2011 Lotus Elise: Installing Cup Airbox

I debated for a while if I was just going to do the snorkel delete like I had in the 2005 Elise, modify the OE airbox, or just go ahead and get the Lotus Cup airbox (P/N ALS3E0157) . I decided to go with the Cup airbox because it was relatively cheap and Lotus felt it was worthwhile for their cup car, so it should be good enough for me. It also provides more filter surface area so it theoretically should provide better airflow with less dirt. The Cup airbox kit I ordered from Sector111 consisted of the adapter plate, pre-filter part of the airbox, and OE filter. I also opted for the TRD air filter that fits the Cup airbox (P/N PTR05-06990-01).

Standard Disclaimer: ANY USE OF THIS INFORMATION BY YOU IS AT YOUR OWN RISK. I ASSUME NO LIABILITY FOR YOUR USE OF THE BELOW INFORMATION.

Installation:

First step is to get the rear driver side of the car up on a jack stand and remove the wheel so that the wheel well liner can be accessed. To remove the liner there are several plastic screw-rivets that will need to be removed- simply unscrew and pull the rivet out of the hole:

With the fender liner out of the way the snorkel can be removed, a few more plastic screw rivets holding it in place have to be removed:

The airbox can now be removed (or if you are having second thoughts you can at least replace the air filter and enjoy a bit more sound with no snorkel). The two clamps can be unclipped to release the airbox :

Unplug the electrical connectors at the airbox, push the release and pull out of the connector- it is tight getting in there to push the release and pull the plug at the same time but your persistence will pay off:

The vacuum line to the left can be removed and replaced with a vacuum cap, this line goes to the valve on the airbox piece that is replaced with the new Cup airbox piece which does not have this valve. The vacuum line on the right side can be removed for now, label it if you will not remember where it goes later. The two screws seen in the second picture below can be removed so that the valve control can also be removed, this makes it a little easier to remove the airbox section:

Loosen the airbox hose clamp at the throttle body:

The airbox can now be pulled out, you will need to unplug one more vacuum line that can be accessed with the airbox pulled out:

With that section of the airbox pulled out, the front section can be removed- three bolts hold it to the firewall mount. You can also see the valve that the vacuum line we capped off connected to in this picture:

A few choices for the adapter- 1) leave it as is (or use a gasket) and it may leak and I would imagine will be painful when it comes time to change the filter trying to line everything up while you clamp it together or 2) use silicone (I like E6000 adhesive) to "glue" the adapter to the post-filter airbox half and seal it up good. If going this route it is a good idea to clamp the entire assembly together and let the adhesive or silicone dry overnight before installing:

The bolt insulators will need to be removed from the old pre-air filter part of the airbox. This can be done by pushing the metal barrel out of the rubber piece, and then compressing the rubber to remove. Installation in the new airbox piece can be done by reversing these steps and can be done while the airbox is assembled/drying:

Airbox assembled, the metal plate is positioned over the tabs in the new pre-filter airbox piece and locked in place by sliding down into the tabs- it can then be clamped onto the post filter piece :

Now for the fun part- adjusting the metal firewall mount to work with the new Cup airbox. Start by unclamping the airbox pieces and then begin bending the right arm of the mount in until the airbox holes line up, you may also have to adjust the left two arms as well but that should be minor. Picture below is before the "adjustments" were made:

Installation is reverse of removal, be sure to reconnect the plugs and vacuum lines from where they were removed, after installation you should only have the old pre-filter airbox piece, old air filter, and the removed vacuum line left over. Enjoy the new sound: