Hi all,
Looking for a bit of advice fitted a de-cat downpipe to my V3 sti today took it out for a drive afterwards and if I give it a bit of a boot in 3rd or 4th gear then take my foot of the gas letting the car slow down the car develops a strong vibration coming from the engine which I can feel and hear whilst driving wondering what this could be.

The car has de-cat centre section afterburner back box and mugen headers and with the downpipe it now has no cats in it at all, as yet it has not been remapped could this be the reason? I am planning on getting it remapped. Was not sure if it is safe to drive it without the re-map?

Any thoughts or advice has anyone drove there scooby with a full decat and not had a remap?

 

A re-map isn't really an option, some can offer you something but a replacement ECU like the Apexi PFC is the way forward and will cater for any further modifications you decide to embark on.

Not in answer to your question but the STi is mapped for 100RON fuel so any modification that would cause this to run leaner than expected (aftermarket headers for one) without anything fuelling mods to support it will cause issues.

 

It sounds like the downpipe is touching the cross member, worth getting the car on a ramp and having a look.

 

Is the downpipe to cat joint spring loaded like the original or is it just two flanges bolted together?

Mine is two flanges bolted together, and now notice vibration through the car after fitting the s/steel system...nothing is touching either.