Fuel distribution issues with alky injection right before TB?

[KyleH]

I have a 2002 Subaru WRX with a stock, fairly small, TD04 turbo. Toward the top of what the turbo can do my injector duty cycle will be something like 90% and I was thinking of running a DIY alky or meth kit anyway as I had great results with -32* washer fluid injection on a supercharged 98 Mark VIII. The difference here however is that the top mount intercooler outlet is just before the TB where in the Mark VIII the only cooling WAS the spray so I could run it plenty up stream. On these intakes, as youll see in the pic below, the runners start immediately after the throttle body. Should I be concerned about fuel distribution problems due to heavier atoms or anything else? My worry is that I'll get poor alky distribution and one cylinder will be knocking and Ill grenade the motor even though EGTs and AFRs may be fine due to the sensors being up stream after the header merges.

EDIT: By the way I came here because it seems to be one of the original places to have a water/meth section, if theres a better alky forum out there let me know.

 

[Razor]

Welcome to the forum,

No there is no better place.

Now the dumb question are we talking straight methanol or mix or windshield washer fluid or ???

The reason I ask this is becuase a lot of imports are hell bent on running washer fluid and calling it meth injection.

To answer your question, if the air hitting the liquid being shot is of high enough temp, the liquid will flash and go where the air goes. No distribution problem.

Meth flashes at 70 degree's water flashes at 180 degree's. So if you use meth, and the temp at the nozzle is at least 70 degree's then there is no distribution issue. Unless there is an air distribution issue. Meaning if cylinder 3 starves for air, it will starve for meth. Hope this makes sense.

 

[WSLN 6]

Great info as always! What would you suggest if the plenum temp was below the flash temp?

 

[Razor]

Great info as always! What would you suggest if the plenum temp was below the flash temp?

Hard to do this. Understand boost vs temp. Every PSi boost=11 degree's So at lets say 7 PSI your at 77 degree's above ambient temp. Even if its zero degree's outside your still over the temp threshold of meth at 7 PSI. The IC will cool that down of course, but I hope you understand what I mean.

Now think of water at 180 degree's.. thats the problem. You need a lot of temp to make it work, this is why its used on turbo diesels a lot.

70 degree's outside.;. 7 psi boost= 147 degree's.. water needs 180..

50/50 is about 125 for temp

 

[TurboTR]

The unpopular answer is- yes, you will probably have serious distribution problems by trying to move liquid equally through a dry flow manifold. The more you have to rely on it percentage-wise, the more serious the potential danger will be.

One thing you could do is, add a dye to the alcohol/water mix. Test it a few times and then examine where the dye stains are. Think it would be very instructive to do this.

TurboTR

 

[Razor]

Once the methanol flashes its no longer a liquid

Hence my post about water :redface:

 

[KyleH]

Unfortunately I'm still waiting on the tuner/datalogger in the mail...was supposed to be here yesterday, so I cant get good info about IATs quite yet. I doubt they will be terribly high though I am running a larger top mount and I've never felt it that hot after a drive to think its getting heat soaked badly or anything. I was planning on turning up the turbo significantly though, to about 18-19psi from 14. Was also planning on porting it as it seems others have gotten good results with that free mod.

I was thinking of 70% or 50% isopropyl through a shurflo pump simply for the availability of it. The only meth suppliers are a ways away.

 

[Quiky One]

Unfortunately I'm still waiting on the tuner/datalogger in the mail...was supposed to be here yesterday, so I cant get good info about IATs quite yet. I doubt they will be terribly high though I am running a larger top mount and I've never felt it that hot after a drive to think its getting heat soaked badly or anything. I was planning on turning up the turbo significantly though, to about 18-19psi from 14. Was also planning on porting it as it seems others have gotten good results with that free mod.

I was thinking of 70% or 50% isopropyl through a shurflo pump simply for the availability of it. The only meth suppliers are a ways away.

Run denatured alcohol. Lowes, home depot, will carry it. Although, might want to get a good pump from Razor...Not sure the shurflo will hold up to the alky.

Jason

 

[KyleH]

Why denatured vs isopropyl? Do I need to worry about having a well sealed tank or anything this is Florida and I'd think the alcohol would evaporate quite a bit.

 

[aminga]

Listen to Julio, Run Pure methanol. It's cheaper to boot.

 

[KyleH]

I'd love to. AFAIK the closest methanol supplier to me is too far to ensure that I'd always have it and I dont really wanna keep huge jugs of it around. Hence the appeal of something I can get at Lowes, Home Depot or Wal-Mart.

 

[Razor]

Lazy

Walmart has HEET bottle.

We that consume.. just buy a 5 gallon pail of the stuff and not worry about having to constantly source it out.

But this assummes you build a system that can tolerate 100% meth

 

[KyleH]

So back to my original question, if I got 120* IATs @ 17psi at the point of injection which will be maybe 7-8 inches upstream of the nearest runner, is it likely that a 75% or a 50% water meth mix will be atomized enough to ensure a good distribution? 130*?

Should I consider making a spray plate that has nozzles on opposite ends?
Is it terrible to run meth as a slight bandaid so I dont have to run such a high duty cycle on the top end?