[s-cars] Re: Air to Water intercoolers

[Lewis, Gary M]

This is all REALLY fascinating!!!!  I'm glad I brought this up...

I think my point was that I believed that the Air to Liquid IC solution offered not necessarily more performance, but more accurate measurements of performance parameters, as the max air temps you would see at the A/to/L IC were lower max on the high end of the temp range than the A/to/A IC.  I.e., I'm at Willow Springs with the POC (Porsche Owners Club, stay with the 911sc and lower group, nice guys) in August with temps in the 105 degree F range.  Easier to tune the car using an air to liquid IC, as the max high air outlet temps SHOULD be lower than with an air to air IC, including heatsoak.  That is why I think many production manufacturers are using them.  They are more idiot proof, software wise.  If the bonehead customer puts in 87 octane, well, the safetys will be easier to predict when the max air intake temps are more or less known.

I'm ignoring the a/c application, seems like too much compromise.  When a more efficient a.c system comes out it might be worth revisiting (in 10 years??).

What we all want is more air density at any given PSI, right?  I saw a 2.2L AAN on a dyno pumping out 450hp at 22 psi, but the turbo was HUGE.  Lag was near 5,000 rpm.  Huge hp numbers, but not street friendly.  So my goal is density at the lowest rpm possible (goal is below 3,200 rpm).  My car is 99% street, 1% track.  I'm testing a # 6 hotside now, will be testing a # 8 in the next month or so.  Hoping a # 8 with a larger coldside compressor (all still K26, but a custom compressor coldside housing with larger intake) will provide more density without a significant (above 3,200) rpm penalty.

I don't think air to liquid IC's are the ultimate turbo/supercharger road track car intercooler device.  Weight and space concerns abound.  But for a street car that you might want to track occasionally, I thought it was worth a look.  And I concluded once again (and every time I look elsewhere) that water injection is the way to go.  Solves the air to air IC temp fluctuation and heat soak problems, solves octance problems, has a low weight penalty, provides a measure of safety, etc.

Gary Lewis

1995.5 S6 Avant, Green/Ecru, RS2 MAF, RS2 Exhaust Manifold, RS2 Injectors, Custom Turbo (K26-6 Turbine, Factory K26 Cold side (Audi Works '999' P/N) with 50mm intake and custom Innovative Turbo compressor wheel), Bilsteins, Eibachs, Big Reds.

1990 200TQW, K24 Turbo, 1991 TQ Intercooler, 1.8 bar, Bypass Valve, Euro's, Bilsteins, Redline in tranny and diffs, FOR SALE




-----Original Message-----
From: mlp qwest [mailto:mlped at qwest.net]
Sent: Wednesday, September 17, 2003 4:37 AM
To: s-car-list at audifans.com
Subject: FW: [s-cars] Re: Air to Water intercoolers


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It could be.  But if you wanted to beat the horse a bit further, I don't
recall where the attached xls spreadsheet came from (heck, it might have
come from the Laminova site),  you could play with the spreadsheet authors
"suggested" intercooler values for an air to air system, where he suggests
the mediums Heat transfer Coefficient be set to 60 & .Specific Heat of
coolant to 24 for air to air vs. an air to water systems suggested values of
100 and 1.0   ~>

Estimated bhp and torque results for a 2.2 liter engine running @ 22 psi @
6000 rpm on a 70 F day come out:

                 Air                Water            diff
bhp         354 bhp           388 bhp          34
torque     310 ft/lbs          340 ft/lbs        30

IF you keep the "mass flow rate of the coolant" and all the other dimensions
of the intercooler, tube lengths etc. at constant values, say 100 lb/min,
for both systems.  I doubt that's a fair way to assess the difference
between the two systems since a lot of those parameters would obviously
change.

HTH  :-)
mike

  -----Original Message-----
  From: Mark Strangways [mailto:strangconst at rogers.com]


  Is the horse beaten to death yet ?

  Not literally !!! ( For those animal rights activists on the list) :-)

  Mark (done with this thread) S
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