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IAT2 proper ducting, spray, fan

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Although we were not able to track down the actual appropriate type of pushpin from Cadillac, I was able to buy a variety of pushpins from various auto supply stores and find a set that have the offending radiator deflector pinned once again against the bottom of the radiator and intercooler heat exchanger.  So now all air flow through the front grills is directed to cooling.

Next I ran up and down the highway to see what impact this had on my IAT2 temps.  It is a warmer day, and the STS-V is heat soaked.  Here is a representative snap for today:

Ambient is around 82F, Intake air IAT1 86F, which is good, and IAT2 is hovering at 120F steady state.  This is the expected +30F or so from IAT1 to IAT2 that I would like to reduce.

Today’s trial of ensuring the ducting gaps around the front mounted heat exchanger (FMHE) for the intercooler are closed showed little impact on IAT2.  I am glad that I have this fixed but I didn’t see a major change in IAT2.

During the drive I did try running the STS-V in 4th or 3rd to raise the revs, which caused an increase in IAT2 as more air flowed through the supercharger.  When I went back to 6th the IAT2 returned to status quo.

For the next trial, after 23 minutes into the test drive, I stopped and let the car idle while I sprayed cool water over the front mounted heat exchanger.

I then drove at 20-45 mph and monitored the impact on IAT2.  This had no or limited effect on IAT2.

After 35 minutes into the test drive I stopped again and used a leaf blower to direct air into the front mounted heat exchanger to simulate a fan on the heat exchanger.  IAT1 rose to 147F at idle, due to the lack of cooling air flow into the system, and IAT2 stayed at 135F.  I conclude that this had limited effect on IAT2.

Intuitively, both a water spray on the heat exchanger and a fan on the heat exchanger should have led to more efficient cooling, and thus lower IAT2s.  There appear to be factors I am not accounting for in my experiment.  I am not measuring the water temperature in the FMHE itself, but rather the resulting IAT2 which is the temperature in the manifold downstream of the supercharger and intercooler.   If the heat load from the intercooler is beyond the capacity of the FMHE, even with help such as the spray or fanned air, it would continue to overwhelm the FMHE and maintain high IAT2 regardless of adders or not?  Thus the conclusion that most modders reach is to supplement the FMHE with a 2nd FMHE and / or replacement for the OEM FMHE.

Quest for Intercooler heat exchanger air flow

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I’ve been thinking about how to make my intercooler heat exchanger more effective before I add more parts.

The intercooler heat exchanger on the 2008 Cadillac STS-V is a small radiator in front of a line of other coolers and the main radiator – item 29 below.

STS-V LC3 Intercooler Flow path & Parts

Air flow paths are key to the performance of any radiator type cooling system. In this case the heat exchanger is facing cool air.

I intended to study the ducting to see what minor improvements could be made — such as sealing air flow to the bottom of the heat exchanger.  However, I was surprised to find that although Cadillac engineered exactly for this item, the plan for my STS-V is not working at the moment.

The way it is supposed to work is that there is a plastic belly pan below the nose of the car, running below the intercooler heat exchanger.  On top of the plastic belly pan is a long rectangular piece of foam that will nicely seal the air flow under the heat exchanger but still allow the water hoses to and from it to pass through.  However, on my STS-V the belly pan is sagging in the middle, and the foam is no longer sealing the lower part of the heat exchanger but rather allowing 2-3 inches of gap for air to flow through.  Since air will always take the path of least resistance, every bit that can is sliding under the car and away instead of cooling my intercooler.

Cadillac STS-V radiator air deflector

My belly pan (item 9) is missing any fasteners #8, which appear to be 14093088 although not shown in this diagram  — so that item 7, the foam bar, fills the gap there.

25802477 DEFLECTOR. Radiator Air
DEFLECTOR,FRT AIR. Required: 01For: DX (2006-2009) (2008 – 2009).

15248340 SEAL. Radiator Support Mounting
SEAL,RAD AIR LWR. Required: 01For: D29 (2005-2011) (2008 – 2009).

14093088 RETAINER; RETAINER FRONT. RETAINER. Front Fender Inner Wheel House. Air Cleaner Intake. Bumper/Fascia. Bumper/Fascia Energy Absorber. Capsule/Headlamp Washer/Wiper. Chassis/Engine Wiring Harness. Cowl Top Vent Louver. Engine Coolant Recovery. Folding Top Compartment. Front and Rear Bumper/Fascia Face. Front Compartment Pan. RETAINER FRT. Grooved. License Plate. Main Wiring Junction and Fuse Block. Mobile Telephone Radio. Radiator Air. Radiator Baffle and Shroud. Radiator Fan Shroud. Radiator Grille and Front End Panel. Rocker Panel Molding. Roof Headlining.

So tomorrow I will check with Pep Boys and Crest and see if I can get 2 retainers and put my intercooler heat exchanger back in the air flow.

Cadillac CTS-V Wins About.com Best Performance Car Award 2012

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NEW YORK — The Cadillac CTS-V is the winner of About.com’s 2012 Readers’ Choice Award for Best Performance Car.

Now in its fifth year, the About.com Readers’ Choice Awards honor the best products, features and services across more than a dozen categories, ranging from technology to hobbies to parenting and more, as selected by its readers.

“This year’s Readers’ Choice Awards program had a record number of nominations submitted across dozens of categories and featured hundreds of finalists,” said Margot Weiss, managing editor, About.com. “We are thankful to all our readers for their participation and congratulate Cadillac on their success.”

Cadillac CTS-V was selected by About.com readers over other finalists including the Ford Mustang Boss 302, Chevrolet Corvette, BMW M3 and Lotus Evora.

The family of CTS V-Series performance models includes a sedan, coupe and wagon – all powered by a supercharged 6.2L V-8 that delivers 556 horsepower (415 kW) and is backed by either a six-speed manual transmission or a six-speed automatic. A collection of technical and performance elements complement the powertrain, including Magnetic Ride Control, Brembo brakes and Michelin Pilot Sport PS2 performance tires mounted on 19-inch forged aluminum wheels.

“It’s no surprise to me that readers chose the CTS-V — its blend of outlandish power, precise handling, and breathtaking styling, especially in coupe form, make it one of the best performance cars in General Motors history,” said Aaron Gold, Guide to Cars, About.com.