Savington

iTrader: (31)

..


...what?

I suppose it depends on your definition of "close to ambient" but the best air/air ICs out there are getting better than 90% efficiency.

Routing the pipes really isn't that hard. I could do two FMIC setups for the cost of just the Spearco core you are talking about too. You seem to know a little bit about it, so I won't be an *** and just tell you to buzz off, but you have to look at the facts here:

-It weighs more
-It is FAR more complex
-It costs a ton more
-More failure points

This really is reinventing the wheel. I can appreciate trying to do something differently, but at the same time, if it's not broken, don't fix it.

Saml01

iTrader: (9)

I swear to god I have seen this done before. I think it was some guy with an MR2,and he was using the air conditioning to cool the intercooler, or something like that.

I cant find the link, but it seems that its exactly what Teddy is trying to do.

Joe Perez

iTrader: (8)

Just FYI, you don't have to cut anything. My FMIC has 2.5" inlet and outlet, and the tubes are routed around the sides of the radiator. I still have power steering in the stock location, and although I don't have A/C, it would not conflict if I did. I made zero cuts to the metal of the car, only some light trimming of non-structural plastic air ducting. Detailed pictures and writeup: https://www.miataturbo.net/forum/t4904/

I'd wager that at least 50% the folks here with FMICs are plumbed this way. Mine's nothing special, I just happened to document the process.


Also, have you considered methanol injecton as an alternative to all this? A 5 liter shifter-kart fuel tank fits perfectly into the trunk opposite the battery. (Pictures of that: https://www.miataturbo.net/forum/t9256/)

Braineack

iTrader: (62)

Looking at my latest dyno logs...

pull #5, 16 minutes after the first pull (11:44am, first pull at 11:28am):

80*F ambient, large single fan in front of car:



4th gear pull, 7201RPM and 14.366psi my intake temps were at 100*F.

80% effective IC while standing still...couldn't have been easier to plumb/mount. Didn't cut a damn thing.

-This system will weigh less
-It is FAR less complex
-It cost under $400
-total of 5 couplers with t-clamps

I suggest you change your reasoning to: want to be different.

Joe Perez

iTrader: (8)

I'm trying not to be too harsh just yet. I find this idea fascinating, and the idea of super-cooling the water charge has proven its merit in the drag racing world.

OTOH, using the A/C as a refrigerant system to maintain (or even accomplish) said super-cooling seems like it might have some issues, not the least of which is the complexity : benefit ratio. Its absence from use in any form of professional motorsport that I'm aware of further suggests that it might fall into the "good idea, but impractical" category.

Still, it's a concept that I don't feel has been beaten to death already (at least not here) and it arouses my curiosity. (Unlike the stormtrooper in the Elise, which arouses something entirely different.)

patsmx5

iTrader: (16)

I have a better idea. No idea if it would work, but I think it might. It would do what you want, and lighter, probably less complex. But it's a whole 'nother thread.

https://www.miataturbo.net/forum/t19183/

fasteddy

Thank you for the analysis. Methanol water injection was my next choice, but for obvious reasons, I dislike methanol.

The analysis of the capacity of the a/c system was what I needed. They aren't called thermogodamnics for nuthin. I'm sold. I've got a spare starion i/c sitting around somewhere.

Define for me "90%" efficient? How it's measured the way you are using it. I'm assuming for now you mean "if the IAT at the compressor outlet is 200*F and ambient is 100, the intercooler will drop the IAT to 110". I like a bar of boost. This and the det limit of street fuel mean I have to use so much retard I start killing under curve area. I hate that.

I ran into precisely the above situation with the starion transplant motor with the pretty fair stock i/c. Except in the last "wonder if it will take another tweak on the grainger valve" iteration where I either ran out of fuel or retard range.

BTW, I was figuring on stock compressor/condensor/evaporator with a graft to (and loop isolation electrovalving for) the accumulator and reservoir evap loop and return. The blank spot in my theory was the actual math. I think you answered that one. TANSTAAFL.

Now for the second puzzle. What is the effect on charge temp of multiport liquid propane injection? On 90% efficient air/air i/c temp intake air at 15psi. I have always liked propane's "octane" rating, but the last time I was tempted by this I had a lot of grief finding high pressure liquid propane injectors, and a reliable purge system. I did find what seems to be an adequate pump.

And answer me one more. What difference if you have a pressure drop across the i/c of 2psi, if your waste gate boost reference is after the i/c, as long as you have pumping capacity to deliver that mass at the predrop pressure within a reasonable island on the pressure map? Or is referencing there a recipe for compressor surge from an out of phase feedback loop. Anybody done the math on the effect on pressure of the cooling of the charge? Been too long since I fooled with ideal gas laws.

One of you said you heat soaked a water/air with radiator i/c system? I'd be curious to know your water/air i/c and air/water rad dimensions and thicknesses. And total water volume.

patsmx5

iTrader: (16)

Yes 90% efficient intercooler = 90% total heat rejection relative to ambient.

Forget propane, use straight water injection (WI). Put a huge tank in the trunk and build a nice fail safe WI setup that has map switching capabilities so if you ever run out of water/have a malfunction with the WI, et, it will fail back to a safe timing map. Peace of mind, function, and it only takes water, which is safer, cheaper, and easier to store/maintain than propane.

Pressure drop across the IC will be insignificant in the grand scheme of things. Less flow looses are good, but it's not the end of the world. Just reference the wastegate to intake manifold pressure.

Sumarry: Big IC and WI.

Joe Perez

iTrader: (8)

I'm afraid that I don't find the reasons for this at all obvious, and even less so in light of your recent mention of propane.

Water / methanol injection is relatively inexpensive, highly reliable, does not consume much space on the vehicle, has extremely simple plumbing, and is inexpensive to operate. I pay around $5.00 per gallon for 99.95% methanol (VP brand M1 racing fuel) which is available at just about any shop that sells racing fuel. I run a 50/50 blend of meth and distilled water, and my 5 liter bottle in the trunklasts for at least a full tank of fuel (when doing nothing but canyon carving under boost) and more generally lasts 3 to 4 tanks in normal street use.

At atmospheric pressure and human-survivable temperatures, a 50/50 blend is non-flammable (even in vapor form) so it's highly safe to carry around.

So, illuminate me- what's the beef with meth?

drbogg

iTrader: (1)

Hmm just buy a portable Fridge/Freezer and dump your intercooler into that, you may have to sit it on the front seat abit of Plumbing and your set to go.

Dr.

boileralum

iTrader: (8)

Instead of re-iventing the wheel, run an efficient air-air setup and bump up the boost 2-3psi. Same power output, much less money, much less headaches.

"Sometimes no one has done it before because it is just a bad idea."

fasteddy

I'm already storing gasoline. If I substiture propane, how am I worse off? Granted, the tanks are heavier (and safer from impact thereby), but are they heavier than gas tank plus water tank? I've torn down propane motors, and they are so clean inside it's almost scary (the thought occured to me that I had pulled and torn down the wrong motor). I'm not talking about a propane mixer here, like you put on a carb/propane conversion. I'm talking about port propane injection. I recall a carndriver article where they did propane injection conversions on a crownvic, and the results were impressive just with a change to 12:1ish pistons.

AND I would get to use the HOV lanes, since it would be a "certified alternate fuel vehicle" and also get some tax advantage thereby. Can't stop at the QT for a fillup any more, but it's not all that expensive to fill, especially compared to racing fuel, and with higher octane than I've ever been able to buy in a drum or can, and the fill locations are a lot more common than racing fuel vendors. And no motor fuel taxes to pay. And almost no speculation on the cost of the commodity to drive my fuel up by a factor of more than two like with oil/gasoline.

I have direct anecdotal evidence of the effects of too much octane in avgas. My father was a pilot in WW2, and some yahoo showed up on the base in England with some 150 octane avgas. That witches brew slagged the plugs and combustion chambers so bad they had 100% engine failures after 5 hours in the Rolls Roycel v12's, and even quicker in the P&W radials.

Methanol is HIGHLY toxic. Handle with care.

Braineack

iTrader: (62)

It is suggested you don't bath in or drink washer fluid...

JimAtFSU

Honestly, if you're charge cooling just to avoid detonation my advice is to improve your cooling system so that the head is cooler. Do the coolant reroute, a lower temp thermostat, big fans and a big radiator. If your cooling system can keep your head at 88 degrees C under full load, you'll have a much more stable and detonation resistant car.

This is a superior approach because:
-the stock cooling system is a broken design straight from the factory. Back when the engine was in a FWD car, it was done correctly. Do the coolant reroute.
-your car is already set up for this sort of cooling, all you have to do is boost the efficiency of the system.
-no matter how cold the intake charge is, you're always going to have to deal with this problem anyway because this cold charge has very little thermal mass compared to the intake manifold and cylinder head. If the engine is hot, your charge is going to get hot by the time the compression stroke is done. The amount of cooling in the combustion chamber you get from bringing the coolant down to 170-180F is much greater than the amount you would get from bringing the intake air down to freezing temps.
-this way is EASY and you need to do it anyway if you're going to make big power or track the car.

sixshooter

iTrader: (12)

I bathe my cat in it. Is that wrong?

I tuned in to this thread to find that the impractical and complicated air conditioning augmented intercooler idea has been supplanted with an equally impractical and complicated propane injection proposal. While not surprised, I am wondering what will be proposed next. After, of course, this is deemed to be too costly and unfeasible.

LP is good for running in your garage with the doors closed, but in my experience with LP powered machinery, it hasn't been commonly used with turbocharging. In fact, I can't recall once. Many forklifts and manlifts are LP gas powered with four cylinder engines. I'd look to them, and not here on this forum for ideas regarding that sort of conversion.

As it was eluded to previously, if it is a good and worthwhile endeavor someone somewhere on the net has successfully done it. If you make it work, let us know.

Personally, I would be more interested in successfully implementing Turbo-Compounding Turbo-compound engine - Wikipedia, the free encyclopedia (not Compound Turbos) as a power recovery device. The technology has been there since WWII (on the Wright R-3350 Wright R-3350 - Wikipedia, the free encyclopedia), but is only now reaching commercial vehicles (Detroit Diesel DD15 Detroit Diesel - DD15 Diesel Engine Performance) and hasn't reached private performance vehicles yet. What a shame.

I guess many of us have our pet ideas.

y8s

iTrader: (8)

I didn't read much or any of the thread, I just came to post that there's nothing that sucks more than adding a significant number of points of failure. the end.

fasteddy

I believe you on the head temps. I thank those of you who analyzed the thermo on the chilled intercooler idea.

Further research on the propane injection shows much more data than previously available. There are propane injectors out there, now. The problem seems to lie in keeping the line propane liquid, which is problematical at engine compartment temps. And in getting enough pumping power to overcome the line pressures required to remain in the liquid phase. Doable, but barely, and expensive.

BTW, I agree that there's not very damn much new out there. Just remixes of the old stuff. This does not preclude originality, but it's rarer than you might think. The world divides conveniently into two parts, the stuff I know, and the stuff I don't. For those of you who nicely moved stuff from B to A, thank you very much. For those of you who did so rudely, thank you too. I learned two things when you spoke. You can't imagine how important your opinion of my intelligence was. I welcome your opinions of my ideas. It's all data.

So I'm back to raising the effective knock limit of the fuel, cooling the chamber, and air cooling the intake air. And fuel dumping. Life was simpler when all I had to deal with was an Olds Jetstar.

BTW, I've worked on a 3350, now that I look at the pics. Never looked at the Wiki article before, thanks for the memory - I love those old corncobs. That was a rather elegant solution to recovery of the heat wasted out the exhaust, but I don't think it's very applicable to a small piston engine due to the low volumes and the need to accel vs. the aircraft powerplant need for max power at steady rpms, and fairly low ones at that. That lost heat is better used the way you already use it, reducing pumping losses and improving cylinder filling. The specific heat of water is also hard to beat when it comes to charge cooling by evaporation. I just hate open systems that I might be able to avoid. Sigh. Back to tiging pipe.

Joe Perez

iTrader: (8)

The compound turbocharging idea interests me.

Propane... I'm just not seeing it. I don't know what state you live in, but I'd be curious to know where a secondary-injection system qualifies you as a hybrid.

Methanol is toxic. I try not to drink it or stick my nose in the bottle and inhale deeply. Other than that, I can't see how it's any more dangerous than carrying a bottle of water, propane, or gasoline around with you.

An aside:

Last night I was driving home from Tampa, and happened to be logging. On the up-side of the Sunshine Skyway Bridge, I did a couple of 5'th gear pulls. First time I just punched it at about 65 and held 11.5 PSI for for five seconds. Second time I slowed to about 55 first, then applied 13 PSI and held it for nine seconds. Here's the log:



Initially, MAT was 53°F, which was about ambient. MAT peaked at 67°F at the end of the second pull. I will point out the my IAT sensor is located before the methanol nozzle, so it reads only the effect of the intercooler, and not the effect of the meth. My intercooler is a cheesey eBay-sourced tube-n-fin, and my turbo is a TD04H-15G, so it was definitely at the outer edge of the efficiency bubble here.

dynokiller90

so this thread has me thinking about a lot of things too. And I have learned some things as well. so here is a question, or thought.

fuel coming out of an injector has a slight cooling effect on the intake charge correct? I'm sure it's minute, but how high of a pressure would it take to start seeing some benefit. I'm assuming this would fit into the compress/intercool/release= much lower temps.

so hypotheticaly if you pumped your fuel up to say 200lbs. ran it through some form of heat exchanger and then out of the injector as the orfice would there be any benefit. injector duty cycle/pulse width aside.

would the Fuel have to be in a gasseus(sp) form or could it be done in liquid form. I realize that in liquid form it's not compressable per se' , but you could sure put it under some serious pressure

next question would be would you have to do one closed loop system(high pressure) with another regulator attached to bring the pressure down to an injectable level?

Again, hypothetical. . . I am aware of the operating window of the stock fuel system and that most injectors would lock up at much elevated pressures.

sixshooter

iTrader: (12)

Because you cannot compress the fuel, you logically cannot then decompress the fuel and achieve a lower temperature.

If the fuel is supercooled it will not evaporate quickly enough from a mist of micro-droplets to a vapor to be burned I suppose. At some point the heat generated by the compression stroke would not be enough to cause the gasoline to vaporize because the fuel and air were so cold to start with. I need someone from north of Tampa to tell us at what point that occurs. I know it would cause flooding and cylinder washdown. Talk amongst yourselves.