High Flow Cat = Less Responsive Than Standard Cat.

[fuzzy_scuz]

obviously GTR's are different I just changed the setting. No need to reset ECU.

whatever works in the end is the best.

[No Crust Racing]

Not sure what hardware/software you're using but I'd assume most people don't have it. A reset is pretty straight forward.

[mokompri]

I would expect the car to require a re-tune, may explain were some of the power is going. I would expect it to be running richer than before....

although a retune isnt *necessary*, i agree with you. a more free flowing exhaust causes an increase of airflow, which gives a higher voltage on the afm for the same load and rpm, which then means your hitting different cells on the fuel maps = running richer. same thing happens on sr20's

This topic has been a matter of contention before. You should gain power from increasing flow but in some cases you will lose some responsiveness in the trade - by this I mean the car will not feel as quick to respond to your throttle inputs but will pull harder once it does. Is this how it feels or are you saying it just feels worse all round?

In my old car I described the sensation as feeling the engine was not as 'tight' - as a stock RB25DET feels quite tight and zippy on the throttle response but you lose some of that feeling with a full turbo back exhaust with the obvious benefit being more pulling power (especially at higher revs).

an exhaust which gives you more power up top, means that it flows better then the previous/stock exhaust. flowing more up top, means it flows better down low as well, its not selective - and with less back pressure response and power is always increased, no matter where in the rev range. the lack of zip is probably associated with the richer afr as explained above.

[No Crust Racing]

An ECU reset is on the cards it seems ^_^

[Munkyb0y]

if i do an ecu reset, i guess whatever the unichip is doing wont be adversly affected?

i know the timing is retarded, but i dont wanna mess with it without looking into the unichip setup, as the unichip does control timing as well as afrs.

[No Crust Racing]

The unichip should not lose any info from being reset. Speak with them if you're concerned.

[Munkyb0y]

yeah, i'm sure the unichip will retain its settings.

i might have to hunt down a cheap unichip tuner (of which there are none ) and get it looked at anyway.

[Munkyb0y]

i spoke to a tuner from unigroup engineering on the phone just now.

he's surprised the upgraded cat would cause a loss of response, or loss of power anywhere.