Why WI instead of WMI for M4 GTS?

[lixiang7349]

I have a B58 M240i currently putting down 490 whp with a stage2+ E50 custom tune with stock turbo. I'm looking to get into (direct port) WMI and have a few questions:

what happens when you are on the road and the tank is out? Can you still go WOT?
Is the DME aware that you have run out and adjust the tune accordingly?
Can you temporarily fill with 100% water?

Why did BMW decide to use just WI instead of 50/50 WMI for GTS?
Is it because the HP gain from WMI is more about the water cooling than the additional fueling?

I think I like the WI idea better because if I run out of WMI tank I can just go buy some water from the gas station and move on with the drive instead of having to keep flammable meth in the car at all times.

[Gomeler]

The water injection system is plumbed into the ECU, with a level sensor in the tank and a pressure sensor in the manifold. The car reverts to the Competition tune when it runs out of water, which is a common issue with the GTS since the water injection system frequently fails. I tracked my car several times with my water injection system not working at 100%, even dyno'd the car to prove it was only making ~440HP.

My understanding is that BMW pursued water injection to permit more timing advance and boost. I want to say the advertising material stated the water injection was strictly to enable advanced timing, but timing isn't adding 50hp on a 440hp base.

I assume BMW opted for strict water for simplicity. I assume it is much easier to tune for, easier to account for with emissions, and maintenance is simpler. I read enough about dudes blowing up their big boost cars in the 2000s because their meth injection system failed and they leaned out. The water injection system is already a trainwreck, but at least when it fails the engine doesn't burn up valves.

Once again, a lot of assumptions, but that's my understanding. I know nothing about the B58, but I've gone big power with an ej257, why not go E85 or Ignite Red/E90? HPFP flow issues?

[lixiang7349]

Originally Posted by Gomeler

The water injection system is plumbed into the ECU, with a level sensor in the tank and a pressure sensor in the manifold. The car reverts to the Competition tune when it runs out of water, which is a common issue with the GTS since the water injection system frequently fails. I tracked my car several times with my water injection system not working at 100%, even dyno'd the car to prove it was only making ~440HP.

My understanding is that BMW pursued water injection to permit more timing advance and boost. I want to say the advertising material stated the water injection was strictly to enable advanced timing, but timing isn't adding 50hp on a 440hp base.

I assume BMW opted for strict water for simplicity. I assume it is much easier to tune for, easier to account for with emissions, and maintenance is simpler. I read enough about dudes blowing up their big boost cars in the 2000s because their meth injection system failed and they leaned out. The water injection system is already a trainwreck, but at least when it fails the engine doesn't burn up valves.

Once again, a lot of assumptions, but that's my understanding. I know nothing about the B58, but I've gone big power with an ej257, why not go E85 or Ignite Red/E90? HPFP flow issues?

One of the biggest selling point of the GTS is the HP increase due to WI, which you guys paid doubled the M4 price for, and you are telling me it's a trainwreck? How is that acceptable? How many lemons were there?

For my setup, I make less power with E85 compared to E50, which will also have terrible MPG.

So if I do aftermarket water injection solution, will I have the same issue?

[Lienrocs]

I've got almost 16k miles on my current GTS and had around 8k miles on my first GTS and apart from a few clogged stone filters I haven't had any issues with the water injection system. I was at chuckwalla last weekend with ambient air temps around 100 and the intake temps peaked at 102. It's a pretty impressive piece of kit for track use regardless of any horsepower gains. Managing temperatures under extreme conditions is always a top priority for track work. I've never had my car on the dyno so I can't attest to the absolute power of my car but it's definitely not slow.

To get to OP's point I think bmw went WI first and foremost to manage temps under track conditions to give a reliable platform to work from. A reliable horsepower increase was probably an added bonus. Everyone, including bmw, knows extracting more power from a turbo engine isn't hard. Doing it reliably is a different story though, thus WI. My .02 cents.

[robbo mcs]

Originally Posted by lixiang7349

I have a B58 M240i currently putting down 490 whp with a stage2+ E50 custom tune with stock turbo. I'm looking to get into (direct port) WMI and have a few questions:

what happens when you are on the road and the tank is out? Can you still go WOT?
Is the DME aware that you have run out and adjust the tune accordingly?
Can you temporarily fill with 100% water?

Why did BMW decide to use just WI instead of 50/50 WMI for GTS?
Is it because the HP gain from WMI is more about the water cooling than the additional fueling?

I think I like the WI idea better because if I run out of WMI tank I can just go buy some water from the gas station and move on with the drive instead of having to keep flammable meth in the car at all times.

The "flammable" thing is probably a big part of it. With lots of different regulations in different parts of the world, I think meth would have been very difficult. It would have to be treated as a fuel, and probably would need a whole lot of precautions, in case of crashes etc. Special tanks, lines, filling procedures etc

BTW the primary benefit of meth injection is cooling, not extra fuelling. Methanol (and ethanol) are much more potent cooling agents in the intake than water, due to evaporative cooling. You can test that by pouring a bit of meth on you skin, it feels really cold, even though it is at room temp.

[lixiang7349]

For aftermarket solution:

what happens when you are on the road and the tank is out? Can you still go WOT?
Is the DME aware that you have run out and adjust the tune accordingly?
Can you temporarily fill with 100% water?

[SYT_Shadow]

Originally Posted by lixiang7349

One of the biggest selling point of the GTS is the HP increase due to WI, which you guys paid doubled the M4 price for, and you are telling me it's a trainwreck? How is that acceptable? How many lemons were there?

For my setup, I make less power with E85 compared to E50, which will also have terrible MPG.

So if I do aftermarket water injection solution, will I have the same issue?

The main selling point of the GTS is the 'package' of the GTS. Limited production, track suspension, CCB brakes, lightweight details, aero.
The M3 CSL had 27hp more than the regular M3 and cost way more. Someone could also say that you can get those 27hp pretty easily. So what? It won't turn a E46M3 into a CSL

The water injection system seems to be delicate in the GTS. It has little to do with regular 'WMI systems' that people hodge podge together. Each injector is ~$1k if I remember correctly.

Anyone can put together a WMI system on a F8X car, for example running a controller like Torqbyte, and get to a solution with a true failsafe that is in the ballpark of OEM, but it's also quite expensive.

[guess2098]

Adding meth requires ecu tune. % of the meth need to be same, not only that, air to fuel ratio needs to right. Run out of water might not give engine any problem other than over heat but run out of meth on track! dude you are in big trouble.

[lixiang7349]

Originally Posted by guess2098

Adding meth requires ecu tune. % of the meth need to be same, not only that, air to fuel ratio needs to right. Run out of water might not give engine any problem other than over heat but run out of meth on track! dude you are in big trouble.

I'm on a stock turbo E50 tune. It's pretty much maxed out so I'm looking for just water injection for added cooling with the same tune. That way if injection system fails or I'm just out of water, it still works without causing engine damage.
I'm basically comparing WI vs intercooler upgrade. WI seems more "on demand" which may be more efficient? I have no idea. I'm at the stage of gathering information.. WI also have problem with freezing so if I have the same tune but add 50/50 WMI, it'll damage the engine? Engine can always choose not to use the additional fuel right?

[guess2098]

Originally Posted by lixiang7349

I'm on a stock turbo E50 tune. It's pretty much maxed out so I'm looking for just water injection for added cooling with the same tune. That way if injection system fails or I'm just out of water, it still works without causing engine damage.
I'm basically comparing WI vs intercooler upgrade. WI seems more "on demand" which may be more efficient? I have no idea. I'm at the stage of gathering information.. WI also have problem with freezing so if I have the same tune but add 50/50 WMI, it'll damage the engine? Engine can always choose not to use the additional fuel right?

Water injection is for cooling only. You can't increase psi by just adding water spray on air intake. The point for water injection is make engine cool when temperatures reaches too high where turbo and engine are suffering from heat soaked.

Water Methanol injection is for adding more hp as additional fuel on air mixture. When you add more water, it will increase engine cooling, on the other hand, when percentage of meth goes up, it will increase more hp but cooling function will drop. As you try to increase % of meth to get more hp, or increase the volume of spray, your engine has more chance to fail if meth injection system goes run.

Also once when engine has custom tune, you can't really change water and meth ratio too much. There much be some safe range but as far as my tuner Cary told me, I can't just go from 50/50 to 100% meth

You can't really shut it off as far as I know. Because it requires custom ecu tune. It is not just plug and play like a intake. Once meth is off for any reason and ecu will read AFR is wrong. I don't know what is going to happen.

[4play]

Originally Posted by lixiang7349

I think I like the WI idea better because if I run out of WMI tank I can just go buy some water from the gas station and move on with the drive instead of having to keep flammable meth in the car at all times.

You answered your own question. Distilled water is extremely widely available and methanol is not.

I don't think you will ever see a factory WMI system.