Az Sti Type R

Ello,

Just a quick one, is the standard size diameter of my v4 sti 2.5"?

Wondering because after having a major service at APi on tuesday (which I was extremely happy with the service I recieved by the way, very thorough! ) they noticed that my back box was actually hanging on by the brackets on the center pipe, it had no brackets on the back box at all!

I've had a brand new full 3" turbo back de-catted system sitting in my flat for about 2 months now, but I don't want to fit that unless I can get it mapped straight after its been fitted to be on the safe side.

So what I want to know is,- can I fit the cat back part of the 3" system I have in the meantime to my original system?

Thanks in advance.
Az.

Gear Head

iTrader: (2)

You would have had a bracket of some sort on the back box otherwise it would drag on the floor!
Yes, it is 2.5 inches, or 2 5/8's sometimes.
You can also fit your full 3 inch exhaust without remapping. Yes, to get the most out of it, remapping is a good idea, but certainly not necessary at the same time.
I don't think you'll be able to just fit the cat back as the flange will be different.

Az Sti Type R

Cheers for the reply mate.

Well not sure exactly what the situation is with the back box, but it does wobble about an awful lot.

I was always under the impression (from what I've read several times on here) that the reason I'd need a remap after fitting a full system with decats is because it could over boost, spike, and possibly run lean? Something I wouldn't want happening obviously, and as I haven't got a boost gauge at the mo I wouldn't know if it was overboosting, I'd just be like,.....'Wow this is bloody rapid!!'....and then bang knowing my luck!

Gear Head

iTrader: (2)

Well its far cheaper to fit a boost gauge at the same time as the exhaust.
Then you can keep an eye on things. This sort of thing is more critical on newage cars. I ran my sti 4 with a full decat for 2 years no problem.
The car who bought it from me ran it for another 18months with no issues.
Then, he changed the turbo, intercooler etc had a remap by a specialist and the engine was knocking within 1000miles.

Az Sti Type R

O.k mate, cheers, thats interesting. I was thinking of just fitting it due to this back box issue and driving it very sensibly (none or hardly any boost) until I could get an ecu and remap, but that would be near on impossible in my book!

winker

iTrader: (1)

your exhaust will be 2.5 a 3inch will not fit flanges i fitted a full 3inch to my sti type r no problems at all.

The rookie

iTrader: (1)

Stock system is 60mm, nearly, but not quite, 2.5".

Unless your decat is all one piece, then why not just put on the back box, (or centre and rear) for now? Its easy DIY and you only need to put the passenger wheels on a reasonable kerb to gain enough room to do it!

Simon

Az Sti Type R

The rookie- Yep the de-cat is one piece, so that was what I was originally asking, to see if I could just fit the center section and back box, but oh well.

winker- Is your exhaust you fitted from turbo and de-cat then? and how long has it been on your car?

Cheers for the replies.
Az.