are my intake temps TOO COLD?
 

So its about 75-78 temp in northern cali today. My intake temps were 20C-25C. I know that they would be going alot lower if I was boosting hard, my question is....at what point are the temps TOO cold?

78 F is about 25 C. So you're seeing temps around ambient. Thats awful good...

I think you'd litterally have to freeze the intake charge such that the temps are colder than the temperature correction tables (or ask for more fuel than your fuel system can provide) before theres a problem..

so far thats what Im hearing. Im just concerned, cause I wasn't even pushing the boost. It seems like everytime the WI runs (even for 1 second) it instantly drops by 5C.

If you have been on the open road, at freeway speeds, and have not been on boost, the intake system should be pretty cool. I'm surprised that it is as low as ambient. That can't be a bad thing.

IM actually talking 25-40 MPH stop light to stop light. Not even the highway. Im serious...This with a BLITZ SMIC not much bigger than stock.

Open her up and see what you get... This sounds really good!

Im gonna take it to the track and see what it does :).

OIC... its a WI thing... hmm, i don't know much about it, but i guess as long as your engine isn't swallowing a gallon of water, and washing away the lubrication to acheive those temps, great.

the water is pushed through a very fine injector at high psi, so its a mist, it evaporates pretty fast, also I use 35 pct alcohol to 65 water. I do have my oil metering pump to send extra lubrication to the apex seal, but I dont know if thats an issue.

That's very surprising. I would expect the engine to heat soak everything, including the intercooler.

;)

Where's the video?

Adam,

Heat soak exists, but its not relevant with WI. Look at it this way, I told the story in the other thread, I had my car parked in my driveway for like 30 minutes and my heat soak temps were 74C. I started the car and coasted down the hill, was at 73C by then (had not boosted yet). Got on the main road, went from first to 3rd gear, shifting by 4K rpm. when I hit 8 PSI in 4th gear I looked at my intake temps which were 39C. That was about 8 seconds. So while your temps can heat soak from sitting, WI will cool the intake before it gets into your engine, regardless of how hot your IC or intake sensor is.

I am just curious how the car can react to intake temp drops so fast. Its pretty interesting to do this, I have my wi set to come on at 8 psi, so pretend I am at 40C on my temps, if I hit 8 psi, even for 1 second my intake temps will drop to about 33-35 instantly. If I dont hit boost again, it will stabilize for about 5 seconds then it will rise about 1 degree every couple of seconds to get back to the 40C it was prior to the water injecting. Its kinda cool. As you can read in the links below, back to back dyno's with water injection vs without, showed that with WI no heatsoak and exact same dyno #'s and without showed a decrease in HP each time. Same thing at the drag strip.



http://www.europeancarweb.com/projec...4ec_projm3_02/

http://www.imoc.co.uk/technical/article/wi.htm

Looks like it's working well. I didn't see the WI either.

too cold is not possible

FYI, with my small blitz SMIC and my water injection, during NORMAL driving on my way home from work just now on the highway my temps stayed from 25C to 30C.

the lowest ive had my intake temps was at 37C, and that was after a 3 hour drive on the highway! you are pretty lucky with your temps, i cant wait to get water injection!

Hey Zero, it would almost seem that your SMIC is useless with WI. Do you think that intercoolers could be ellimnated all together if you used a continuos 2 stage system like I suggested to you a couple weeks ago? Think about it, during cruising (no boost) conditions intercoolers have no benefit at all because the incoming air isn't heated. The car is basicaly naturally asperated under these conditions. With the WI kicking in only when it's needed, the intercooler could be elliminated. Any takers care to experiment with this idea? :D I may try this this myself.

when your injectors clog, your pump dies or your tank cracks and you run out of water, you can stick a fork in it, its done.

I read some where that the IC Compresses the air, so there is more air to cool when the water hits it, so its good to have both. I dont know.

I considered to put a 2 GPH nozzle at my IC exit, 5 GPH one where my 7 GPH is now. But, I dont need it, my intake temps are stable, I mean when it cools to 30, it will stay at 30 for around 8-10 minutes before climbing (if I dont use my WI in that 10 minutes). Its almost impossible not to boost for a period of time that would cause your temps to rise.

What will I do next? Im gonna get an air temp switch :).

That could also apply to your fuel injectors, fuel pump, fuel filter, and low fuel in the gas tank.:D We all know about those problems are cars are prone too. It's an R&D type of thing. I think it would work. Once you have gotten everything together with your setup, I may experiment with my NON rebuilt 20b thats going into my Fd here shortly. If it blows up, it's getting rebuilt anyways. :D

I run my fuel till my low fuel light comes on sometimes, I dont believe a rotary will detonate cause of that.

As far as the other things, well thats far less likely to happen than the water injection. I dont think water injection should be relied on, but its damn sweet. :).

Just my opinion. But I agree with you, the intercooler is probably almost useless with WI, although I think it does compress the air, which maybe that makes it better when the water hits the air... So in a nutshell a small IC is good (except stock caust thats sucks).

Do you have twins or a single? Am I the first twin turbo Rx7 with WI on this forum?

just curious...how much did ur WI system cost? Do u have a thread that shows all u did?

"I read some where that the IC Compresses the air, so there is more air to cool when the water hits it"

Unless I am reading that incorrectly....the turbo is compressing the air.
Therefore the air is denser "more mass per volume" when inside the intercooler.
The compressing of air causes it to heat up, and that is why we use a intercooler to cool the charge and increase the density of the intake air even further.

Time to get a Air to Water IC! :)

That sounds too cool for a stock mount. Make sure the calibration is correct. When you start the car cold do the air temp and water temp read the same?