I'm trying to finish up an old project without throwing a bunch more money into it. I have a stock LS3 in my 260Z(boring as hell) and have decided to put an 86mm Comp turbo on it to give it a bit more pep. It came with a water meth spray ring set up on the compressor outlet and and I'd like to try running this instead of adding an intercooler. From what I've read, if I keep the boost down below 8psi or so, the water meth along with the larger turbo shouldn't really need the intercooler. I have the Holley Dominator EFI so we can ramp boost in slowly(this large of a charger won't come up too fast any way) and I believe the Holley can control the water meth as well.

 

Do you have a question about it? It will be ok, but I would highly recommend trying to find somewhere for an intercooler, even a medicore one will increase performance.

 

Yah, all you need to do is "keep the boost down!" Good luck with that! You'll end up an addict like all of us!

 

Really, 6-8 psi is all I want.... Wait, let's see what 10psi feels like, HOLY ****, let's try 12psi now.

Next thing you know, you're building a new shortblock to push 25psi through it.

 

^^^Aaaaaaannd there it is!!!

 

That turbo seems rather excessive.

 

Plenty of self control here. Not a lot of faith in LS connecting rods so far.

 

I like that you think an 86mm is just for a "little more pep...."
I vote yes to do this. Street car that thing and just keep adding meth until your heart is content...

 

I vote you spray pre turbo. post turbo gives up alot...esp with no IC. Looks like a cool little rig though. Maybe "T" off it and spray pre turbo too... What fuel?

 

what fuel?

my car will be non intercooled next year
renegade e85, no meth

ive seen 25 psi with a gm iat sensor pegged

im pulling zero degrees of timing for any air temp and i havent seen any ill effects yet

 

I never thought about spraying pre turbo. When I first got in to diesel stuff, a lot of guys were spraying water/meth trying to eek out the last bit of power from their VE pumps. I went with a p-pump instead and never tried it.
No E85 locally.

 

100% meth pre turbo in large volumes does a ton. Up's the efficiency on the compressor map and adds octane.

 

Is it best to let the Holley EFI control the solenoids, or would it be better to just install a kit from Snow or one of the others?

 

I don't see the spray getting past the boundary layer with that set-up.

 

Curious about guys spraying pre turbo, is it possible liquid could accumulate
in lower areas of the plumbing, like IC'er, lower pipes, etc-or does it dissipate.

 

Yes, it is absolutely a concern if you spray too much.
Call Rodney at AIS to get sizing of you want to spray pre-intercooler.
For non-intercooled setups, spray whatever you want, but keep in mind that if you spray enough volume that the mix is within the fuel's ignitable afr you can have an explosion in the intake if the car ever backfires.

 

Isn't it a little dangerous spraying 100% pre-BOV?

 

Depends on the mixture you are spraying and what you want to accomplish with it.

I run E85 and an IC so I don’t need the aux injection to keep me out of detonation. I just use it for a little extra cylinder cooling. So I run 30% meth washer fluid. 2gph pre-turbo and 7gph post. The idea is the 2gph is pretty much in vapor form when it exits the turbo so it won’t collect in the IC.

With no IC you get the max benefit spraying pre turbo with tons of meth, more the better. If you really want to push the meth injection and run serious boost, you should run some sort of pressure release valve or burst disk on your charge pipe. Hogan’s sells the low pressure (125psi) burst discs for $130. You can also use the adjustable BOV with say 10psi more spring pressure than your max boost levels and not hook it up to a manifold source. It will then blow open and vent the “explosion” in the case of a backfire. Really not a hard or expensive safety precaution.

At 500hp worth of airflow each 8gph of 100% meth will drop charge temps about 30* until you hit the boiling point of methanol (148*)
At 1000hp worth of air each 8gph is good for roughly 15* drop in charge temps.

Water is about 160% more efficient than meth at dropping temps. But will only cool the charge temps down to the boiling point around 212*. While methanol can drop them to around 150*! Meth also adds lots of octane, and is flammable. So it won’t drown out spark in large volumes like water will. For the ideal effect you want to calculate (or gather the actual) charge temps. Then mix just enough water by volume to drop charge temps to around 212* and use meth for the remaining cooling. That will give you the benefits of water in the CC and max efficiency charge temp cooling.

With your engine/turbo combo I really doubt that turbo will be in its max efficiency island at 8lb or under. If you really plan on 8lbs or less. I think that’s a poor turbo choice. It won’t spool very fast, and it won’t be very efficient. (awesome turbo, just not matched well for 8lbs)

Honestly in your case the above is probably overkill and then some. With 6.2 liters around 6800 at 8lbs a10gph nozzle with 50/50 water/meth is all you should need. 8lbs is nothing and with that huge turbo it won’t heat the air up enough to even need the water/meth to keep out of detonation at those levels IMO. Pre or post injection… Whatever is simple/easy would be my suggestion in your case.

If you want to get serious you should be able to run 20-25lbs with very reasonable charge temps and no detonation on pump gas using the method described above.

Good luck! Let us know how it goes…

 

Spraying pre-compressor does increase turbo efficiency and adds octane, but it isn't without its downsides.

The cooling effect is diminished somewhat. When you spray, it can only cool the intake charge so much between temperature change and evaporation. When you spray pre-turbo, you're introducing a major heat source into that cooling path. You get the benefit of increase efficiency from cooling pre-turbo and keeping compressor temps down, but you lose most of your intake temp cooling. It wouldn't be much of an issue if the compressor was being heating from compression alone, but being bolted to the exhaust is going to supply an endless heat source, which means that some of the energy in the water/meth that's being used to cool the compressor wheel/housing is effectively wasted.

Surprisingly, this matters very little. Once you increase the octane, intake temps become less of a problem. You would technically help make more power spraying pre-compressor from efficiency alone. Your heads also flow less oxygen at increased temps, so if you can, put a secondary nozzle after the turbo. You can just use a push-lock T fitting and run fluid to both of the nozzles.

 

I run pre and post blower for my meoh/water injection.