De-cat uppipe

[arthur t]

I have bought myself a De-cat uppipe for my 2005 wrx but now confused....

I have been doing some digging, I believe there is a sensor in the uppipe pipe that is replaced with a sensor.

Is that right correct?

If so why is this needed?

[ScoobieWRX]

You're talking about an EGT sensor in the uppipe. That can be removed but will switch on the Check Engine Light (CEL) so you either turn it off in the mapping on the ECU or use a 1K resistor in the cars connector to the EGT sensor to turn it off.

[arthur t]

Thanks for the response .

What does the sensor do?

I know u said it can be removed, but is it needed?

[ScoobieWRX]

Exhaust Gas Temperature Sensor - EGT

It's there to monitor what is says, but pointless when WRX's rarely get EGT's that high if at all, and STi's don't have them so why bother with WRX's. removal doesn't affect the running of the car.

It's about emissions and Euro4/5 Classification and Standards compliancy for car manufacturers.

e.g. WRX's have 3 cats, STi's 2.
WRX's have TGV's, STi's don't.

It's all about emissions.

Manufacturers have to have a certain amount of cars sold that meet these regulations/criteria so they can sell other cars that don't without being penalised/fined.

[arthur t]

Thanks for the response ... You learn something new every day!