Pre-compressor methanol injection

[Devilsown]

Results on your intake air temps after your 1st and 2nd blower?
Or are you just wanting to know which will make you the most power?
or how much fluid on a tubro before you warp the wheel?

I already have data on how much fluid it takes to drop x amount of heat moving at x cfm.

 

[Car Cannibal]

I was running a solid 22psi before and then a solid 23psi after, mod done within a few days time so no crazy outside temp change.

I am not able to monitor IAT temps but the fact that the compressor gave back 1psi says it all to me.

DO has a bunch of Preturbo injection dynos graphs and 50/50 was the power winner and they also showed that Preturbo helps spool up.

I used thread sealant around the nozzle as a boost leak test showed a minor leak.
I'll have to find my pics but my nozzle is about 9" from the blades.

Chance brings up the two battles of injection, 100% water vs 100% Meth. While water does take out more heat per mist vs Meth, Meth can be used to an extreme volume and take out more in that scenario. It's what the GN crowd has been doing for years with success as post turbo injection.

But I don't think the above method is appropriate for Preturbo and DO has data to back up their suggestions of 50/50 Preturbo.

 

[KGB Pilot125]

Can I ask why you want to do pre compressor? I am doing a nozzle pre intercooler and one pre TB. It was tested by aquamist and they had huge gains by injecting pre intercooler. I will dig up the article and post it in a bit.

Josh

 

[Devilsown]

Well you will make more power the more meth you have. But the line is whats a safe tune and whats going to give you issues.

With spraying into the turbo it self, it has been done for 30-40 years or so. Its still widely done in the industrial world. But in the car world you have to worry about fluid in your ic core. high % of meth sitting in your core will eat thur it over time. Also have to worry about it eating at the wheel. Lots of varables there but i would chauk some of it up to cheap turbos with thin wheels, Being to hot before the fluid hits it. To much fluid hitting it, fluid not being small enough mist, to low of pressure in the system.

It could be any one of them issues. And no one has done any hard core testing. Turbo dynos are way expensive to rent. Only a hand full of them. Then coming up with 20 turbos to compare is not cheap either. Just x person has ran y nozzle pre compressor and it worked or didn't work etc. I just know that i like to play it safe. Why we don't have lot of customers running around who have destroyed turbos and blown motors.

 

[KGB Pilot125]

Here is the email from aquamist

>From: "Richard Lamb" <[email protected]>
>Reply-To: "Richard Lamb" <[email protected]>
>To: "Ivanko Barbell Company Authorized Dealer" <[email protected]>
>Subject: Re: Intelligent Intercooler Spray Control Module
>Date: Thu, 16 Oct 2003 23:02:14 +0100
>
>Hello Adam,
>
>We have been considered the option but recently we have come across
>something interesting and decided not to go for that particular product yet.
>
>One interesting finding recently whilst doing a product development test on
>a WRX. We placed a 0.4mm jet in front of the intercooler and a 1mm jet after
>the
>intercooler. During the 7- hour intemittant dyno runs, the intercooler never
>go above
>ambient - below ambient during idle when some residual water is still being
>evaporated.
>
>As soon as we removed the 0.4mm in front of the interccoler, we can see the
>speed the temparature on the cores rise, you can feel the heat as you
>approach it with
>you bear hand, never had the bravery to try, so we quickly spray the
>inetrcooler with the
>water jet and continued for 10 minutes., it was still too hot to tuoch!
>Another amazing
>thing we discovered - we were only injecting 70cc/minute! It is an
>interesting fact
>that spraying the intercooler externally does not have the same effect as
>internal WI.
>
>
>Richard
>
>
>----- Original Message -----
>From: "Ivanko Barbell Company Authorized Dealer" <[email protected]>
>To: <[email protected]>
>Sent: Thursday, October 16, 2003 9:18 PM
>Subject: Intelligent Intercooler Spray Control Module
>
>
> > Any plans on producing something like this?
> >
> > AutoSpeed
> >
> > Love your products. Keep up the good work.
> >
> > Thanks.
> >
> > Adam Auerbach
> > GMC Syclone #2419
> >

And a follow up from richard

Quote:
Originally Posted by 4C FED
Quote:
Originally Posted by ivanko barbell
Think of the a2a intercooler as more of a heat sink than a radiator.

So my question is:
Why was there no heat radiating from the IC when water was applied from the onset?
Is it because the water was helping retain the heat inside the IC or because it was removing so much heat that it never had the chance to get hot?

If the latter is true, why was it still hot after re-apHello Adam,

The front jet was taken out and use it manually to douse the core
externally - we took it out to measure the flow and forgot to put it back.
In moment of panic, we just try to col it externally because the heat of the
was unbearable to do any re-fitting.

If the intercooler never got hot with such a small amount of water, should
it be there in the first place?

Please suppost and join this forum - a detailed discussion on water
inejction solely.
http://www.turboice.net/forum/

I posted the same topic to the forum:
http://www.turboice.net/forum/viewtopic.php?p=13#13



Regards
Richard
plying the front water jet even after 10 minutes?

Here are the answers you requested from Richard Lamb at Aquamist.

 

[Car Cannibal]

Preintercooler CAN NOT extend the compressor map or aid spool up like Preturbo can FACT.

What Aquamist is showing is how to keep the intercooler from heat soaking and helping the MAT temps from it. Fine, run all 3 if you know how to evenly compensate each nozzle but I'd rather run Preturbo vs Preintercooler and do so.

 

[Enraged78]

I was running a solid 22psi before and then a solid 23psi after, mod done within a few days time so no crazy outside temp change.

I am not able to monitor IAT temps but the fact that the compressor gave back 1psi says it all to me.

DO has a bunch of Preturbo injection dynos graphs and 50/50 was the power winner and they also showed that Preturbo helps spool up.

I used thread sealant around the nozzle as a boost leak test showed a minor leak.
I'll have to find my pics but my nozzle is about 9" from the blades.

Chance brings up the two battles of injection, 100% water vs 100% Meth. While water does take out more heat per mist vs Meth, Meth can be used to an extreme volume and take out more in that scenario. It's what the GN crowd has been doing for years with success as post turbo injection.

But I don't think the above method is appropriate for Preturbo and DO has data to back up their suggestions of 50/50 Preturbo.

My own personal experience is word for word exactly the same as Car Canibal's. I can back up just about everything he has stated. I am running an Evo III 16G at 23PSI. I am running a 2Gph nozzle about 10 inches from the turbo inlet, about three inches behind the MAF. I gained 1PSI doing this mod, and spoolup decreased by about 1-200 RPM. I have been running this setup for about 20,000 miles, and it is a great system. No compressor blade damage of any kind, but my turbo housing is turning blue from running -20 smurf piss for long periods of time. Also, I run a 5Gph nozzle just after my BOV. 1 Gallon usually nets me a full tank of gas, or about 260 miles.

Recently, my pump took a shit on me, and I had to go back to a non-meth tune. 19 PSI is all I could get without sacraficing my timing map. I just purchased a new 250 PSI pump to replace the 100 PSI that went. I will post back if anything new comes of this. Theoretically, my atomization should be better and my pressure much more consistant. I should also get some more flow out of it. I'm not sure if I can get any more than 23 PSI on pump/meth out of this turbo. The Evo III really isn't meant to flow this much. I do run 26PSI on race gas, but even then, it's not terrably efficent.

Oh, and Chase: Thanks for taking the time with me yesterday. I appreciate the customer service even without me buying something. That says a lot about a company.

Thanks,
Matt

 

[Devilsown]

I don't mind helping anyone out. If we would have had what you where looking for you would have bought it i am sure. Maybe next time i will be prepared.

 

[dsm-onster]

Paul, I think your case is very specific; and what I think you should do does not go with convention of what preturbo injection should be used for.

Typically you don't want aluminum eating methanol before the the aluminum compressor wheel. As well, methanol DOESN NOT COOL BETTER THAN WATER. It does take out heat at a faster rate "typically" because it comes out of the nozzle with more surface area, due to lower surface tension. But when you are working with what the larger turbine engine manufacturers call "wet compression" or pre compressor injection (yes it is commonly used; it's not a new concept), the water instantaniously and explosively changes state close to the compressor exducer. There's no need to run something with less surface tension to cool the air fast because the water SUDDENLY turns to steam and SUDDENLY takes out the heat energy causing the aircharge molecules to reorganize and "smooth out"; instant high efficiency. So no one should be running methanol because the benenfits of methanol are not what's needed here. You need something that takes the most heat out, period. Not something that takes the heat out faster.

IN YOUR CASE however, since you're compound charging the motor, you need something BETWEEN the stages that is an effective intercooler, since we know that cooling between stages GREAT affects the outcome heat post all stages even more than aftercooling all the stages alone. As proven by volvo, cooling BEFORE the second stage GREATLY affects the total outcome more than jsut cooling very well after ALL stages, which I mentioned to you (and the reason we have the term "inter"cooler when most of us use it "after" every compression stage). Also IN YOUR CASE, you said you were concerned with space. So you need something to instantly cool the charge down before the second stage like an intercooler does and since you're second stage is a very affordable evo3 16g compressor, I recommend running methanol. . . Or a mix would even be better. With the mix you would get that instant intercooling effect, AND becasue the water is there, you will get that "wet compression" effect where the compressino is done thermodynamically and saves energy the compressor requires. So therefore you would get superior staged efficiency AND the second stage would be even MORE effective/efficient.

Just my input. My father and I ran his hotair T-type with preturbo injection and we saw great results with just distilled water. no real gain going to methanol. Methanol however did VERY much better than preturbo injection (with proper amounts for both) with our direct port injection setup on that car. But that was just because we didn't have enough fuel in the first place, I suspect. But we never compound charged that sucker . You need a good INTERCOOLER not neccesarily something that would help the efficiency of the second stage. If you want more, you can just up the boost of your primary stage (especially with a +100% efficient intercooler that methanol is) and not ever take the secondary stage off it's peak efficiency island. With preturbo meth injection just be prepare for a chalky white mess of a compressor wheel after a bit of use. Keep an eye on it and you'll just be replacing compressor wheels every once and a while, instead of whole center sections.

 

[Sp1kE]

So you need something to instantly cool the charge down before the second stage like an intercooler does and since you're second stage is a very affordable evo3 16g compressor, I recommend running methanol. . . Or a mix would even be better. With the mix you would get that instant intercooling effect, AND becasue the water is there, you will get that "wet compression" effect where the compressino is done thermodynamically and saves energy the compressor requires. So therefore you would get superior staged efficiency AND the second stage would be even MORE effective/efficient.

How would injecting Meth inbetween charges be more benificial than injecting pure water directly at each compressor inlet?

The amout of methanol you would be able to inject inbetween stages would be greatly reduced aswell, because you want the liquid you are injecting to be fully atomized before it can even reach the compressor wheel to prevent damage, which requires a much smaller nozzle.

The purpose of preturbo injection is to cool the turbo to make it more efficient, not the air temps.

 

[dsm-onster]

But the point of intercooling between stages IS to cool the aircharge. Regardless of compressor efficiency (they both can be through the roof), when you cool the AIR between the stages of compression you net a FAR better result than just making the compressor more efficient whether by reshapeing the wheels or "wet compression". The methanol is there to cool the aircharge between the stages. I say mix in the water to get the second stage compressor at an even higher efficiency though yet he'll be only runnin gat a 1.5PR with that any way and it won't even be remotely inefficient as is.

You'll need to look up staged intercooling and see what I mean that cooling the aircharge back down, regardless of the efficiency of the compressor used to compress the aircharge, is much more effective than simply increasing the efficiency of the wheels of each stage. Adabiatic proccess is NOT efficiency. The compressor can be 95% efficient and raising the boost still adds alot of heat.

Now, I'm not saying that preturbo or "wet compression" isn't incredible. But even if used, it still doesn't cool the aircharge back down to close to ambient temps going into the second stage. The colder the air going into the second stage the more mass second stage takes in, it's that simple.

. . .Wet compression alone changes efficiency by sometimes 10%. But going from 70% efficiency to 80% efficiency only changes the temp from 322*F to 295*F at 20psi boost: click to calculate compressor outlet temps.

. . .However, using methanol to cool that 322*F 70% efficient compressor at 22 psi feeding the second stage which is about 100% efficient and NO pressure drop puts the temp right back to where it was BEFORE the primary stage compressed the air. Teh second stage will see 22psi + ambient ant ambient temps vs 22 psi + ambient at 295 degrees. It's all about getting the best QUALITY charge to the second stage in a compound setup.

Wet compression is best with single stages where you want faster spool and where you can't keep the last stage at its highest efficiency to make the most power. WRT spool his spool is way too fast anyway . As well, with compounding, say the compressor efficiency of the second stage is 85% at 30psi over the primary stage. That means the outlet temp is 346*F. You don't need to change any of those numbers with a compound setup because all you have to do is change the primary stage boost and make the intercooler between stages more efficient and methanol is already the most efficient at charge cooling. Again wet compression won't help with the primary stage as much since changing efficiency even by 80%/70% = 14% overall only changes the outlet temp 10%. However cooling AFTER directly takes the temp down to close to ambient.

 

[forcefed86]

In compound situations you always run a pre-nozzle at the inlet of each turbo. Or so says the all the tractor pull guys that have been doing this for years. If you inject at the 1st stage only the meth will have vaporized before reaching the 2nd turbo.

I would go with a 1gph or smaller on your "little" turbo and a 2gph on your "big" turbo. The pre nozzles should have check valves with 10psi+ cracking pressures as close to the nozzle as possible. I have mine mounted on the nozzle itself. I'd also suggest the 250psi pump if you are running post IC injection as well. A 150 psi pumps pressure will drop considerably running a 15gph post and 3gph pre.

FWIW
I run a 2gph unit pre at 250psi and 15gph unit post turbo on my 68mm 3.8 buick. Spool-up time increased and total boost output jumped a full pound after adding the pre nozzle.

My DSM runs a .75gph pre and a 7gph post at 250psi. It also gained in spoolup time, although I did not see the full lb of boost increase. I'm assuming this is because I have already maxed out the little 16G.

I have not seen any issues with compressor or turbo corrosion/errosion. I've been spraying the buick for around 2 years and only a few months on the talon. All of my cars use 100% meth.

Lots of guys in the buick community run 2 kits. One with distilled water for pre injection and one with meth for post. I think this is the best setup.

 

[dsm-onster]

Yes running preturbo on BOTH compressors is IDEAL. But Like i said. Running between stages is most important by far.

IF he injects preturbo in the primary stage that doesn't mean that he should run significantly less in the second stage. because like you said the meth has already changed state. and it's all about catching the injection WHILE changing state. That's why water for wet compression works better than meth, and meth for post turbine injection works better than water.

Injecting meth before the first stage only lowers the intake temps from ambient (not very much) and is less effective than water at taking out the heat at the compressor tips (wet compression). Increasing the efficiency by 15% (preturbo injection) only drops the temp from 320ish to 295ish *F at 20psi. While all the fluid is already evaporated. But then injecting AFTER the 1st stage cools like an intercooler the charge at 100% efficiency and puts you at ambient temps before the 1st stage while maintaining the 20psi insteand of having it sit at close to 300*F at 20psi going to the second stage. So no matter how he doesnit the MAJOR difference will be from injecting between stages and there will be a minor benefit from injecting before the first stage if he does that in addition to that.

In all it certainly is to his benefit use methanol in his case because he's not concerned with compressor efficiency as much as actual charge cooling between stages. There NEEDS to be "inter"cooling between stages. compund setups who don't have intercooling between stages are severly hampered. And water doesn't intercool like methanol it is most effective at altering the second stage's compressor efficiency, which he doesnt plan on floating off the map anyway.

If he were running only one stage, I would say not to waste time with methanol preturbo. But run pure water. It will do better for the purpose of preturbo injection. Inject meth to cool the charge inject water to make the compression more efficient either at the compressor tips or during the compression stroke of the motor.

 

[Sp1kE]

DSM-onstar:
I still don't see how you plan on cooling the charge to the second compressor as dramatically as you say you can.

Like ForceFed said, he runs a 2gph nozzle pre turbo without any signs of corrosion or wheel damage.
It will work, but I see it being next to pointless with such a small nozzle.

 

[dsm-onster]

sp1kE. the calculator is right there. . . take the 1st stage as 20ish psi and at 70% efficiency. The temp before the second stage is 322*F. now plug that into the calculator below on that page and add a 100% efficient intercooler which meth injection does do. OR jsut plug in an 85% intercooler efficiency instead. You see the huge difference now?

Preturbo injection alters efficiency. But large efficiency changes have not so great an effect on final temps vs. cooling the aircharge down AFTER it has been compressed each stage.

That doesn't negate the great benefit that wet compression offers, it's just not effective for what Paul is trying to do: cool down that charge to something reasonable before it enters the second stage. Imagine 322*F inlet temps going into an evo3 16g compressor thats still only at 1.5PR and sitting at 78% efficiency. . . No don't imagine. Plug the numbers in: output temps are over 600*F after the second stage !!! At what temp does aluminum melt?

Wet compression doesnt negate the value of intercooling especially with a compound setup. IT DOES make compressors more efficieny and spool speed increase. Which are awesome since most of us are running out turbos off the map and are getting larger and larger hotsides to counter backpressure.

 

[99gst_racer]

Great posts, guys. Keep 'em coming.


Matt - Do you think surface tension plays a role in compressor wheel errosion? IE: Would the higher surface tension of water make it more seceptible to erroding the leading edge of the wheel?

 

[Sp1kE]

How do you assume a 100% or even 85% intercooler efficiency?
Shouldn't there be some sort of calculation of air volume vs meth/chemical intercooler used.

You could spray a .5gph at 20psi and X cfm. theres no way it would cool the charge back to ambient temp.

 

[dsm-onster]

Just bypass the leading edge of the wheel, Paul . If you're going to pray before the primary stage. Spray towards the compressor nut and close to the compressor nut. Surface tension DOES alter the amount of erosion, IMHO. When you get the material at the weakes t and fastest parts of the compressor wheel, though. . . . But if you're injecting methanol with proper nozzle sizing (a number of smaller nozzles) into 300*F aircharge (after the primary stage), that stuff is going to vaporize LONG before it gets to the second stage compressor blades and in the process take all that 300*F temp out of the aircharge. I'm just worried about the methanols chemical reaction to the second stage compressor wheel. But It will be ok for a while for sure. Just check that stage say every oil change or so.

sp1kE, I'm assuming that NOONE would use methanol injection without using the proper total nozzle flow to yield a better intercooler efficiency than an air/air charge cooler. That's silly . . . Good air/air intecoolers are about 85% efficient if properly sized. Methanol injection makes my intake manifold sweat on a hot july day. That's better than 85%; that's better than 100%. It's fairly obvious that proper nozzling should be used.

 

[Sp1kE]

It's fairly obvious that proper nozzling should be used.

Yes, but what I am getting at is, you will not be able to use proper nozzling inbetween chargers without corroding the wheel.
I'd say hes better off running to a stock sidemount rather than trying to cool the air between charges with loads of meth risking the turbo.

 

[autotalon]

I've set mine up 2" away from the leading edge of the wheel. (about 1 1/4" from the nut.) is that close enough?

I tested the 1gph nozzle from Devils Own, and it has a 2.5" wide spray fan @ ~3" distance. I am assuming that under compressor vacuum the fan should narrow as its being sucked into the inducer?

Also, from what I gather, if you use methanol it can erode the aluminum of the wheel. But, if you use water the higher surface tension will do the same? Kinda 6 to one, half dozen to the other isn't it?

Guess I'm gonna need another pump.

 

[dsm-onster]

^^^Most inject closer than 2" like right at the compressor inlet plane. or over 12" away to insure the particles are fine enough naturally.






Understandable, sp1kE. I mentioned this too. I don't think he will do TOO much damage that early though. If it's the RIGHT amount it will all be vapor since it is entering 300*F charge temps. He should use 3-4 smaller nozzles. So no corrosion from striking the blades.

So the only issue will be the chemical reaction of the methanol with aluminum. The boundary layer on the compressor blades will help protect from the chemical erosion by minimizing the methanol contact with the blades. It will last a while. He should keep a check on it. It's just an evo3 16g compressor. As long as he doesn't let it go so long that it puts the wheel out of balance. He should get good miles out of it before swapping. He'll likely be changing bearings out of such a torque monster about as frequently.

A small price to pay to have ideal between stage intercooling, where he won't need a clammy tiny charge cooler that will stop up all that great flow potential. There's no room for TWO frontmount intercoolers. So he'll be fighting 4-5 psi pressure drop that will GREATLY increase the charge temp. 4psi above 20psi raises charge temps 40 degrees at a 70% efficiency that the primary stage will likely be around (he's running a 60-1 compressor at the primary)!

Ultimately, he'll have to try this and tweek this hands-on to varify any of this either way. This is all based on adiabatic "theory".

 

[Sp1kE]

How do you calculate the "right" amount?

Don't you think 3-4 mini nozzles is quite rediclious, to cool down a charge that is only going to be reheated?
You can just cool down post turbo with tonnes of meth, and like you said that would act as a 85%-100% if not more efficient intercooler, to bring the charge down to ambient temperature?

 

[dsm-onster]

'If it's going to be reheated' . . . but we all know cold air intakes work well with turbo cars. It shouldnt matter if the turbo is just going to heat it up.

It's better to have efficient intercooling between stages and good charge cooling after, then having mediocre at best charge cooling between stages and good charge cooling after.

Lets go back to the calculator. . . .

Stage 1:

Input Temperature 100ºF (under-hood temperature)
Input pressure 14.7psi (use absolute pressure: -0.5 psi/1000 ft elevation)
Output pressure 20psi (gauge pressure: usually 1-2 psi more than plenum pressure)
Compressor efficiency 70% (typically 60-75%)

--------------------------------------------------------------------------------
Output temperature 320*F

Crappy small IC needed to fit:

IC input temperature 320ºF (Turbo discharge temperature)
IC Efficiency 55percent (example: enter 80 for 80%)
IC pressure loss 5psi (greater than or equal to 0)
Ambient temperature 80ºF (outside air temperature)

--------------------------------------------------------------------------------
Stage2 inlet temperature 189*F

Stage 2:

Input Temperature 189ºF
Input pressure 20psi (use absolute pressure: -0.5 psi/1000 ft elevation)
Output pressure 38psi (gauge pressure: usually 1-2 psi more than plenum pressure) [20psi inlet and 38psi outlet = 1.5 pr so evo3 16g is still in peak efficiency since efficiency is about PR not boost.
Compressor efficiency 78% (typically 60-75%)

--------------------------------------------------------------------------------
Output temperature 482*F

Good FMIC for final aftercooling:

IC input temperature 482ºF (Turbo discharge temperature)
IC Efficiency 85percent (example: enter 80 for 80%)
IC pressure loss 1psi (greater than or equal to 0)
Ambient temperature 80ºF (outside air temperature)

--------------------------------------------------------------------------------
Plenum temperature 140*F


Better charge cooling between stages

Stage 1:

Input Temperature 100ºF (underhood temperature)
Input pressure 14.7psi (use absolute pressure: -0.5 psi/1000 ft elevation)
Output pressure 20psi (gauge pressure: usually 1-2 psi more than plenum pressure)
Compressor efficiency 70% (typically 60-75%)

--------------------------------------------------------------------------------
Output temperature 320*F

Meth injection:

IC input temperature 320ºF (Turbo discharge temperature)
IC Efficiency 100percent (example: enter 80 for 80%)
IC pressure loss 0psi (greater than or equal to 0)
Ambient temperature 80ºF (outside air temperature)

--------------------------------------------------------------------------------
Stage2 inlet temperature 80*F

Stage 2:

Input Temperature 80ºF
Input pressure 20psi (use absolute pressure: -0.5 psi/1000 ft elevation)
Output pressure 38psi (gauge pressure: usually 1-2 psi more than plenum pressure) [20psi inlet and 38psi outlet = 1.5 pr so evo3 16g is still in peak efficiency since efficiency is about PR not boost.
Compressor efficiency 78% (typically 60-75%)

--------------------------------------------------------------------------------
Output temperature 323*F

Good FMIC for final aftercooling:

IC input temperature 323ºF (Turbo discharge temperature)
IC Efficiency 85percent (example: enter 80 for 80%)
IC pressure loss 1psi (greater than or equal to 0)
Ambient temperature 80ºF (outside air temperature)

--------------------------------------------------------------------------------
Plenum temperature 116*F​

. . .CLEARLY it's better to have 116*F charge temps ant 38psi vs 140*F charge temps at 38psi.

Nevermind that the density of the air coming into the second stage will be MUCH higher so there will be far more mass flow. 25 degrees difference in final temps and the air getting the the second stage has over 100*F difference. This will alter the MASSflow that enters the second stage immensely!!!!!! No contest. Final density ratio (which is all that counts) is 2.67 vs. 2.29. That's over a 16% increase in total massflow. That's about 100whp more potential at 550whp initially. No contest!

It's no too rediculous to use 3-4 small nozzles to increase the surface area and still total the proper nozzle flow for the airflow. It's done all the time. And is especially important since it reduces the size of the droples dramatically. Remember this is still be fore the second compressor.

 

[forcefed86]

How do you calculate the "right" amount?

That is like asking someone what the "perfect" AFR for a motor is. There is no right answer. You tune it at teh track or on a dyno and look for peak power, fastest spool, and lowest intake temps. I don't believe multiple nozzles are required with the amount of pressure and the ability of these new nozzles to atomize. Devilsown has some informative articles on there nozzles. I forget how many microns they claim, but they are very efficient.

With the proper high pressure pump and nozzle, I really don't' feel compressor errosion/corrosion is an issue either. I believe the turbo will wear itself out long before needing to be replaced due to impeller damage. Some of the turbo buick guys have been running methanol since the late 80's logging 50+K on there motors and turbos. I personally know of several turbo carb'd SBC and BBC guys running non-intercooled setups with very large 35+gph nozzles pre-turbo. No blade wear has been documented. (you can find a lot of good info on theturboforums.com)

The only compressor wear issues I have seen are on diesel setups where they are injecting a ton of pure water on a constant basis. (always in boost towing etc) Most were not using a proper pump or nozzle I might add.

 

[Sp1kE]

Hum.
I would REALLY like to see some numbers then.