Yes, another "WTF do I need?" question.

[Allan]

Hello everyone,

I'm working on a science project and I need to lower IAT's a bit.

I'm thinking the HFS6 would work great for my needs, but I'm still not quite certain as to what size nozzle I would need.

I am interested in a dual nozzle set-up, post Intercoolers (one nozzle per intercooler). I've read up on pros and cons of pre-turbo injection, and frankly, I don't feel like washing out the turbo compressor wheels.

Engine is an M275 6 Liter Twin Turbocharged Mercedes Engine in a CL65 AMG.
The engine is making 704 ft lbs of torque and 535 Ponies at the wheels. Accounting for 18% drive train loss, it's making 830/631 at the crank. AFR at WOT is right around 13.4 as read by a dyno sniffer.

I would like to bring the IAT's down a bit, as it gets pretty toasty in that engine compartment - and by extension, that heat transfers to the intake air on top of the turbos heating it up-. Pre-turbo IAT's are about 10 degrees F over ambient and post turbo are about 40-50 cruising, depending on ambient temperature. They do spike up to 70 above ambient when driving in city traffic though.

With that said, what size nozzles would the gurus recommend? Remember, I need TWO of them.

I would like to be able to turn the WI system off when I don't really need it, like when on the highway or even when running about set PSI on the WI controller. The plan is to run a 3 or 4 gallon trunk mounted tank with the pump in the back by/in the tank.

Thank you for any suggestions and/or insight.

A few questions. What fluid do you want to run, or have ruled out? If you want to be able to turn it off you don't need any failsafes, correct? Do you know what your injector size is? What fuel octane do you usually run?

[Allan]

Hi,

Thank you for your reply. I was thinking 50/50 water/methanol (I have a practically unlimited supply of methanol, all free), or something along the lines of 60/40 Water Methanol. Not quite sure what the mixture will be.

I have the ability to dyno "tune" the mixture(s) and delivery sizes on a Dynojet, but before then, I will need to get a basic nozzle size going.

I am not quite sure what size injectors are on the car. It's one of those things that my friend Google has a hard time finding out.

Would you please be kind to check my math? I would really appreciate it.

Assuming 600cc @100% IDC injectors (a little overkill IMHO), they would flow 480cc's at 80% IDC and flow roughly 548lbs of fuel per hour (82.65 Gallons per hour) in order to keep 13.4:1 AF ratios.

In order to keep about 15% of the mass using 100% water, (82.65 x .15) we would need 12.39 Gallons per hour or 46,927cc's per hour to support 15% mass. That should come to 782cc's per minute.

This sounds a little high to me...?

Of course, I could be totally off base with the 600cc injector sizes.

I, of course, would like to be able to turn the whole system off, but at the same time, I would prefer failsafes when the system is running.

I typically run anywhere between 93 at high altitudes (6000+ feet) and 100 octane (well, truthfully, probably about 97 octane - marketing, and all that always adds 3 points) at 1000 feet altitude.

There's two ways to look at it. 600cc injectors x 12 = 7200cc x 15% for water = 1080cc We would sometimes bump this up for pumping losses.

We usually ignore the DC because it's a relative item with the system, if the car is at 50%IDC, so is the kit.

We can check the numbers this way. A rough estimate is 150cc per 100hp. So 631hp would use 946cc. It's somewhere in that ball park.

We have a customer in South America who tried 100% water and felt he lost power using two 1.0mm jets(about 950-1000cc) It was probably too much straight water for cooling. Using 50/50 would help that quite a bit. He was going to dump straight ethanol in the tank and see what happens.

Taking a minute to look at the numbers, you probably only have 320-350cc injectors. Using 350 and 15% gets 630cc of spray. So we have a range from 630 to 946. Assuming you are going to use two jets in the system, we could supply 4 jets, two to get you up to 950, and two a couple steps lower and you could see what works out for you.

P.S. The kit comes with 3 jets so you would need to buy one more.

[Allan]

Thank you for your reply.

I'm thinking that 3 injectors should be enough if we space them out a bit (size wise). I say this because the intercoolers dump into the throttle body very close to each other. Please see attached picture of where I'd like to install the injectors.

This close together, I wouldn't think they would have to be evenly matched (size wise), since they will be so close together? For example, I could get a 450,cc, a 350cc, and say, a 180cc injector and mix and match them until the better of the combinations reveals itself. I'm not certain what injector sizes are available from you guys, but I hope you understand what I'm saying? Because I sure don't...

What you are saying makes perfect sense. The injectors are spaced about 50-60cc apart in sizing so there is a good range to choose from.

The jetting chart is here:

http://www.howertonengineering.com/M...etrate+txt.gif