lightwave693

hi

which cat is the best to remove for a bit more grunt and some noise? i want to leave one on for now as mot is coming up soon and dont wanna be rolling around on the floor changing exhaust bits in this weather! so decat downpipe or center decat?

car a my98 turbo wagon uk.

Cheers
Rich

Brun

Downpipe every time if you want to notice a power increase. An mot pass is likely but not deffo with this option however

GC8

Do UK 'Wagons have a centre catalytic converter? JDM cars only have a cat in the downpipe; what appears to be a centre cat is, in fact, a resonator.....


Simon

Roojai

Yep, JDM cars have the resonator with no cat, and uk cars have two cats, but I am not sure if later jdm cars also had a second cat

EddScott

Twin dump or open neck?

I wait with anticipation that someone will finally give me a definitive answer

I enjoy a twin dump

GC8

Better out than in!

WUZ

iTrader: (14)

Twin dump give more BHP, less Torque and the Open Neck is the other way around.

Russell

Trap2Terrorist

iTrader: (3)

Definately the downpipe.

scoobfan

Torque rules !!

Rob

EddScott

Hmmm, I'm a torque man myself.

Cheers mate

cat7

centre decat does bugger all, the down pipe is where the gains are however its a bugger to remove and replace if the bolts are old and rusty.

lightwave693

brilliant guys, downpipe it is then. shouldnt be to fit as the clutch was changed not long ago. i will do a full decat after mot, then only need to mess about once a year hehe.


thanks for ur knowledge!

Rich

Trap2Terrorist

iTrader: (3)

Not entirely true but not far off.

I gained a whole 7bhp from changing just my backbox (standard MY01 WRX), decat centre and Green panel filter.

(Mind you I then had an ecutek remap which added another 40bhp, now running ~262bhp )

I would expect a decat downpipe, uppipe and remap to add another 10-20bhp.

Tuts

Sorry for highjacking the thread but I'm after doing something similar with a 53 wrx.

Options are:
1. Sports cat d-pipe and no other cats.
2. Up and down decat and leave centre cat.

Full decat is not an option for me.

If option 1 is best will a down pipe from a PPPed sti be good enough or would I need a proper sports cat? (Not sure if this is changed as part of the PPP for an sti, anyone know what is changed on one?)

Thanks
Chris

tmo

Just take them all out