In Turbo Water/Meth... hmm...

[doug@frankenturbo.com]

The point of the video was to show that WMI, even when "only" at the turbo outlet, will have a significant impact on charge temperatures. The two temperature gauges clearly show that. So running a nozzle inside the housing, a bit more upstream, should work at least as well as what you see in the video.

I've been running pre-intercooler meth since the FrankenTT's inception. I have always believed that the sooner you start cooling, the better.

[Marcus_Aurelius]

The point of the video was to show that WMI, even when "only" at the turbo outlet, will have a significant impact on charge temperatures. The two temperature gauges clearly show that. So running a nozzle inside the housing, a bit more upstream, should work at least as well as what you see in the video.

I've been running pre-intercooler meth since the FrankenTT's inception. I have always believed that the sooner you start cooling, the better.

Oh, I get all that Doug!

I was asking if this had anything to do with pre-turbo injection and the discussion we were having. I know you had ED weld a pre-turbo nozzle mount for you at some point, did you ever get anywhere with that?

(I have an email coming your way about some stuff )

[doug@frankenturbo.com]

I posted that video as encouragement for what the OP is doing now. Pre-compressor injection is something I will explore, but I still see good reason for running it after the air has been boosted. Also, notice how quickly the airflow temps recover after the first run. Even when lacking some kind of induced "coolant" the metal housing obviously benefits from simply having air blowing through.

Also, I think it's worth re-linking this calculator for the heat byproduct of compression. It clearly shows that compressor efficiency plays a minor, secondary role in temperature rise. It's almost completely owing to the compression itself. That's something to remember when a big turbo guy dismisses your K03 as a "hair dryer".

[RadRacer513]

I don't see the point of cooling before the intercooler. If the air in the intercooler is already cooled, wouldn't the intercooler actually heat it up then? Or are you not reaching temperatures that low yet? Also, what kind of mixture do you plan on running?

Sent from my Xperia X10 using Tapatalk 2

[DMVDUB]

Rad'
The point of spraying precompressor is to move efficient range not really cool flow. It causes a chemical reaction when the atomized H2O hits the blades at high speed and the air mid compression. While the two mix post compression is causes the turbo in effect to act like a larger turbo.

[Marcus_Aurelius]

I don't see the point of cooling before the intercooler. If the air in the intercooler is already cooled, wouldn't the intercooler actually heat it up then? Or are you not reaching temperatures that low yet? Also, what kind of mixture do you plan on running?

Sent from my Xperia X10 using Tapatalk 2

Let's ignore pre- turbo injection, even in normal setups and suitable applications, pre-cooler injection is desirable if done properly.

The intercooler could care less about what's happening to the air before, what matters is the air temperature when it reaches the IC inlet. Depending on ambient temperature or precisely the temperature of the air flowing over the core, the heat exchange will happen at X percent of efficiency. So, you are correct in your assumption that the IC is more efficient in its ability to remove heat, but that doesn't mean it stops working if air temp is lower when it reaches the core.

Also, water injection can only do so much! Cooling lava from a small frame turbo at boost levels that makes them relevant, is a tall task for a single nozzle or even two nozzles to handle. Spraying pre-cooler will remove some heat but not enough to make the intercooler highly inefficient to the point of heating up the charge (not in the applications discussed).

I tested the effect of water injection alone in my car, as a single variable. I run AWIC, so taking the intercooling out of the equation was real easy. This was the result with a total of 5 nozzles total. The data shows that water injection alone had a sizable delta temperature and not capable of handling the cooling task by itself (it is to be noted that I push the k04 more than most, if not all). Even with an elaborate water injection system with 5 nozzles, intercooling is still needed and would be totally efficient. With a nozzle pre-cooler, I am getting great intercooling efficiency, so depending on the application, I wouldn't say that it's pointless.

I did some more testing with the car, but this time with water injection as my tested variable... IAT was rising steadily at full boost and not able to even keep the air charge temp constant.

4th gear pull




3rd gear pull





2nd gear pull





Part throttle drive 15 min drive

[doug@frankenturbo.com]

....water injection can only do so much! ...
I tested the effect of water injection alone in my car, as a single variable....The data shows that water injection alone had a sizable delta temperature and not capable of handling the cooling task by itself... Even with an elaborate water injection system with 5 nozzles, intercooling is still needed

Coincidentally I got in touch with Ed yesterday to walk him through an idea for running the F23 without an intercooler. He was skeptical, but I told him the purpose was to find out how much boost can be handled by (an admittedly elaborate) wmi system alone. It will also be interesting to measure "pressure losses" versus a good FMIC.

[Marcus_Aurelius]

Coincidentally I got in touch with Ed yesterday to walk him through an idea for running the F23 without an intercooler. He was skeptical, but I told him the purpose was to find out how much boost can be handled by (an admittedly elaborate) wmi system alone. It will also be interesting to measure "pressure losses" versus a good FMIC.

I recorded a sizable pressure drop when I was deleting one of the TT SMICs (around 3 psi from 5k - up). It would be interesting to see how much those bigger cores are scarifying.

If the purpose is to test the pressure drop, it's fine... but I don't see running sans-cooler working as a permanent setup since you can't spray continuously.

We'll see what you come up with with your "bigger" than stock core

[RadRacer513]

Rad'
The point of spraying precompressor is to move efficient range not really cool flow. It causes a chemical reaction when the atomized H2O hits the blades at high speed and the air mid compression. While the two mix post compression is causes the turbo in effect to act like a larger turbo.

Interesting. I never really though of using it this way; sounds plausible. Can't wait to see what data you guys come up with .

[All_Euro]

I posted that video as encouragement for what the OP is doing now. Pre-compressor injection is something I will explore, but I still see good reason for running it after the air has been boosted. Also, notice how quickly the airflow temps recover after the first run. Even when lacking some kind of induced "coolant" the metal housing obviously benefits from simply having air blowing through.

Also, I think it's worth re-linking this calculator for the heat byproduct of compression. It clearly shows that compressor efficiency plays a minor, secondary role in temperature rise. It's almost completely owing to the compression itself. That's something to remember when a big turbo guy dismisses your K03 as a "hair dryer".

Thanks Doug - much appreciated

So things were up and running but the manifold bolts were coming loose already... so I just pulled everything apart to re-torque. One of the turbine threads stripped out when I was tightening it up though - kind of switched one leak for another. I suppose that comes with the territory when working with these old... used parts.

It's all snugged, and exhaust putty'd, up so maybe that will hold long enough to get some decent logs.

On the plus side... I'm getting pretty quick at knocking that shoe-horned snail off its hiding spot

BTW - I logged several runs to check exhaust temps and ignition timing & CF's were nothing until the mani bolts loosened and exhaust temps under any circumstance didn't get over 765*C. I've got the temp sensor wired up but Home Depot or Lowe's don't carry NPT hardware so I'll find a supplier and mount the sensor later this week... until then it's an under hood sensor. I've got it positioned between the charge pipe and firewall and it maxes at about 50*C.

[All_Euro]

Well as to be expected with a missing manifold stud by cylinder 1 & one of the three turbo to mani bolts (by cyl#4) missing... a little exhaust is leaking... but I did some 2K to 6-7K 3rd gear pulls tonight on my way home to test things out anyways.

Before injecting into the compressor housing I was hitting 26psi from 3-4k and tapering from there. Now I'm hitting 27psi in the same rpm range but not holding... still 26 after until 4k and tapering. So nothing earth shattering but a step in the right direction under less than ideal conditions.

I'm thinking of tapping the stripped turbine housing threads to the next bigger size so I can seal it up without ripping everything apart... we'll see.

[PRY4SNO]

I made friends with the local Nut & Bolt Supply House for odds and ends that came up last minute on my motor build. They'll have a much higher spec, far better selection and way better pricing than a retail hardware store.

[Gulfstream]

Has anyone actually seen any benefits from spraying before the compressor?

I'm not sure it has the wanted effect of increasing performance as the compressor will suck in less dense air. The charge air will be cooler but contain much less oxygen per mass...

[All_Euro]

I made friends with the local Nut & Bolt Supply House for odds and ends that came up last minute on my motor build. They'll have a much higher spec, far better selection and way better pricing than a retail hardware store.

Agreed about the quality - happen to know of any in my neck of the woods?

Edit: I see what you did there… Open Weekdays: 7:30 a.m. - 5:00 p.m

Has anyone actually seen any benefits from spraying before the compressor?

I'm not sure it has the wanted effect of increasing performance as the compressor will suck in less dense air. The charge air will be cooler but contain much less oxygen per mass...

Well... until we have evidence I suppose it's all hearsay. Once I've ironed out these couple wrinkles in my system I'll test/log with the in-compressor spray both on & off - then we'll know

I'm not opposed to hitting a dyno either... they're $100 & up for three pulls here though so things need to be running well enough to make it worth while.

[Marcus_Aurelius]

Has anyone actually seen any benefits from spraying before the compressor?

I have seen gains, and have been testing a pre-compressor nozzle on/off for some time now. I have gathered a decent amount of data that I won't post until I have a dyno to prove what I'm seeing on a consistent basis (increased overall pressure made and increased recorded mass air, and that's back-to back-to back switching the nozzle on/off). I have a project thread that also includes several other upgrades as they were finalized, subscribe and you'll see the data when I have some dyno graphs to support or refute the data gathered.
http://forums.vwvortex.com/showthrea...-approach-quot

I'm not sure it has the wanted effect of increasing performance as the compressor will suck in less dense air. The charge air will be cooler but contain much less oxygen per mass...

What you're missing is that normal compression is adiabatic, so the gas heats up as it compresses. This implies that power is taken out of the shaft energy (exhaust generated) to perform the heating, on top of that you need to use a form of cooling somewhere upstream (further reducing efficiency). When injecting pre-compressor, you remove the heat buildup and makes the compression closer to ideal isothermal (That is why this is seen by some as a compressor map reconfiguration). What this does is:

1) less exhaust gases are needed to generate the same boost
2) If you're pushing things like me, more boost is achievable with a constant exhaust pressure.

Say you were maxing out the hot side pressure (truly the limiting factor in terms of energy available to a turbocharger), at that constant pressure limit you'll be making more overall cold side pressure AKA boost. And as we all know more boost with less heat is more efficiency and power if you can use it.

[Gulfstream]

What you're missing is that normal compression is adiabatic, so the gas heats up as it compresses. This implies that power is taken out of the shaft energy (exhaust generated) to perform the heating, on top of that you need to use a form of cooling somewhere upstream (further reducing efficiency). When injecting pre-compressor, you remove the heat buildup and makes the compression closer to ideal isothermal (That is why this is seen by some as a compressor map reconfiguration). What this does is:

1) less exhaust gases are needed to generate the same boost
2) If you're pushing things like me, more boost is achievable with a constant exhaust pressure.

Say you were maxing out the hot side pressure (truly the limiting factor in terms of energy available to a turbocharger), at that constant pressure limit you'll be making more overall cold side pressure AKA boost. And as we all know more boost with less heat is more efficiency and power if you can use it.

I am aware of adiabatic heating with compressed air. My point was a compressor can only move so much mass of air and this mass should be as dense as possible (cold and dry). Moisture makes air less dense.

Anyways, if you have positive effects with spraying before compressor I'd sure like to see the results.

[Marcus_Aurelius]

My point was a compressor can only move so much mass of air and this mass should be as dense as possible (cold and dry). Moisture makes air less dense.

But what do you think the heat generated from compression does to the air mass and its density? Your reasoning that "moisture makes air less dense" is correct but should be applied to heat as well. The positives from the process outweighs a negative that would be there regardless ...

[Gulfstream]

But what do you think the heat generated from compression does to the air mass and its density? Your reasoning that "moisture makes air less dense" is correct but should be applied to heat as well. The positives from the process outweighs a negative that would be there regardless ...

I'm thinking like this:

The compressor has to suck in xx amount of air per revolution. This air should be as dense as possible for the compressor to bite (pardon my layman's terms). Now, if the air is less dense each rev will move less energy. The airmass after compression is a whole different story because now we have already compressed it. It's passed stage 1 which was to compress as much air as possible and now we have intercoolers and what have you not to cool it down while keeping flow. So in my logic it's better to focus on cooling the air after compression.

but hey what do I know..

Looking fwd to your stats

[Marcus_Aurelius]

I'm thinking like this:

So in my logic it's better to focus on cooling the air after compression.

Both have their advantages, all you need to add to the logic is that the actual compression process (from inducer to exducer) can be cooled as well with great benefits. Conventionally, without the pre-compressor spray, there is a great deal of air mass loss from compression due to heat (far greater than the marginal saturation of the air with water that also atomizes instantly from the compression heat).

[Gulfstream]

there is a great deal of air mass loss from compression due to heat

Still my two braincells tell me the mass isn't lost... Unless you have a leak, it's in your charge pipe all pressurized, hot and bothered screaming towards the IC to chillax. As you correctly stated the adiabatic heating is a result of compression but as far as the airflow over the inducer is concerned this is chapter two and will be dealt with downstream. Still for me most important is mass of air moved per revolution of the compressor. The most dense air is dry and cold with as little humidity as possible.

Dyno your car with pre and post compressor WI and tell me I'm completely wrong. I welcome it

edit:

Then again I could just google "wet compression" and educate myself:

http://www.zevanya.com/en/amco/wet-compression.htm

And this, I particularly enjoy his last post; the conclusion:

http://www.supraforums.com/forum/sho...o-big-power%29

[Twopnt016v]

Then again I could just google "wet compression" and educate myself:

http://www.zevanya.com/en/amco/wet-compression.htm

And this, I particularly enjoy his last post; the conclusion:

http://www.supraforums.com/forum/sho...o-big-power%29

[Marcus_Aurelius]

Then again I could just google "wet compression" and educate myself:

More education for all on pre-turbo injection and the effects of wet compression.

http://www.max-boost.co.uk/max-boost...OMPRESSION.pdf

And below is an extract from an article I like to call "Everything Water Injection"



... but what happens inside the compressor impeller occurs at a molecular level.

Think of it this way If you could freeze frame time, and stop what was happening inside the impeller while its spinning at 120,000 rpm. Each impeller passage between adjacent pairs of compressor blades contains a wedge shaped parcel of air. When spinning at 120,000 rpm the air is subject to huge centrifugal forces as it moves away from the hub of the impeller and toward the rim of the compressor. The trapped air would like very much to be slung out of the impeller but like a crowd at a stadium after a match it simply cannot all get out as fast as it would like. As a result it stacks up (compresses) as it gets near the exit. In this process a lot of internal friction occurs. The air near the tips of the compressor might be moveing near the speed of sound at maximum flow, this heating makes the air try to expand. This increases the pressure which fights the outward movement of the air. Eventually a balance is achieved between the centrifugal forces trying to throw the air out of the impeller and the pressure build up due to the compression and the pressure build up due to the heating. The addition of the water mist removes a very large fraction of the pressure gain due to heating. As a result more air can exit the impeller over a given period of time, and more of the pressure gain is real compression rather than waste heat. The net result is a more isothermic compression which is always more effecient than an adiabatic compression.

A compressor moves a certain VOLUME of air. Even though most compressor maps list airflow by mass (lbs/min), it's actually a matter of VOLUME (CFM), that has been translated to mass by assuming a certain temperature and pressure (~25C and 1 atmosphere).

So, what this means is that a compressor that maxes out at say 55lb/min airflow on it's compressor map, should be able to flow about 10% more (60 lb/min) if the inlet temperature was 0C (0C air is about 10% denser than 25C air).

I imagine another big part of the limitation of the compressor is the amount of force of stacking up the air and compressing it. Although the ENGINE benefits from a intercooler, the compressor really doesn't care. It's still working hard, and making hot temps. These hot temperatures which result naturally from compression, work to expand the air, while the compressor works to contract it.

So, what if you could "intercool" the compressor itself? Add a mist of methanol/water to the inlet, which would vaporize and cool the air as it passes through the compressor? I'm still unsure on this, but wouldn't that mean a even bigger jump in the efficiency and upper limit of a given compressor, seeing as how it has to work against the air far less?

My guess here is that a compressor works on relative volume in vs out. When you see a compressor map, and one section says say 75% efficient at 60lb/min and a 3 pressure ratio. What REALLY matters, is how much volume is going in, vs going out. You get a 3x reduction in volume through compression, and gain 30% volume through heat expansion (25C in, 150C out). That's a mass boost of 2.1:1.

Now, IF the out temp of the compression process was reduced to say 40C through methanol vaporization, look what happens:

Pressure ratio of 3:1 remains
Temperature gain now only expands the air by 5%.

3*.95=2.85

So, if I'm not missing anything, the same compressor, operating at the same 3:1 pressure ratio, will be able to flow 2.85/2.1=35% more air if the air only heats up to 40C during the process instead of 150C.

Combine the gains of pre-compressor cooling to freezing temps, and the integrated cooling (actually heat gain reduction) during compression, and a compressor rated to only flow 55lb/min could flow: 55*1.1*1.35=81.675lb/min.

[All_Euro]

More education for all on pre-turbo injection and the effects of wet compression.

http://www.max-boost.co.uk/max-boost...OMPRESSION.pdf

Good link - thanks for that

A couple things that caught my attention were:

• Since one-half to two-thirds of the turbine output is typically used to drive the compressor, a reduction in compressor work directly translates to an increase in net turbine output.
• Typically, the reduction in output is 3-3.5% for every 10°F increase in the air temperature.
• This water spray corresponds to about 1% of airflow - seems like a good rule of thumb for max pre-turbo injection
• reduction in the air temperature is limited by the ability of air to absorb water - this has been a concern for me as winter temps can be -40 deg here in the winter… even moderate engine bay temps will obviously help though but it's just something to consider in the planning.
• The objective is to place the nozzles as close as possible to the compressor inlet to prevent water agglomeration and water wastage prior to entry into the compressor - it was interesting to see how fogging, to cool intake air, was done further away whereas the wet compression is facilitated at the wheel… makes perfect sense so maybe a stainless line attached to a slim nozzle & holder pointed right at the comp wheel nut would do the trick without chewing up too much real-estate.
• ...demonstrated a gain in output of approximately 9%...

[21silverbullet]

cooling the air before the intercooler means that the intercooler can drop temps even further, so in respects you could run a smaller ic (stock sidemount) with the same effect as a larger one without the worries of heat soak. and we all know that a smaller ic= less pressure drop in general. i am really liking the sound of this and might have to hop on this band wagon of testing. another point is that as the air is being compressed by the turbine at high temps causing expansion and once it hits the IC it is then being cooled and condensed again which = more of a pressure drop. so in theory cold this cause less of a pressure drop seen in slightly larger fmic? i know that it still has to fill a larger volume before actually building boost but if the charge air hitting the ic is allready cooled and condensed close to the temps of the ic itself would that alter the pressure drop percentage

[Gulfstream]

More education for all on pre-turbo injection and the effects of wet compression.

soooo, any news regarding wet compression?

[Marcus_Aurelius]

soooo, any news regarding wet compression?

Been working great for me! I have been gathering stuff to put to the test on a dyno day and will post my wet compression results. I want to try a few intake manifolds, at least two TB sizes, a couple of exhaust manifolds, and switching the pre-turbo injection on/off to see what it does in terms of measurable TQ.

[Gulfstream]

seems to me like there is a fine line with wet compression. No more than 3% of the airflow should be sprayed in or you'll see a drop in rpms. I've read of guys testing this and made no more than 10psi on dyno bcs their minimum nozzle was spraying too much. Water hitting a compressor spinning at 120 000rpms is like

If you can find a nozzle that gives good atomization and supply 2% of your airflow I think you'd see some interesting results.

I kept my 5 gallon WMI tank and spray 80/20 distilled water/denatured alcohol 12" before my TB for cooling. But only above 15psi and only 115cc. Could tee in a nozzle there and feed the compressor if you prove some good results.

So for a 50lbs/min turbo I'd need a 10cc/min nozzle? Thats mighty tiny...

[All_Euro]

soooo, any news regarding wet compression?

Sorry for the delay - life has gotten in the way a little but I'm hoping to have my third turbo/exhaust mani bolt hole fixed this weekend with test result soon after

... I've read of guys testing this and made no more than 10psi on dyno bcs their minimum nozzle was spraying too much...

I agree there is a limit to how much spray you can blast the comp wheel with before it physically slows down… not so sure of that 3% of the airflow figure. I suspect the person who was unable to boost more than 10 psi was having other issues as well.

When I was injecting pre-turbo it was with a 63ml/min nozzle and into a K03. At that point I was hitting 26 psi by 3000 rpms no problem. I'm using a 47.25ml/min nozzle inside the turbo at the moment but I don't see an issue with that nozzle pre-turbo… especially considering the size of wheel you'd be spraying.

[All_Euro]

Been working great for me! I have been gathering stuff to put to the test on a dyno day and will post my wet compression results. I want to try a few intake manifolds, at least two TB sizes, a couple of exhaust manifolds, and switching the pre-turbo injection on/off to see what it does in terms of measurable TQ.

In for these results as well - it makes sense to test a few things at once What size nozzle are you using pre-turbo?

[doug@frankenturbo.com]

My guess is that this has been linked before, but one more time can't hurt:

http://www.customperformancesolution...injectioncalc/

[Gulfstream]

My guess is that this has been linked before, but one more time can't hurt:

http://www.customperformancesolution...injectioncalc/

That calculator will drown the compressor Doug. Looks to me like the sweet spot for wet compression is around 2-3% of air mass rated by the compressor wheel.

[Marcus_Aurelius]

That calculator will drown the compressor Doug. Looks to me like the sweet spot for wet compression is around 2-3% of air mass rated by the compressor wheel.

I'd like to think that most serious water injections users won't totally rely on calculators because they are simply pointers of a starting point applicable mostly to conventional setups. While some are better than others, I have yet to see one that accounts for all the relevant factors (nozzle location, operating percentage of the volumetric efficiency applicable to the particular setup etc.). They will more or less give an approximation of the overall flow requirements, but nothing about how to divide the total volume to size-sensitive nozzle locations like pre-turbo or a direct port for example.

As far as that 3% of compressor flow being the limit, it's another rigid rule of thumb that may magically apply to one setup and completely off for another. Although my custom nozzle used pre-compressor is relatively small, I am positive that going over 3% of the max compressor flow will not negatively impact the blade speed as suggested. Just look at the DSM guys, or the Supra guys, or the RX7 guys injecting pre-turbo, they are literally flooding their compressor in terms volume injected and still reporting results like increased boost and power (these guys do it to make their monster turbos even bigger than they are). If you are interested in giving pre-turbo a try, drop me a PM and I'll point you toward nozzles designed for that purpose.

[RadRacer513]

I sent you a pm...

Sent from my x10 using Tapatalk 2

[Marcus_Aurelius]

I sent you a pm...

Sent from my x10 using Tapatalk 2

Replied!

[tedgram]

Interested!