FMIC's

[wrinx]

No, 205x65mm.



Core
L=310
W=205
T=65

Overall (includes ends of pipes)
L=485
W=305

This is good....from http://www.halme.fi/Q4/mods.html



wrinx

[Evodelta]

Now we are clear, hallelujah - thankyou.

I'll put something together......

[Evodelta]

Intercooler theory and practice Part one

Abbreviations:

IC = Intercooler

Ambient = The temp of the air outside the car

Charge air = the air coming from the turbo to the engine

Tubes or tube length = This is the passageways that the charge air goes through.

AKA = As commonly known as...

CFM = Cubic feet per Minute (A measure of airflow)



I don't like imperial measurements, we (in the UK) have been Metric since 1971. BUT for the sake of simplicity here I am going to write in inches (") because it makes the numbers easier to digest for you.


Ok, let's start with the basics, the turbo on an engine compresses the air so more of it can be forced into the engine: More air (and petrol to match) = more power.

The main trade off is that compressing air also makes it hot, this is where the intercooler comes in - to cool the charge air. Cool air = more power AND reliability - hot air causes uncontrolled detonation with in the combustion chamber which in turn leads to major engine damage and failure. Colder air is more dense (It contains more oxygen) so it gives more power.

The intercooler must meet two criteria, the first we just covered, the second is where most people mess up; Tuners, 'cooler manufacturers, even car manufacturers: *It must be able to flow enough air for the engine to breathe properly*, get it too small and you will strangle the engine and lose you power.

Let's look at a 'cooler in detail, there are two types of core: Bar & plate and tube & fin, it refers to the way they are manufactured and the shape of the tubes, there are some minor advantages/disadvantages, but they are not really worth mentioning. B&P is slightly more desireable, but not worth fighting over.

Bar and plate detail:



Tube and fin detail:





Take a look at the zig zag fins, these are known as 'Turbulators' or fins, this is because they cause turbulance in the air. Basically the hot air hits and bounces over the turbulators as it goes through the tubes, when it does this it loses its heat, the fins then pass this heat (by convection) to the outside of the cooler, a similar process then happens - cooler ambient air passes through the fins and cools them.

It is all down to heat transfer. The next facts are very important:

Turbulators slow the air to take the heat from them, the longer the tubes, the more you slow down the air, (velocity) do we want the air to slow right down? Of course not!! Slow lazy air = bad throttle response, AKA: Turbolag. Loss of power, economy etc.

FACT:
In a good efficient core the majority of air cooling is done in the first few inches of tube.

The rest is just waste, yes it drops the temp a little bit more, but nothing worth shouting about and is more than offset by the fact that that the air has practically gone to sleep....

What is a good figure here? About 7 to 8 inches, 12 - 16 as a max.

7 - 8"? Really?

Yep.

So why do aftermarket manufacturers make 'double pass' intercoolers which make the air go through 48" of tube and a U bend?



To make money out of people who don't know anything about ICs. Take a look here: http://www.forgemotorsport.co.uk/con...duct=FMINTMK4F



They either don't know what they are doing or it is a blatant rip off, that's nearly ?1000!!!!

And it's crap!! Is the temp chart for real??

Are there any flow figures (CFM)? Pressure drop? MPG? Power? Nope, I wonder why....

So with what you now know, In the link provided here: http://shop.wiltec.info/index.php/ca...ftkuehler.html

You would go for No. 2 (better than No.1)

There is more, a lot more.....

Later I can explain this * earlier statement.

Anything anyone doesn't understand so far? Don't be shy, it's no problem to discuss if you don't.

[Brul(tm)]

Anything anyone doesn't understand so far? Don't be shy, it's no problem to discuss if you don't.

I can follow you, please continue. I find it very clarefying

Greetings,
Marc

[wrinx]

Interesting, thanks...so Sammi's custom IC in the pic above is a good design?

...and all these really wide and slim FMIC are a waste of money?

wrinx

[AJ]

Interesting post. What I would like to see, which is easier said than done - is a proper measured comparison of the standard cooler against others so that it's efficiency/inefficiency can be meausured.

[axaQ42]

If i understood right than this one:

Klik

...is a very efficient design?


But the main problem for me is installing such a tall IC on the Q4..if you put a custom taller one in the original place the airflow is catastrophical if you go FMIC then as you can see from Gery's installation, you need to customize the crossmember and there is still not much place(he uses a 23cm tal(N.6)l the N.2 from the link is 30cm....).

[Evodelta]

Interesting, thanks...so Sammi's custom IC in the pic above is a good design?

Correct, it's been made larger in all the right places (although I do not know the thickness, I am assuming same as or thicker than OE?) From dealing with Amworks in the past and seeing some of their cars I would say that they are a good company and do know what they are doing.

...and all these really wide and slim FMIC are a waste of money?

wrinx

Now you are getting your terms mixed up, you need to go wider, thicker and not longer....

[Evodelta]

Interesting post. What I would like to see, which is easier said than done - is a proper measured comparison of the standard cooler against others so that it's efficiency/inefficiency can be meausured.

Correct, later I will show some testing I did, sadly not on a Q4, but you will get the idea.

[Evodelta]

If i understood right than this one:

Klik

...is a very efficient design?


In theory, yes, more efficient - we'll get back to that exact cooler later on.

But the main problem for me is installing such a tall IC on the Q4..if you put a custom taller one in the original place the airflow is catastrophical if you go FMIC then as you can see from Gery's installation, you need to customize the crossmember and there is still not much place(he uses a 23cm tal(N.6)l the N.2 from the link is 30cm....).

I don't have a Q4 so it is difficult for me to say how to or what fits....
You guys will have to help there with pics and diagrams. Again, please refer to a 'coolers dimensions correctly: Length (of tube) and end section is width x thickness otherwise we will get lost.

[axaQ42]

This is what i was talking about:
http://forum.berlinasportivo.org/att...0&d=1210008194
http://forum.berlinasportivo.org/att...9&d=1212922008
http://forum.berlinasportivo.org/att...5&d=1214122354

And this is the 23 cm wide IC core(550x230) with cutted crossmember ....

I found this one look quite good for a Q4 becouse the in and out is on the same side
Click

[wrinx]

Now you are getting your terms mixed up, you need to go wider, thicker and not longer....

Yes....I meant length

wrinx

[wrinx]

I found this one look quite good for a Q4 becouse the in and out is on the same side
Click

Isn't that similar to one mentioned earlier, very bad design as it doesn't allow the air to flow through effectively?

wrinx

[axaQ42]

Nope...this is the wrong design


Which really enters and flows out on the same side...now look this one and i bet you will see the difference and what i mean in a moment

[wrinx]

Ok, I see the difference...

wrinx

[jimnielsen]

Thanks for your work on this, Evodelta - I appreciate it. looking forwards to chapter 2!

jimn~

[Evodelta]

Great stuff, now I can see you guys are begining to understand how to size a 'cooler properly. It's the number of tubes, not the length which matters.
To make a basic comparison, you have a guy who can run a marathon and you stick a drinking straw in his mouth, tell him to breathe through it and send him off, he gets 1/2 a mile before collapsing with exhaustion, why? Because he cannot get enough air to his lungs, so you pick him up, dust him off and give him a drink and a rest then stick a 3" pipe in his mouth and send him on his way again, he finishes the 5 mile marathon..... Your engine is just like the marathon runner.


Now for some basic maths, if you look inside a 'cooler:



You will see that roughly half is tube and half is blank, so only 50% of the total area will actually flow air. Lets take the Q4 cooler and compare it, thanks to Wrinks we know it measures 8 x 2.5", so a quick sum gives us 20sq" remember, only is half is tube so:

8 x 2.5 = 20 x .5 = 10sq"

An integrale 'cooler measures 8 x 3 (x .5) so = 12sq"

This:
http://cgi.ebay.co.uk/FRONT-MOUNT-IN...d=p3286.c0.m14

Is a pathetic 9"

And then we move onto this complete mess of an attempt, oh yes, the good old 3 x 12 x 24 double pass (oh my god):

http://cgi.ebay.co.uk/Large-TwinPass...d=p3286.c0.m14

The air has to travel a whopping 48" to get through it and it has a flow area of 9".
It flows less air than the OE Q4 cooler.
Jeez, I bet you could measure the turbo lag with an egg timer.

Glad you never bought one now eh Jim?

How do we know for certain we are on the right track? Where to look for good designs? Other newer cars of course, they don't always get it right, but here are a few good examples:







The last one is a VW, check out the well shaped end tanks, designed to give well balanced flow to all the tubes. Also note Subarus nice job, short tubes, compact and the idea of twin pipes to equalise the flow again. The Pug one is just good basic design, tapered end tanks, lots of tubes, a very bad 90' bend on the end pipe, but still, you get the idea.

So, an off-the-shelf good design? Let's look at this:



First of it's suspiciously cheap (it's Chinese), the end tanks are not really tapered enough and the tubes maybe, just maybe too short, but look at the flow capacity : 30sq" That's 3 times as much as the Q4 item! If you can make it fit, at $80 it's got to be worth a try....

This one:
http://shop.wiltec.info/product_info...3821fb5372eb41

Again looks a little cheap, take a look at the tubes inside, they seem a lot smaller than the bars, the inlet/outlets are a strange 80mm for some reason (75 is more common) and you may find pipes hard to match, this one:
http://cgi.ebay.co.uk/Medium-Interco...713.m153.l1262

Looks similar, but better built.

[wrinx]

Isn't the last one on the extremes of tube length at 18"?

wrinx

[wrinx]

This would flow approx. 50% more air and may fit the same space as the OE cooler....if my calcs are correct!

http://shop.wiltec.info/product_info...3821fb5372eb41

wrinx

[cuore_sportivo_155]

keep up the good work, can use this on my 2.4 jtd aswell....

[Evodelta]

This would flow approx. 50% more air and may fit the same space as the OE cooler....if my calcs are correct!

http://shop.wiltec.info/product_info...3821fb5372eb41

wrinx

Yes, I think that 18" is getting a little long, but still acceptable though - the tubes in a B&P design are bigger compared to T&F so we can go a bit longer and not lose out on flow. It's a bit of a balancing act, but yes, the one in your last link looks like a winner if you could fit it in.

[Evodelta]

I've had a few PMs in the last few days, I haven't answered 'cos I'm a bit busy, but will get round to it eventually....

[axaQ42]

This would flow approx. 50% more air and may fit the same space as the OE cooler....if my calcs are correct!

http://shop.wiltec.info/product_info...3821fb5372eb41

wrinx

I know is a long shot...how much BHP you think this IC can support??

[j1v]

http://picasaweb.google.com/jivco.sh...74812593358962

This is a cooler that fits quite easy without any major modifications and front bumper cutting. It is quite good and of course much better than the stock one.

005:core size 550*180*65 Overall size 700*180*65

http://topspeed.bg/product.php?iid=778

It can be easily found on ebay too.

Note: 270BGN is about 140 euros.

[j1v]

I must mention one thing, when talking about intercoolers - the airflow that goes to it to cool it.
Don't forget why they call the subi intercoolers interheaters

I totally agree that the OEM should be better than this

This:
http://cgi.ebay.co.uk/FRONT-MOUNT-IN...d=p3286.c0.m14

Is a pathetic 9"

But than again ... 9" against 10" of the OEM, but B&P design ... compared to the "pathetic" airflow the stock IC receives ... guess what, that IC cools a lot better.