RE: Retrofitting an intercooler into an UrQ

["David G. Lawson" <dbldmnd@compuserve.com>]

>> Perhaps we need another fizzicks lesson here Martin ... excuse me, I
>> mean engineering fluid dynamics.  The intercooler on my car is mounted
>> fairly close to the lower grille ... I'd imagine the pressure there
>> would be pretty much the same as that at the grille above the bumper.
>> The area behind the intercooler is fairly open ... at least there isn't
>> an engine sitting right behind it!  If there is a problem it is the hose
>> from the turbo outlet that runs across the back surface of the IC ...

>The opening in the lower grill is not very big.  The size of the IC 
>itself is not so great and all that piping doesn't help either.
>If that location is so good why didn't the rally team use it?
>The rally cars had a hudge IC right in the grill.
>For that kind of money don't you think they should have come up with 
>a better design.  And how cheap do you have to be to run a second 
>radiator instead of increasing the size of the single unit.  Tilt it 
>sideways like in rally cars if you have to.  It looked like cost was 
>not an object for $35,000 back in mid eighties.

A few observations... I agree that the stock ur-q IC isn't very large, it
measures 11.75x5.5x3 and is a single pass design. The IC in my 200 TQW
measures 13x7x3.5 and is a 2 pass design. The length of the plumbing isn't
the primary issue, the thing to look for is the number and radius of bends
in the plumbing. The ur-q comes out of the turbo(small bend), into IC(say
180), out of IC(90), 
and straight up with a couple of 45s. The 200 does a 180 at the turbo
outlet, 90 going into the IC, 90 to now go across the lower section, 180 to
turn it around, and a 90 at the IC outlet. Add um up and I get 360 for thr
ur-q and 630 for the 200.
The 5kT and 200 do have good IC placement but I think the ur-q is pretty
good and not as bad as you may think. Now for the rally car IC placement, I
don't think below bumper level is the correct place for this on a rally car
and you need to look closer to the way the plumbing on the 10VT was
configured on the A1/A2 cars. I was lucky enough to hold an A2 EM in my
hand a few weeks ago and it is a piece of art. And if you look close to the
under car photos, it can be seen that the wastegate is mounted at the front
of the engine and upside down(relative to the stock orientation). The A2
cars also had the throttle body mounted at the back of the engine. So if
you trace out the A2 intake path a 90 into the IC, 90 out of IC, long tubes
which have a gentle arc to the TB at the rear of the engine. Very few bends
and it trys to use very large radius bends at that. A very efficient
layout. 
 
>> Perhaps you can give us the benefit of your studies into the efficiency
>> of the IC mounting position ... I would certainly appreciate the chance
>> to read it!

>If it's good enough of a spot for the rally teams than it's good 
>enough for me.  Just think about it.

There is more to the IC effectiveness than location. 

-
Dave Lawson