[Anthony1s]

What do you guys think is better and why... 93 with meth injection or e85 without meth? Assuming you're on the highest flowing pump, so no bottleneck there.

[F87source]

Personally I think E85 is the best option to go with, it not only gives you the sufficent octane to run high amounts of boost and timing, but it also offers evaporation cooling to all the cylinders giving your engine a noticeable decrease in coolant and oil temps as tested by motoiq. If you rely on meth for octane you must have a really good setup with great failsafes like aquamist or torqbyte or else if the system fails you will have a blown engine, and if distribution is poor some cylinders will knock. There are so many things to consider when running meth like: misfire hyper lean conditions, progressive spray, leaks, hardware failures, etc etc. So imo if you have the HPFP capable to run full e85 go e85.

[Anthony1s]

Hmm, yea, distribution might be an issue if you do charge pipe injection. Though I haven't seen anyone here say it's been an issue for them. But I think engine cooling is similiar between them. And meth has the added benefit of cooling the intake charge, which e85 doesn't.

I've been doing a bit of research on the topic and my main concern with e85 is the large variation in quality. Between stations and between different times of the year. 93 with meth would be tons more consistent. Also, in my area, there is only one e85 station available and the next closest is an hour away.

According to this, the pump e85 they used (which they tested at 40%) didn't make much more power than 93 w/ meth. Not sure if fuel quality got better in the two years since the article was written.

https://www.dragzine.com/tech-storie...inner-crowned/

I also read that cars should be tuned for 93 first, then for e85 after. The reason given was that it's easier to tune for 93, since you can use AFR and tuners are most familiar with it. So work out the kinks with 93, then tune for e85.

And there is the added corrosion of e85 too.

So, as of right now, my mind is in favor of meth.

Thought I do see e85 as simpler to run. If fuel was more consistent and available, I think e85 would be better.

[F87source]

Originally Posted by Anthony1s

Hmm, yea, distribution might be an issue if you do charge pipe injection. Though I haven't seen anyone here say it's been an issue for them. But I think engine cooling is similiar between them. And meth has the added benefit of cooling the intake charge, which e85 doesn't.

I've been doing a bit of research on the topic and my main concern with e85 is the large variation in quality. Between stations and between different times of the year. 93 with meth would be tons more consistent. Also, in my area, there is only one e85 station available and the next closest is an hour away.

According to this, the pump e85 they used (which they tested at 40%) didn't make much more power than 93 w/ meth. Not sure if fuel quality got better in the two years since the article was written.

https://www.dragzine.com/tech-storie...inner-crowned/

I also read that cars should be tuned for 93 first, then for e85 after. The reason given was that it's easier to tune for 93, since you can use AFR and tuners are most familiar with it. So work out the kinks with 93, then tune for e85.

And there is the added corrosion of e85 too.

So, as of right now, my mind is in favor of meth.

Thought I do see e85 as simpler to run. If fuel was more consistent and available, I think e85 would be better.

No distribution is not an issue with quality nozzles, but it is more of an issue with crap charge pipe nozzle placement. I didn't want to get this deep into meth discussion but here we go:

1) The huge factor for distribution is atomization - the better a nozzle can atomize the meth spray the better it can be distributed into the air stream and be evenly distributed into the individual cylinders. Another factor for this is having the nozzles as far from the throttle body as possible giving the meth time to distribute and be suspended in the air stream evenly, and for this to be even more effective you do not want huge turns or stuff in the way.

This is why the choice of charge pipes are so important, the CTS charge pipe, BMS charge pipe and iirc ER charge pipe have meth bungs that do these things really well:
a) Have the meth nozzles far from the throttle body
b) have the meth nozzles far from sensors or obsticles in the charge pipe
c) no welds and fragments or cracks in the pipe that mess with meth atomization.
d) the meth bungs are mounted away from each other so there is no destructive interference with meth spray patterns from each nozzle which leads to meth pooling which is bad.
e) The meth nozzles mount flush.

Some examples that are not ideal is FTP, they put their secondary meth nozzle right beside the maf sensor and way too close to the throttle body, they also have some pretty poor welds inside of the pipe from what I have seen in the past which makes the pipe interior not smooth affecting meth atomization and distribution.

This is just one factor, there are so many more details that I could get into and have done so for every single part of the meth loop on another forum.



Yes meth can cool the intake charge, but spraying meth onto tmap sensors shortens its life span. That is why I only use distilled water. The benefit is not too huge maybe you will get a few degrees of iat reduction, but at this point you will have so much octane with e85 and meth iat induced knock is not a factor.


Yes e85 quality varies alot from pump to pump, which is why flex fuel is so beneficial imo, you never have to worry about the e85 mix being lower at some pumps. Luckily for me the one station in my city has e85 at exactly e88 every time and it has never been off for the past few years it was here.



If you are spraying enough meth you will get a good enough octane rating to match e85 power levels, but like I said it is riskier. If you system fails your engine fails unless it has good failsafes - aquamist and torqbyte no one else. At this moment I favor aquamist until torqbyte gets that IR flow sensor they have been rumoring on the market. Also your tune is important because some tunes like mhd allows the ignition coils to be shut off if you misfire so you do not run into hyper lean conditions. This is another reason why I prefer just distilled water, no possible way to get hyper lean conditions with an incombustible fluid you will actually protect the cylinder. But you can hydrolock in both scenarios so make sure your controller can look for misfires, I think torqbyte will be able to solve this since they are tapped into bmw's canbus. You also have to remember the risks invovled too like meth vapors are toxic and can lead to blindness so you must have a 1 way cap or externally vented tank - again that is why I run water only. Next if your car rolls over you need to have a system with a check valve vented cap so no meth spills out. Also remember with meth if your insurance finds out you will be screwed since it is a flamable fluid. Also make sure your meth lines going into the engine bay are far away from hot objects or they will melt and cause an engine bay fire. Also one more thing now that I am ranting do not forget check valves or you will experience vacumn siphoning. Also with a meth kit get good filters and clean your loop very well from time to time to prevent clogs. I always had a cap with the vent valves built in drilled out in favor for a check valve with a pcv air filter on it to prevent any dust from entering the tank. Also make sure you have the pump in a location where it does not over heat - iirc they sold heat sinks for pumps too. Again if I can find my thread where I broke down every single component to the most minute details (I was super into meth back in the day pre bmw and especially when fuelling solutions was not available for the F series) I will link it to you but I cannot remember which forum it was on.


For tuning advice contact your tuner, but yes start with pump first.


For me I always will choose e85 if possible then use water injection for iat cooling, cleaning of intake valves, and additional steam cleaning of the cylinder which will also take even more heat out of the engine. That is not to say meth is bad it is not, but it is more risky than running something fully controlled by the ecu, but to minimize those risks run a good meth kit. I will only say this once - there is only 2 companies aquamist and torqbyte that I would ever trust with my car, do your research and you will see why. No comment on other manufacturers of meth kits.


E85 is not only simpler to run, it is safer as well even when compared to the best meth kits. To simplify even more get a flex fuel tune.

[Anthony1s]

Oh, that's the other thing. Is there anyone that makes a flex fuel tune for our car? I know bm3 doesn't.

[detroitm2]

Originally Posted by Anthony1s

Oh, that's the other thing. Is there anyone that makes a flex fuel tune for our car? I know bm3 doesn't.

Not OTS as far as I know. BM3 has an E30 and racegas tune. I'm sure one of the many tuners out there have a full E85 tune ready to go.

[Anthony1s]

Originally Posted by detroitm2

Not OTS as far as I know. BM3 has an E30 and racegas tune. I'm sure one of the many tuners out there have a full E85 tune ready to go.

Yea, e85. I'm talking about flex fuel, because pump e85 isn't consistent.

When tuning for pump e, we get tunes like the e30 tunes, because tuners are playing it safe with the inconsistent e85 quality.

The flex fuel sensor would need to communicate with the DME or something, so that the tune can adjust for the variation of fuel quality.

[detroitm2]

Originally Posted by Anthony1s

Yea, e85. I'm talking about flex fuel, because pump e85 isn't consistent.

When tuning for pump e, we get tunes like the e30 tunes, because tuners are playing it safe with the inconsistent e85 quality.

The flex fuel sensor would need to communicate with the DME or something, so that the tune can adjust for the variation of fuel quality.

Ah, sorry, I misread that.

[Anthony1s]

Originally Posted by detroitm2

Ah, sorry, I misread that.

No worries.

[F87source]

Originally Posted by Anthony1s

Oh, that's the other thing. Is there anyone that makes a flex fuel tune for our car? I know bm3 doesn't.

As of now only ecutek, mhd is next.

[F87source]

But Anthony1s if you have to end up changing tunes it might not be worth the cost, and you could just use a high quality meth system which would address the concerns I had before.

So I should also make one thing clear imo e85 is a safe choice for octane because of the reasons I listed above that can go wrong with meth, but with a good meth system you can eliminate most of those issues and make meth a very close second pick. Albeit I will choose e85 every time.

[Nezil]

There were a few things that led me to go WMI when I did just over a year ago, and though the situation has changed since then, I would probably do the same again if I were starting out now:

- Upgraded HPFP very expensive (XDI was available, but only just released)
- Premium Pump 91 AKI gas in CA is roughly equivalent to 93 RON; lower quality than European base grade
- I wasn't looking for immense power, and may upgrade the turbo at some point

Since that time, additional lower cost HPFP solutions have come to market and those can now allow full E85. If you have a local source of E85 that is consistent, as it seems to be with F87source, I would go that route because the cost will be similar for a decent meth setup compared to the upgraded HPFP.

As F87source has stated however, E85 is often inconsistent, and you really need a Stage 2 HPFP to run Full E85 and perhaps even additional top of engine lubrication if you go to full E85.

I tried running an E20 mix before I went WMI and it was painful to mix E85 and / or have E85 on hand at home every time I filled up. I wouldn't mix E blends because it is annoying. My closest E85 station is about a 20 minute drive, which isn't really that painful, but it's annoying enough that I didn't want to bother a lot of the time.

So I'm now running an Aquamist WMI setup with 50:50 mix (by weight). 50:50 water methanol isn't a flammable liquid on its own, so it's safe in the engine bay, but still offers you IAT cooling and a little bit of octane. In my case, I actually don't have a fail safe currently set up, but I'm also running a map intended for 91 AKI and I have 91 AKI (albeit CA 91) in the tank. Running meth prevents timing pull, but I'm not pushing the map to the point where if meth fails, my engine fails.

I do plan to put in a fail safe at some point, but I was hoping for a more elegant system than simply breaking the link to a sensor / actuator and causing a limp mode. There has been some talk by MHD of adding the flow sensor output in to the DME and then using this as a kind of flex fuel system which would be nice.

So what I'm really waiting for is either a Flex Fuel based E85 approach, or a flow based Meth fail safe. At that point I'll probably tune for more power, possibly with an upgraded turbo. Right now though, I'm trying to have the lag between shifts fixed because that makes by far the biggest difference in performance for 6MT cars!

[F87source]

Originally Posted by Nezil

There were a few things that led me to go WMI when I did just over a year ago, and though the situation has changed since then, I would probably do the same again if I were starting out now:

- Upgraded HPFP very expensive (XDI was available, but only just released)
- Premium Pump 91 AKI gas in CA is roughly equivalent to 93 RON; lower quality than European base grade
- I wasn't looking for immense power, and may upgrade the turbo at some point

Since that time, additional lower cost HPFP solutions have come to market and those can now allow full E85. If you have a local source of E85 that is consistent, as it seems to be with F87source, I would go that route because the cost will be similar for a decent meth setup compared to the upgraded HPFP.

As F87source has stated however, E85 is often inconsistent, and you really need a Stage 2 HPFP to run Full E85 and perhaps even additional top of engine lubrication if you go to full E85.

I tried running an E20 mix before I went WMI and it was painful to mix E85 and / or have E85 on hand at home every time I filled up. I wouldn't mix E blends because it is annoying. My closest E85 station is about a 20 minute drive, which isn't really that painful, but it's annoying enough that I didn't want to bother a lot of the time.

So I'm now running an Aquamist WMI setup with 50:50 mix (by weight). 50:50 water methanol isn't a flammable liquid on its own, so it's safe in the engine bay, but still offers you IAT cooling and a little bit of octane. In my case, I actually don't have a fail safe currently set up, but I'm also running a map intended for 91 AKI and I have 91 AKI (albeit CA 91) in the tank. Running meth prevents timing pull, but I'm not pushing the map to the point where if meth fails, my engine fails.

I do plan to put in a fail safe at some point, but I was hoping for a more elegant system than simply breaking the link to a sensor / actuator and causing a limp mode. There has been some talk by MHD of adding the flow sensor output in to the DME and then using this as a kind of flex fuel system which would be nice.

So what I'm really waiting for is either a Flex Fuel based E85 approach, or a flow based Meth fail safe. At that point I'll probably tune for more power, possibly with an upgraded turbo. Right now though, I'm trying to have the lag between shifts fixed because that makes by far the biggest difference in performance for 6MT cars!

Excellent you are only using meth for octane on top of a map meant for your fuel meaning you are not actually leaning on meth for octane which is smart since you do not have a failsafe implemented currently.

It is actually quite easy to use aquamist's fail safe, it connects to a pin on the DME and grounds out the waste gate causing it to open dumping boost when a problem is detected. Another benefit is that when it does open the waste gate it will trigger a limp mode too which will really be a benefit to saving your motor.


Technically 50:50 water meth is flamable, there are videos on youtube showing that it is, and the flame is almost clear making it really hard to tell.


Overall yes I agree ethanol mixes are really difficult to get right or pump e85 might not be consistent so that is why I like flex fuel. But it is still safer than meth in all instances if your tune is set for the proper ethanol percentage. If E85 is hard to get in your area or ethanol is really inconsistent then go for the next best option which is a quality meth kit.



Also you are correct about ethanol and its lack of lubricity, that is why I when I ran E85 in the past I used top cylinder lube + fuel stabilizer mixed in which kept the e85 fresh for really long periods of time and gave me the proper lube.





BTW: twisted tuning is selling their rebranded torqbyte controller which can fully integrate into the ecu for n54 cars and soon to be F series cars when MHD implements flex fuel. You can read more about it on their site.