Last Updated
12 November, 2004

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Engine Bay Fans

  This was similar to my initial fan project, for wiring up a SPAL fan to my GReddy intercooler. This time, I had a couple of extra fans for the engine lid, plus the temperature control would come from the TEC ECU.

Another change is the reversal of the circuit to a pull-to-ground configuration. This was required due to the nature of the ECU's General Purpose Outputs (GPOs). It simply means the switching opens and closes the ground leg, rather than the 12V+ leg.


  • 30/40 amp automotive-type relay (Midtex V421B3D2 or similar)
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    This relay includes the diode that I hand-wired in my original project. All Electronics.

  • Relay socket (Custom Connector BR05-FW or similar)
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    I bought these due to their modular design multiple sockets can be locked together. Relay Specialties carries them. If you choose these, you'll also need to get the female spade connectors with locking tabs that fit inside the individual sockets:
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    I found these AMP-Tyco connectors that Custom Connector recommends at Allied Electronics. I bought two sizes,  60249-1 (12-16 AWG) and 42281-1 (14-18 AWG).

  • DPDT rocker switch (Eaton Euro SR #8006K40N1V2 or similar)
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    These switches fit perfectly in the cutouts for the MKII dashboard, and they look more "stock" than the OEM fog light switch.

  • Tripac 7.5" puller fan. (or similar).
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    I chose the Tripac over the SPAL for its curved blades, which have a slightly higher CFM rating, yet are quieter. The Tripac has the same mounting hole locations, so it fit perfectly on my IC shroud. This fan draws about 5 Amps maximum.

    Unfortunately, this is am OEM fan, so none of the small number of Tripac retailers can get it. After a couple of requests directly to Tripac, they offered to sell me one directly. Cost is about the same as a SPAL fan.

  • Tripac 11" pusher fans, mounted in the VMax carbon fiber engine liner. These draw about 9 Amps each.
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    I don't think Tyson Teeter (VMax Performance) sells these engine lid liners anymore, but I heard rumors that someone else was considering making the liner without the fans for a pretty good price. Check the MR2 Message Board for info.

  • I'm also using the fuse box from my initial fan project.
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    This will provide a central source for any additional electrical accessories I add, without adding a lot of inline fuse splices. More information available here.

  • Plus assorted wire, fuses, electrical connectors, and other small electrical circuit parts.

Doing It

I took the time to modify the Visio circuit diagrams I used on the previous project.

  To be continued....  

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