Replace The Stock Cooling Fans With Dual 10"" Pullers on a Lotus Exige
Cooling issues for track driven Lotus cars are no secret to anyone. However, finding the right solution for your specific needs is not a simple cookie cutter exercise. The optimal solution is dependent upon the use of the car (% track vs road), AC required, native climate, etc..
Those needs aside there is one item in common with all Lotus Elise and Exige models. The stock cooling fans mangle the AC condenser fins restricting air flow over time. This is a widespread issue with the only solution being replacement of the fans and alternative mounting.
A great solution to all these problems is converting from the stock bottom mount 10" pusher fans to top mount puller fans. Whether you opt for dual 10" fans (AC requirement, primary road use), single 10" (somewhere in the middle) or single 8" (90+% track use) is up to you and your needs.
- (2) SPAL 10" Low Profile puller fans IX-30100435 (or equivalent) Summit Racing
- (2) SPAL Fan Mounting brackets IX-30130017 Summit Racing
- Derale Electric Fan Mounting Brackets 13001 Summit Racing
- 4 x M6x20mm bolts and 4x 6mm nylon lock nuts
- 2 x M5x16mm bolts and 2x 5mm nylon lock nuts
- 1/16" x 3/4" x 36" Aluminum angle stock (18" minimum length)
- (2) Weatherproof electrical butt connectors 16-14ga Amazon
Before starting please know there are 4 common methods to accomplishing this conversion.
- This guide, call it the DIY approach
- ProAlloy - Mount and fans in a kit
- EliseParts - Stainless steel mounts
- EliseShop - Anodized aluminum mounts
All four work well however the others all require full access to the radiator, which means draining and removing. This DIY method allows conversion while leaving the radiator installed and filled.
Remove the front clam
Remove the black plastic shroud above the radiator covering the brake master cylinder, A/C Dryer, and most of the A/C plumbing and electrical connections.
Remove OEM 10" pusher fans
Disconnect fan electrical connections
- Cut the zip-ties securing the electrical lines together and to the composite radiator surround barrier.
- Disconnect both electrical terminals
- Cut the fan electrical wires where they turn 90 degrees leaving at least 3" of wire on the wiring connector.
The wiring connectors will be reused and the 3" wire pigtail is needed. Set these aside for later instructions.
Each fan is secured by two bolts front and back to a metal bracket. The metal bracket can't be removed without complete disassemble of the AC condenser and radiator.
Use a wrench to remove the nuts shown (one front and back per fan) securing the bolts to the mounting bracket. There is a matching pair of nuts on the opposite side of the fans, remove those as well.
- Use a Dremel and cut-off wheel to shorten the exposed bolt as close as possible to the mounting bracket it is threaded through in the front. This will allow you revert back to stock fans, if that is not a concern the the bracket/tab can be cut along the top and removed.
- Pry the mounting bracket forward until the bolt slips through releasing the fan.
- Slide the fan toward the front of the car to disengage the rear mount
- Pull the fan wiring through the composite barrier and remove the fans completely.
Prep new fan wiring for Lotus wiring harness
The new SPAL fans do not have a compatible wiring connector to plug into the Lotus wiring harness. If you have the skills and tools you could either (1) replace the connector with a compatible one, or (2) replace the connector on both ends with a better Deutsch DT 2-pin. This guide will not cover those options as additional wiring tools are needed.
The following will outline how to modify the SPAL fans to work with the Lotus harness using basic wiring tools (cutter and crimp) and easy to find butt connectors.
Prep the new SPAL fans to work with the Lotus wiring harness
A. Use wire cutters to cut the black and blue wires to remove the SPAL wiring connector.
B. Using a Utility knife or box cutter remove 1" of the wiring jacket material on the SPAL fan wiring by the connector
C. Use wire strippers to remove 1/4" of the insulation on each wire.
D. User fingers to lightly twist the exposed copper to avoid frayed / damaged ends
The OEM Lotus wiring connectors removed in step 3 will be used and installed on the new SPAL fans. Gather the wiring connectors which from the prior step.
A. Use wire strippers to remove 1/4" of the insulation on each wire exposing the bare copper.
B. Use fingers to lightly twist the exposed copper to avoid frayed / damaged ends
C. Use butt connectors to join the OEM Lotus wiring terminals to the new SPAL fan wiring. Ensure black to black, blue to blue when connecting.
D. Use the Wire Crimper to crimp the butt connectors to each wire. This means two crimps per butt connector, one per end.
E. Use a Heat Gun to heat the butt connectors to the point of melting to provide a weather proof seal. Rotate the butt connectors while heating to keep an even heat distribution, stop heating once they no longer shrink or change shape.
The new SPAL fans are ready for install and to be plugged into the Lotus wiring harness!
Note: There are many ways to mount the fans and your choice will depend upon the materials, tools, and time you have available.
The methods outlined below worked the best for my situation; however you may opt for a different approach. The goals of the method below are to minimize shroud modification and ensure a secure mount for the fans.
Test fit fans to ensure fitment and determine mounting locations. If fans do not fit use a Dremel to methodically remove material until desired location is possible. Ensure you spin the fans with a screw driver to verify the fins never contact the shroud, radiator, or other material. DO NOT power the fan on to test clearance, use a screw driver.
Below is an example how my fans were modified to fit. Removed 1 rib from the top and slimmed down the side casing until it fit below the shroud.
Fabricate a mount for the top of the fans since the radiator cut outs toward the center prevent direct mounting.
1) Use a hacksaw to cut aluminum angle stock to 17.5" long and debur the cut edge.
See image below, the stock must extend past the left and right most mounting holes on the radiator, ensure 17.5" is enough for your radiator.
- Insert an IX-30130017 bracket (A) in each fan's bottom center slot.
- Test fitment of fans under the shroud.
- Remove the foam pads from the top of the shroud on both sides (B). A putty knife makes quick work peeling them off. Try not to destroy them as you'll have to reinstall or replace them. The clam rests on those foam pads and prevents rubbing between hard surfaces. 3M VHB double-sided tape works to secure them again or hold down alternative foam padding. Anything will work of similar thickness.
- Drill a 3/4" hole in the shroud roughly 3/4" in from the front left and bottom. The hole must be large enough to get the Derale universal fan mounts through. The goal is to create a access hole to allow installing the Derale mount through the hole in the fan bracket (A). If you have small hands you might be able to fish it through under the shroud without creating an access hole.
- Repeat for the other fan.
- Place fans on the radiator at desired location.
- Hold the angle stock in position on the radiator with your non-dominant hand or use a clamp
- Use a marker to mark the angle stock with the hole locations for the top two mounts on each fan
- Use a marker to mark the angle stock with the hole locations for two of the center holes on the radiator.
- Remove angle stock
- Use a 1/4" drill bit to drill the 4 holes where the fan mounts from step 3
- Use a 3/16" drill bit to drill the 2 center holes from step 4
- Use 4 x 6mm bolts and 4 x 6mm nylon lock nuts to secure the fans to the radiator and angle stock
- Use 2 x 5mm bolts and 2 x 5mm nylon lock nuts to secure the angle stock to the radiator from step 4.
The fans are now secured at the top of the radiator! Next up the bottom.
Install the Derale universal mounts in the bottom of the fan
- From the top down push the plastic mount "rod" through the hole drilled in the shroud down through the IX-30130017 bracket, through the radiator, and through the A/C condenser. Use needle nose pliers to help apply pressure without bending the plastic to get through the Radiator and AC condenser.
- Once feed through pull the rod all the way down until the plastic top ring in resting on the IX-30130017 bracket
- Remove the backing tape from one of the included foam pads and thread onto the rod sticky side up.
- Install the included plastic disc pushing it and the foam pad tightly against the A/C condenser.
- Trim the plastic rod below the plastic disc with wire cutters.
- The plastic rod is small enough it will fit between the fins in the radiator without damaging them. Just line it up and apply even pressure to push it through.
- The foam pad prevents the plastic locking disc from damaging the AC condenser fins, do not forget to install it!
Clean up and test.
- Test spin the fans with a screwdriver one last time to ensure they are not hitting anything.
- Clean area around the holes placed in the shroud with denatured alcohol or brake cleaner. Cover holes using a heavy duty duct tape or equivalent. Reinstall the foam pads removed or replace with new.
- Doublecheck nothing was dropped into the fans or the area around them.
- Start car and let it run either waiting for it to warm up or turn on the AC to get fans to kick in to ensure they are working and not hitting anything at operating speed.
- Tidy up the wiring with zip ties as needed.
- Reinstall the top shroud removed in step 2 above the radiator.
Congratulations you now have a much more efficient cooling system that will not damage the AC condenser.
Now reinstall the front clam.