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E85 Questions

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Hi Andre and forum members,

I have a few questions on E85 that i need answers to.

The problem :

I am in Sri Lanka and the restrictions on Ethanol by the government are very high so it is tough to get a hold of. It is only 96% pure. It is also very costly to dehydrate it to 100%. Without dehydration a 200l barrel of 96% Ethanol costs roughly $1800USD.

My Questions are:

1. For purpose built drag cars that will only be running the E85 at events and tuning. A max a 100L on blended fuel 85% Ethanol & 15% 100 octane AV Gas Low Lead per event. Will i be able to run the 96% pure ethanol without dehydrating it without causing damage?

2. Any other solutions for the above question if the answer is 'NO".

3. Methanol is widely available and it costs only $500USD for 200L. We currently use it with our water meth kits without a problem. I have read that M85 is another fuel blend that can be used, but the data for it is quite low online. Firstly i want to know if i can blend 100 octane AV Gas with methanol and what ratio's can be used.

4. If question 3 is 'YES'. How does M85 compare with E85 in terms of power output? can i make the same amount of power, using higher boost and ignition like with E85?

5. I know that with E85 we need to add roughly 40% more volume of fuel due to the density of the fuel. I know that for pure methanol that i have to increase even more. So with M85 how much more % of fuel would i need to add on top of the current 100 octane AV Gas maps that i have done. I need to know this to know if our current fuel systems can take it up.

I would kindly appreciate quick replies as it is absolutely detrimental that i use higher octane fuel now as i have hit peak performance on most of the cars and the only way forward is the options i have mentioned above. We are unable to legally import racing fuel also because of government restrictions.

Thanks in advance!

If methanol is cheaper and they are drag cars don't mess around with mixes, providing you are happy to replace pumps and injectors which are fuel compatible and appropriate volume (which you would likely need for e85 anyway) straight methanol will make the most power anyway. You shouldn't have cold start problems due to temperature where you are even in 96 eth 4 water but given the pricing I would definitely go straight to methanol. Anything else is hard work for less gsin unless you are trying to run a car in a fuel based class.

Thanks Michael!

So what you are saying is i can run the 96% eth 4% water without issues?

Also our regulations don't allow for full alcho fuel. Hence, why i asked if we can run a mix. Also i tune about 30 cars for this drag event, and its on the 12th of August. Not all will be able to convert fuel systems in time so i thought of playing around with the percentage in the blends so that i don't max out the fuel systems. eg. 50% eth or meth with 50% Av gas or even 25%:75% etc. And i'm just crossing my fingers hoping the fuel pumps last only this event.

If i was to run 95%meth and 5% Av gas, what is the estimate fuel volume percentage i will have to increase? I have read that its 4 times the amount of pump fuel for pure meth.

Appreciate your input!!


There is a diminishing return on knock resistance vs ethanol content. E10 to E50 buys you more knock resistance per % than E50 to E85, or E85 to E100. Pump E85 should be good enough for most scenarios if you have a flex fuel sensor.

Port injected cars show most increase in knock resistance to about 40% ethanol. Blending that ethanol without dehydrating it sounds problematic, I imagine it may separate. Again given the relative cost I would be tempted to go straight to methanol mixes. You should be able to run it at any mix with hydrocarbon fuels. You work the relative volumes and then effective afr and combine them for effective mixed afr for given lambda. Happy to try and put something in a spreadsheet as an estimator.

Raymond, we don't have pump E85. Only 95 octane euro 4 at our sheds. We have only been using Av gas for racing. I have now hit a plateau for power over the last couple of years due to this.

Michael i am also leaning towards methanol blends now. I will post some of my workings here for you to check my work.

I tune in lambda so just as a reference what lambda target should i have for 4g63 and ej20 engines running about 10.0:1 cr at 2.5 bar of boost? I have read sometime back with pure methanol target lambda should be around 0.65. Is this true? I use Innovate, plx and aem widebands. The richest they read are 0.65 lambda.

I think i will choose a ratio of around 50%meth and 50%av gas since i am new to alcho fuels and need more experience with it. Will this ratio be enough for me to see significant gains over AV gas? if so what sort of percentage gains am i looking at?

Any help you guys provide will be helpful as i am totally lost when it comes to alcho blends. I only know what i have read online and learnt from the courses here.

Really appreciate your input Raymond & Michael.


I don't really have practical experience but have studied the science. I imagine without even considering knock threshold limitations that just the evaporative charge cooling of port/throttle body injected should be near 10% more power, depending on your knock limitation and mechanical robustness of the engine system/driveline I would imagine you might approach 20% more power at the same boost and have the option of going higher if you have the compressor flow/block robustness to deal with more boost. I have seen comments from guys running 10 or 20% meth saying there was immediate increase under the same running conditions but the fuel obviously allowed for more boost as well. In boost lambda targets of around 0.65 are what I have seen elsewhere too.

Thanks Michael,

Even 10% Increase of power is a big help for me. If i get 20% ill be laughing.

Some of the cars i can increase boost and some i have peaked out. Its more ignition that i am looking at without having to change the injectors currently installed. I also have some Meth Kits in some of the cars so they will also provide additional meth/water where i wont have to max out the fuel injectors.

By my calculation i cant increase more than 40% on fueling without maxing out injectors. So i have decided to go with a 50%meth 50%av gas which will give me a 36% increase in fuel volume over current 100oct setup. I also decided that my target AFR to start with on the 50/50 blend is going to be 0.715. I came to this by averaging my current target AFR 0.78 and Methanol Target AFR 0.65. Please correct me if i am wrong with this assumption.

I came to the conclusion that my fuel system would have to cope with an increase of 36% by using Andre's E85 Blend Calculation Sheet. Here are my results. Please check if it is correct.

Target Methanol volume % 50.0%

Volume of mixed fuel 100.0 litres

Methanol Density 0.792 kg/l

Gasoline Density 0.739 kg/l

Methanol Stoichiomteric AFR 6.4:1

Petrol Stoichiometric AFR 14.7:1

Initial Injector Scaling Value 500 cc/min

Calculated Values

Methanol Mass per litre of blend 0.3960 kg

Petrol Mass per litre of blend 0.3695 kg

Blend Density 0.7655 kg/l

Methanol/petrol density ratio 1.0717

Methanol/petrol mass blend 51.73%

Fuel Volume Required (Compared to Gasoline) 136%

Stoichiometric AFR of Blend 10.41:1

New Injector Scaling Value 367 cc/min

Fuel Volume Required for Target Ethanol Blend

Litres of Ethanol Needed 50 litres

Litres of Gasoline Needed 50 litres

Ethanol mass 39.6 kg

Petrol mass 37.0 kg

Blend mass 76.6 kg

That looks ok to me.

Can you explain to me why your Methanol target is 0.65 lambda, richer than your gasoline target?

Raymond, this is based on what i have read online and also what Andre has said on a few posts on this forum.

For example

I would prefer to run leaner if i could, but because i have no experience with methanol fuels i have decided to choose a richer mixture. If you think i can run leaner safely i don't mind. I will not be surpassing 2.5 bar on any of the cars. and some will only run between 1.5-2 bar.

Some of the higher hp cars i will be running are currently producing around 550-600whp with a 100 shot of nitrous and AV Gas. And the others with stock frame turbos and no nitrous are at about 350whp. All read on mainline dyno at 15m above sea level.

Raptor, you may be better of only using the raw lambda figure - that is a measure of the unburned oxygen and what is converted to an AFR value, which is going to be different for every fuel mix.

Something you may need to take into account, also, is that methanol is much, much more corrosive than ethanol, and you need the fuel system to be designed for that fuel.

I've never run a car on a methanol blend, only pure methanol. If you were to run a 4G63 with 10:1 CR and 2.5 bar boost on pure methanol I'd expect to be in the 0.65-0.70 vicinity. At that sort of boost level I wouldn't try running much leaner than 0.70 or you're likely to end up with a bunch of melted parts. The problem with tuning on a methanol blend is that I don't have any experience I can share with what sort of lambda target you should shoot for. If you need to be 0.65 on 100% methanol and let's say 0.78 on 100% pump gas then it's reasonable to assume that a 50% mix is likely to want to be somewhere in between but I can't say with certainty. What I would say with methanol is that there is no risk in being very rich except for a rich misfire. Unlike gasoline, the power doesn't drop away at very rich mixtures and the additional fuel from the rich mixture has a significant cooling effect on the combustion charge. On the other hand being lean will very quickly end in tears and there's nothing to be gained in terms of power..

In terms of the fuel requirements on methanol I work on the basis of 2.5 times what you need on pump gas. This is admittedly a little generous but won't have you come up short.

Thanks Andre,

I will stick to a lambda target 0.70 to start with and see where it takes me.

Would it be advisable to add some 2 stroke oil to the fuel to make it more lubricating?