MazdaManiac

iTrader: (3)

Think blade clearance...

globi

I know, this is why posted this:
In order to create blade clearance you need a significant temperature drop directly on the blades, which is why I posted the above and explained why this is unlikely.

MazdaManiac

iTrader: (3)

I can't discuss this any further. You'll understand if and when you get your hands on one.

John Corbitt

Aircraft have a product called erosion tape for the leading edge of wings. Water hitting them at high speed dulls our aluminum leading edges in one flight. Running water carved out the Grand Canyon. Turbine blades are normally made of high strength alloys, But they erode as well.

John

globi

Thanks John for this information. This is what I thought the reason would be as well. (But I wasn't 100% sure whether you can indeed provoke erosion without any addition of sand particles as well).

globi

Me neither. You'll understand when you read what I wrote.

r0tor

iTrader: (1)

while i was somewhat joking about adding inlet fogging to my AFSC (that i don't have)... its rediculous to say it can't be done as its done all over the place in large axial flow compressors in the power industry.

you can go "dry compression" or "wet compression". With dry compression you raise the humidity of the incomming air to 100% humidity - meaning your adding a specific amount of water (in a fine mist form) where it evaporates and completely saturates the air before it even hits the compressor blades. No additional wear on the blades occrur since your just putting really humid air into the compressor. You typically can reach 100% compressor efficiency with this strategy.

Wet compression you add even more water - in this case the amount you add is determined by your specific compressor design. The air heats up as it gets compressed with each stage and the air can actually hold more and more water with every stage - so you figure out how much water the air holds and add the amount it takes to saturate the air after the second to last compressor stage and use the last stage to superheat the air as an insurance policy against putting an incompressable fluid into something that will try to compress it. Compressor efficiencies of 120% can be reached with this strategy, but excessive wear on the leading edge of blades can be experienced (especially if you have large droplets).

MazdaManiac

iTrader: (3)

We are not talking about any "general" axial flow compressor here. This is very specific.
I am not at liberty to discuss why this won't work beyond what I have said here.

SmokeyTheBalrog

The 2 big problems i see with the adding water are:

1. A complete or at least major redesigned of the AFSC. You guys want this asap right?

2. If would defeat the KISS idea behind it.

Again, just my 2 peso's worth (old valuation not new)

HeavyMetal699

Earlier in the thread (maybe years ago ) RP was going to attempt to add a fuel injector before the axial flow compressor. I know gasoline and water have different properties, but now I wonder which difference is the culprit.

SmokeyTheBalrog

Oh I was talking about the staged water injection idea.

a fuel vapor system would be pretty cool. But I understand they are a pain to engineer properly and emissions could be a problem.

I don't know squat about water injection

cavemancan

Any chance anyone could give me an update on the super C or at least direct me to the right page? I really dont want to read 250 + pages.

california style

Hi Cavey wavey....

The AFSC is nearly ready (yay!) and is undergoing final fitment and tuning testing.

It should hopefully be ready after Xmas in the US and is a "fire and forget" style bolt on kit, which should provide a nice power boost and torque improvement, but not Uber huge power.
Its intended for daily driver applications. It wil come with a reflash tune, so will not need external engine management.

hope this helps..(and is fairly accurate!)

globi

As long as you inject water AFTER the supercharger it won't affect its operation.

globi

Water has 6 times the latent heat of gasoline. This means one spoon of water requires 6 times more heat to evaporate than 1 spoon of gasoline and this again means water will cool the intake air 6 times more. Also by injecting additional gasoline to cool the intake charge you will eventually reach an air/fuel ratio below 12 and this will reduce power. With water injection there's no reason to enrich the air/fuel ratio. Besides water is cheaper than gasoline.
The only drawback is that the overall system is more complex and you have to remember to fill up a water reservoir.

cavemancan

Hay now! No one calls me Cavey wavey without Dinner and a movie first!

Thanks for replying so fast though! I am sure many have asked so by all means direct me to the page but will there be a higher boost application in the works?

MazdaManiac

iTrader: (3)

Correct. That is part of my point.

rotarenvy

I've read about injecting water before the SC on roots style blower to increase the sealing and increase compression. because of the fine clearances too much water becomes a problem.

bripab007

Using water nozzle rigs like these (about 3/4 the way down the thread) in the mouth of the 'charger would help lessen the impact of the water droplets hitting the blades: http://www.aquamist.co.uk/phpBB2/viewtopic.php?t=838

EDIT: Actually, I just looked at pics of the inlet to refresh my memory, and it's a side-inlet opening...so this wouldn't really help at all. Nevermind :-)

rommel

Its so easy a caveman could do it!

Richard Paul

iTrader: (5)

I can only tell you what I know about water injection. I'm not against it, but there are some things to consider. First comparing it to a turbo is a little iff'y. This is due to the fact that in a turbo the mixture centrifuges itself out of mixture. The liquid being heavier runs out onto the scroll and needs to be atomized again.

We have had great success with fuel before the compressor because it gets homoginized by hundreds of blades traveling hundreds of MPH. The mixture gets very mixed almost to solution if that were possible. In the past we have seen no effect on the blades. The reason there may be a better environment for the blade here is that in airplanes they run at peak or near to efficiency (read RPM) and we rarely see that speed and only for a short time. Most of auto engine operation is done at less than half speed.

Whatever the reason I don't see it as a problem. I do like the idea of misting it into the inlet, anyway it can't hurt. After all that is how the gasoline was after it came from a carb or t-body injector. When I was thinking of water/alki injection I was thinking of using an injector nozzle. It doesn't matter with this compressor if you inject it in the side or center, it gets mixed.

Can it increase the efficiency? I suspect yes it can. Besides lowering the temperature it might seal the tip clearance somewhat. We are not talking about a hose stream here only a small amount. As long as you are doing it you should use a 50/50 mixture with methanol.

My only experience with this comes from the racing P-51 Merlins. These had water/alki injection in both the manifolds and the scroll of the supercharger.
Zeuschel has gone to the big race track in the sky now and I can't ask him what the trade off was betrween the two. All I remember is that there was plumbing for both. Just remember they were running 40-50 psi in those things. Also they only needed them to live for an hour. That is not the same conditions as your road car.

A little added info for some of you, Z tried nitrous a few times. The fact is that this is where the whole idea came from. When Dave got surplus engines some of them had a bunch of tubing all over the place going to the ports. After examining the microfilm at Langly AFB he found out about nitrous. Both the German and English studies were about the same, 5 lbs of nitrous per min added 100 hp. It doesn't make any difference if you burn it in a Merlin or a lawnmower it's 100 hp per ~5lbs.

The story goes on as he did not use it first in the Mustangs, he tried it in drag boat hemi's. Remember now, no one knew this stuff existed except dentists. So was it legal in gas class or not? His boats used it and they called them "Button Motors" as long as they were just rumors. It got so obvious that he had to tell the sanctioning body. But that first system was a pair of tubes running under the carbs in a spacer block. That type of system is still used.

But to get on with it they tried it on the race planes only to find it too volatile. It just blew up too many engines. In war it was only used for split seconds, in racing they needed more time. Interestingly it took bottles the size of oxy welding units to run a race. In addition he ran an extra nitrogen bottle to keep the pressure the same for the entire contents. In cars they just use the nitrous pressure and as it runs down, the mixture gets richer. In the end he just gave up the nitrous and upped the blower pressure. With that, Stilleto held the closed course record for years.

To counter that theory "Rare Bear" runs nitrous. I know this because some of the components were built in my shop.

Fred, how about that for one finger.

rotarygod

You probably started typing that a week ago!

r0tor

iTrader: (1)

glad to see i'm not off my rocker

I'm going to check into see if there is any increased compression with water injection from better sealing. I don't believe so but i'm not sure... air outlet temps are definately decreased though

Xpress

sorry if it's answered but:

-It works fine with race midpipe?
-SC needs special strut bar?


Thank's

swoope

iTrader: (5)

1 it is not out yet, but no reason it would not. but no testing has been done..

2 it is going to come with the kit...

beers