I tried 2 difffrent one from diffrent makers and both failed. I gave up and didi the check valve. Just my luck or lack thereof. :eyetwitch

been running mine for some time now?
OD

+1 on the check valve. I used to run a solenoid and in the process it killed the Snow electronic box first and later it failed within a year. I swapped the solenoid for a check valve and it’s been over 6 months without any issues. :eyetwitch

here is one of them, http://www.coolingmist.com/detailmain.aspx?pid=11
I don't remember the other one.

Sorry to hijack. No solenoids here.

http://www.rx7club.com/showthread.php?t=809559&page=9

The power of alcohol!

B

its probably isnt a problem but wouldnt a check valve leak when you are coasting or close the throttle and you are pulling more than 22 of vac?
OD

Wowsers Brian! 22 psi and only 95*F intake temps on a 78* day without an intercooler!!! Awesome! I love how AIT's go down as boost goes up. That's pretty cool. What I find really interesting is how once you're at about 1 bar of boost, AIT's stay basically the same even when boost continues to go up. This can't happen forever of course but it's still quite curious. I don't know of an air/air intercooler anywhere that can hold AIT's to within 20 degrees of ambient at over 20 psi. Nice work.

This is a baseless statement.

If you have an intercooler that is 50% efficient and a turbo that produces 40° above ambient temps at 9 PSI on its 75% efficiency island, it will produce exactly the same 20° above ambient IAT anywhere on that efficiency island, regardless of Pr.

Sounds great on paper but I've never seen it myself, either. I agree with Fred. That's part of what makes all of this shocking.

B

You bet. I'm having a blast with this. Seems to ruffle feathers. I guess that's it way it goes sometimes. :)

B

Really.
So you've never seen outlet temps on a 20 PSI app that were only 20° above ambient?
What the hell kind of turbos are you using?


Of course, if you are primarily reaching into the outer reaches of the flow map, you will see higher temps.
But that will happen at 4 PSI on the wrong turbo.

Boost pressure has nothing to do with charge temps if you are in the prime efficiency range of a turbo.

Sorry, but only 20degF temp increase for 20psi boost is thermodynamically impossible at 70degF ambient. It a fundamental ideal gas law -- look it up.

20 psi == pressure ratio 2.4

Temperature gain: (PR ^ .28 - 1) * Tabs

70 degF ambient = 530 Tabs

Thermodynamics demands *at least* 147 degF temperature rise and no turbo is 100% adiabatic efficient.

You left out the intercooler.

He didn't run 9 psi. He ran 22!!! He did it without an intercooler and only had roughly a 20* increase over ambient. A baseless statement? Are you really going to be this anal about terminology in an effort to try to somehow make a point or can you just not mentally comprehend what I meant? Apply it to HIS boost number and go from there. You won't find an air/air intercooler anywhere that will do that. I take that back. If you find one that could reject that much heat that fast, it would be so big that there'd be terrible lag from the room sized area that you'd need to pressurize and you wouldn't be able to fit it in the car. I guess you could tow your monster cooler in a trailer behind the car or perhaps push it in front for a clean air supply! For all intents and purposes though, you will not find one as it's worthless if you can't use it.

However if you think it can be done Jeff, go do it. I want to see you run 20+ psi with only an air/air intercooler and I want to see your IAT's at only 20* F more than ambient. Results speak for themselves. No results are just words. Just remember, Brian's statements came after his results proved it and not before. Here's your chance to go prove you're right though! It shouldn't be that hard. Go out, do some runs, and post your logs. When we see your numbers at that boost level with only that much temperature rise, then you're point will be proven. Until then, it isn't happening.

Okay, lets try this then. A 75% adiabatic efficient turbo boosting 20psi will create a temperature rise of 196 degF. To drop that down to 20degF rise, you need a 90% efficient intercooler. A 90% intercooler is a top-of-the-line setup.

This is also complete untrue and a physics/math "fail".

75% adiabatic efficiency will produce turbo outlet temps still dependent on pressure ratio. I think you're forgetting that adiabatic efficiency is a measure of how much *more* the temperature rises above the thermodynamic minimum. The minimum temperature rise (that of a 100% adiabatic efficiency) is determined by pressure ratio.

Proof:

50.% efficient intercooler, 9.0 psi boost, 75% adiabatic efficiency will yield precisely 51degF temp rise at 70.degF ambient. (1.612^.28 - 1) * 530 * 1/.75 * 50/100

50% efficient intercooler, 20 psi boost, 75% adiabatic efficiency will yield precisely
96degF temp rise. (2.360^.28 - 1) * 530 * 1/.75 * 50/100

96 degF is not equal to 51 degF

? AGAIN! DO check valves leak when vac is greater than 22 such as on closing the throttle?
OD

check valves crack pressure is rated in PSI. So if the check valve has a 15psi crack pressure it takes aprox 30inches of vacuum to open. So anything over 15-16psi is excessive.

Once again, flow is being compared to boost.

No, not really. You're wrong here.

Guess what causes flow? Pressure differential. Pressure differential is boost. Its really not that complicated.

Where the heck did this comment come from anyway? It really kind of smells like a setup for a straw-man style logical fallacy http://en.wikipedia.org/wiki/Straw_man Sort of like when a discussion about torque needs to be derailed, mention how its really supposed to be about power and vice versa. Very predictable and entertaining, but nobody's falling for it. :)

Instead of bringing up this flow vs. boost nonsense, refute the math or the gas-laws brought up proving that previous deduction you made about IAT's and adiabatic efficiencies wrong. Please. :)

Nope. Certainly seem that you are right.

All the math pans out.

It just doesn't jive with actual measurements I've taken with a big turbo setup on a piston motor.

thanks devil--appreciate the info--check valve will be for me also when the time comes.
OD

Well, as many I've seen on this forum like to quote, "If theory doesn't mesh with reality, then throw out the theory"

The only problem with that is that the theory that would be thrown out here is one thats worked in almost every other application of compressible gases since it was formulated 200 years ago. But, yes, maybe -- just maybe -- we've found an exception here on rx8club.com to thermodynamic law on piston motors with big turbo's. But somehow, I really doubt it.

I really don't think you're trying to B.S. us, but I do think either 1) you only have a marketeers understanding of what adiabatic efficiency is about or 2) you abandoned what should have been a healthy skepticism of your measurements and formulated and peddled wrong conclusions on air temperatures as it relates to intercoolers/FI as a result. In other words -- classic "intellectual laziness"

Jeff just back up your statements and show your datalogs. That's a very simple and easy request and there's really zero excuse not to post them to prove a statement. If your logs back it up, cool! Hard to argue with that. Your car has a turbo and you know the compressor map and obviously know what boost level you can run. You can very easily datalog things as you do it all the time. Forget 22 psi. I'll be happy seeing a temp gain over ambient with even a 10 psi run. Let's actually see it firsthand all backed up with results. It's a good learning experience. This should be nothing more difficult than going outside, doing a few runs, and then posting the results. I've seen Brian's as they have been made public and I've got to say, we just won't see an air/air setup that comes anywhere remotely close to doing what he is with methanol injection. I love the fact that he shares what he learns. That's how it should be. Helping others learn and improve is a good thing.

Now saying that, it doesn't mean that aux injection is the be all end all when it comes to what should be run in everyone's cars. Not saying that at all. There's a time and place for everything. Same thing even holds true with superchargers but we won't get into that here.

one thing we have found is that yea we can get the lower intake temps down BELOW ambient with our w/m systems--no prob--but it takes an amount that kills top hp to do so. Understand I am speaking of substained temps on the track ---not a short street run.
It is possible to overcool an intake charge :)
OD

^^ You just need to tune for it :)