[Terry Syd]

Metric/Imperial - it's still the same distance. I'm one of the ol' guys that goes back and forth between them. I still can only think of suspension travel in terms of inches.

I'm looking for more "intercooling" effect on the engine. I've read elsewhere that for cylinder cooling (especially in petrol [read 'gas'] engines) that a position closer to the valves is better, while moving the nozzle further away from the engine gives a better cooling of the air charge. Izzat true?

If so, then I'm wondering about installing the nozzle in the manifold PRIOR to the turbo. There is an inlet in that manifold that normally draws the crankcase fumes in through it. That inlet is presently not being used and would make a good mounting position.

[Dust]

Although I don't know if imperical evidence has come through yet, pre-turbo spraying may cause problems with your turbo blades.

[Terry Syd]

I note that the early aircraft engines had the WI before the turbo. Considering that an engine failure in an aircraft is a much more serious affair than a truck on the road, perhaps those early engineers did their research -or maybe they figured that combat aircraft had a limited life anyway!

Anyway, about the positioning of the nozzle. Is is generally true that to get better 'intercooling effect' of the intake charge that the nozzle should be further away from the engine?

[dvldoc]

Spraying before the blades is kind of like sand blasting them, over time you will have notiable divets on the impeller along with rust in those divets and a bit of white scale built up around the opening (if not a quality stainless or aluminum), Yes I know a guy who decided to do this and let us check his vehicle this perticular unit was a older DSM (kind of a beater to begin with and he had upgraded turbo to install alread so he really didn't care. So thats where the visual observation comes from.

The turbo still functioned fine with no measurble lose of boost, It just did not look pretty and those little chucks are going some were like into your motor.

Being we actually R&D things, You will see less then a 5 degree temp difference mounting the nozzle pre turbo. Verified by digital temp probes. Not worth the extra wear on the turbo and the tiny little metal chips being sucked into the motor.

Remember water/alcohol cools at the same rate at the same volume.

Edit: to post Found out old boy has been running with no filter for a few months while waiting on his New K&N so once again no solid evidince that post compressor injection harms the impeller. We have coral roads here so thats were the damage likely came from.

[Terry Syd]

OK, that clarified that issue. No WI pre-turbo.

What about the issue of distance to the intake valve? Will an increase in distance of the WI from the intake valve tend to drop the intake temperature more than a nozzle close to the valve?

[Pig Bodine]

I don't check the board for a while and Syd picks up the slack for the Yota folks, strong work!

Definitely go post-turbo, I've seen new rebuilt turbos go to hell really quickly with water injected pre. I think that mounting the nozzle in the elbow (i.e. after the crossover pipe) would be much easier technically due the increased thickness of the metal there but I still don't know if it would completely vaporize by the time it reached the valves/cylinders? I'll probably go just before the rubber hose coupling in the crossover pipe, or actually in the coupling if I can get an airtight seal. Also much easier to replace if I screw up than the intake elbow or crossover pipe.

Dvldoc thanks for the info...

[dvldoc]

The mist coming out is very fine and at well over 190psi combined with hundreds of CFM of air is more than enough to equally mix with the incoming air. If the air is making it to all the cyl then the alcohol is right along with it. The only way you can really appreciate it is doing it though clear a clear Plastic intake tube, (yeah we have done it) I don't think people realized just how much is pushing through a 2.5 inch pipe under boost.

You can pretty much be assured you will gain hp over your full rpm spectrum, will have no detonation, and knock your EGTs down big time. TD's love and I mean love alcohol injection. Not to mention the turbo will spool up much quicker.

[Terry Syd]

PB, I'm looking forward to your results, I won't have my WI system for a couple of months, hopefully you will have it all sorted out by then.

I was thinking about putting the nozzle in the crossover pipe myself. If the water/meth was fully vaporized before it got to the engine, then I could see two advantages. First, the 'intercooler effect' on the intake charge (which also drops the EGT down a bit). Second, the water/meth would already be in a vapor state before it got into the cylinder.

Correct me if I am wrong, but it is my understanding that shifting water from a liquid state to a vapor state ABSORBS energy (such as the cooling of the intake charge). Liquid water into the cylinder might be desireable if we wanted to drop a high EGT, but if the EGT was already running fairly cool, then further cooling of the engine gases may not be desireable.

[dvldoc]

Lets put it like this, the water in the mist form is what is pulling the heat out of the intake charge, Touch a aluminum intake manifold after injecting durring a WOT pass, It will be ice cold as well as anything after the nozzle such as the throttle body. The vapor is what you want in the cylinders to cool combustion and further reduce EGT's and eliminate detonation as well as the extra octane to control detonation as well.

[Terry Syd]

Just to refresh your memory, we're talking about a diesel engine here (cetane).

So you're saying that the cooling effect and vaporisation is virtually immediate. That being the case, then a shorter run might allow a cooler intake charge as there will be less heat soak from additional plumbing in the engine bay. Although I'm at a loss to understand why there would be an additional couple of degrees drop in the intake temperature when the WI was injected pre-turbo.