|
|
|
Dec 30, 2014 23:57:04 GMT
|
I have many questions about charge cooling. I didn't even know what it was or that it existed until it was mentioned in an episode of Project Binky by the Bad Obsession Motorsport boys. I could wait until they build their one but it's around three months between episodes and they have only just released episode 8. Basically I have a 300tdi Discovery. I have tinkered with it and yes I know it will never be a rocket ship because it weighs as much as the moon. I have done the usual, EGR delete, straight through exhaust, tuned the injection pump, upped the turbo boost. I still have a standard intercooler and was wondering about charge cooling. Naturally I don't want to buy one because I am a colossal tight  , but that won't stop me trying to make one from bits I find in the skip at work. So, I understand it's essentially a radiator with the charge piped through the fins so here are my questions; 1: How can I make one? 2: Do you use the same coolant as the engine or run a separate system? 3: If you do use separate coolant, do you then need to cool the coolant which is cooling the charge? (Keep up with me) 4: If you do use separate coolant, do you also then need a cooler to cool the coolant use to cool the charge?  ? (still with me) 5: Am I going to notice any power increase or should I just bodge in a larger intercooler? Much interwebs research has uncovered not very much. I think that the principle is that coolant used in the charge cooler, absorbs the charge heat more readily than the traditional air to air intercoolers. Are intercoolers used because they are cheaper? Discovery's have quite a bit of space under the bonnet and in front of the radiator so space isn't an issue, plus if the BOM boys are planning on using one in Binky they can't need that much space?? |
| |
|
|
|
|
|
|
|
|
|
1. You'll need a charge cooler unit, radiator, water pump, header, loads of pipework. 2. Nope, it runs it's own system. Otherwise you may be warming air to put into the intake. And adding to coolant temps. 3/4. Yes, it runs a different system through its own radiator and I turn cools the charged air. 5. Probably not. Fitting a bigger intercooler is much easier. They look cool hanging out of the front too.  |
| |
|
|
|
|
|
Dec 31, 2014 11:56:40 GMT
|
|
If you're running a turbo and thinking about cooling the air entering the engine you should probably think about measuring the air temp inside the manifold, so that you can be sure that it needs further cooling. Most people that use water injection and other cooling methods do so because they don't have room to fit a big intercooler. But it sounds like you do have room.
Why don't you just fit a larger, or more efficient intercooler? I was running a 4X4 Cosworth intercooler which sits above the radiator on a Sierra. I paid £25 for it and when I asked a turbo specialist about recoring it to make it more efficient I was told it is as good as it gets - a very well designed, efficient, compact intercooler. And its bloody cheap.
Charlie
|
| |
|
|
froggy
Posted a lot
Posts: 1,099
|
|
|
|
|
With the engine in the front and room to fit a larger air to air then it's a no brainer . Water to air can be more Efficiient but only until the water temperature rises to the point it can't absorb the heat out of the charge . I run a decent chargecooler set up with a pwr barrel cooler and large front rad along with two Bosch pumps to get the flow rate up . It works really well and will do 25mins of track day abuse before the coolant gets up to 45c then I let it cool before going out again . If I could run air to air I would but my car is mid engined with no place to fit one .
Ducting an air to air can improve performance and recovery rate quite a bit too
|
| |
|
|
luckyseven
Posted a lot
Owning sneering dismissive pedantry since 1970
Posts: 3,839
Club RR Member Number: 45
|
|
|
|
|
I think chargecooling has a lot of compromises that mean it should be a last resort rather than a first solution. A decent, well-constructed air-to-air intercooler is so efficient there's usually no need to add the complexity of a water system and all the associated plumbing. There was a trend a few years back to charge cool rotaries, which struggle with temperature buildup pretty badly when turbocharged. It pretty soon fizzled out as people came across all the drawbacks.
IMHO it's a useful solution for cars like turbo MR2s where the engine is mid-mounted, space is horribly restricted and there's no easy access to throughflow of air and thus an air-to-air intercooler is very difficult to package efficiently into airflow without catastrophic turbo lag resulting. A chargecooler can simply be routed into the rear boot to utilise otherwise "dead" space. Provided you don't need to carry golf clubs, of course. Most other cars... well, there's probably a good reason intercoolers are the go-to solution
|
| |
|
|
ChasR
RR Helper
motivation
Posts: 10,195
Club RR Member Number: 170
|
|
|
|
1: How can I make one? 2: Do you use the same coolant as the engine or run a separate system? 3: If you do use separate coolant, do you then need to cool the coolant which is cooling the charge? (Keep up with me) 4: If you do use separate coolant, do you also then need a cooler to cool the coolant use to cool the charge? ? (still with me) 5: Am I going to notice any power increase or should I just bodge in a larger intercooler? Much interwebs research has uncovered not very much. I think that the principle is that coolant used in the charge cooler, absorbs the charge heat more readily than the traditional air to air intercoolers. Are intercoolers used because they are cheaper? Discovery's have quite a bit of space under the bonnet and in front of the radiator so space isn't an issue, plus if the BOM boys are planning on using one in Binky they can't need that much space?? IMO the below answers it but I felt the need to expand on it . 1. You'll need a charge cooler unit, radiator, water pump, header, loads of pipework. 2. Nope, it runs it's own system. Otherwise you may be warming air to put into the intake. And adding to coolant temps. 3/4. Yes, it runs a different system through its own radiator and I turn cools the charged air. 5. Probably not. Fitting a bigger intercooler is much easier. They look cool hanging out of the front too. IMO these points matter: 3)The chargecooler coolant is cooled down by the circulation of water through a chargecooler heat exchanger (a chargecooler radiator if you may). In a number of kits these tend to be undersized and tend to result in the air not being cooled all that well. These radiators need to be large, ideally as big (if not bigger) than a car radiator as a rule of thumb. Naturally this leads to more space being used and more complications. 4) Answered in the above like Scratcher's post. I would agree with LuckySeven's post. Chargecoolers tend to be used where space is a premium (confusing with the above I agree!) and where it is not practical to mount a chargecooler in a suitable location. As an example my Escort would be possibly better on an intercooler system. Of course for it to be suitable alot of would have to change; quite a lot of the front would need chopping up, something many Series II RSTs had had done to get those low charge temperatures. However, the system in my car (to be as effective as it is now) is a far cry from what a stock system that was supplied as a plug and play system for my car via a well known company, and it clearly gave the previous owners a headache ; the chargecooler radiator is about 3-4 times as large than the stock C/G rad despite running 5PSi less than what the company said the chargecooler could run at. Despite the efforts trying to keep it small and effective would I change the system? In my case no (I quite like not having the front of the car cut up alot and in my case the car happens to come with quite a bit of free space up front (for an additional radiator but not an IC!) but on other cars I would go for an IC anytime! Whilst Intercoolers can be roomy items they are also quite simple in their operation when compared to a chargecooler and in most cases (in terms of VFM etc.) tend to be more effective). With an intercooler some pipework, an IC and good airflow to the IC are required. These requirements differ for a chargecooler. A suitable chargecooler is required, with a more suitable radiator being paramount should you require the CC to actually cool the charge air (some radiators take up more space than an intercooler in many applications) before you get to a pump and the pipework so as to carry the coolant etc. |
| |
|
|
|
|
|
|
|
|
Firstly, petrol or Diesel the charge cooling requirements for both are rather different ?
Whats the available airflow like ?
Road car ? race car ? high average speeds (And corresponding airflow over the matrix) or lots of cruising about with the occasional squirt on full boost ?
Water has 4 times the Thermal Inertia of Air, so to raise the same volume of water up by 1 degree will take 4 times the heat energy.
Most air/water chargecooling systems are let down by too small a system volume, too small a Low temperature Radiator and too high water flow rate.
For road use on a gasoline engine they are a very good solution, for short duration motorsport or relatively low vehicle speeds they are very good.
For Diesels which are on boost a lot more they are less beneficial, likewise if you are going flat out with high vehicle speeds and good airflow, then an Air-air solution is often better.
Mine is Supercharged and water/air chargecooled, the Chargecooler matrix is something like 85-90% efficient, I will be running a sensible water capacity, good sized Low temp radiator side by side with vehicle rad (So both get maximum cooling potential) and less than 10L/Min flow rate for good heat transfer and maintaining a good temperature differential.
Hope that helps
Dom
|
| |
|
|
|
|
|
|
|
|
I've often thought that throwing a massive intercooler out front just increases the volume of the system between compressor (whether turbocharger or supercharger) and throttle butterfly, and correspondingly increases the time taken to reach a certain level of pressure at the butterfly... Surely on a road car, a charge cooler with a properly designed system as Dom noted is a much better idea?
*n
|
| |
Top grammar tips!
Bought = purchased. Brought = relocated
Lose = misplace/opposite of win. Loose = your mum
|
|
tim124
Part of things
Posts: 128 
|
|
|
|
|
Having some inlet / inter cooler volume on a well designed system won't be a problem, I've been in a Mustang with rear mounted twin turbos, it was quick with out lag.And no the turbos were not tiny, it had about 600bhp, it was using ball race GTr Garrets
|
| |
|
|
luckyseven
Posted a lot
Owning sneering dismissive pedantry since 1970
Posts: 3,839
Club RR Member Number: 45
|
|
|
|
|
Lag is more a function of the response time of the turbo itself than the pipework between it and the throttle body. The volume of air being reduced can make a small difference, but less than you'd suppose. I swapped from a stock-mount but uprated intercooler on my FD (mounts just in front of the engine with a very short pipe run) to a big front-mount (mounts right in the bumper aperture with a long and twisty pipe run) on the same turbo and it made almost no discernable difference to the lag. Made a massive difference to intake temperatures though. It was only when I upgraded to a head-sized plain-bearing turbo that the lag crept in
|
| |
|
|
|
|
|
|
|
Are there any equations to calculate the efficiency of a chargecooler? I must know more... Right now I'm thinking of making my own or have one made to my specifications, I can't find anything to buy that satisfies my needs But I'd like to avoid the "try & error" approach  |
| |
|
|
|
|
|
|
|
Ok, so I've gathered some information that I'd like to arcive here... First of all: the basic layout of a charge cooler. In an ideal world, charge air & water are in a counter-flow. Meaning, cold water enters on the cold side of the chargecooler. Instinctively I would have done this the other way around. But the reason is simple and very much logical: if the warm coolant is on the cold side of the charge cooler, the temperatur of the air exiting may never fall below the coolant temperature. So; you want the coldest water at the coldest end of the chargecooler. On the "hot" side, warm water can still dissipate heat from the hotter charge air...! So - if you then look at many of those eBay charge cooler kits, you'll notice that sometimes water inlet & exit are even on the same end of the core, side by side. This of course means water will not flow through the full core (principle of least resistance/shortest way). They are basically not efficient. In short: ounterflow of coolant & air, and cross-flow of coolant through the core. This is my - current - design for a charge cooler with a rather long-ish core to give the air time to give heat away. Water inlet & exit are across the core:  apparently those cheap chargecoolers also make use of "reversed" intercooler (air/air) cores which in this application aparently are less efficient then a "real" chargecooler core. Then the radiator: This should be of a low-temperature design and as large as possible to exchange as much heat as possible. Normal car radiators are designed for higher temperatures of coolant. Te coolant should be as cold as possible when it enters the chargecooler. The bigger the differential in temperatures is, the better the heat exchange works. I wil possibly, if space allows, include fans for the chargecooler radiator. Why not? What I'm still unsure about is the coolant pump. Or better flow rate of the coolant pump. I'm still looking for a basic assumption/formula to calculate the best flow... And neither am I good at physics nor math So any help here is muchly appreciated! I guess first I would need to know my rate of air-flow & air temperature for starters. It's rather obvious that a air-to-air intercooler is a much simpler thing... Though in my case it's harder to find a space up front for a decently sized (thick) intercooler. And neither am I going to cut up the bonnet for a top-mount IC But a long, tall and flat radiator I can probably fit much easyer across the front. So - against my first plan I'm most likely going for a chargecooler. Just my thoughts about all this... I may have repeated some stuff, I know. If I'm talking boIIocks, educate me, yes? Cheers, Jan |
| |
|
|
? (still with me)
