vindaloo

I am currently running the standard exhaust on my P1 complete with standard catted downpipe. I'm thinking of replacing the system or at least the downpipe and middle pipe.

What configuration to go for though? Is there any benefit in having the cat. in the downpipe as opposed to the middle section of the exhaust?

Downpipe will be replaced with open neck type design if I go for the 'centre cat' option.

J.

vindaloo

bttt

David_Wallis

use a decat.. off the shelf sports cat DP's etc are crap IMHO.

vindaloo

Short and to the point

J.

911

If you want to max the performance from the exhaust mods then, as David says dump all the cats and fit a centre one for MoT's.
An open neck design will work wonders on your car, go for a 3'' system as you will need it to compliment the further mods you will inevitably undertake very soon!

I had a 'nasty' sports cat on my modded Sti v3, 3'' and not an open neck design.
Sure passed the MoT cleanly but thought to be restrictive.
Change back to my 3'' Magnex de cat and can't feel any change, BUT, the car ran 407 bhp on the rollers...

If you have a green streak then a modern sports cat is really your only option.
The TSL and Miltek units look good to me.
The cat in the d/pipe will run much hotter and so be efficient with the emissions.

Hayward & Scott have a new centre pipe/sports cat for sale now.

Graham.

hades

Depends on what you're trying to achieve. I've got an APS sports cat system (not one of Mr Wallis' favourites, IIRC - but personally I rate it, fairly quiet but nice noise, decent power, good quality). This produces slightly better power/torque output than most similar decat/Tek'd 02WRX's, so I don't believe the exhaust is holding me back at 284bhp/272lbft (power engineering). If - like David - I was trying to run twice that power (or more), I expect it would be restrictive

vindaloo

It struck me earlier on what a complete bol*x I made of the question as I didn't state any power goals.

I'm aiming north of 330bhp (as much torque as possible) and getting the turbo to spool up as soon as possible. Cat. has to be able to support those ambitions. I'll be e-mailing H&S. I did look on TSL and Milltek websites but the sportscat dp's they advertise seem to be newage only.

I'm not into NOISE, so the car has to be capable of brumbling around without being louder than my existing P1 BB and not be too noisy inside the car either.

J.

911

Please forward on here the outcome of the H&S conversation please.
Graham.

vindaloo

Graham,

I e-mailed them before lunch. I've asked about the power potential and whether they've any friendly STi owners who have had them fitted.

J.

DaveW

H&S should also be able to provide you with a 3" exhaust which is no louder than your standard one.

vindaloo

After talking with H&S...

For performance figures etc. I need to speak with Xtreme Scoobies.
H&S have been making the centre sportscat for about six months.
It's recommended to get the car 'hot' before taking it for MOT to ensure the cat. is lit.


J.

Mike P

Try Graham Goode Racing, as they do an open neck 100 cell Cat DP.

Perhaps they can tell you what sort of power it'd be good for before it becomes too restrictive.

David_Wallis

the ggr one fits really well.. Not!

David_Wallis

PS, H&S would be my choice.

Mike P

The GGR one fitted on my car perfectly, David.

vindaloo

I've spoken with Xtreme Scoobies.

They did a test a couple months ago with different exhaust configurations on a 2.5. I don't think I'm letting anyone's secrets out as there was an article done for Scooby magazine.

An opened necked d/p plus centre sportscat was worth 10bhp over an open necked sportcat downpipe with a decat centre.


J.

hades

I'm sure that 10bhp difference also depends on application - I simply don't believe it will be the case for e.g. a TD04 2L car.

The highest powered 2L TD04 car that I know of (312bhp on PE's rollers) actually had the GGR cat downpipe fitted. My car - 02WRX, decat up-pipe, APS sports cat system, ITG panel, ECUTEK (to 1.15 bar sustained - i.e not v. aggressive mapping) and some samco hoses has twice given over 280bhp on PE's rollers. Most full decat, ecu-tek etc 02WRX's give around 280 on PE's rollers. I really don't believe that I'd get mid 290's just by taking the cat out or fitting a different downpipe.

OK, on a 400bhp 2.5, sports cat might cost you 10bhp, but so might bad downpipe design. I haven't read the Scooby mag article, but do we know which exhausts were compared, and how?

coulty

Better not mention what Andy F got out of a TD04 then

hades

I know he got 330ish from a hybrid TD04, but did he get more than 312 out of a standard one too?

MDBinaWagon

TSL's Thundercat dp fits a classic (I've got one on mine), just a shame they don't mention it on their site.

Martin.

WRX_Rich

iTrader: (5)

im happy with the tsl sports cat but not to bothered if I loose a few horse's.... if I was after 350 bhp + a decat would be on the cards,

the tsl sports cat downpipe is the same length as the classic downpipe,

BRD did mention the best cat to look for would be short and fat rather than long and thin... have you tired roger clarks as they do offer a sollution,

911

My Sti v3 has a full 3'' decat and has run 407 once at Well Lane.
I have a jap spec semi twin pipe 'short fat cat' 3'' d/p.
Tempted to put it back on the car and return to Well lane!

With the cat on it went through the MoT like the wife's Yaris.
Drove really well. Only took it off because we thought it was stopping the TD05 20g from boosting 1.4 all the way to the red line.
The car will still not boost all the way despite the d/p change.
Food for thought.

Graham.