The sniffer CAN tell. The convertor acts as a catalyst (hence the name) it
basically heats up really hot to convert some of the harmful gasses into
inert gasses. The convertor is essentially useless under heavy load or full
throttle, but it is effective at idle and low engine speeds. If you cut the
cat off of a post '96 vehicle (OBD II) it will cause the engine to make
improper adjustments to the fuel mixture causing loss of power and torque. It
can be cut from a pre-'96 vehicle but the loss of backpressure will cause
torque loss, the smaller the engine displacement the more you'll notice the
loss. There should be an increase in HP at the top end but since you have to
scream the engine to get it you might not notice much.To compensate you can
increase compression, run larger injectors and a cam.
I chose to go with a high flow cat with a 3" inlet/outlet in order to
retain some torque. I definitely lost torque but definitely gained power. I
also plan to to do alot of other performance work. I currently have DT
headers, 3" gison exhaust with the afformentioned cat, MSD digital 6+
ignition and HVC coil, 8.5 mm wires and HD cap and rotor set, MP PCM, K&N
filter, 4.10 gears with an Auburn LSD. I plan to get some aluminum heads and
am hoping I can shave 'em to increase the compression to aroun 9.5:1 (stock
is 9.1:1) I also plan on a cam and the MPI manifold and quick D TB. I get
around the emissions testing by registering the truck as a commercial vehicle
and I get the 7 ton sticker for my plates (in OHIO you don't have to take
emissions tests if your plates are 7 tons or heavier).
My point is DONT CUT THE CAT unless you are planning serious p[erformance
mods and have a way of getting aroun emissions testing
JOHN
This archive was generated by hypermail 2b29 : Fri Jun 20 2003 - 11:56:11 EDT