John,

the centre pipe change makes a small difference to the noise if it's a magnex and a decent difference in top end power (about 5-10 bhp I'd guess). Scoobysport one seems better (louder) http://bbs.scoobynet.co.uk/biggrin.gif as I think it's just a straight pipe whereas magnex has a mini silencer thingy in it.

easy to fit - 2 bolts each end, 15 minute job if it's on ramps.

Downpipe -BIG difference in turbo spin up.
I was behind a guy with similar mods to me the other day but he has the downpipe, I don't. Off the mark his car raped mine http://bbs.scoobynet.co.uk/eek.gif but higher up the rev range it was almost even. http://bbs.scoobynet.co.uk/smile.gif
You could see he was coming on boost a good few seconds before me. Hence the well needed trip to Mr. Goode. http://bbs.scoobynet.co.uk/wink.gif

Hope I've helped

Rich

Dim question I know...

I've got a scoobysport back box, I hear people talking about changing downpipes, mid sections etc, what bit can be changed leaving the cat on?
How do cars pass the MOT without the cat fitted?

Cheerz
John

John,

You won't pass the MOT without cats, but I have heard of some Japanese imports passing without cats (but that's another story and I think Pete Croney has explained it a few times)

You car will pass the MOT without the sentre cat. The centre is the warm running cat, so it would only reduce the emissions slightly. The Prodrive Performance Pack replaces the standard centre and backbox.

On my old MY97 UK car, I had a ScoobySport downpipe and backbox, but I retained the centre cat. I had the car tested, and it would pass the MOT checks, but only if it was warmed up beforehand.

The downpipe is the one with the cold running cat. This is the one that causes the most restrictions, and the spool up of the turbo is much quicker, but it's the one that removes the most crap as well!!

When the MOT comes around for my current car, I will look at getting a high flow cat centre made up by Haywood & Scott (the makers of the ScoobySport exhausts) Either that or replace the centre section, and make sure the car is warmed up!! http://bbs.scoobynet.co.uk/smile.gif

Hope that helps
Andy

Andy
I'd also be interested in a high flow cat somewhere in the centre.
I've got an STi v4, so it's only got the downpipe cat - but I don't want to mess about with replacing the downpipe for MoT every year, so sticking a high flow cat in the middle sounds good.
Even if it gets put in just for the MoT once a year,it'll still be easier than changing the downpipe.
Nick

Hi John,

Scooby exhaust has two cats, one in centre section, one in downpipe. If you remove the one in the centre pipe, the car should pass MOT ok. If you remove the one in the downpipe as well, you'll have a cat free system which SHOULDN'T pass the MOT. Although I have heard of a brand new imported 22b passing the import tests without cats (but don't know if that's as stringent as the MOT????) http://bbs.scoobynet.co.uk/confused.gif

I've got a magnex back and a decat centre and I'm saving up for the Graham goode downpipe with sports cat (so I don't have to faf about putting the cat back on and off for the MOT as you would with a cat free dowpipe). Unfortunately, it's £399+vat and £90+vat for fitting. http://bbs.scoobynet.co.uk/eek.gif I've emailed them at GGR to ask if I'll pass the MOT with just the sports cat on and I'm waiting a reply.

Hope this helps

Rich

Ok thanks for the info guys..
So if I change my centre pipe I will lose a part of the cat system but will still be ok for the MOT..soundz good to me!

Just one other thing, do you reckon this will make much difference to performance and noise?

ps is this the bit I need from scoobysport web site??
De-cat stainless centre pipe 92-00 £90

How easy is it to fit??

Thanx
J

[This message has been edited by blimeycharley (edited 01 May 2001).]

John,

Just changed my centre and rear for a Scoobymania de-cat centre and backbox. Unlike the Scoobysport the centre section has a 3" diameter compared with 2.5". I've heard people say that this reduces back pressure too much, therefore reducing power when pulling away but increasing power at higher revs. In my experience of this system all I have to say is "my car pulls like a bitch on heat!!!" It also sounds very deep and grumbly - Not unlike a TVR.

The whole system was about £320.00(inc.vat) but if you're after just the centre this was about £60.00(inc. vat).

Whatever you choose your car will sound a lot better without the centre cat and even better with a decent backbox.

Enjoy

Maffa

This might seem like I'mgoing over the same ground here but today I got an HKS decat downpipe fitted. Instantly quicker spool up on the turbo but combined with a standard centre section and a trust back box there is no improvement in exhaust note.

Not what I expected at all. Would changing the centre pipe for a straight through pipe make any difference or does the tone all come down to rear box. If so, are HKS Superdrager and Blitz NurSpecR any good(ie noisy) and what should i pay roughly.

I don't want to be the noisy kid on the block but next door's Fiat 126 sounds butcher in the morning than my 95 WRX.

Any help would be greatly appreciated.

Jerry

Maybe I dreamt this but I thought I read somewhere that WRX's + sti's will pass mot with no cats as UK mot centres have no emission data on 'grey' imports??