Pre-Cat Eliminator WARNING: The removal of your Pre-Cat is not a legal modification to your exhaust system. By doing this you are risking fines and penalties from your licensing authorities. Any claims made here are based on personal experience and by installing this part, you are taking full responsibility for any changes to your car regarding emissions, and any other performance issues. By installing this part you are doing this at your own risk! To quote from the write-up on aftermarket exhaust system in this website: What is a Pre-cat you ask?? Well, it is put at the start of the exhaust system to function for "cold-start emissions." As such it is smaller than the main catalytic converter and thus heats up more rapidly to become active first with regards to catalyzing the exhaust gases. Removing this part is against the emissions laws in the US. This part is therefore intended for off-road use only, and can be interchanged with your original precat if you chose--the rest of the system is totally legal in every way, shape, and form. (Mine was so rusted-out that it clearly was no longer functioning much at all! You can see the pictures of it here http://www.lotuselancentral.com/exhaust.htm --click the pictures to see them in their full splendor! Doug) It s has been my experience, that removing the Pre-Cat from the Lotus Elan M100 -- yielded the greatest amount of power increase of any previous exhaust modification. This is measured by personal driving experience, not by dyno results. We recently had a custom muffler shop in Orange County, CA make a beautiful custom Pre-Cat eliminator to replace the stock Pre-Cat. It is approximately 1/10 the weight and treated with high heat resistant ceramic coating. It is plain beautiful and an almost perfect fit.
After inspecting several Lotus Elans, we found that Pre-Cats for the Elan s were not alike. There are apparently 2 types of Pre-Cats on the Elan s; one with an EGR sensor, used for cars to be driven in Japan, and the other, with a plug where the sensor would normally be found. This does not mean that if you live outside of Japan, you will have the one without the sensor. Both types of Pre-Cat are found in cars anywhere in the world. They both look identical, but the angle of the outlet is slightly different. The muffler shop has the mold to make either one.
It's incredible what a difference it made on my Elan. This part was installed on different Elan s; both with custom made stainless steel 2 1/2" piping free flow exhaust system from pre-cat back. After replacing the Pre-Cat with the new part, both Elans felt like totally different cars. It's was amazing how much more power they produced. Torque seemed to increase; both low end, as well as high end. The turbo seemed to spool up instantly, and the car seems to car pulls like crazy. It made the exhaust note slightly throatier. The tone will all depend on the exhaust system that you installed. My system is running 2 1/2" stainless steel pipes through out, and has another glass pipe before the straight flow through Magnaflow muffler. The glass pipe really helps to cut down the sound without restricting the flow.
This is a true bolt on part, it uses the existing studs on your turbo to connect the top part, but you will have to use some bolts to connect the lower flange to the rest of your exhaust system. The picture above shows the Pre-Cat eliminator with the bottom part showing the three holes..
The previous picture is another view of the Pre-Cat eliminator. You can see from this picture the ceramic coating that keeps it cool. To install, you will need to use the original gasket from the Pre-Cat. The bottom part needs a new triangular shape 3 hole metal gasket that can be bought at any auto parts store like NAPA, or I can provide them with a gasket, bolts, and nuts when they order the pre-cat. The top part will attach to the turbo, using the turbo studs, and the bottom you will need three new bolts, and it will attach to your downpipe of your exhaust system. Removal of the old Pre-Cat from the turbo, normally require lots of Liquid Wrench and WD-40 to get the nuts loose. Once you are able to loosen the nuts, the rest of the installation is fairly simple. Pricing for the pre-cat eliminator is $225.00 excluding the bolts and metal triangular gasket, which you can get at any NAPA store. Shipping is also not included. For more information contact: William Sun STIUSA@aol.com Ed Miller emiller1@san.rr.com