would i need a remap after fitting a de-cat up pipe?

[impreza27]

would i need a remap after fitting a de-cat up pipe?

[Steve_PPP]

No. I (well, Jaffa) replaced my uppipe for a decat years ago and the cars never been mapped. No issues at all, even with track abuse.

If you do change it, it will trigger the CEL light as you won't have a EGT sensor plugged in anymore - probably still have some spare resistors of the right value to make this go away (if i can find them....)

[impreza27]

ive got a hole for the egt sensor in my one steve.

[Steve_PPP]

In the decat pipe? Mine didn't have any holes so had to remove the sensor.

Tbh, I thought it was only there to monitor exhaust temps to stop the uppipe cat burning up (its also known as the cat-on-fire sensor). Oh well, if you've got a hole for it, no problem then, just plug it in

[impreza27]

ok cheers steve.

[asperformance]

i would not refit the cat sensor in the up-pipe after decatting personally, i have seen them break up...........

[impreza27]

if you find any spare resistors steve i'll have one if you can find them mate.

[robinmgb]

I recently bought a sti decat up pipe for my wrx and when asked I Neil at slowboy racing was told I would definitely need a remap as it will alter the air/fuel ratio, to be safe that would need checking and was also told that you only get the full decat benefit once it's been remapped

[Steve_PPP]

I'm no expert but not sure i agree, the cat in the uppipe is a piddly little thing really. If you had a custom ecutek map on the car and then decatted the uppipe, i'd agree as the map is tailored to that specific exhaust system, which has then been changed. But on a standard map, I don't think its necessary.

[robinmgb]

Originally Posted by Steve_PPP

I'm no expert but not sure i agree, the cat in the uppipe is a piddly little thing really. If you had a custom ecutek map on the car and then decatted the uppipe, i'd agree as the map is tailored to that specific exhaust system, which has then been changed. But on a standard map, I don't think its necessary.

I agree with you but I'm no expert that's why I spoke to Slowboy Racing and since Duncan from Racedynamix who also said it will need a remap, I therefore chose to take their advice assuming they were right and it was the safe thing to do

[Scott.T]

if just fitting the up-pipe to an otherwise standard system you should be fine, as Steve has found after many years and many track laps.
if the car is already running a decat downside it will need a remap due to the much improved flow and turbo spool once the up-pipe cat is removed.

[Jolly Green Monster]

I'd be inclined to check it