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Discussion Starter #1
Hey, so I was Doug some research on e85 but I wanted some personal opinions. Do you think that e85 gas would be benefitcal to the engine for tracking on the Cla250? Or would it just be better with 91/100 octane gas? Any personal experiences/opinions?
 

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I dunno ... I suppose there will be all sorts of "experts" on this going both ways ... but the fundamental concern is nonzero-hol varnishing effects.
If they want to promote EXX gasohol for whatever environmental or financial reasons fine, but put in a varnish breakdown agent or something.
It's like ... DUH.
 

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PHP:
Hey, so I was Doug some research on e85 but I wanted some personal opinions. Do you think that e85 gas would be benefitcal to the engine for tracking on the Cla250? Or would it just be better with 91/100 octane gas? Any personal experiences/opinions?
Mercedes doesnt recommend E85

For you to run E85:

1. Change your fuel lines
2. Need bigger injectors
3. Bigger Fuel Pump
4. Calibrate or tune ECU for E85
5. Idk what else I am missing... this is from experienced...
 

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Discussion Starter #4
PHP:
Mercedes doesnt recommend E85

For you to run E85:

1. Change your fuel lines
2. Need bigger injectors
3. Bigger Fuel Pump
4. Calibrate or tune ECU for E85
5. Idk what else I am missing... this is from experienced...
Interesting ok. So run 91 then.
I might be doing a dyno as well and run 91 then 100 to see if their is any major changes.
 

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Hey, so I was Doug some research on e85 but I wanted some personal opinions. Do you think that e85 gas would be benefitcal to the engine for tracking on the Cla250? Or would it just be better with 91/100 octane gas? Any personal experiences/opinions?
Whether any model years of the CLA can use e85 aside (it certainly seems like some are), it's always been my understanding that e85 creates less energy that gasoline. I can only regurgitate what I've read but here's an interesting article from Edmunds that compares the two:

E85 vs. Gasoline Comparison Test

Assuming Edmunds is correct, wouldn't using e85 make your car slower than using the recommended 91/93 or even a higher octane race fuel?

-Eric
 

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Running e85 will not make a car slower than using the recommended 91/93. It has less energy by volume. It will givve less mpg. The engine also must be tuned for E85. More fuel has to be added and the fuel/air mixture has to be correct for it. That means the car needs bigger injectors and a fuel pump to handle the greater fuel flow. It does allow for much higher boost without causing pre-detonation
 

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Running e85 will not make a car slower than using the recommended 91/93. It has less energy by volume. It will givve less mpg. The engine also must be tuned for E85. More fuel has to be added and the fuel/air mixture has to be correct for it. That means the car needs bigger injectors and a fuel pump to handle the greater fuel flow. It does allow for much higher boost without causing pre-detonation
Sacrificing overall efficiency for some blind and poor policy (history has already judged this one) is stupid in anybodys book.
Note I did not say fuel efficiency cuz over 10 years thats not the overall systematic damage caused ... life cycle cost and all the (otherwise not needed) associated chemicals and related outgas into atmosphere to minimize said LCC is one messed up case study.
But anyway I still gotta find a good local Ezero station ... my M270 is practically screaming at me ??
 

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Discussion Starter #10

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E 85 will have less BTU's than 10 or 15% gasohol. That is one reason why you require larger injectors, you have to pump more fuel in order to obtain the same results, hence lower MPG. In addition I believe it may void your MB warranty if they can show a fuel related problem. ]
 

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Discussion Starter #13
quarter tank 91 octane... dump some octane boost then fill it up half way for race track or full tank daily driving 
How much would you "Dump" in. Last thing I wanna do is do too much.
 

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I don't get the octane booster thing. Octane is a fuels resistance to the air/fuel mixture igniting from compression before the spark. Therefore higher octane allows you to run more advanced timing. If you're not adjusting your timing for the track why do you need octane booster? Upping the octane rating doesn't mean more power without adjustments.

Or am I missing something? Placebo effect?
 

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I don't get the octane booster thing. Octane is a fuels resistance to the air/fuel mixture igniting from compression before the spark. Therefore higher octane allows you to run more advanced timing. If you're not adjusting your timing for the track why do you need octane booster? Upping the octane rating doesn't mean more power without adjustments.

Or am I missing something? Placebo effect?
Its a safe way of having a higher gas?!?! boost RON?


IMG_4765.PNG
 

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Its a safe way of having a higher gas?!?! boost RON?


View attachment 36121
I understand adding an octane booster if you suspect the fuel you use is lower than your engine is set up to take. Most 'adaptive ECUs' don't boost performance based on higher octane fuel, they are designed to retard the ignition, etc if sub-standard fuel is used because the correct grade isn't available.

So the idea of 'I run my car on normal fuel but I'm going to use higher octane this time to go faster' makes little sense.

It's great marketing by the oil companies though. You should run a car on the fuel it's set up to run on.
 

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If i wanted to simply boost octane, I just buy a can of toluene. It's common, inexpensive and very, very effective. Parts of the following are from the World of Chemicals. Toluene aromatic hydrocarbon industrial applications as fuel octane booster, racing fuel additive

For those that want to boost their octane rating number of their gasoline, it is not really difficult-- add toluene to your gasoline. Toluene is an aromatic hydrocarbon; it contains only hydrogen and carbon atoms. When burned, the byproducts are CO2 and H20-- nothing that will damage the cat or O2 sensors. It is a primary ingredient in gasoline, especially in aviation gasoline.

The fuel sensitivity of toluene is 14-- making it a good fuel for an engine under a heavy load. Sensitivity is RON minus MON. (toluene has a RON of 121 and a MON of 107).
Fuel sensitivity is something most people know little about-- nor do they need to . . for those that want to know, they can check this out. The Underlying Physics and Chemistry behind Fuel Sensitivity
With a fuel with a "high' sensitivity , like the alcohols, which have a sensitivity over 20, the performance of the fuel suffers under an increasing load. Toluene's low sensitivity means that it performs very well in a heavily loaded engine . Loading on the engine is particularly high in drag racing.

Typical gasoline has a density of about 0.73 g/mL ; the density of toluene is higher at 0.83 g/ml and thus contains more energy per equal volume of gasoline. Not only does toluene increase the anti-knock properties of gasoline-- it releases more energy when burned. This is sharp contrast to adding bethyl tert-butyl ether, ethanol, and other oxygenated compounds to raise the octane rating. More energy means more heat leading to hotter exhaust gases that also bring more kinetic energy to the turbo charger impeller -- get more boost and get it sooner.

A simple Google search will let one know where to buy pure toluene and how much to mix in to your gasoline. While is easy to boost the octane well over 100-105, one should keep in mind that 'normal' and higher performance GDI engines were not designed to burn this fuel. With more energy released at combustion, there is more stress on the engine components. With higher exhaust temperatures and added kinetic energy in the gas path there is more mechanical as well as thermal stress on the turbo components.

It is also noted that just because a gasoline has a higher octane number, it does not necessarily mean the gasoline contains more energy per unit of volume-- much depends on how the fuel is blended to achieve the higher octane number-- many octane booster compounds actually decrease the available energy in the fuel; other compounds are added to offset these losses. Octane is increased to RETARD combustion under higher compression. Toluene increases both energy and octane; however, without an increase in compression ratio, the full benefit of the increased octane rating and increased available energy will not be realized. As with most "benefits" there is an associated "cost". Nirtomethane (dragster fuel) actually contains LESS energy than regular gasoline per unit of volume-- but it is rich in oxygen, and less air is needed for it to burn-- so you and burn more fuel with a like amount of air: more fuel = more energy. When you need to go 0-100+ MPH in 1 second in less than 60 feet-- you burn a lot of fuel (gallons of it).

Methylcyclopentadienyl manganese tricarbonyl (MMT) is also a gasoline octane enhancer produced by the Afton Chemical Corporation (Afton), formerly known as the Ethyl Corporation. I think this is an ingredient in Lucas Oil Octane Booster. A frequent diet of this will not be good for a catalytic converter. Toluene, on the other hand, does not produce any combustion byproducts that will not damage the cat. Using too much toluene can cause real problems-- because the very high octane, combustion is retarded and on engines not designed for such fuel the exhaust valves can open while the fuel is still burning. This will really make your turbo spin fast but not for long and the excessive heat will do bad things to the entire exhaust system and associated sensors.

Toluene renders some of the lubricants in gasoline ineffective-- at high levels (over 15%), addition lubrication needs to be added to the fuel; Marvel Mystery Oil or ATF work well. Normal gasoline contains toluene (2-3%)- some commercial racing fuel (100-105 octane), up to 25% + added lubricants..

More reading: Toluene - Octane Booster FAQ
 
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