Hi,

Just fitted the Afterburner Decat Downpipe and Afterburner R 3" Centre section and backbox onto a Sti Wagon Ver3 1996.

The decat downpipe goes to 2.5 inch, from there the centre section and back box are all 3 inch and the tailpipe is 4.5inch.

Since fitting the power seems to be quite flat and down on what is was before. The car is a 96 Version 3 Sti Wagon and had the OEM exhaust before this. Mod wise just a filter and now exahust so would take a guess at around 280hp bearing in mind the age. Would I have been better to get the normal Afterburner centre section and backbox which is 2.5inch?

Thanks

 

Has it been mapped since you fitted the decat??? if not theres your problem.
You will notice next to no difference unless the car is setup to make full use of the free'er flowing/breathing exhaust system

 

Despite the above you should notice a difference with a decat as there is less restriction. A remap would make full use of it though as you may find you overboost slightly in the cooler weather and hit fuel cut.

My advise would be to check the exhaust everywhere for leaks

 

I will at some point get stand alone management as the ECU on these can't be fettled, from what I have been told the older classics don't fair to badly without a remap after fitting a turbo back exhaust when compared to the new ones but obviously yes it would extract the full potential.

I was going along the lines of that there may be too little back pressure now, which would effect turbo response making the car feel flat? Bearing in mind 3" is recommended for 350+ and am no way near that or plan to be.

Worth changing to 2.5inch all the way through?

Thanks

 

to be honest if your downpipe terminates at 2.5 inch then there should still be enough back pressure in my way of thinking. My old 92 wrx had a tsl grp a decat downpipe and that was a 3inch to 2.5 and then it was mated up with a scoobyclinic unresonated centre and backbox and that was fine (even on 95 ron fuel )

As said, just double check for leaks, you may not hear them as the exhaust will sound different so check from underneath

 

as i say i fitted a 3" H&S system to my Type R which also used a 3" open neck downpipe tapering into 2.5" at the flange then onto a 3" centre and backbox and it made no difference to the power (well not noticeable anyway) until i got a PFC and AndyF mapped it .
The big lesson to learn is not to expect a big power increase just by fitting a full decat as without a tweak of the map it will gain you 2hp at best

 

Looks like management is what I'll be saving for next, all I planned long term was an exhaust, filter which I've done and then stand alone management as it's an import. I didn't expect huge gains just didn't expect it to be flat, and possibly slower than before!

Defo no leaks but will check again! Next thread will be what management

T

 

Apexi or Simtek

 

Simtek these days, far superior to the power fc with more features to boot, added benefit of knock control as well

(jaytc2003 ex power fc owner)