[RemlapaN]

Originally Posted by jlcool007

so, will doing a intake silencer mod mess up the a/f ratio like you did in your sig?


-spyder

no, it wont. A/F ratios are affected by changing the diameter of the MAF housing. By removing the silencer all you are doing is changing things before the filter, which really has no bearing on what the MAF sees. It will however, make your car seem noticeably slower for a few weeks as the ECU adapts to the changes. Really it shouldnt make a difference, but it does.

[b_boy]

I am somewhat concerned about the compressor errosion from droplet pelting, but I think it's worth an experiment. I also think that as long as the droplet size is small it may never even reach the compressor wheel in liquid form. There are guys out there who have been running pre-turbo injection for thousands of miles. The original injection into plane engine turbos was this way too, but they didn't have our light weight wheels.

In some ways if the stock turbo goes after a few thousand miles I won't be disappointed-- I will have learned something about WI, done an experiment, and get to buy a new larger turbo. If it lasts 50,000 miles that's data to post as well.

[wgknestrick]

Installing a properly functioning WI setup is time consuming and tedius. It was much harder than either my turbo or FMIC install to get it working properly with the stock H20 water spray pump (this primes the high press WI pump). The big problem with WI is that there is no EM that can monitor the status of the WI AND change it's map back to the base map if a problem occurs. The aquamist 2D system (what I have) has a nice error function/warning light function, but if you don't see that at WOT when something bad happens, you are screwed. I can't say that I would be overly aware of a tiny LED as I am WOT on a 400+whp car, but it would be nice if my EM was.

This is a mod for advanced cars/users/ and people that must get max HP out of lower octance gas (91 or 93). The $ and effort just isn't worth it over a new turbo/FMIC/ good tune. If you already have these, then it is a different story. It's always nice to add a "permanent" and non consumable power adder first. Expect 20-40 hp gain based on mod level and water vs alc injection.

[wgknestrick]

oh, and another thing, you would never inject water/alc prior to turbo, always post turbo.

[hirevn]

the alcohol setup offered by smc is designed just for wrx/sti,cools much more efficint than the h20 systems.also you use 1 once of klotz lube per gallon for the system so no corrision are possibilty of pump failure due to corrison.granted the alcohol is 9.00 a gallon and the lube isnt free but a gallon tank will last a month or more of normal driving unless your at full boost everywhere you go.pump starts spraying at 6 psi up to max boost,and is also controled by digital cotroler so you can fine tune the spray.this will allow you to run pump gas even plain unleaded with out detnation. with 90 oct when pump starts to spray you will be over 95 and at full boost 100 or more octane.with proper tuning in theroy you could run a race gas map if anyone had one on pump gas without fear of detnation.in are area there will be over 20 guys running these systems and i know of 1 sti that has had it installed for over a year and a wrx that has been spraying alcohol for over 50,000 miles with no problems.these cars have the old analog controllers but the new digital controllers are now available.

[b_boy]

It depends on the EM. With the Hydra I can reference the "blocked jet" signal if I want and bring the car into limp mode. Not sure it's true with UTEC, but yes with Xede and e-manage, definately not an option with EcuTek.

The parts you talk about are pretty straight forward installs, but the Aquamist is not difficult. It requires some basic plumbing and wiring skills but most mechanics could do it easily.

Yes, the "problem" with WI is the risk of no water for whatever reason (tank dry, pump fails, jets clog). It is more complicated than a intercooler upgrade, but with good diagnositcs and alerting of the EM I think it can be a pretty "safe" mod. You are correct; you need more advanced knowlege of how your car works to run WI, but most enthusists are already there. Coupling with computer monitoring of the system is key. Right now Aquamist provides the signal to do so, but it's up to the owner/tuner to make sure the ECU is hooked in.

Injection before the turbo compressor is definately experimental on my part, but you certainly can inject pre-turbo and the purpose and effect are quite different. Water droplet size must be very small to avoid erosion of the turbine blade, but the benefits of pushing the compressor towards isothermal compression are obvious. I would only take that route at high RPM and boost, and even then, I still run the risk of impeller erosion. A search of Google with "water injection" compressor+erosion turned up lots of data, both for and against the idea. In the end, it is the orignal form of WI dating back to the '30s. Intermittant, brief pre turbo injection may have very little effect over the long haul, but I agree constant bombardment of the impeller is not a good idea. See also the waterinjection.info link above for more "pre turbo" discussion.

[VV]

WI prior to the turbo is doable, and more common than most would like to admit. You can even set it up so that no pump is required and the boost pressure acts as the motive force to siphon the water and spray a mist like an airbrush. It is effectively evaporative cooling, which will provide an increase in performance as if the intake temperature was cooler. Keep in mind if you live in a humid area, the likelihood of the water completely evaporating before reaching the turbo is slim. You will see a much bigger improvement if you live in a dry area. Also, injecting water before the turbo, although improving performance due to cooling, will also make the compressor work harder because you are increasing the density of the air it must compress. That is why injecting at the TB is better, you still get the cooling, plus you are effectively adding mass to the intake charge without having that mass going through the compressor. Your WI pump is aiding the compressor, allowing more power out of the same turbo.

Also keep in mind that it WI before the turbo will provide no resistance to ping, since all of the liquid droplets that make it to the compressor will evaporate during compression. IMHO, you would probably be better off putting WI at the TB, and if you want inlet cooling, splice in a small A/C core to subcool the intake. Or you could do WI in both locations. I just think having WI before the turbo, but none at the TB is a waste of a good WI system.

BTW, they used to WI airplane turbos before the compressor, but now all gas turbine engines with WI inject at the combustors. Pumping is much more efficient than compressing.

[b_boy]

Yes, I'm advocating both. I would not suggest pre-turbo WI to a neophyte, it's definitely advanced with the possibity of compressor wheel erosion. I plan on only doing it at 5-6000 RPM and above and on boost of 15 psi. I hope to stretch the compressor's compression out just a bit with the isothermal compression (the idea here is that the water absorbs the heat generated by compression leaving only the air compressed). I'll still be injecting near the throttle body for further: cooling, anti-det, and in-cylinder cooling. I'm just going to split off about 2-3% water for the pre-turbo injection at high RPM and see if I can squeeze out 2-3 psi more up there. Yes, I want to have my cake and eat it too; don't we all.

I read a paper on turbine engines where they varied injection site and droplet size. The reduced droplet size gave less wear on the combustor with the same cooling effect as injection at the compressor, and also showed less wear than injection at the compressor from "fogging". There are also a bunch of papers on what they term "wet compression" same sort of stuff, but injection at the compressor. Turbine engine's don't seem the best model for our tiny lightweight compressors. 747's still use pre-compressor water spray on take off, then dump the remaining water, cool huh.

A guy on another board says he's been running pre-turbo with low pressure (i.e. bigger droplet size than Aquamist) for 7000 miles with no visible wear, and only slight wear by inspecting with at 10X lens (even that he can't say was the result of WI, since he ran for 30,000 miles prior to that with a few "no intake sessions on the track").

Next maybe I'll cover the compressor housing in Peltier and chill it down to -20. (that's a joke) I did see some guy rigged his intercooler with Peltier patchs and brought the temp down 9F, but he found water spray worked better. I applaud the experiment anyway.

Any ideas on getting droplet size down from about 50 microns with Aquamist to 10 microns. Everything I've seen requires about 1000 psi, not easy to make in an engine bay.

[donmei]

I've been reading this post with great interest. I am a big fan of water injection. It DOES work wonders, allowing engines such as unlimited Reno racing aircraft to eliminate the drag inducing inter cooler in its entirety. Just a couple of thoughts:

1) Aquamist seems to be a great, very sophisticated system.

2) My first turbo car was a Saab 99 turbo. We did water injection just past the air mass sensor plate (primitive Bosch K Jetronic). Funny thing was we didn't know any better and just used a windshield washer pump with a smaller jet. The turbo never seemed to suffer any ill effects of this primitive setup.

This car had no kind of knock/feedback system to adjust either boost or timing in the event of detonation, so this was a reliability tweak to allow us to use more boost.

Don

[b_boy]

Don you have a lot of cars. The more I have talked about wanting to try the pre-compressor injection, the more comes out of the walls that other's have tried it. I will keep an eye on corrosion to avoid disaster. With that caveat, its an experiment to see how well it does with the stock turbo.

[donmei]

One other thing bboy. Back then you were lucky if a turbo lasted 30K miles. They were not water cooled and most had not yet discovered the joys of full synthetic.

Chances are, the bearings (then seals) went before any compressor wheel damage occured.
The older saabs also had BIG Garet turbos that weren't spinning that fast in that application.

Don

[VV]

A couple of ideas for you b_boy.

First, McMaster-carr has a misting nozzle that can get 20-60 microns using 100 psi air and 20 psi water. Look at www.Mcmaster.com

I think there are some better ways to get what you want without spending $180 on a nozzle. You could spray opposite to the air flow, making the water have to turn around, separating the larger droplets and evaporating more before the compressor. You could use a foam type air filter and spray it from the inlet side. Of course you'd have to remove all oil first, but the water could help filter, and you would greatly reduce the likelihood of water droplets.

And then there's the one option I've always wanted to try - true intercooling. Injecting water into the vaneless space between the impeller and the compressor exit diffuser would be the theoretical best place to spray for wet compression. Half of the compression occurs in the impeller, raising the temp, then you spray right before the other half of the compression occurs in the diffuser. Of course getting it to work in reality would be impossible, but a guy can dream. With this system, you could spray in three places, before the compressor, in the vaneless space, then at the TB.

As for the Peltier patches, they guy put them in the wrong place. You should chill before the compressor and water inject after it. Water injection boosts your mass flow without adding compression costs. Chilling before the compressor would increase the density, giving higher boost, without increasing the incompressibility of the gas like water injection does, which would decrease the compressor outlet temperature.

[Neanderthal Racing]

Originally Posted by b_boy

Combined with the Element Hydra all sorts of options become available for programming. You can cycle the Aquamist high speed valve at any frequency you would like, plus add in a new site of spray in a different location when you need it most. Other engine management systems can be configured to do the same thing with a little more hardware (I can elaborate if you want).

dude, that was as good an explanation on a technical subject as ANY i've seen in here <clapping>.

i've got a crawford shortblock, hydra and a gt35r on the way and this is right on time. i think i'll be spending some time in here:

http://www.aquamist.co.uk/phpBB2/index.php

[traction_issuez]

http://www.smcenterprises.com/