Project Viper Part 5 Rad Fan CoverProject Viper GTS: Part 5 – Radiator Fan & Wiring Upgrade

by Billy Johnson

The Viper is a “racecar for the street” in more ways than one; and like a racecar, it does not like to sit in stop and go traffic and can run hot and overheat without proper airflow on a hot summer day. To combat this we upgraded the radiator fan on our 1997 Viper GTS with the higher flowing, larger fan from the 1998-2002 cars. In addition, we safeguarded the potentially flawed wiring and relay box by running standalone relays with dedicated power and ground wires.  To further extend the life of the relays we used a trick pair of “NOsparc®” spark supressors in the harness.

It is apparent the factory Gen 1 and Gen 2 radiator fan was not up to the task of cooling the Viper’s V10 engine on a hot summer day due to the redesign and increase in diameter 1998.  We turned to the Viper experts at ROE RACING to upgrade the fan in our 1997 GTS with the more powerful 1998-2002 fan.  We also picked up a 60 Amp circuit breaker, 50 Amp relays and NOsparc® Arc Suppressors to prevent melting the factory relay box.


Viper Radiator Fan NoSparc Circuit breakersThe 1998-2002 OEM fan is a direct fit for 1992-2002 Gen 1 & 2 Vipers.  While the electrical connection is plug and play for 1996-1997 cars, 1992-93 RT/10s require modifying the wire in the high and low speed settings for the fan and 1994-95 cars require reusing the original fan plug. Sitting next to the fan are the NOsparc arc suppressors, 60 Amp circuit breaker, 50 Amp TE relays and relay harnesses that we are going to mount to the fan for a standalone wiring harness.

It’s not hard to believe that Vipers run hot since they have one of the largest engines ever fitted in a production sportscar.  Despite a very small grille opening, they typically don’t have a cooling problem when on track where speeds are rarely below 45mph.  On the other hand, stop and go traffic can be a killer since it’s solely up to the radiator fan and shroud to provide enough airflow through the radiator to cool the car’s engine while stopped.


Front GrillWith only 119 square inches of front grille opening in Gen 1 & 2 Vipers to feed the oil cooler, A/C condenser, a 400 sq. in radiator, and power steering cooler; there is a relatively small inlet to cool the large 8.0L V10 engine. By contrast, Project E90 M3 has 220 sq. in of inlet area to cool an engine half the size of the Viper.
Stock Viper Fan Pre 1999 MountedAfter removing the airbox, we have access to the radiator fan and unplug it from the car harness.
Fan BoltsThe original fan is held on by six 10mm bolts which are easily removed.
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Monday, September 14, 2015 8:27 PM
Nice work! Your solder joints are way cleaner than I can do too. Pretty fascinating about the evolution of design of the fan shrouds.
Monday, September 14, 2015 9:34 PM
Great article. Love the detail. Reminds me of the Sport Compact Car days. It's always good to see the intricacies. Just to know the details behind decisions made and the potential outcomes of those decisions. Love the 2nd Gen Viper, too. TCan't wait to read the next installment. Thank you.
Tuesday, September 15, 2015 10:10 AM
spdracerrut - the right tools and process is key. Use flux if you aren't doing so already. The quality of the soldering iron makes a huge difference.

A $90 Weller soldering station with adjustable temp is going to be a lot better than a cheap $20 stick iron. Also, once the solder is set, give it a quick 'tap' on the ground to shed excess solder.
Wednesday, September 16, 2015 4:57 PM
You know, there might be a lot more benefit to installing KW coilovers, but I'd much rather see more of these articles and less KW installs. Every platform has a different suspension install procedure, but good ideas and well though out processes like this are much harder to find on forums or other websites and much more applicable to other cars. My Miata is far from a Viper, but I can apply a lot more of this to my car than much of what has been coming out here lately.

I agree with CCClassic, very SCC like. I'd love to see more stuff like this, the seat install in StarletBusa, and the S2000 mods. Great ideas and thinking outside the box that we can all use and be inspired by.
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