My Lotus Elise ForcedFed Header Installation (Bill Henderson, 01-06-07)



*   Standard Disclaimer: The following is my experience provided for informational purposes only, any use of this information by other parties to conduct installation is at their own risk, no warranty/guarantee that information is accurate is expressed or implied.





Tools Used:




Time: 4-5 hours dependent on skill level







Steps prior to ramps: There are a few things I did prior to getting the car on the ramps. First I jacked up the car on the passenger side and removed the rear wheel and wheel liner (5 plastic screws); this provided access to the air injection tube. Using needle nose pliers I removed the clamp for the cap on the end, and then pulled the rubber hose off:



Next, I removed the bolt holding the tube to the motor using a ratchet and a swivel extension:



The wheel and wheel liner were reinstalled and the jack was moved to the driver side and that wheel was removed for access to the post cat O2 sensor. The O2 sensor was removed and left hanging:



The trunk was opened and I removed the upper exhaust manifold heat shield bolts (2) on top:



Steps after the car is on ramps: The car was then backed on to a set of Rhino Ramps for lower access. The diffuser panel was removed (3 bolts on each side, 5 bolts under the license plate, 2 large bolts towards the front of the car, and 5 small bolts where the diffuser joins the other lower plate:




After the diffuser was removed the exhaust clamp was loosened, and the passenger side exhaust mount hanger bolts were removed so that the exhaust could be removed:




The driver side exhaust hanger bolts were loosened a little (but not removed) and the exhaust was carefully dropped under the car to the ground and moved to the side:



The next item to be removed was the pre-cat O2 sensor, once removed it was left hanging:



The catalytic converter can now be removed by removing the 2 spring tension bolts that hold it to the exhaust manifold (the riveted heat shield was not removed for use with the new header). The upper heat shield lower bolts (2) were also removed as seen in first picture below:



The lower engine/transmission mount heat shield is now accessible, 2 bolts hold it to the frame:



The lower exhaust manifold mount can be removed, one bolt on the manifold and two bolts on the engine block:



The upper exhaust manifold heat shield is removed, kind of like a puzzle - be patient, it will come out in the right position without bending or cutting:



Next, the lower exhaust manifold heat shield bolts (4) and heat shield were removed. This one was a little tougher than the upper heat shield as there was not a lot of room to maneuver but as above, treat it like a puzzle and be patient, it will come out:



Only thing remaining is the exhaust manifold bolts/nuts: Two Torx head studs with nuts on either top side, one bolt top middle, and two lower bolts. Using a combination of ratchets, socket handles, and bars all of these can be removed. By first loosening the nuts on the Torx head studs, the tension is removed and then the Torx socket/ratchet can be used to remove the studs. This is necessary to provide clearance to remove the exhaust manifold with the air injection pipe intact. NOTE: The Torx socket used is a size E8:




The exhaust manifold is removed from the bottom of the car, it may take a few tries to get it in the right position to work the air injection pipe out between the tensioner and engine but it is possible. Compared to the new header, the welds in the collector are noticeably cleaner and the pipe size is larger:



The Torx head studs are reinstalled:


The old exhaust manifold gasket was removed and a new one installed. This gasket is a crush gasket and it is good insurance to replace now, it only cost $20 at the Toyota Dealer, P/N 17173-88601. This gasket was reinstalled the same way the original was, with the arrow in the center pointing towards the passenger side:



The header can now be installed, there is even less room to work than there was before. The top nuts and bolts can be accessed with a torque wrench (spec is 37 ft-lbs); the bottom could not so I tightened those by feel with a small ratchet. The exhaust manifold heat shields are NOT reinstalled:



The test-pipe or high flow cat is attached to the header with three springs, I found it easiest to hook 2 springs while the pipe was at a 90 degree angle to the header and then to stretch the pipe into place, this only left one spring to wrestle with pliers to get in place. The post-cat U-pipe was installed with supplied clamp and the O2 sensors were reinstalled as well. I used the GPMoto CEL fix which extends the post-cat O2 sensor away from exhaust flow to prevent the Check-Engine Light (CEL) from coming on due to a test pipe or high flow cat install (see note UPDATE at end of article for this CEL fix issue):



The exhaust reinstalled (exhaust clamp and hanger bolts/hardware) along with the lower transmission/engine mount heat shield:



I test fit the diffuser and used a rubber mallet to position the exhaust within the diffuser cutout before tightening the clamps. After making sure the clamps were tight and everything lined up, the diffuser was reinstalled and the car was left to idle for 15 minutes to give the ECU a chance to adjust to the new header.


Time for a drive to see if all the work paid off (may not want to be too hard on the car for some miles as it may run a little lean until the ECU has some time to adjust the fuel maps)..


[UPDATE] The GP Moto CEL fix did not work (error "P0420- Catalyst System Efficiency Below Threshold" every 50 miles) but I have found a few options:


1)    I have found another mechanical CEL fix (different design) that has worked for the past 300 miles and no CEL, available on eBay from seller strutking. It is a much lower cost option than the first one I tried and works much better. I did have to drill some for additional depth but communicated this to the seller and he has told me that in the future he will make them a little deeper (about deeper than other applications). GP Moto on left, strutking on right:



2)    Other people have had de-cat success with the Mini version of this electronic O2 simulator from :