Some KC advice please.

I understand that there are 2 ways of routing the water pipes that go to and from the KC.

1: pump - kc - ic - tank

2: pump - kc - tank - ic

I've been running mine on option 2 for a number of years. I'm having some work done on the car and now would be a good time to try and improve on my KC set up. I have 2 queries:

a) Is option 1 better or worse than option 2 and why?

b) Would it be more beneficial or less beneficial to keep the h/e in the loop - plumbed in series with, but before the KC and why?

I'd appreciate advice on these issues

 

It doesn't matter which order you set it up.

Water will be at an equilibrium throughout the whole system.

 

Water temp is not at equilibrium. I have a temp gauge for the tank water which receives the coldest water from the KC which then goes to the IC. You have a tank full of the coldest water ready to feed the IC where it needs it most. After the IC the water is the hottest and goes to the pump then the KC. I have run this way for 2 years now. Even with a fixed pulley which does raise the minimum temp compared to a clutched pulley I can get the tank water down to 2-3 deg C. A 1/4 mile run raises the tank water temp 15 deg C. That is still under ambient temp which a regular heat exchanger will not do even in cruise.

 

Thanks for the feedback.

trabots, nice set up. Unlike you, I'm running a trunk tank. The routing on mine is currently the same as yours. I'm exploring whether it is viable to switch to pump - kc - ic - tank based on the following assumptions:

a) The water is at its coldest as it exits the KC and should therefore go from the KC directly into the IC.
b) If the water has to travel from the KC to the trunk tank and then from the trunk tank to the IC (rather than from the KC directly into the IC), there will be some heat transfer.

If these assumptions are correct, then the only possible advantage to the pump - kc - tank - ic routing would be that one would have a tank full of cold water immediately accessible when going WOT (during which time the a/c disengages). That makes sense to me. However, the tech doing the repairs on my car has suggested that the a/c does not stop cooling as soon as one goes WOT and that it will continue to cool long enough to support a WOT run to 220km/hr - about 15 seconds. If he is correct (and if the quarter mile is the target rather than the half mile), would it not make sense to plumb the system so that the coldest water goes directly from the KC to the IC rather than going via the trunk tank?

 

I'm no expert on this, but that makes no sense to me. If the pump stops then the only reserve cold in the system is the kc exchanger. I would recommend more investigation before you reroute hoses.

 

The KC alone will not keep up under WOT even if the AC pump stays pumping. Better to have a tank full of almost freezing water which will last for most hard pulls. A fixed pulley as I have, is always heating the water in the IC. A variable pulley will allow the tank water to get below freezing when just cruising. I have had both situations, having to add some antifreeze for the latter. Having the temp readout of the tank water lets you work out how best to set the cabin AC controls for maximum cooling of the IC water. It also lets you see in real time the temp recovery after a pull.

 

Read the OP where he asks for an optimum setup.

It won't make any difference how it's routed.

The whole system will be a very similar temperature due to the high flow of the water. If the water was stagnant, or very slowly moving throughout yes there would be a big difference between water in the block and the water in the reservoir.

But since there is good pump pressure and flow, there water will be circulating constantly which will cause the water to become an equilibrium.
The water hitting the IC is not going to be much hotter than the tank. It will be a marginal difference.

I've been building PCs for a long time with water cooling setups and the same principal applies.
It does not matter how the system is routed as temps will always be very similar throughout.

 

I say you are wrong. You are referring to the "water in the block". The engine coolant must be isolated from the IC water. Under load there is a big difference in water temp coming out of the KC and thus the temp of the tank water than the temp coming out of the IC and thus the temp going into the KC, during and after a pull. Having the 2.5 gal tank of cold water ready to feed the IC is definately the way to go. Going bigger than 2.5 gal may be fine for 1/2 mile or 1 mile top speed runs but the recovery time takes much longer. I will say it again, unless you have a temp gauge in your tank water you won't know. With my tank water sitting at just above freezing during cruise, there is no way it is that cold coming out of the IC. You can give the throttle a stab and moments later see the tank water increase in temp before dropping again. The KC bloke agrees with me on this. He runs 2 KCs in series on his Mustang.

You say you have been building "PCs", computers? How is that anything like the variable heat loads seen in a supercharged car? Yes, at cruise one would imagine the IC water temp delta getting to a minimum like with the constant heat load in a computer.

 

Water in block vs isolated IC system makes no difference, same principal applies.

Water moves fast, it's not going to be hot like you think it will be right after the IC.

PC cooling is no different. GPU block with a 500w constant head load will not cause the water coming out of the "out" port tubing to be much hotter than the "in" port. The temps will be very similar throughout before and after the heat source.
This is how it is and it's been proven.

Cars are not inherently different. You can test this by putting a thermal probe in multiple parts of the system if you really don't believe me.
I've done this in water cooling setups so I know exactly how it works from first hand knowledge.

 

Nope I don't believe you. You refer to a "500w constant heat load". These cars do not have a constant heat load, it can be highly variable depending on load and throttle opening. How else will the KC work if the IC water temp going in is the temp coming out? Why is it better to have the refrigerant gas going the opposite direction to the IC water in the KC? It is to increase the temp delta between the two fluids which maximizes cooling efficiency. You can feel the difference by hand on the IC water pipes in and out of the KC. I will bet you my house that if you instantly added a further heat source to your running computer, your multiple temp sensors would immediately see big differences until things settled down at a higher temp. That would be the same as giving the throttle to our cars, a variable heat source. You seem to ignore the extra heat produced by increasing the fuel/air volume (opening the throttle more).

Put another way the KC is simply a 2nd evaporator on our cars and which is found in the cold drink dispensers in fast food joints. The variable heat source is a customer needing a supply of room temp syrup and water into that evaporator for chilling before filling his cup. Of course as you say, if the supply was constant, equilibrium would be reached. That is not the case with the drinks cooler nor is it the case with our cars except when cruising at constant throttle. When on cruise control and I hit even a slight hill I can see the tank water temp increase and then going down hill it will decrease.

Further, I did use a qualified refrigeration mechanic when installing parts of my KC set-up who confirmed that I had it right. Also, I did take some refrigeration when obtaining my BSc in mechanical Engineering.

 

trabots and Agent, many thanks for the feedback. Interesting debate and too technical for me to offer any meaningful retort. Regardless of who is right, it seems I must leave the routing as it is. (If trabots is right, then the current routing is optimal. If Agent is right, then the current routing is as good as the alternate option).

Any insights in regard to my 2nd query i.e. why would "IC - Pump - KC - Tank - IC" be better than "IC - Pump - HE -- KC - Tank - IC". Would it not make sense to have the water coming out of the IC first cooled as it passes through the HE and then further cooled as it passes through the KC?

 

Don't get too caught up on specifics in my examples.
PCs too are very variable depending on setup and what programs are running.

500W constant in this case would be max throttle in the car. (worst case scenario/highest heat load).

As for your bet about adding more heat sources, you would be incorrect about the multiple probes seeing big differences.

In fact, my current PC setup has 2 graphics cards and a CPU and Voltage regulator water block.
That's 4 heat sources. In the worst case scenario for determining temperatures, you run benchmarks which are programs designed to put the highest stress on the system.

You could easily see 1000w on overclocked systems like mine.
While running these benchmarks, the water is at an equilibrium after a short while of run-time.

As for refrigerant comparison, there are TEC water chillers for PC cooling too. These are high wattage systems that use refrigerant gas(separate line from water-cooling for PC components) to chill the water to below ambient temps.
In this case, it would be similar to putting ice in the KC.

After a short time of a constant 'cold source', the water does reach an equilibrium.
The load being constant or variable does not matter as the water temperature will vary as a whole throughout.

Water is being pushed fast with high pressure so there are no hot or cold spots.
With such a setup, the difference between the hot and the cold would only be a few centigrade.
You could put the probe on a heat source and one in the reservoir and it will be 1-2c difference max.

Look up thermodynamics and you will see how that all makes sense.

 

Remove the HE as it does NOT help. As one of the early ones to use the KC after a few tried it prior to me but most got on board after me just keep it simple.

Simply go IC > KC > tank

for extra power and cooling add meth and have the best cooling system. KC and tank for street use and then meth for longer and WOT runs

 

Thanks for the reply.

My current set up is overly complicated and I'm trying to simplify it. I have a 3-way by-pass valve in the mix which channels the flow as follows:
a) IC - Pump - KC - Tank
b) IC - Pump - KC and HE simultaneously - Tank
c) IC - Pump - HE - Tank

With this set up, my logs show that:
1) when cruising, a) is best
2) when going WOT, b) is best

It seems therefore that the HE helps when going WOT. Because I'm running the Weistec charger, meth does not help with IATs at all - probably because the nozzle is located pre and not post. It seems sensible therefore to keep the HE plumbed in to help on WOT runs.

I can leave my set-up as is but in the spirit of simplifying it, I'd like to remove the bypass valve and simply run the HE in series i.e. - IC - Pump - HE - KC - Tank. If that is not likely to have a material adverse impact on cruising IATs, then that's what I'll do. Just need to establish whether that set-up is likely to have a significant adverse impact on cruising IATs

 

IC - pump - HE - KC - tank would work beautifully if you had a variable speed pump or even an on/off switch controlled by a thermostat. Without it you are warming up the water from the KC with your HE while cruising. I wouldn't say that's simplifying but you will have the best of both.
Better yet, thermostatically control the three way valve you already have.

 

Thanks for this. It answers my question and makes sense to me. Appreciate the feedback.

 

The fact that you say "it would be similar to putting ice in the KC" "to chill the water to below ambient temps" says plenty. The KC firstly has no way to physically accept any ice. Secondly here in Perth my tank water is always below ambient and is why a KC is so much better than an air to water HE which can never get the water below ambient temp. Lastly, my hand can feel what you say does not happen. During recovery after a pull, the water line going into the IC is cooler to the touch than the one coming out, fact. My tank water heats up within seconds of a throttle mash, fact. The tank water then drops temp afterwards, fact. For this to happen there must be a temp gradient in the system, fact. The ONLY thing I agree with you is that the system will eventually return to a minimal temp gradient between the components when cruising on the level at constant speed.

Do not run a heat exchanger with a KC as it undoes the cooling of the KC. There would be a very small benefit under WOT and only if the whole system was over ambient temp. As I have pointed out my tank doesn't even reach ambient temp after a pull. On a 23 C day with my tank water at 5 C at the start of my burn out, it only reached 20 C after a 1/4 mile run.

 

how Much boost are you guys running ?

 

Noted, thanks trabots

cnterline, not sure if your question was directed at me, but on the Weistec s/c I'm seeing 15 to 16 psi at 5,500 feet above sea level. I'm running the stock crank pulley with a 56mm s/c pulley. I know that this altitude robs the car of about 4 psi

 

I wish I knew, another gauge to install. I have a 74mm fixed pulley, Race IQ tune, on a stage 2 EC kit, no cats. My V-box says 3.7 sec to 100kph, spinning all the way and 11.0sec to 200kph. My only trip to the strip confirmed the speed as the et was only 11.4sec but at 124mph. That however was with a 2.1 sec 60ft. I am told that what you save in 60ft time you get back, plus more, in lowering the et. I note that your car does a 1.44 sec 60ft so can I assume if I shaved 0.5 sec off the 60ft I might break into the 10's?

 

I’m asking because imo a high boost car will not reap the rewards of the KC set up ,I’m talking a 19-20 psi boost set up .again my opinion a few back to back runs in hot weather will destroy that reserve

 

Yes, I agree. Guys running the stock blower seem to rely on meth for cooling on repeat WOT runs. The KC is a nice add-on. On the Weistec set up, meth does nothing at all in the way of cooling. I need therefore to keep the HE in the mix (even if it marginally negates the work of the KC). If there is a better cooling option for my set-up, I’m not aware of it

 

The new Dodge Demon uses a KC type evaporator with no air to water HEs. I would say they have done their homework.

 

Would love to see a 20 psi Mercedes M113K car run this at the track just to see lol

 

How would you boost 20psi if there is the 17psi limit on the map sensor that sends the car into a "lean map" state under boost...