unfeasablylargegonads

iTrader: (3)

Hi,

I currently have a full miltek sports cat exhaust. I am thinking about going down the md321T road, so was wondering if the sports cat will be a hinderence at 400+ bhp in either spool or power achieved?

additionaly I quite like the sound/volume of my current set up (its not very loud untill you hit WOT), would replacing the sports cat with the complete decat section increase the volume level alot?

Cheers

Dan

scoobzie

romove the sports cat and port the exhaust headers this will give better spool up and reales a little bit more power if you have a sti stick with your sti up pipe this will also help spoolup as it isnt that big and help the turbo

Mocom Racing

iTrader: (2)

Ultimately the sportscat is a restriction and creates unwanted backpressure increasing with map and rpm, so running a turbo at 1.4bar to 7000rpm will see less of a restriction than running the same turbo at 1.8bar to 8000rpm

As to how much of a restriction it'd be to you I couldn't say as the MD321T's I've had experience with run full decats. I do however have experience of a MD321H with a sports cat system which performed very well, the car in question does have a relatively low rev limit of 6900rpm

unfeasablylargegonads

iTrader: (3)

Thanks for the feedback, I decided to go the full decat route as the current turbo I am running is a bit laggy anyway so hopefully this will help a little bit and the only downside is the MOT pain.

Just hope the increase in noise is not too much, I think I upset my neighbours enough a few years ago with my old classic complete decat

IainCam

Doesn't anyone make a decent sports cat for the centre section?

This would make it a lot easier for someone to swap in/out as and when they needed it but still keep it fully decat'd for most of the time (or vice versa).

ccSTi8

I currently have a full Miltek exhaust with sports cat on my STi.

My car is going in next weekend to have a new Turbo (MD321H), 650cc injectors, APS cold air ind kit and an Apexi AVCR fitted then a re-map by Andy F. I will probably be taking the cat out and getting it mapped fully de-catted then i might try putting the cat back in and see if that slows it down. This is being down after talking with Andy F.

I will let you all know how i get on.

Chris

steve_wr1

i'm doing very similar myself soon,rcm headers/up pipe,md321h,650cc's and full 3" exhaust,already have induction kit and uprated spark plugs.let us know how you fair with the remap
back on topic,mines full decat at the moment but want a 100 cell sports cat welded in to the mid section,andy forrest told me that works quite well.worth considering with the cat m8.i'm trying that route,so time will tell
as for noise,yes its a lot louder with no cats.i'm running a decatted blitz nur spec r and it sounds amazing,dont think my neighbours would agree though

gussy

iTrader: (2)

Dan I have the latest Miltek with the cat in the centre pipe I removed it and put a miltek decat centre pipe in its place Im keeping the cat centre for mot time as for noise it hasnt made any differance to what it was before.

unfeasablylargegonads

iTrader: (3)

Thanks Gussy, Mine is the older generation with the CAT in the downpipe which I think is a bit more restrictive. I have ordered the decat replacement so will soon find out

Juice

I know this is an old post that ive dug up

BUT, did it make a difference to power? (did you notice anything?)