistance to predetonation (or spontaneous ignition due to pressure and temperature rise) as well as that control of the even flame propagation is what makes 93 octane special. He said the temperature and dynamics of the flame is different for different engines and that is more crucial to combustion chamber temperatures than 87 versus 93 octane fuel.


In the end he simply stated what others have said quite a few times in this thread, use the octane that is equal to or slightly higher than what was specified in the vehicle.

 

Props to John!

For some reason, I'm thinking LS1s come MAF stock. What ECU is performing the map for speed density?

I'd also like to hear you opinion on speed/density vs MAF. From work I've done on B204L engines running T25, TD04, T3 and GT30BB with speed/density, I've found the tuning to be very temperature sensitive with heatsoak being a major pain. While waiting to stage, how does your buddy compensate or manage heatsoak?

Also, to run 21 psi did you do any bottom end mods for your engine, what injectors and what turbo(s) are you running?

 

LS1's come with a MAF stock. Some folks are copying the Australian guys who are big SD freaks and starting to use SD for big cam tuning etc.

I think for moderately modded cars regular tuning is fine. I think highly modded cars can benefit from SD tuning. I don't know what they do regarding any issues, maybe ask on www.ls1tech.com or www.hptuners.com.

I have a built 8:1 348ci LS1 with forged pistons etc.

I am running 83 lb siemens injectors, a BS3 aftermarket pcm, Vortech YSi-Trim 1600 cfm supercharger, and a Griffin FMIC.