Intercoolers

[markiii]

Not wanting to hijack Philsters Radiater thread.

but a thought ocurred to me.

any benefit/problems to running th a chargecooler and an air to air?

[philster_d]

Do you meen both intercooled and charge cooled ?

if so I believe the argument against this is lag and pressure drop in the system.

[markiii]

well lets say your intercooled to start with, like me.

a chargecooler should add no lag surely?

I can see that yoru right in teh reverse situation.

[philster_d]

Well then pressure drop through the system

I said lag because any more paths for the air means more delay in the response (almost sound like I know what im talking about, scary)

Philster.

[Tem]

What's the difference between intercooler and chargecooler anyway?  s:shock: :shock: s:shock:  


I know intercooler originally meant a cooler between two chargers, but I'm assuming you don't mean that...?

[kanujunkie]

thought intercooler was an air to air cooler and a chargecooler was air to liquid cooler, i.e. uses a charge

[philster_d]

Air to air ic is ineficient.

*edit* and prone to heat soak

[aaronjb]

thought intercooler was an air to air cooler and a chargecooler was air to liquid cooler, i.e. uses a charge

Technically "chargecooler" and "intercooler" could be used to mean either, but commonly by "intercooler" we mean air/air chargecooler and by "chargecooler" we mean air/water chargecooler.

Confused yet?  s:lol: :lol: s:lol:

Mark - a/w & a/a in one system would be overkill IMHO, a good a/a setup or a good a/w setup with the power levels you're running should be more than sufficient.  Adding a second cooler in will just add lag (because of extra pipework etc) & more of a pressure drop (so you'll push the compressor further and further toward the top edge of it's efficiency map just to maintain the same manifold pressure).

As Phil says, a/a tend to be more prone to heat soak, since they are (on our cars) sat right next to the engine - but once moving should perform just as well at these levels as an a/w chargecooler, IMHO, E&OE etc  s;) s;)

[Tem]

thought intercooler was an air to air cooler and a chargecooler was air to liquid cooler, i.e. uses a charge

Technically "chargecooler" and "intercooler" could be used to mean either, but commonly by "intercooler" we mean air/air chargecooler and by "chargecooler" we mean air/water chargecooler.

Thanks guys  s8) s8)

[Anonymous]

as said the main dissadvantage of a an air to air is heat soak, or if the unit is moved far enough away from the engine to compensate for this then you start to incur pressure loss due to the excessive piping between the blower and the engine.

another advantage of a charge cooler set up is that the water in the cooling system continues to be moved around the system when stationary, thus reducing the increase in air charge temps often found when sitting at the lights etc.

many high performance car owners wont race away from the lights due to this very situation, they will monitor their air charge temps closely when stationary as they can rise to within danger temps in a relatively short period of time on a very hot day.

[markiii]

thanks guys, just idle speculation at present, however

surely if a barrel chargecoler like on Bens was used where teh heat exchanger effectively is the intake pipe attached to teh throttle body, you would get no pressure drop?

As teh intake path would be no longer?

[Tem]

surely if a barrel chargecoler like on Bens was used where the heat exchanger effectively is the intake pipe attached to the throttle body, you would get no pressure drop?

I'm not sure what he has, but basically anything other than a large straight pipe will have a pressure drop. When it comes to coolers, some believe that a large resistance, which usually relates to pressure drop, is actually a good thing. The air is supposed to cool down there and the best way to do it, is to create some resistance, not a good flow.

If you just cooled the exterior of your pipes to 0C or below, the hot air within it wouldn't have much time to really cool down. 1.8l engine inhales over 200 liters of air every second at 7000rpm and +1bar. That's quite a pace.

I agree with the rest, there's really no reason for both, unless you want it for the show.

[aaronjb]

surely if a barrel chargecoler like on Bens was used where the heat exchanger effectively is the intake pipe attached to the throttle body, you would get no pressure drop?

Like Tem was saying - that barrel chargecooler, while looking like a bit of pipe on the outside, is actually filled with something much more like an intercooler (lots of fins & small passages to increase the surface area for thermal transfer)..

[philster_d]

thought intercooler was an air to air cooler and a chargecooler was air to liquid cooler, i.e. uses a charge

the air is the "charge"

[kanujunkie]

just found this nifty little pic

[mph]

Air to air ic is ineficient.

Incorrect, or at least, misleading. Given a particular airflow, an air-air will always be the most efficient. However the ability to achieve equivilent airflow for our setup between straight air and a liquid transport offsets the inefficiency.

Also note that the additional weight (and complexity) of a liquid based system must taken into account when calculating overall efficiency.


If I were doing it again, I might well opt for air-to-air supplemented with water injection.

[philster_d]

Air to air ic is ineficient.

Incorrect, or at least, misleading. an air-air will always be the most efficient.

""Air has a specific heat value of 1.01 (at a constant pressure), while the figure for water is 4.18. In other words, for each increase in temp by one degree, the same mass of water can absorb some four times more energy than air. ""

--------------------------
Heres another very useful charge cooler link to temper the first IC explanation.

http://autospeed.drive.com.au/cms/A_0090/article.html

[mph]

"Air has a specific heat value of 1.01 (at a constant pressure), while the figure for water is 4.18. In other words, for each increase in temp by one degree, the same mass of water can absorb some four times more energy than air. "

(Oh my, I'm feeling out of my depth again as per the post-turbo MAF thread!   s:oops: :oops: s:oops:  )

No argues from here there, but I'm not conceeding yet!

The reason is that while water has a high value, it's not water that's the concern - it's the extra layer of metal that I'm concerned with.

Copper (which is a pretty good metal) has a specific heat value (approx) 10 times less than water. Alu and mild steel have lower values still.

(The 0.10 value as an approx value of copper)


air (atmosphere) <- metal <- air (intake)
1.01 <- 0.10

vs.

air (atmosphere) <- metal <- water <- metal <- air (intake)
1.01 <- 0.10 <- 4.18 <- 0.10


As such, can the air/water solution be as efficient given the extra two transitions?

[Anonymous]

Heat Soak and Hi-speed
What happens in a A/W setup when the coolant temp meets or exceeds the compressor outlet temperature?

In an A/A setup one would never have to worry about it unless the sky was on fire  s:shock: :shock: s:shock:  
Now that my ignorance is evident...
  s:D s:D  
Everything I know about I/C is from books such as Max.Boost by Corky Bell and thats 10-yo tech but I think its still safe to say that an A/A is still simpler, more reliable, cheaper and works as well as if not better than A/W at high speed .An A/W has better efficiency at lower speeds and less pressure loss.

Because of its greater efficiency an A/W cooler may be required because an A/A large enough to do the job simply wont fit in the space allowed.

If an I/C is already 70% efficient and its core size is increased by 10% then the gain is 10% of the remaining 30% or just 3%.

The basic equation for efficiency is work done divided by work possible.
in the case of an I/C its:

COmpressor outlet temp (COT) minus I/C outlet (IOT) divided by Compressor outlet (COT) - Ambient (AT).

COT-IOT
-----------
COT-AT

Given compressor outlet = 250F , ambient =  75 and I/C outlet = 125 then

250-125
--------- = 71% = This what the HASS stage II A/A is rated at.
250-75

Thats all well and good but max efficiency only accurs at maximum flow.
When does that occur inan A/A? Not tootling around town or even ever given the rear engine low hanging position of the Hass I/C. The only way to insure max flow is to front-mount it but then the throttle response and pressure drop of an A/A would hurt drivability.

Im going to put an probe on the compressor Outlet and compare that to I/C out at various speeds and loads and perhaps, add a couple 1000CFM   s:shock: :shock: s:shock:  pull-thru fans on top of the I/C.

[mph]

Not wanting to hijack Philsters Radiater thread.

but a thought ocurred to me.

any benefit/problems to running th a chargecooler and an air to air?

Me thinks I've dragged this off topic from the original.   s:oops: :oops: s:oops:  

To answer the question, the efficiency gain by having both will likely be less than it's composite complexity, weight and pressure drop.


In summary, are we saying (for our application):

chargecooler benefits:
- will be 'better' under general driving
- less pressure drop
- allows shortest run from turbo to throttle

intercooler benefits:
- will be 'better' under motorway driving
- lighter
- simpler
- (usually) less restrictive
- (usually) cheaper

[Tem]

- less pressure drop

- (usually) less restrictive

Aren't these basically the same thing?  s:? :? s:?

[mph]

- less pressure drop
- (usually) less restrictive

Aren't these basically the same thing?  s:? :? s:?

Err, yes. Obviously not having a good day today.

That does remind me though - the stock PE kit didn't watercool the turbo housing. I presume Hass kits are, but just thought I'd raise it anyway.

[Anonymous]

Yes, the GT series turbos are cooled by engine coolant and HPT provided SS braided lines and banjo fittings for it.