Category Archives: Intercooler

Updated intercooler hoses, retest hot S3TC heat exchanger

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This morning I took the front clip off my STS-V once again to replace the intercooler heat exchanger hoses with Spectre braided stainless sheathed hoses and then retest.

I did a first shake-down test run, then let the car sit and heat soak, then did another 20 min test capture.


The chart shows intake air temperature 2 (IAT2) after the supercharger over time during a 20 min test drive. The spikes on the chart are acceleration runs.
Today’s weather is overcast, with 72F air temperatures, similar to the historical data file for the OEM capture. What this suggests is that the S3TC heat exchanger in series with the OEM heat exchanger acts to lower IAT2s around 10F.  The end of the test was curtailed due to a traffic stackup; I stopped scanning and capturing data to save time on conversion.

Because today’s temps are similar to the historical air temps, I compared today’s run to the historical data without modification.

Overall the new S3TC Heat Exchanger results continue to be good.  The Spectre hoses are on and do appear to have better success at avoiding kinks or crimps than the rubber heater hoses did.

Here is a zoom-in on the acceleration run today, showing the trend for IAT2 vs RPM and Speed.


In this graph we see initially there is actually a decrease in IAT2, as the throttle opens, all the flow goes through Supercharger as opposed to the bypass, and the intercooler is at max cooling. As the supercharger continues to dump heat into the system, the manifold heats up more than the intercooler cooling system can sustain.

Spectre stainless steel sheathed intercooler hoses

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One of the great things about OEM heater systems is that they have hoses exactly bent and shaped the way needed, so that the hose is perfectly formed for the job.  Good advice for aftermarket installations like my intercooler cooling mods is to measure out exactly what type of hose you need, then go look at the big books of existing OEM hoses at an auto parts store and find the one snowflake that is similar to your needs.

Another option is the Spectre stainless steel sheathed heater hose, 39798, which is designed to allow a variety of hose turns without kinking or crimping.

Spectre hoses in their packaging

The hoses I need are 3/4″ inner diameter. These Spectre hoses are rubber hoses with a stainless steel braided sheath around the rubber.  For Spectre 39798 the hoses are 4 ft (48 inches) long.
Here is a shot out of the packaging:

Vanity shot of the hose out of the packaging

The sheathing helps prevent hose crimping. After playing with one of the hoses in various bends I would say it is helpful in resisting but does not eliminate crimping. So I will still need to ensure that the hose routing helps as much as possible to avoid crimping the hoses.

AVS 1 gal inline tank for the Cadillac STS-V intercooler loop

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Got the AVS tank I ordered in the post today.  Very interesting.  Previous mention:  Cadillac STS-V inline flow-through intercooler tank

AVS tank in the box

I ordered this as a possible inline tank addition to my Cadillac STS-V intercooler coolant loop. Additional coolant would act as a buffer to temperature changes (both up and down). The stock system has 2.6 quarts. My system has the S3TC heat exchanger added, which holds 2 quarts, so it is running 4.6 quarts. The new tank would add 4 quarts, for 8.6 quarts total.

The tank has a drain at the bottom, 1/2″ NPT fittings that handily I have 1/2″ NPT to 3/4 inch hose barbs from my 45321 experiment to fit, and a 1/4″ NPT fitting for a gauge which I will either stick a stopper in or a temp gauge.

1/2" NPT to hose barb attachment added

I will have to decide whether to add the tank during in this weekend’s big install adjustments session, or wait and test with the new Spectre hoses in place first so I have a clean baseline, then redo the circuit with the tank in place. Notionally with the angle brackets on the bottom, this tank would just sit directly on top of the S3TC.  Choices are good.

Update:

This temperature gauge, with 1/2″ NPT fitting, 2″ probe length, and 0-220F temperature scale could work and hopefully be visible through the grill on close examination.  Hmm.