Sizing up the ZZP S3TC Heat Exchanger

Got a nice but surprisingly light box delivered today, with the new front mounted heat exchanger.


This one will go below the front bumper, and I plan to use it in series with the OEM heat exchanger.

Here is a shot of my new intercooler cooling team together:

OEM Heat Exchanger and S3TC Front Mounted Heat Exchanger together

Sorry for the rapid image cropping, but I knew you’d want to see it sooner than if I took the time to fix it perfectly.

The new HX arrived with hoses and fittings, so the install should be getting the front clip off again, drilling two holes in the bumper to mount the new HX, putting back in the OEM HX, and then connecting hoses etc.

After the install we’ll get new IAT2 numbers over the test area, and see if I get the expected improvement, or we have some new factor at play here!

Tim C can be contacted at for inquiries on the Heat Exchanger, STS-V upper pulley, and new cold air intake.

2 thoughts on “Sizing up the ZZP S3TC Heat Exchanger

  1. Running these coolers in parallel instead of series should reduce system head (vs a series installation) and likely give better results. Have you considered this?

  2. I agree that plumbing the HX in parallel would reduce the system pressure head and increase flow. I agree increased flow is better all other things equal.

    The disadvantage might be in cooling, since the coolant would be exposed to less heat exchanger surface area — right now the coolant flows across the OEM HX and air flow and the S3 HX and air flow to be cooled; in parallel it would flow through one or the other.

    I have not tested the HX in parallel to see if there is a measurable advantage over the OEM HX alone. My sense of symmetry would be to use identical HX in parallel, but I suppose the flow will equalize in proportion to the resistance to flow of each HX regardless.

    I did consider extending to a 2-zone system: One side with Pump1 to Intercooler to a tank, then another side with Pump2 to HX to tank. Provision to ensure mixing of the coolant in tank. This would make each pump only have to overcome the head of 1/2 of the system. It would add complication of course.

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