Ignition Timing / Ignition Advance and E85 🌽 ⛽ [FREE LESSON]

Ethanol based fuels are common place in the automotive world and since ethanol is a renewable resource and a cleaner burning alternative to gasoline, ethanol, or mores specifically ethanol blends, have become a popular choice in many countries. Pure ethanol or E100 isn’t typically used as a fuel since its lack of volatility (compared to gasoline) can make it hard to start when the engine is cold. The most common blend we are used to is referred to as E85, consisting of 85% ethanol and 15% unleaded gasoline. It’s worth noting however that the actual ethanol content of E85 may fluctuate quite widely in pump E85 - For example it’s common to see ethanol content in a winter blend of E85 reduce to perhaps 60-70% to aid starting in very cold climates

While E85 is great for the environment, performance enthusiasts quickly found out it’s also great for producing power. So where does the advantage come from? On the face of it ethanol actually has a slightly lower energy content than gasoline per kilogram, but it also has a much richer stoichiometric AFR (9.8:1 for E85 vs 14.7:1 for pump gas) which means we need to use more of it to mix with the same mass of air. In general when switching to E85 we will find that we need to inject around 35-40% more fuel to make the same power we saw on pump gas. E85 also contains around 30% oxygen by weight and it has a higher effective octane rating than pump gas - This is often listed as 105, however we have seen E85 perform as well as specifically blended race fuels with motor octane ratings of 116+.

One of the key advantages of E85 over gasoline is that it has a higher latent heat of evaporation than pump gas. This means that it absorbs more heat from the combustion charge as it goes through a phase change from liquid to vapour. This draws heat out of the combustion charge and coupled with its high octane rating, makes the fuel very resistant to detonation. For those interested in performance, this means we can run more boost, more compression, more ignition advance, or all three with relative immunity from detonation. Note that contrary to popular belief, knock can still occur on E85, but it is much less likely.

We recently performed some testing on our Toyota 86 fitted with a Borg Warner EFR 6758 turbo and a MoTeC M150 ECU. In stock form the 12.5:1 compression engine was heavily knock limited on pump gas, producing 198 kW at the wheels with 7 psi boost - That’s still a decent increase from the 114 kW measured when standard though. With a tank of E85 on board, we were able to optimise the ignition advance at the same 7 psi, achieving 226 kW at the wheels. This gain was achieved because we could optimise the ignition timing without encountering knock. In the end the engine took an extra 6-8 degrees of ignition advance over what it accepted on pump gas.

Once we had achieved MBT timing (Find out in our EFI Tuning Fundamentals online course) at the minimum boost level of 7 psi, we used the MoTeC’s electronic boost control to raise the boost pressure. With an extra 2.5 psi boost (9.5 psi peak), the engine produced 266 kW at the wheels and the ignition timing could still be advanced to MBT with no sign of detonation. Note that the stock FA20 engine runs a very high 12.5:1 compression, making it a challenging task to tune when coupled with a turbocharger. Obviously we could have pushed the boost further but we would like the stock FA20 to hold together for a little longer right now.

So E85 allows a degree of immunity from knock which obviously lends itself nicely to high boost turbo engines or high compression N/A engines. What happens if your engine is naturally aspirated and isn’t knock limited though? We have found that even in these situations you can still expect to see an additional 5% more power, making the switch to E85 a worthwhile consideration. The only downside is that you will be burning more fuel and hence your fuel economy takes a hit. On top of that you may need to rethink your fuel system with larger injectors and fuel pumps often an essential aspect of any upgrade to E85.

#highperformanceacademy #learntotune #e85 #flexfuel

[TPantologist]

I've been tuning for close to 14yrs now, and seeing the approach taken to cover tuning topics, is superb! Well done!

[ToysLife]

One of the best e85 tuning videos on youtube!

[strawmannhonda]

You are so professional, precise and clearcut with your examples, i really appreciate your videos.... Thank you.

[SrExclusivity]

Cool content !! Here in Brazil E100 is totally usual .. we are even used to calculate if it worths more going over Gasoline or Ethanol once filling up the tank ... Almost all cars have the ability to accept both fuels .. we call them flex fuel .. but some new models are going to be only Ethanol again to increase its fuel economy ..

[hermannweinzierl]

wow, absolutely great!! Thanks for your work you did for us. Wish you much success for everything you want to reach!!

[relixio]

in your experiance are knock sesnors a reliable tuning tool for a drag racing right around 1000hp e85 and 10-12psi of boost? looking to switch to efi trying to select a ecu, wondering if knock sensors are going to be something I want to use or if they will give weird issues

[no-damn-alias]

E85 fuel is a very good choice for high compression ratio engines and the fact that you can run MBT will offset some of the lower energy content

[joseglory]

What was the octane rating on pump gas and was the e85 you used pump or racing gas

[PANTYEATR]

I love these lessons! I can't wait to start tuning my megasquirt controlled turbo car again.

[SoadOwnsUrFace]

This channel is amazing. I've learned a lot from these videos. Cool to hear a familiar accent.

[TheHippieDog]

Need a programmer for a 2002 ford thunderbird. Tried SVT and other brands as well, tripped the pas anti theft system before even downloading the stock tune. Can't find any compatible tuners on the web. What's the big secret?

Anyone know why a simple tuner won't work on this model car when they work on almost any other model ford?

[fabrb]

You also seat at 45% throttle vs 60% throttle for the same engine speed in Ethanol test, + engine run ~20°C cooler at the start of the test . I assume that can change the output too, not only the fuel .

[BulliKid]

Once you put the e85 in. Did you adjust the proper e85 lambda before doing the ignition timing?

[aacgaming]

If I want to EFI tune a BRZ/86 and a honda BRIO do you have lessons that are in flowing sequence?

[SuperMBARutgers]

Would be good to see how teducing iat with water injection affects max tq and timing

[FPS]

Outstanding modules! Well explained and relatively simple to follow. Not sure if anyone else is interested, but I would like to see a course on tuning MFI NA and blown motors utilizing E85/E98. Thank you!

[peterkroeker]

Well done sir! At this point all I have to do is watch your videos and I wont have to go to a tuning school and spend many many thousands on a formal education

[dandarnall]

How does timing affect the AFR’s and vise versa? If adding more fuel how would that affect spark timing?

[boostedbuiltgarage]

This is very interesting indeed! Some solid info!

[trevorseals]

So why does the engine want less timing on ethanol? I had assumed it would want slightly more timing because the octane rating of E-85 is higher than pump gas, and it takes longer to burn. What octane was the regular gasoline you used?