Chargecooler kits

Not a Red Dwarf fan, then Pete? Series 3, episode 1, "Backwards" the very last scene.

Yep, not just a geek about engines.......

Everyone has a secret fetish ... ... ...

it would be unwise, however, to underestimate the cooling recquirements. for 300 hp the air cooling need is roughly 40 kw. at a dt of 50 c° this means 13 l/min of coolant flow. i dont think you would want to heat up the cooling liquid to 90 c° though, so at dt of 10 c° its 65 l/min of coolant flow to get an in temp of 40 c° and an out temp of 50 c° (pre rad, that is). now if you imagine cooling 40 kw at an dt of 25 c° (ambient= 20 c°), it works out to 0.046 m2 of air at 100 km/h. the core then should be 2 x 0.046 = 0.9 m2 and due to pressure drop and inefficiencies probably 0.18 m2.
that is 20 x 90 cm at an average speed of 100 km/h. this also casts a light on the pumping requirements. no way to get this through the a/c radiator for example.


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Very interesting, apart from the fact that power output against charge temps are not at all related, so you can't say 300hp needs 40kw. A 9 litre engine making 1000bhp with only 15psi will not have charge temps as high as a 1 litre engine using 30psi to make only 200bhp, and is also highly dependant on compressor efficiency, core design in chargecooler/prerad etc, so put the calculator away...

when do you actually go to sleep? (3:39 am ?)

Of course you cannot just say that, but you can calculate it for a specific case (please point out any flaws the following might have):

300 hp, 1.4 bar, 20 c° amb., loss intake 0.3 bar
(273 + 20 + 5)(2.7)^0.285 = 298 x 1.33 = 396 k°, dt =98 k°
that is at 100 addiabatic efficiency. now assume you have pushed the compressor far out to 60% (time to get a larger one): 98/0.6 = 163 k° = dt

300 hp @ 250g/hp/h (we once agreed on that)
is 0.07 g/hp/sec, 0.07 X 300 hp = 21g/sec (gas that is)
@ 12.4 (mixture): 12.4 X 21 = 260g/sec (airflow)
@ 1J/g.k° is 260 w/k°
163 k° x 260 w/k° = 42 380 w

so we can see 40 kw was close. yes we have air comming out of the compressor at 188 c° (in reality slightly more, because it would pick up heat from the turbine), but this is hardly ever measurable, as it happens so quickly (k-type of probe is not fast enough).

I never sleep. too much to do

Your going to be seeing around 105 degrees out of the compressor if you went with the 'theoretical' 100% adiabatic efficiency at 1.4 bar on this engine, at 75% around 135 going up to around 160 with the efficiency way down below 65% which in that case you need a different compressor.

Its still not related directly to horsepower though. Chargetemps are only dicated by pressure, and compressor efficiency, and inlet and ambient temps, the actual engine doesnt come into the equasion, and hence any power levels or KW quoted.

one last thought on this topic:

if you go out and get an extremely powerfull fan in the 180 mm class (e.g. papst 6424, diregarding its 24 v) its rated 500 m3/h and will probably pull somethisg like half of this through an radiator, if your lucky. so get two of those and you have 500/3666 x 1.3 x 25 = 4500 w cooling capacity, assuming a temp. dif. of 25 c°. now 4.5 kw is not really much, in view of the above.

what i want to say, is: its not enough to put the radiator someplace and having some fan pulling a bit air through it somehow. you need to decide what you expect from it and design the system accordingly.

what i want to say, is: its not enough to put the radiator someplace and having some fan pulling a bit air through it somehow. you need to decide what you expect from it and design the system accordingly.

Yes, in the ideal world, but if the ideal system doesnt fit or can be located in the best place, then what can you do? We work on cars, its all a compromise.

Simple rule of thumb in a CC system is to have the front prerad as large as feasibly possible, as much water volume in the system as possible, and lastly the most efficient chargecooler design. The unit I do is a countercurrent design, most other units are not, and this is the most efficient form of heat exchanger type.

cutting holes:

let me add this. instead of cutting large holes you might want to cus two small ones and install jets that will flow lets say 1 ltre/min of water at 1 bar. connect the jets to a water reservoir that you place in a cool spot and and pressurise that with a hose to the intake manifold.

1 l /min = 16 g/sec, lets hope one half of this evaporates
8g/sec X 2256 J/g = 18 KJ/sec = 18 Kw.
lets say the water heats up by 50 c° before evaporating
16 g/sec x 4.2 J/g x 50 c° = 3.3 Kw

so you just created a cooling capacity of 20 Kw on demand. not really bad. and unexpensive as well.

now if you are precooling the charge through the liquid intercooler, the effect will be less, but still something like 10 Kw, which is probably more than your dissipatig through the pre rad. a good idea would be to put a switch into the hose, that switches on the pressure when your on full boost only.

i have used such a set up before switching to the liquid intercooler. a had a 5 l metal fuel canister behind the right wheel, it was a pain to fill it up, though. later i used the space for a methenol injection tank.

On with fitting the charge cooler at last Just wondering if any of you guys that have fitted one could confirm the order of the components when fitting, i.e im using one of Davids expansin tanks which will be setting up front in the boot, with hot going into the rad would it be best before or after the rad:?
Young Steves got one on the GTA, but just wanted to be sure its plumbed up OK
Got the pre-rad fitted bang centre in front of the coolent rad--all seems OK re looks and coolent temps, so at least it isnt restricting the air-flow to the main rad.

Sure there was a topic on here somwhere with the CC layout

Ideally, the pump should be as low as possible and be the lowest item in the circuit. The header tank should be at the highest point in the circuit. It is also better to have it on the side of the circuit that feeds the CC, so hopefully it will reduce any air getting to and into the CC.

Also Ideally, it is best to have the CC take offs pointing vertically upwards and the CC tilted so that the output end is higher than the inlet end. This is the bast way to stop the CC storing any air locks in it.

It does not really matter where in the circuit the pump is, but i chose to put it after the pre rad, so as it was kept cool by the water (might prelong the pumps life) and also it is then pushing the water directly into the CC.

You MUST connect the cold water inlet to the end of the charge cooler which is closest to the turbo. This is for 2 reasons, 1-when the items are at extreme temperatures to each other the greatest heat transfer will take place, 2- in theory the water temp at the turbo end of the CC is the theoretical lowest that the air temps could ever be, so you want the coldest water here.

I choose not to use a header tank. The water expansion is very small. I used a tee piece in the circuit at the highest point for filling and bleeding, and works fine. I have run the car for about 2 months since last bleeding the system, and last weekend theere was only about a few small bubbles locked in the CC.

Thanks for that Simon looks like a busy weekend for me hopfully get the cc sorted and over to motorscope for some setting up, which it needs badly THANKS

Just called over to Nor-Mal fabrications to get a pump holder bracket made up for the CC pump, hope its not to bling he asked me if it wanted polishing
[img][img]http://i30.photobucket.com/albums/c314/leylandracer/Normalccpunpholder1.jpg[/img]
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[Alpineandy]

what's wrong with plastic ties?

I used a big jubilee clip to go round the pump, but your bracket does look very professional.

I hope the aesthetics of a bracket doesnt take precidence over where and how it is going to be mounted..

Any idea what sort of charge temps i should expect to see before the CC and interccoler? Just fitted two thermocouples before the CC and after the intercooler, just wondering whats norm & max should have it working to,oz if the sun keeps shining