Im looking to put a de-cat on my MY96 sti import.
Ive been told to get the most power to remove both cats. If i just remove the rear cat what would the benifit of this do?

Is there any thing that i should know about before getting this done?
MOTs are not problem!!!

What about the sensors?
If any one can help it would be great.

 

You can gain about 35 BHP by removing both cats on the impreza, and of course you will get an increase in torque.

I've read that removing just the centre one, and replacing the back box may gain you about 15 BHP, and removing the front cat may gain you 20BHP. I can vouch for the change of the front one gaining 23BHP on mine.

The turbo will tend to spool up quicker if changing the downpipe, and peak torque will probably move down the rev range.

I had no problem with the sensors when changing it, some people don't even plug it back in, although I'm not sure if this is wise.

Be warned though, changing the downpipe CAN be a bugger of a job, just do a search for turbo studs on here Try and get a fixed price if you're not going to do it yourself

 

What does the sensor on the down pipe actually do??

 

Sti will only have a car in the front downpipe..

Centre has a resonator in it but no cat..

If you change the downpipe you will need to ideally get hold of or borrow a centre cat section for mot.. although some people manage to get away with the mot tester not finding the car details on the computer.

Sensor in the downpipe is the Lambda sensor..

JGM

 

I wouldn't recommend just leaving it unplugged..

there is another sensor on older cars (96 shouldn't have it though) which is a cat working sensor and this can be left unplugged. If your sensor is near the turbo then it is the lambda sensor.. measures air to fuel ratio when you are off boost so the ecu knows whether to add or reduce the amount of fuel it is injecting.

 

Is it not a good idea on a Jap STi to get a remap when decatting to avoid blowing your engine up through det?

Steve

 

You meen re map the ECU???

 

96 car so that would be a ScoobyECU then..

email David Wallis..

david@wallis2000.co.uk

JGM

 

What do i need to ask him?

 

try

"Can I buy a ScoobyECU please?"

and "Can you fit the socket to the normal ECU please"

finish with "What is the total cost please?"

Specify your car - 4 or 5 door, TD04 or TD05 turbo, UK or jap import, and robert's your mum's brother!