Will the M3 with a Tune see anymore gains with Race FUel?

[M3MamBo]

Let me know guys.

[phusion974]

You can tune your car to run race fuel by advancing the timing. You will see some gains.

[jimmy ny]

I think its good to use time to time. It does help clean out the engine and you can see a small increase in power. I would mix 2 or 3 gallons of 100 octane with the rest being 93 or 91 if 93 is not available in your area.

[jimmy ny]

i can tell you personally that running higher octane fuel, does burn better and will help clean out the combustion chamber, by burning complete, hence running better. sorry.

[kitw]

Obviously, he opened up his cylinder head and licked the combustion chambers and tasted less gasoline or something.

I've actually seen high octane unleaded gasoline (100 Octane) leave MORE deposits, because it typically doesn't have the same detergents/additives that regular street gas does. I'll leave leaded race gas and avgas out, because obviously it does the same.

[Legion5]

First off race fuel DOES burn better than regular fuel simply due to higher engineering tolerances. You can expect to see gains of 4% at the same octane, which isn't useful for real life because it still costs $7-$30 a gallon but is useful for racing. I've studied this from an engineering perspective.

Whoever says race fuel or 100 octane cleans out the engine is absolutaly wrong though, 100 octane will actually cause your engine to be much dirtier. I've killed cars by running higher octane fuel by accident in just a few thousand miles due to build up. 100 octane literally does the opposite of what you think.

TrackRat summed up what you can expect with horsepower gains, but I also want to add that most modern engines tend to benefit at least a bit up to possibly 100 octane fuel with the proper tune with regard to modern street engines. I cannot stress enough that you need the proper tune though.

[jimmy ny]

im talking about 100 unleaded fuel. maybe in your neighborhood you dont have it available. big shot. not 110 leaded.

[captbilly]

Almost every car made today has to significantly retard ignition at high power setting to keep the fuel from detonating. If you look at the compression ratio of older cars compared to new cars, and then look at the fact that the available octane of fuel has actually gone down, you can see that modern cars are designed with a different philosophy regarding detonation and fuel economy. In the "day" car were designed to run high enough octane and low enough compression ratio (among other things) so that the engine would never detonate at any power setting. Today cars are designed to not detonate at normal power settings where the vast majority of driving is done. This allows the designers to build highly efficient engines for normal driving. But the result is that at high power setting virtually all engines retard the timing (and sometimes increase fuel air ratio) to keep the engine from detonating. The result is less than optimal timing, and therefor power, at high power settings. If you run 100 octane in an unmodified car you will see zero (or near zero) power increase, because the engine computer isn't designed to run on anything higher then the specified octane fuel. However if you tune for 100 octane, so that the timing and fuel mixture are optimized for 100 octane, you can see significant performance gains.

Anecdotally; I have an Audi A6 2.7t (I am still waiting for my M3 to arrive from the prep center in SoCal). I have been running a chip that allows me to switch from the stock engine map to a 1 bar map, but also allows me to specify 91, 93, or 100 octane fuel (with the same boost). I also have a VagCom device that allows me to monitor virtually every engine parameter in real time, and graph. When I switch from 91 octane to 100 octane the HP goes from about 310 to 360 (according to APR) but the boost remains the same. What does change (according to the VAGCom graphs) is the ignition timing. With 91 octane I often see TDC or even past TDC timing at high power, but with 100 octane the timing is maybe 20+ degrees before TDC. There is a quite noticeable improvement in power throughout the RPM range, and the engine simply "feels" better (even I don't know what I mean with "feels" better). I cannot imagine that the M3 engine, with 12:1 CR, doesn't need some serious ignition retard at high power settings to keep detonation in check. I would love to see a 100 octane chip for the M3 but it seems like nobody does such a thing on non-turbo cars. I know many racers who run 100 - 115 octane in their cars and do significant retuning as a result, I don't know why it wouldn't work in a M3.

[Draff1]

I've seen posts on this forum referencing Pencil Geek's tests with 100 octane race fuel yielding dyno gains of 30HP. Is this incorrect? I recently added VP race 100 to my tank and honestly noticed nothing in terms of butt dyno.

What is the real expected advantage of increasing octane on a basic stage 1 Dinan tuned E92 motor? 10HP? 0HP?

[B-52Gunner]

Just make sure you use a quality unleaded racing fuel. Sunoco 260 GT and 260 Gold are both excellent and street legal (100 octane).

[Legion5]

Originally Posted by TrackRat

You're kidding right? Higher engineering tolerances on the fuel?

To be clear what I meant was that they have tighter quality tolerances for race fuel, which results in a gain in performance compared to consumer grade fuel on average.

You've killed engines by running higher octane fuel causing a build-up of carbon deposits????? I doubt it unless the race fuel was Diesel and had so much retardant in it that you needed an MSD 44 amp magneto to fire it.

I didn't say it killed the engine, it just killed the car. The carbon built up on the catalytic converter which caused an engine fault, which killed the car. It was computer limited not engine limited so it wasn't that serious. Still not a good thing to do.

PLEASE... Show me the SAE test data where "racing fuel burns better" as in more complete, when only the octane has been increased from 93 to 100 octane and the chemistry has not been changed.

I'm not sure you understand what I'm saying, I think you think I'm trying to make the old mistake of thinking that higher octane fuel has more energy content.

What I meant was that testing has shown that consumer grade fuel can vary in it's energy content several percent from the factory. Racing fuel is made more selectivly so you get the fuel with higher energy content than the consumer fuel on average, but still within the range that consumer fuel falls into. Does that make sense?

Think of it like this, if a store selling car batteries sells consumer and racing batteries. The consumer batteries are sold with an initial voltage of between 12v and 13v. The racing batteries are the same model, but the manufacturer controls the quality better to make sure you only get the 12.5v-13v batteries.

Increased knock resistance in higher octane fuel allows a small increase in timing and power at the specific points where the engine is knock limited and no where else. Oxygenated fuels can offer a small increase in power but that has nothing to do with octane.

At least you understand that higher octane fuel only offers a performance improvement if the engine is re-calibrated for the increased octane. Sorry but the other stuff you posted is incorrect as is Jimmy NY's post.

Like I said I wasn't talking about that and I was very clear in the post that we're talking about racing fuel compared to consumer fuel at the same octane not different octanes.

[Dave07997S]

First off most racing unleaded fuel that is street legal is oxygenated and does run detergents. Also, the point of diminishing return comes into effect here as once you go past 95 octane there isn't that much more to be gained.


However, I remember PencilGeek ran straight 100 octane in his car and dyno'd and ran a 361 rwhp on a dynopack while the car ran 333rwhp with just plain jane 91 octane.

Here's the graph..



Hey PG..hope you don't mind if I used this..

I personally run a blend of 100 octane just to get me back to 93 octane and offset the piss water we get here in Cali.

Dave

[Dave07997S]

Originally Posted by TrackRat

For clarification: In your wildest dreams you would NOT get 30 HP from a change in octane only.

If he is using oxygenated fuel, it's NOT just a change in octane.

I was surprised by this as well, however, PG is not one to put up dyno info for the hell of it. I found him to be pretty meticulous in the way he did his dyno's. I just posted this up for a FYI..

Dave

[Draff1]

I think we all appreciate the input but with due respect, a Dyno chart from a respected member of the forum classifies as data and supporting facts for me. While I do believe you are offering a valid point of view and you appear to be far more knowlegeable than many (inlcuding me) you only provided theory. So your point is that the dyno chart is wrong or misrepresented? Keep in mind that CA cars must run on crappy 91 so the bump in octane may have a different non linear result.

In God we trust - everyone else must show the data.

[Dave07997S]

Originally Posted by Draff1

I think we all appreciate the input but with due respect, a Dyno chart from a respected member of the forum classifies as data and supporting facts for me. While I do believe you are offering a valid point of view and you appear to be far more knowlegeable than many (inlcuding me) you only provided theory. So your point is that the dyno chart is wrong or misrepresented? Keep in mind that CA cars must run on crappy 91 so the bump in octane may have a different non linear result.

In God we trust - everyone else must show the data.

I agree..

Dave

[Sales@Evolve]

Originally Posted by TrackRat

As I have indicated in other dyno threads, chassis dyno data isn't worth the paper it's printed on because of the fudge factors used and the complete lack of control over the test conditions. This is why car makers use engine dynos and not chassis dynos for engine development.

People believe what they chose to believe even when the information is false. My information is not theory it's from over 10,000 hours of actual engine calibration work for the car makers on NA and turbo engines. When I tell you you can not get 30 HP from a change in octane only on an NA engine, you can take it to the bank. If PG used oxygenated or other power additive fuel then certainly you could expect more than the typical 12 HP gain you would see in a V-8 engine from a change in octane only.

I fully understand those who do not have expertise on engine calibration probably have no clue what to believe but I know from firsthand calibration what is and is not possible. You're free to believe whatever makes you happy but that doesn't make it true.

What of a chassis dyno test that is controlled and not fudged?

We dyno test M power cars every day and focus on the gains made rather than trying to tell people this is the HP at the crank. We dyno a car stock until we see consistent numbers, do what ever upgrades and then retest until we get consistent figures. Everything is kept equal and we have no problem is seeing consistent changes in graph shape time and time again.
If the correction factors are displayed then you have transparency and this is the problem in the US... no one wants to give out the correction factor data before and after the test...... I wonder why.
I totally agree that a dyno graph without correction factors displayed is for the bin.

As for octane on the E92 M3. We have conducted this test many many times.

A car on 95 Euro will produce around 15HP on average less compared to 99 Octane.

We have seen 30 sometimes but this is strictly not purely down to the fuel but the correction factors being so different on the two test days. The dyno either over or under compensates as it assumes the engine will be making more or less power based on the conditions and the reality of it is that it doesn't react like that. SAE corrections work only within a small range.