Injecting prior to turbo comp' impellers

[redvictor]

it's been a while since i posted here but i have heard on good authority that high end turbo cars on pump gas are going with pre turbo injection.Richard,did you get those castings done? if not have you got an adaptor that will allow the plastic pipe to go through the inlet pipe without leakage of air?
some pics of the install as it is now,water injection is into the plate under the throttle body and into the intake pipe(not shown)....

[redvictor]

WI nozzle placement and BOV....

[Richard L]

Andy, what a nice set of pictures.

I look forward to read them carefully in the weekend.

Thanks for posting them.

[Richard L]

I was not able to see the images in too much details.

Did you allow the full pattern of the jet be developed - the core shape of the spray should not be touching any bore surfaces.

Here is a spray pattern of our jet (if they are the ones you used)

[redvictor]

mmmmm,they look like the ones i have.......i'd say the bottom one no...the 2 side ones yes...maybe i can delete the bottom one and rely on the 2 side ones? don't forget there is 4 in the plate under the throttle body....and we can add a boss at the top of the pipe for a straight shot into the throttle body.....did you ever make those bosses for the pre turbo WI jet? i;d like to try that.....

[rarson]

Quick question: if the nozzle forms a "cone" spray pattern in a fine mist, wouldn't that mean that spraying directly at the turbo, even if it was mounted right on the inlet, would result in the water droplets hitting the blades?

I'm trying to imagine spraying at the compressor nut. I'm thinking a "stream" instead of a fog would be necessary, in order to fling the water off to aid atomization.

[NAnderson]

Digging this thread back up because it's quite interesting and informative.

This summer I'll be running a dual stage water/meth setup (1/3 water-2/3 meth) with one nozzle before the turbo, spraying directly into the compressor and one nozzle after the intercooler, spraying into the upper intercooler pipe. My question centers around the order of activation of these two nozzles. Should I activate the pre-turbo nozzle first (~15 psi) to cool the incoming charge and the post-intercooler nozzle second (~20-25 psi) to help with knock supression? Or am I thinking backwards on this? Any input or suggestions would be GREATLY appreciated.

I'm shooting for ~30-35 psi on a 2.3L (stroked 2.0L Mitsu 4G63) and would like to run 93 octane, but have access to 100 octane if necessary. I'd be glad to supply any additional info about the setup if it's needed.

[JohnA]

Originally Posted by NAnderson

... My question centers around the order of activation of these two nozzles. Should I activate the pre-turbo nozzle first (~15 psi) to cool the incoming charge and the post-intercooler nozzle second (~20-25 psi) to help with knock supression? ...

Your logic makes sense.
You should also think about the relative size of the nozzles, as they are directly related. The more the first one sprays, the lower the compressor discharge temps are bound to be. Also some of that water will still make it to the chambers, reducing the need for a bigger nozzle post-intercooler. :wink:

Ambient temps and fuel octane also play a major role obviously, in the winter with race fuel you'll need smaller nozzles compared to pump fuel in the summer.

I'm experimenting with a similar setup by the way.

[NAnderson]

Originally Posted by JohnA

Your logic makes sense.
You should also think about the relative size of the nozzles, as they are directly related. The more the first one sprays, the lower the compressor discharge temps are bound to be. Also some of that water will still make it to the chambers, reducing the need for a bigger nozzle post-intercooler. :wink:

I'll actually be running two similarly sized nozzles, but being that the pre-compressor nozzle won't have boost working against it it'll see full pump pressure (if not a touch more due to vacuum). The post-compresor nozzle will have anywhere from 25-35 psi of boost pushing against it and thus won't "seem" as large as it actually is.

So John, would you recommend activating the pre-compressor nozzle first, and the post-intercooler nozzle second?

[JohnA]

Originally Posted by NAnderson

..I'll actually be running two similarly sized nozzles, but being that the pre-compressor nozzle won't have boost working against it it'll see full pump pressure (if not a touch more due to vacuum). The post-compresor nozzle will have anywhere from 25-35 psi of boost pushing against it and thus won't "seem" as large as it actually is.

That's very true. The precomp nozzle will flow a bit more compared to a post-comp nozzle of the same size.
There is actually an older thread where we calculated that difference.

So John, would you recommend activating the pre-compressor nozzle first, and the post-intercooler nozzle second?

It depends on how hard you drive your turbo(s) I suppose.
If they are pushed way out of their efficiency islands then I'd start precomp injection a bit before they start getting outside the manufacturer's max boost intentions. But all this is experimental you see, we are all learning from our own (and those of others) mistakes. Hopefully.