87 + Meth

[16EBPPAY]

I've noticed that in the last year the price differential between 9x octane and 87 seems to have doubled.

As I'm in Michigan, it's not hard to find -25 washer fluid and it's typically under $2 / gallon.

Would it make sense to use Meth injection tuned for 87 octane fuel? Would performance be better or worse than just running 9x octane fuel? From a price point on fuel vs. meth it's cheaper. It may take a long time to come out ahead in the long run given the cost of the additional hardware and tuning. I'm also thinking that the meth should help out to some extent with heat soak, and there's no reason to have an extra tunes for 91 / 93 as well for added performance.

It may be more of a theoretical question as the Mustang is the wifemobile and she's not always a fan of my "FrankenCar" concepts.

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[Livernois Motorsports]

We would not recommend utilizing methanol injection along with 87 octane. You will be wasting the supplemental power and efficiency introduced by the meth. If you are after efficiency, the slower burning 93 octane combined with methanol will increase your economy better than 87.

I have run our 93 octane tuning on now 3 EcoBoost cars. After crunching the numbers on each car the MPGs with 93 has always either outweighed or washed the cost delta. Obviously, driving style, route and traffic load have a ton to do with MPG's. I have a fairly popular route to work that has daily stop and go traffic, but I still squeak out a better MPG:$ ratio!

 

[v8440]

I personally found no detectable difference in mileage between 87 and 93 octane when I had my '16 ecoboost. This was when the car was stone stock. I settled on 93 octane anyway because of the performance advantage, but it seemed to not contribute to better mileage at all. Why is it that 87 wastes the power and efficiency of meth? It seems that meth added to 87 would raise the effective octane more than meth added to 93. NOT that the effective octane would be higher with 87, but rather that it would be increased more when used with 87. Is this not so?

 

[Livernois Motorsports]

The fueling trims post tuning are MUCH different VS stock though. All stock you are probably correct. As I am sure you can imagine my cars don't make it much past 100 or so miles prior to getting modded!

 

[v8440]

Yeah, I can imagine. My ecoboost made it almost 800 miles before getting tuned. Thanks for the insight. Though I don't have the car anymore, I like learning stuff like this.

 

[16EBPPAY]

I wasn't actually looking at it from a MPG perspective, but that's probably worth considering too.

My line of thinking was that there wasn't much performance difference between 87 and 9x out of boost which was most of the time, and adding the Meth when in boost would still match or exceed stock power levels when under boost.

 

[Livernois Motorsports]

There is plenty of difference! The ECM automatically starts to pull timing, boost and holds the TB closed far more often with lesser octanes on board. To give you some perspective a vehicle sees a delta of about 6hp/tq per octane level variance. You will not notice the difference in your butt dyno with a single tank.

 

[16EBPPAY]

That would work out to around about 36 hp between 87 and 93. I was trying to determine how much of that with meth and tuning could be gained back.

 

[Busser48]

That would work out to around about 36 hp between 87 and 93. I was trying to determine how much of that with meth and tuning could be gained back.

But at that point why not just run 93? Are u trying to be economical driving your car? I'm asking in a serious manner not mocking

 

[KrisR]

But at that point why not just run 93? Are u trying to be economical driving your car? I'm asking in a serious manner not mocking

I can kind of see where he's going with this. I personally have a 60-mile roundtrip commute every day for work, with the cruise set at freeway speeds. I could understand the appeal of just using 87 for that long boring commute stuff and not wasting money on cruising around with unnecessary octane. Then, when you need it, the meth will add the octane the car wants at WOT. I'm not going to do it, but I can see some logic in it.

 

[v8440]

Yeah, I can see that too. I'm hoping Torrie can put some sort of super-lean cruise afr into my gt so that the 100 mile a day trip to class and back will cost less. Something where it's really lean at very light load, and instantly returns to normal afr's when the accelerator is stepped on.

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