WAIC Intercooler schematic

[Gizmoman]

Do any of you "turbo specialists" know what charge temps I should expect from a stock K14 running at 15-18 PSI would be?
The engine is an AAZ and the pump is from Giles built to provide up to 150 HP IIRC.
Libby says he's seen 200F+ @ 20 psi and CRSMP5 says it could go as high as 600F.

Reason I ask is I may need a larger radiator for my WAIC or I may add water injection to cool things down. I'd really like to get this right the first time.
I've searched on GOOGLE for a chart or any basic info - no luck.

Any help appreciated.

[theman53]

Depending on how heat soaked everything is I could see it range from ambient temp to probably 300f at the hottest point. 200f is what libby sees so I would say that is accurate as there is no need to doubt him. But that would be full pressure, as soon as you let it down some the intake charge would come down so it isn't like you would have to cool 200f every running second. My K24 could burn your hand pre IC if you touched the pipes after hard running. It was cool to the touch on the post IC side at the same time.

Most awic setups are for 250+hp gas engines, so what ever rad you have is probably fine. There is no such thing as under kill so I like to over kill everything, and you could get a huge rad. It won't hurt, but if you are already using a rad designed for a 250hp gas engine it is already 100hp overkill.

[theman53]

BTW I wouldn't T it. This could solve all your issues by running it into the tank as others have said. Then the bigger the tank you have the less temp change you have and it is harder to keep cooling the same water over and over. If you had 2 gallon tank it would be easier to keep the quart continually cool and use the other to help cool the small amount. Your system may hold close to 3 gallons with a 2 gallon tank but the coolant won't heat soak so bad and turn it into a heater like you are worried about. Also, I run Redline's water wetter in most things I worry about cooling. It really does work to help the heat transfer. In my off road only Ford I see 30F difference in coolant temps. It is compatible with all antifreeze that I have seen. You could add some of it and try it if you don't think it is working properly. Basically it pulls the heat out of the coolant better but even more than that it pulls the heat out of the rad to get it to cool it better. Just some of my .02

[CRSMP5]

ave no idea what to assume the intake temp charge is... but i can beleive 200-600 is possible via red hot turbo vids... when the hot side glows red no way the cold side is cold...

egt 1200f.. id say max heat transfer via heat soak is 50% at worst which is why i say 600f could be possible... where my number comes from...

now how can intake temps getthere.. intake ports between exhaust ports on head.. if they pushing 1200f out.. they on both sides of intake ports.. that heat transfers too...

so head port, ic gas temps, turbine out temps is all voodoo... no one i know of has gauged such readings to know... so i build for worst case...

do the rad you have for now.. its voodoo.. gotta play to test.. you look to have things monitored.. use thoise gauges.. test..

with oil temp, egt, water temp, boost and your waic temp gauge you should be able to tell thermal overload.. honestly you will see the oil pressure to get a little wanky when you start to reach it.. then paying attention to the other readings, heat so on.. you can see when your at it..

if you see the need for more.. add a 2nd rad in line with the 1st one... put it in the middle.. audi 5000 td had a 2nd smaller rad between grill and timming belt for the added little it needed..

you lack ac right?? get custom rad to fit where ac condensor would go.. those are huge on a vanagon.. so use what you have.. test.. you have room to grow..

[Gizmoman]

Thanks Theman and CRSMP5 - all good info. Just for the record, I'd never doubt Libby - he just didn't seem 100% confident in his statement. I was looking for some numbers but there doesn't appear to be any - so it's still a bit of "voo-doo" as CRSMP5 suggested.

For some reason, I don't have a lot of room at the front radiator even though I don't have AC. I remember a post from either Libby or Synchronicity that mentioned making a water tank from 55 gal plastic drum ends (can't find the link right now) that replaces the spare under the front end. I may go this route for a huge water tank as my tall tires are now too big to fit in that spot .

I'll keep you posted. As usual, it's slow going as I mostly only work on it weekends.

[CRSMP5]

voodoo it is... but my voodoo comes with 23000 miles of my box and what im noticing at 4000lbs of weight.. for a few thousand (4-5k) of them miles.. i have 02a gearing and all vs the vanagon buzzbox..

its only why i can say over do the cooling.. imo on a 80*f day pulling a 800ish pound shell at 70ish mph with hills.. say 2 people.. camping ccrap id say close to 4000lbs total.. vs a 40*f day at 80mph with a easy 500-1000lbs more weight.. the 80*f day could kill the toaster... i know how to read my instrumentation though... saved me with the oil usage n 6400mile trip.. and kept me from cooking it the other weekend... and that was pure ambient temp vs load... way to madness no thermal issues like this.. but 60*f is alot cooler temp..

but i also have many miles under the belt of its normal 2600ish weight.. so knew where my normals are.. for me to get to thermal issues... = 3 digits mph.. big long hills.. and 1200f on egt.. for miles when i say long... hell 140 gal of bio in the back in drums no issue... on 70*f days.. but 4000lbs seems to be the number it does not like on a 75*f day... vanagon camper close to that... and you want to drive in warm weather..

for me to tow the jackrabbit around as a real running car.. oil cooler and bigger rad are planned now.. but i got room for that growth.. square box makes it easy..

i know diesel rads different vs the gas counterparts int he vanagon.. wonder if they are different in size.. how i know different is the bleeder diesels have is like a brake bleeder vs the gasser bolt/washer set up.. have to hit libby on that...

i too agree with libby knowledge.. expecialy since he likes vanagons.. i do not..

[Gizmoman]

voodoo it is... but my voodoo comes with 23000 miles of my box and what im noticing at 4000lbs of weight.. for a few thousand (4-5k) of them miles.. i have 02a gearing and all vs the vanagon buzzbox..

its only why i can say over do the cooling.. imo on a 80*f day pulling a 800ish pound shell at 70ish mph with hills.. say 2 people.. camping ccrap id say close to 4000lbs total.. vs a 40*f day at 80mph with a easy 500-1000lbs more weight.. the 80*f day could kill the toaster... i know how to read my instrumentation though... saved me with the oil usage n 6400mile trip.. and kept me from cooking it the other weekend... and that was pure ambient temp vs load... way to madness no thermal issues like this.. but 60*f is alot cooler temp..

but i also have many miles under the belt of its normal 2600ish weight.. so knew where my normals are.. for me to get to thermal issues... = 3 digits mph.. big long hills.. and 1200f on egt.. for miles when i say long... hell 140 gal of bio in the back in drums no issue... on 70*f days.. but 4000lbs seems to be the number it does not like on a 75*f day... vanagon camper close to that... and you want to drive in warm weather..

for me to tow the jackrabbit around as a real running car.. oil cooler and bigger rad are planned now.. but i got room for that growth.. square box makes it easy..

i know diesel rads different vs the gas counterparts int he vanagon.. wonder if they are different in size.. how i know different is the bleeder diesels have is like a brake bleeder vs the gasser bolt/washer set up.. have to hit libby on that...

i too agree with libby knowledge.. expecialy since he likes vanagons.. i do not..

OKOKOK - I get it dude, really, I get it.
I'm putting a high temp system in and you not liking vanagons is fine, I agree, you shouldn't get, drive, fix, ride or camp in one. But I still appreciate your answers 

[libbydiesel]

My previous comment was based on some testing I did a while back with temp sensors both pre-intercooler and post-intercooler.  The temperature would change fairly rapidly with changes in boost pressure.  There also was a fair amount of hysteresis to the temperature probes, boost tubing, etc...  The highest pre-intercooler temps I saw were around 225° on extended grades pushing 20psi or so while driving at 7,000ft elevation.

Temperature Rise = (ambient Absolute temp)[({outlet Absolute pressure/inlet Absolute pressure}^0.286)-1]/compressor efficiency

Lets say ambient temp is 80°F(300°K) and that boost pressure is 14.7 psi at sea level (14.7 + 14.7).  For convenience, lets assume inlet pressure is atmospheric although the air filter will cause a bit of a drop.  For convenience lets also assume a compressor efficiency of 75%.

Temperature Rise°K =  300[({29.4/14.7}^0.286)-1]/0.75 = 88°K

300°K + 88°K = 388°K = 239°F

[bbob203]

Crs has nightmares about his whole lot of cars being mysteriously turned into vanagons and audis. 

[Gizmoman]

My previous comment was based on some testing I did a while back with temp sensors both pre-intercooler and post-intercooler.  The temperature would change fairly rapidly with changes in boost pressure.  There also was a fair amount of hysteresis to the temperature probes, boost tubing, etc...  The highest pre-intercooler temps I saw were around 225° on extended grades pushing 20psi or so while driving at 7,000ft elevation.

Temperature Rise = (ambient Absolute temp)[({outlet Absolute pressure/inlet Absolute pressure}^0.286)-1]/compressor efficiency

Lets say ambient temp is 80°F(300°K) and that boost pressure is 14.7 psi at sea level (14.7 + 14.7).  For convenience, lets assume inlet pressure is atmospheric although the air filter will cause a bit of a drop.  For convenience lets also assume a compressor efficiency of 75%.

Temperature Rise°K =  300[({29.4/14.7}^0.286)-1]/0.75 = 88°K

300°K + 88°K = 388°K = 239°F

Now that's some great info right there, thank you libby. I sent a PM to Synchronicity regarding his 7 gallon spare tire tank he made. That should be a good heat sink

Crs has nightmares about his whole lot of cars being mysteriously turned into vanagons and audis. 

I do appreciate his point on heat soak but that is still funney

[Syncroincity]

I ditched it... it leaked too much. The lid just wouldn't seal. If we could find a one-piece tank for that location with a similar shape, that would be nice.  Even without the reservoir, the system holds just over 2 gallons of coolant, using 5/8" hose. If I decide I need a reservoir for it, I'm going with a section of 4" PVC pipe instead, probably in the return line under the van. Right now, I don't seem to need it.

My chargecooler is always cool to the touch in the engine compt. when running, but it does warm up when the van sits after. Try to add an insulation blanket between the turbo & intake if you have room, and/or use a turbo hotside heat cover.

[vanbcguy]

For what it's worth, there is no reason to bother making the AWIC a sealed system.  It is only soaking up turbo heat when you are under boost, which is really only a small percentage of the total time.

I run mine with a small vent hole in the lid of my tank.  I do loose a little tiny bit to evaporation but I'm talking like a 1/4 cup every few months.

In terms of fluid temperature, I would definitely agree with CRSMP5 in that the AWIC coolant will soak up engine bay heat when you are stopped.  If you come off the highway, stop and pop the hood the boost pipes will be cold, after sitting for 10 mins they are hot to the touch just like everything else under the hood.  Same goes for the AWIC. With my system it doesn't seem to matter though, as soon as either the rad fan is on or the car is moving the heat is gone from the AWIC system pretty quick.  The hottest temperatures I have ever seen in my AWIC burp tank are after the car has been sitting shut off for a while.

I definitely don't see temperatures anywhere near boiling in my AWIC coolant.  The air exiting the turbo is definitely that hot but heat transfer goes from hot things to cool things - it is not necessary to heat the coolant up to boiling temperature in order to cool the charge air down, in fact quite the opposite.  The hottest AWIC core exit temperatures I've seen on my system under normal conditions have been about 15-25°C above ambient, though I can only check that by driving hard then jumping out and opening the hood to see the thermometer in my tank so the actual "under boost" reading is probably higher.

My AWIC radiator is about double the size of the one in the pictures here so YMMV.  I went with a monster one because I could make it fit - the only penalty to running an oversized AWIC is the extra weight of the water / components.  Really though we are only talking about a few pounds so nothing worth worrying about unless you have a race car.

[Gizmoman]

All great info!

As I said earlier, I'm no thermal Engineer but it seems obvious that the size of the tank is somewhat a non-issue. Just like the stock overflow tank on the hot engine (very small), if the rad can't cool the liquid, I'm fighting a loosing battle anyway. In other words, adding more liquid to an undersized system just buys more time as it will all eventually get too hot as well - again, if the rad can't keep up. The size of my radiator may be too small for the task, and I'll have to see on that. Adding a large tank is not really going to help on a long 6-8 hour trip.

BTW, I have no idea how much "continuous" boost I will need pushing the bread-box through the wind at 65-70 MPH, but before it went South, 10 PSI was the norm. Even slight hills put me to the 15 psi mark (max boost adjusted by the DIY controller).

I expect fours driving at 10 PSI, stopping to let the wife do her thing while I get diesel, heat soak will be an issue as I get going again. A few minutes of fan over rad should bring things back in line - that is if the rads not too small to begin with.

Now I have and EGT sensor (DUH), a Giles pump and a WAIC, things may change a bit but I want to design towards a worst-case scenario to minimise the tow charges

Again, many thanks to all - I'll keep you posted (albeit slowly).

[libbydiesel]

The temperature of the charge air varies dramatically and very quickly.  Having a higher coolant volume will reduce peak temps, especially if your radiator doesn't always cool the coolant down to ambient during peak loads.   

[Gizmoman]

The temperature of the charge air varies dramatically and very quickly.  Having a higher coolant volume will reduce peak temps, especially if your radiator doesn't always cool the coolant down to ambient during peak loads.   

Hmmm, peak loads - good pointy libby