X98 vs 100% Meth WMI
 

So I have been reading that people are switching out 100% meth for X98 ethanol in the WMI tank. Anyone have any dyno comparison of the two? Or any other i information. Thanks!

I can give you some scientific data.
Methanol takes way more energy to vaporize than ethanol
You can burn about twice as much meth for the same amount of air as ethanol so methanol makes more power.

Water takes way, way more energy to vaporize than methanol. So...

I was was able to crank out a 11.44@118.84 with pure1 E18/100% meth vp m1 *dual cm7s* with major closures.
I have since added x98 to the meth tank and it pulls much better already with no closures at the exact same setting.
Hard to get 1/4 mile data on the street as it spins all 4 in first and halfway through second gears. Hoping to hit the track soon, will report back but the x98/meth mix works very well thus far.

Do you have 100% X98 in the meth tank?

Just a mix of ~80/20 for now. I’m adding x98 as I go.
80-meth
20-x98

With our stage 3 turbo the car makes 20 more hp on x98 than full methanol with a much nicer torque and power curve. No throttle closures at all.

At what point do you have to start considering adding foam to your tank?

Was everythung else equal? Boost, timing afr and trims

AfR was a little bit richer and trims were much lower. Same boost, same car, same day, same dyno. All settings were the same as well.

So are we saying we should be spraying ethanol rather than methanol?

What was the afr and trims reading before and after?

14.3 meth and 13.7 X98, trims: meth=maxed out, X98=36~32

Agree with everyone on X98 my logs look way better. Much more consistent almost no throttle closures and timing looks better. I wouldn’t ever switch back, car feels much better

What are peoples thoughts and experience with GEM fuels? the recipe is 37% Regular gas 21% Ethanol 42% Methanol.

https://gutts.nl/gem-fuel-best-practices/

http://www.azmeco.com/?mid=132

I'm running 100% meth on e30 fuel without any throttle closures.

Interesting I just tried 95% by vol rubbing alcohol form the pharmacy and the car is noticeably faster, but logs looks the same, if anything I am getting more throttle closure, then before but it is faster, so I do not think it is related to throttle, timing is similar as well, so something else is going on the engine just like it.

0-100km times dropped form 4.8-5.1 to 4.6-4.9, 3rd gear 40-120km pull dropped form about 6 seconds to about 5.6 seconds. Its like 10% more power with nothing visible in the logs weird.

Relative DA will have a huge effect on a boosted car especially.
And it changes min to min

Can you post up a log, what % ethanol ?

Does anyone know how to disable the target boost limit when using map 7?

In my car the TARGET is limited to DME_BT + 13.5 psi, which makes for unpredictable TARGET behavior, when using anything above a 40 adder as it is colder now my car can have a 5 PSI DME_BT, when this happens it results in a boost limit of only 18.5 PSI.

I really want to run 21-22 psi with consistent target setting, but cannot find any way to do it so far, especially as really need to be 1-2 psi below target to avoid throttle closures.

I know I can just run map 6 but I really like the protection in map 7 and I do not want to be limited to 18.5 psi on WMI.

Thanks,

Dual CM5's with E98 runs pretty well. Don't run any water on the B58, it doesn't like it. 100% meth works fine, too.

It's a little hard to dial in meth at tip in, as your AFR will be very rich for the first second or two. But hopefully things will improve with time (and hopefully flash tuning).

:burnrubber:

I hate to revive this old thread, but anyone still running X98?

curious as well. i have several unused 55g drums as my race car broke before the summer

We might need to start a thread on BimmerPost since this section of N54Tech is ghost town.

I'm bumping this thread. I am about to get a WMI kit for my M240i and am wondering if x98 is the way to go.

My personal experience on the N55 engine is 100% Meth made more power than 100% E98.
The car did however feel just a little bit smoother with E98.
I tried even mixture of both maybe 70-60% Meth and the rest E98 .. made almost same power as 100% Meth.
So now I just stick with 100% Meth.

Might be different on B58 though, but give both a try and see which one works for you.

FYI I have BM3 with my own tune at about 25 psi, and e20 + 98, JB4 for meth, but no boost control, so I just run in map 0, with meth trigger set to 4.

Still running x98 on my car, I did try mixing in a bit more water again, like 25, 15, and it seems like at 25% I start to lose power, however the timing is perfect, so the water seems to be slowing the combustion down, or improving timing correction, but lose a little power.

I did increase the knock tables a little, and now have pretty consistent timing on both, however, there is a definite correlation to the % water, and timing corrections, so that would tell me that running more water is likely more safe for detonation.

One interesting comment, I have been adding more timing to my tune and , with more timing the power loss with added water is less noticeable. That supports my theory that the water is slowing the combustion and moving the MBT timing up. When I only had about 10-12 deg timing, adding 25% water was a noticeable and repeatable power loss like around 8%. However now with 14-16 deg timing, it is barley noticeable, or in the range of only 2-3%.

It may be that to get the benefit of the added water you need to add a few degrees of timing, but without a proper day of dyno testing I think that would be hard to know conclusively, as you would need to do many runs to compare different water % and different timing tables.

Hate to dig up an old post but the above is scientifically inaccurate

For the same amount of air the energy released by ethanol and methanol for combustion is almost identical. Enthalpy of combustion is 1367 kJ/mol for ethanol, 726 kJ/mol for methanol so once you consider that for the same amount of air (always the limiting factor) you burn twice as much meth but meth produces half the energy, the result is more or less the same.

The WMI being injected also doesn’t actually vaporize in the intake charge (at least not by much), it atomizes (tiny liquid droplets as opposed to undergoing state change to become a gas). So given the amount of this fluid undergoing state change is minimal, the specific heat capacity is the metric we want to use, not the heat of vaporization. Specific heat capacity of ethanol and methanol are almost identical so there’s very little if any benefit for one versus the other.