Water/meth injection: a theoretical and practical discussion

[Danbob]

Hi JD,

I’m just about to start drilling into my Rev 3 manifold as well so will be good to discuss the best place.

From the position you’ve marked there will you not have some difficulty accessing the jets due to the fuel rail and all the harness/pipework that runs around that area?
I was planning to mount the injectors on the other side, so they can be accessed from under the car.


I’d like to figure out the best place to mount them in terms of how high up the runners and where there’s enough metal to tap a good secure thread


I PM’d Bob to ask his advice and he said that on top of the manifold would be better but not much room there so on the bottom may be the best place as you will be able to get them from the bottom of the car.
And that he fits them down as close to the head as he can.

[2mad]

I PM’d Bob to ask his advice and he said that on top of the manifold would be better

thats where i'd fit them too .. on the back side if clearance is better

And that he fits them down as close to the head as he can.

Id want a bit of time for mixing , good atomization .. thats why I`d inject at the highest point .. Bob probably know best though

[T.F.S.]

Been out in a propane injected diesel before that ran nitrous also, was good.

For a SW20 running circa 300bhp 250cc per min is a max amount of H20, you should aim for 200cc IMO, running 800cc of meth is a must, as far away from the valve as is possible.

[Danbob]

I PM’d Bob to ask his advice and he said that on top of the manifold would be better

thats where i'd fit them too .. on the back side if clearance is better

And that he fits them down as close to the head as he can.

Id want a bit of time for mixing , good atomization .. thats why I`d inject at the highest point .. Bob probably know best though

Yeah, I'm not 100% clear, but I think he was meaning further up would be better, but for access he mounts them lower down?

I don't know how close to the bulkhead the top of the runners are on a Gen 3? Is there a good enough space there to access the injectors if necessary?

[2mad]

I've got a gt4 at the mo so cant check clearances .. my advice would be to listen to Bob hes got experience with direct port w/m injection

[JD]

Thanks very much all for your input - it looks like it will indeed be too tight a squeeze really so looks like I'm gonna go with the idea of mounting them on the back side or underneath. I don't have access to a scissor life or a two post so working on stuff under the car isn't really feasible for me so at the moment I'm leaning toward at the back near the top.

Btw, TFS you never responded to my PM last year, is yer box full? It was just about the CM four-branch mani with integrated solenoid but I've gone for the DO parts anyway.

Next question! Being a system with fluids in it, what'll be the best way to bleed it? DO sell a bleed valve with barbed fittings but this is for boost control apparently. I don't really understand. Can anyone recommend a good solution?

I should probably move this over to twobrutal at some stage, lol.

[Danbob]

You don't need to bleed it as it's not a sealed system like coolant, you can just purge the lines and then there shouldn't be any air left after that as the check valves or solenoid should prevent any getting in.

Just like a Nitrous purge or your fuel pump priming

[JD]

Nice. thanks

[T.F.S.]

Sorry I didn't get a PM from you about that, maybe a forum glitch?

I was injecting around 1.5L through the inlet and had a lot of success, ignition advanced, no intercooler, bigger turbo, lower than stock inlet temps, no need for direct port IMO.

[JD]

That is interesting - I do remember your forum posts with all yer science and bits and pieces however, I'm doing it anyway, and possibly adding a spray bar to the IC just for the hell of it as i can run it off the same boost switch, and plumb it into the washer bottle. I'm beginning to actually feel inspired about this again

I think the great thing about actually having an intercooler is that it doesn't suddenly just stop working, as electrical/mechanical things might. I'll be giving mine a thorough clean out, though as for a big part of it's life, it will have been the victim of a recirculating crank breather. Yuk. Not on my watch!

[Kongaroo]

Are you going to run one check valve per nozzle JD?

I sprayed about 850cc pure methanol about 6 inches pre-throttle body for several years via a single nozzle. The car was mapped for it by reducing the amount of fuel injected in the boosted cells the car operated in whilst spraying methanol. It worked well and reduction in temps was obvious on the datalogit logs shortly after each boosted run if the methanol activated. (Disadvantage being you needed to be very on the ball as to checking if the methanol system was working otherwise you would get det from being too lean+lower fuel octane rating whilst running more ignition advance).

One thing I would be worried about with the direct port idea you are thinking of is spotting leaks. Generally I found each check valve became faulty/leaked after about 6 to 12 months and required replacing (some lasted only a few months).

If you are going to have a check valve in front of each nozzle this means 4 times the hassle. And at least with a single nozzle in front of the throttle body you have easy access to check or swap it out.

Just some thoughts

[JD]

I'm running a single solenoid valve before the split, so no check valves to check, and will be easily accessible. Thanks for your input though, I am very interested in all the different setups that folks have applied to this.

In terms of water and meth, I'm leaning toward just water at the minute - or a mixture with a w/m ratio of something like 3:1. You reckon I'd be better off with more methanol in there?

[Kongaroo]

I'm running a single solenoid valve before the split, so no check valves to check, and will be easily accessible. Thanks for your input though, I am very interested in all the different setups that folks have applied to this.

In terms of water and meth, I'm leaning toward just water at the minute - or a mixture with a w/m ratio of something like 3:1. You reckon I'd be better off with more methanol in there?

Do you have a mappable ECU?

Spraying methanol without reducing fuel injected in the map in the cells that the car operates in under boost+methanol will just make you run too rich.

If you are running just water for safety I would just go with a very small nozzle as you will find the car will bog down if there is too much water. I wasn't really impressed with water alone when I tried it.

Will be interested to see how you get on long term with the solenoids - let me know if it proves to be reliable

[JD]

I'm running a single solenoid valve before the split, so no check valves to check, and will be easily accessible. Thanks for your input though, I am very interested in all the different setups that folks have applied to this.

In terms of water and meth, I'm leaning toward just water at the minute - or a mixture with a w/m ratio of something like 3:1. You reckon I'd be better off with more methanol in there?

Do you have a mappable ECU?

Spraying methanol without reducing fuel injected in the map in the cells that the car operates in under boost+methanol will just make you run too rich.

If you are running just water for safety I would just go with a very small nozzle as you will find the car will bog down if there is too much water. I wasn't really impressed with water alone when I tried it.

Will be interested to see how you get on long term with the solenoids - let me know if it proves to be reliable

Yes I have a Power FC so an old school "period mod" perhaps, lol, but mapped by Ryan Griffith last year. I'll be using the 63cc per minute nozzles from Devil's Own and I'm still worried they might be too big. I'm gonna ask Ryan to adjust the map once it's all set up. I've got a summary up with my current setup over on twobrutal now as that seemed like a good place to share ideas too. Perhaps pure meth is the way to go

Btw, thanks very much for taking an interest, I've heard about your car via the forums and it's unfortunate demise but it sounded pretty spectacular - hope it's resurrected soon

[Kongaroo]

Cheers bud. My wife imposed a one year ban on me doing anything car related. Glad that's over with now

Regarding methanol - yes it works great if you map the car for it but you have to be very anal about checking it is all running properly. I could run about 2 degrees more ignition advance safely with the amount I was spraying over my non methanol map.

Good luck with your project

[mr2magic]

Just to add a thought here:

The best placement in my eyes is directly opposite the throttlebody spraying into the air stream at a slight downward angle. This promotes atomisation, makes the mixture more homogenous and allows droplets not caught in suspension during air entry to be caught on the way into the head.

Other than that I'm really with corky bell on this.....Water/Methanol injection is a bandaid for bad tuning.

[raptor95GTS]

.........Water/Methanol injection is a bandaid for bad tuning.

I used to think the same and like you was completely wrong. Yes it can be used to cover up a bad tune but so can using higher octane fuel and /or lower boost levels.

[mr2magic]

Please elaborate....Why am I completely wrong?

To explain.....for any normal vehicle I see no gain that cannot be had by using an appropriate fuel (e85 if you wish) or having decent knock control.

If on the other hand your building an all out balls to the wall drag car or a car on the ragged edge of the power limit it may be usefull.....
although I don't see to many people still using these systems....I could be wrong though!

[raptor95GTS]

WI also cleans up the combustion chamber, slow combustion down thus preventing knock bit like running expensive fuel but only used when needed under boost conditions, or as you say for those flat out moments. Sure, it can be used for a bad tune but so can most things. Have a look for articles on WI in world war 2 by a guy called Frank Walker, quite interesting stuff.

[JD]

Just to add a thought here:

The best placement in my eyes is directly opposite the throttlebody spraying into the air stream at a slight downward angle. This promotes atomisation, makes the mixture more homogenous and allows droplets not caught in suspension during air entry to be caught on the way into the head.

Other than that I'm really with corky bell on this.....Water/Methanol injection is a bandaid for bad tuning.

I see your logic. It'll be mapped for again anyway. One man's "bandaid" is another man's solution in this case. Not that I have anything to solve at present, but it's essentially a much more compact setup than a chargecooler, or a boot-mounted IC - and the SMIC will still be there anyway, probably with a spray bar, too. Ryan worked wonders with the tune before, but this adds in a bit more overhead. There will be naysayers, but even if my little project amounts to sweet fanny all, hopefully there will be learning involved that can benefit thems whats interested