I have a Magnex back box on my MY98 Impreza Turbo and was wondering how many more sections I need to have full system?

Do I have to stick to Magnex pieces or can I mix 'n' match?

Thanks

Gavin G

 

To have a full decat from turbo back on your car, you need a centre section and a downpipe as well as your back box.

You can mix and match. I have a SS back box, magnex centre, ss downpipe. Just confirm you can mix and match if you go for any less well known makes.

 

Sorry to jump in Gavin (go for the full change, you know you want to )

...P20 - we've currently go SS backbox and magnex centre and are debating between SS downpipe and TSL downpipe (although tbh, there doesn't seem like much difference ) - what do you think of your set-up? Much louder? Increasing pick-up lower down? Any problems fitting?

Thanks (and sorry again to Gavin...)
Jen

 

Also hijacking (sorry ), but P20, which SS downpipe did you go for the 3" or the 2 1/2" one?

 

Chris as you have the 2.5" Magnex centre you would be better off with the 2.5" downpipe.

 

Gavin,

You will need a downpipe and a centre section to complete the system, and you dont have to have all Magnex, althought VFM wise the Magnex centre section is great at approximatly £55

I have fitted to my car :-

Scoobysport 2.5" Downpipe
Magnex Centre (Straight through)
Prodrive PPP Backbox

Ian

 

Right trying to answer the questions, had this setup on for 3 years on 3 scoobs now. Very happy with it, quite on cruise (inside cabin) but loud on WOT.

Easy to fit, sometimes, somtimes not.

Downpipe size is 2 1/2inch. you notice so much difference when the downpipe goes on. The centre pipe alone does not make that much difference IMO, but the downpipe does. Big grins

 

Thanks, I think that's conclusive!!! Jen do you want to order the downpipe or shall I?

 

I know that the centre section would probably be easy enough to install but am I right in saying that the downpipe wouldn't be a DIY task and would need a professional?

Gavin G

P.S. Is it better to have the Magnex straight through centre section or the one with the resonator?

[Edited by Gavin G - 9/19/2002 1:00:25 PM]

 

yeh DP can be a bitch. Heatshield might need cutting back, and bolts holding old DP to turbo are usually seized up.

 

The resonator one is a little more expensive and very slightly impedes the flow of air through the exhaust, but does prevent the sound being too intrusive in the cabin. We got one of those and are very happy with it, although it doesn't get going til it's warmed up a bit, then it sounds

 

Chris
What's in a resonator that needs warming? I thought they were just hollow boxes.
And while I'm being mentally challenged, If a resonator resonates, how does it make things quieter?

Oh and one other thing, what is the quietest system/ combo that anyone has heard? ( For a full system that is, so don't say the OE exhaust! )

 

JulesB,

I'll warn you now, that I'm only piecing together what I've heard so I'm sure someone will correct me if I stray! The resonator is a hollow box and it gets louder when it gets warm, so I assume it's something to do with warm air flowing differently to cold air? Not sure how it can be quieter, other than the fact that the airflow is broken up by the resonator?

Chris

 

If you are going to do the downpipe yourself make sure you have good ramps or jack and axle stands. You need some clearance to be able to get the downpipe in and out.

To undo the turbo
1. undo and remove the intercooler
2. undo all bolts around the heatshield, IIRC there is about 7/8.
3. undo 2 nut and bolts at top of turbo, make sure you have good strong spanners/socket set.
4. undo 3 bolts at bottom of turbo, same again strong spanners.
5. discoonect sensor for lambda
6. undo bolt halfway down downpipe that bolts to gearbox
7. undo bolt a bit further down attaching to body.
8. undo 2 spring bolts to centre.
9. remove dp gently watch you dont bang the lambda.
10. remove lambda
11. revers above with new pipe
12. cut accross back of heat shield to just before the nut that goes onto the back of the turbo an dthen go straight down from there.

Good luck

 

P20SPD,

Is there any possibility of any major disasters when canging the DP, e.g. bolts shearing etc. that I should know about??

Thanks

Gavin G

 

Yes there can be, on any of them. Just go steady with each one, and if it feels "wrong" then its probably cross threaded or about to sheer.

Use plenty of WD40 well before you start doing it and then as you go.

Also, obvious but just in case, make sure you have not just been for a blast cause it can get very hot. Allow to cool a bit.