Blog Post: @Cadillac STS-V Supercharger & Intercooler Ideas #Motorama

[Bruce Nunnally]

The Cadillac STS-V (2006-2009) featured the 4.4L DOHC VVT LC3 V8 with a custom Eaton M122 Supercharger and integrated intercooler. This photo shows the Cadillac LC3 engine without the ‘beauty cover’, looking from the rear of the engine — so the front of the Cadillac would be right and away. Air flows in the black [...]

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[Cadillac Jim]

The last paragraph of the blog post, poses a question about the cross-pieces in the air flow slots in the tubes that hold the Laminova heat-exchanger tubes. The cross-pieces are stiffeners. Without them the tubes, and the Laminova heat-exchager tubes, will be much more susceptible to vibration, and to lower-frequency vibration. I would look at widening the slots, but not removing the cross-pieces.

The higher air pump volume and larger open-air portion are good ideas. You can get more cooling by spraying water on the outside cooler to reduce the temperature of the air going through it to the dew point. You can add an A/C evaporator in front of it, or integrate one with it for direct exchange of intercooler air with evaporating Freon. You can add a holder for ice, or dry ice. It all depends on what you want to do, and for how long. It might be argued that full maximum power is never needed outside a race track for more than 15-20 seconds at a time, and only for a small percentage of the time. At Nuremburg or in an Autobahn duel, you might want something more constant like the A/C evaporator siamesed to the heat exchanger.

[Bruce Nunnally]

My goal would be to have something that works all the time as opposed to just optimized for a short period.

Based on my limited study, most people start with a larger front-mounted heat exchanger (outside cooler), which also holds more coolant than the stock system (stock capacity 2.6 quarts).

D3 recommends an outside cooler with an independent fan. D3 also engineered a large reservoir to simply expand the amount of coolant in the system.

Reservoir alone

Reservoir and front-mounted heat exchanger with fan

D3 STS-V Intercooler mods priced $595 for the heat exchanger and $695 for the reservoir.

Next, the intercooler coolant circulating pump is either supplemented or replaced with a larger flow model.

The Perma-Cool 12318 or Flex-a-lite 45321 (without fan) or Flex-a-lite 45265 (with fan) have been tried or utilized.

6-pass Perma-cool 12318 on Amazon

10 1/2 in. x 21 in. x 4 in. Cooler, 10 in. Fan, 3/8 in. NPT Female

4-pass Flex-a-lite 45321

10 1/2"x21"x1 1/2"

[Cadillac Jim]

I'll agree that a typical daily driver will not want to deal with replenishment.

These seem very prices compared to similar offerings from the same manufacturers for similar products for oil, transmission or power steering fluid, or fuel cooling.

How about hard data on before and after times and speeds? Do they have any data?

[Bruce Nunnally]

D3 says in their experience the stock intercooler becomes heat soaked (overloaded) after a single dyno run causing a reduction of 30 hp. With their setup -- extra fluid capacity and larger heat exchanger they were able to minimize this delta, to around 6 hp.