I was looking to buy a set of gt40p heads and I realize that they dont have the thermactor holes. I am basically wondering how difficult it is to delete the whole system, what I would need to do, and if there are any problems involved.
I was looking to buy a set of gt40p heads and I realize that they dont have the thermactor holes. I am basically wondering how difficult it is to delete the whole system, what I would need to do, and if there are any problems involved.
Correction....you do if you have a stock H-pipe and precats.
Basically what happens is this. Our cats need oxygen in order to work. Since all the oxygen is burned during combustion, it must be pumped in. The smog pump does this. However, we have 4 cats. The two closest to the engine are for immediately after startup. The smog pump pumps o2 to the exhaust ports on the heads which flows into the closest pair of cats helping them convert gases.
As the car warms up, the lower pair of main cats take over. The car then switches the diverter valve and changes the o2 from flowing into the heads...to flowing into the pipe that feeds the main cats. So basically you are pumping o2 to either set of the cats at once.
SOOO.... if you have no cats...delete it all, not needed.
If you are running a stock 4-cat h-pipe....well your two closest cats will clog soon without the thermactor ports.
If you are running a 2-cat pipe...eliminate the 3-way valve and just run a new hose directly from the smog pump, through the bypass valve and to the tube running to the h-pipe. Cap the vac line that ran to the 3-way valve and leave the bypass valve hooked up. Now the pump will supply o2 to the main cats at all times.
If you need to pass emmissions, it's critical you get the car hot before going in for testing since you only have the rear pair of cats.