Hi,

Have an 03 STi with PPP,prodrive backbox and sorts cat.If i fit a de cat centre section,will it need a map tweak? or would it be safe to run on PPP ecu.

Thanks,

 

I'd say it'll be close but you'll probably be fine, I've done 10k since putting a sports cat into a car mapped without and it's been fine, but this will have had far less effect than removing the original OE cat. You definately won't get the best out of it without remapping.

 

but the down pipe cat is the bigger of the 2 rigth? I have only just put the PPP on so would be a shame to have to go and map it now. I just want it a bit deeper and louder.

Thanks,

 

I think you will find there is no cat ,the small pipe that joins onto the down pipe looks like it has a cat but its just a heatshield and the pipe joined onto that one is just has a resonator .I know this because i have this same setup and bought a decat small pipe only to find i already had one covered by the heatshield for a cat. Also Bob Rawle confirmed this .I would still go for a remap my ppp map wasnt very good on mine the vf35 has plenty more to offer.Remove and replace the upipe,

 

i'm talking abut the centre section that joins the back box to the cat. as I say I just fitted the PPP so i'll stick with that for a while,without more modding I can only go to around 335 with an ECUTEK map anyway.

 

its not a cat

 

As Wayne said its a resonator not a cat, it will make next to no difference in performance if removed and does not require a map tweek. Have you put a PPP ECU in your car too or had it mapped?

 

wayner845 is right its not a cat! it is a resonated section or some call it a silencer, you can change it with out a map tweak with no problems, was thinking of doing this myself but still unsure as i don't want any unwanted noise in the cabin area (already have decat) but do want some extra burble from the back
I have found a few on Ebay for £90.00 new (Scorpion i think) let me know how you get on if you decide to do it.
Cheers Gonzo.

 

Hey,

ahh right I was told there were 2 cat's? one in the down pipe and the other in the center section.

Yeah i'll definitely be fitting one,will probably wait for a second hand one to come along tho,just want a burble and a bit more roar!

thanks!

 

There is another cat in the turbo up pipe from the exhaust manifold/headers and is a good mod to replace,however you are getting into different teritory where a remap is adviseable and people will say only worth doing if you are getting a bigger turbo etc.Personally if i was getting a remap i would change the upipe for a suitable matched decat ported item from harvey.
And the list of mods begins ,all good stuff.

 

not on the newage there isint mate, where in oxon you from im in carterton?

standard there is

a cat in the downpipe
then a 2nd cat joing from down pipe to centre section
centre sectionn has a resionator in it (silencer)
back box

he wnats to de-cat the 2nd pipe the one that goes from the ppp sports cat to the centre pipe, you can get them from scoobyworld, or scooby parts and i would say you wont need a remap to decat that bit, but if you go full decat on the downpipe you will as you will get boost spike and det

 

There is a precat upipe and no cat after the sports cat downpipe.

 

As above the new-age STI has no up-pipe cat like the wrx has.

Has a cat in the downpipe then one in the second section and a resonator in the third section.

 

Ok i'm not sure about the up pipe but the one that i have here just removed from my 2003 uk sti is a precat .and as for the pipe after the sports cat downpipe the sti has the heat shield for a cat but just a straight through pipe underneath.I queried this myself cos of the heatshield but was told by Bob Rawle the sti never had the second cat .

 

yes for the ppp the second cat is removed in standard form there are 2

 

Thats what i thought myself initially and makes sense to me which is contracting what i said earlier.
Always learning.