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Discussion Starter · #1 ·
Please your advise and help, i still have the standard exhaust system fitted to mt ST3 and thinking of changing the cat to a Dream Science Sports-cat or keeping the standard cat and change the turbo downpipe to a Dream Science Turbo Down pipe. i am keeping the standard exhaust form the cat back and have no intention of changing this. What i want to know is which one i should change, Sports-cat or Turbo Down pipe? Which one will give me the greater performance? also will changing one of these make the exhaust louder and pop more if so which one. Very undecided in which way to go and want as much feadback from you all as possible, but remeber im keeping the standard exhaust system and only wanting to change either the Sports-cat or Turbo Down pipe
 

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Take a look at this thread. Click
Oh and I would do both and they will give you more pops and bangs but not quite as many as if you were to change the cat back too.
 

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Changing the cat will give more tangible gains but changing both will more overall gains as it will help dissipate heat faster from the turbo body so reducing intake temps bizzarely! I would save up and get both at the same time personally!
 

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By the way keeping the standard cat back will hardly affect performance at all! On a rolling road day my car which had the 3" downpipe and 100cpi Sports Cat but the standard cat back produced just 2 bhp less than an ST with all the same tuning parts but running a cat back! Its also really stealth and makes Carrera 4S drivers even more surprised lol!
 

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Discussion Starter · #8 ·
Ok uve twisted my arm fellows, both it is then. Is Dream Science a good choice to buy?
 

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QUOTE(bully09 @ 6 Jan 2010, 09:54 PM) <{POST_SNAPBACK}>Ok uve twisted my arm fellows, both it is then. Is Dream Science a good choice to buy?

Knowing the DS attention to detail then i would think it would be top notch kit! You will probably find you can get cheaper though! Give Jared a ring (01482 224433) first as they do a discount for owner members!
 

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I have a Scorpion De-cat and Down Pipe and together............they sound much better than a stock exhaust mate, do BOTH.....you'll be happier !!
 

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Just changing the cat gave 75% of the improvement of cat & down-pipe.
The car had a fair bit more urge and throttle response improved over standard when I had the PDUK 100 cell sports cat fitted.

The down-pipe I changed later because I found I was doing more track days than anticipated
& as Andy has said already, it prevents heat-soak in the turbo/manifold so it's one of the few mods that potentially increase
power and aid reliability.

With the down-pipe & 100 cell cat; the turbo does spool up quicker still, throttle blips on down changes are definately crisper.
I've not dyno'ed my car, no idea if it makes any more power/torques, a lot noisier though.

The sound level with just the cat was in my opinion 'just right'. I measured it as +6dB.
The down-pipe increased the cabin noise by quite a bit when on throttle, steady state motorway miles are still fine.

Depends on your usage, I actually think changing the down-pipe has taken something away from the package as a road car.
If the ST was my only car I'd put the down-pipe back to stock, but that's just me.
In the cabin it sounds like a rutting deer when opened up.

HTH, Jon.
 

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Discussion Starter · #12 ·
QUOTE(JayGee @ 6 Jan 2010, 11:51 PM) <{POST_SNAPBACK}>Just changing the cat gave 75% of the improvement of cat & down-pipe.
The car had a fair bit more urge and throttle response improved over standard when I had the PDUK 100 cell sports cat fitted.

The down-pipe I changed later because I found I was doing more track days than anticipated
& as Andy has said already, it prevents heat-soak in the turbo/manifold so it's one of the few mods that potentially increase
power and aid reliability.

With the down-pipe & 100 cell cat; the turbo does spool up quicker still, throttle blips on down changes are definately crisper.
I've not dyno'ed my car, no idea if it makes any more power/torques, a lot noisier though.

The sound level with just the cat was in my opinion 'just right'. I measured it as +6dB.
The down-pipe increased the cabin noise by quite a bit when on throttle, steady state motorway miles are still fine.

Depends on your usage, I actually think changing the down-pipe has taken something away from the package as a road car.
If the ST was my only car I'd put the down-pipe back to stock, but that's just me.
In the cabin it sounds like a rutting deer when opened up.

HTH, Jon.

In the cabin it sounds like a rutting deer when opened up.

Is this only when under full throttle, when giving the car some serous pedal
 

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QUOTE(JayGee @ 6 Jan 2010, 11:51 PM) <{POST_SNAPBACK}>Just changing the cat gave 75% of the improvement of cat & down-pipe.
The car had a fair bit more urge and throttle response improved over standard when I had the PDUK 100 cell sports cat fitted.

The down-pipe I changed later because I found I was doing more track days than anticipated
& as Andy has said already, it prevents heat-soak in the turbo/manifold so it's one of the few mods that potentially increase
power and aid reliability.

With the down-pipe & 100 cell cat; the turbo does spool up quicker still, throttle blips on down changes are definately crisper.
I've not dyno'ed my car, no idea if it makes any more power/torques, a lot noisier though.

The sound level with just the cat was in my opinion 'just right'. I measured it as +6dB.
The down-pipe increased the cabin noise by quite a bit when on throttle, steady state motorway miles are still fine.

Depends on your usage, I actually think changing the down-pipe has taken something away from the package as a road car.
If the ST was my only car I'd put the down-pipe back to stock, but that's just me.
In the cabin it sounds like a rutting deer when opened up.

HTH, Jon.

Thats weird Jon coz mine made hardly any difference to the exhaust sound at all? Are you running a cat back as well? Admittedly i changed both downpipe and cat at the same time so maybe i didnt notice as much but even on track you need to wind the windows down an inch before you can really hear the exhaust! I get a bit more roar and DV noise out of the K&N 57i kit on mine but again its certainly not intrusive inside the car! My downpipe is a Magnex as is the 100cpi cat by the way!
 

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The noise is definately coming from the other side of the fire-wall or at least that's what it seems.
I have got a Mongoose cat-back, very pleased with that (looks nice, not too loud, not a performance mod though).

Profile fitted the down-pipe & I've just remembered they did say that it was very tight on the mounting rubbers,
in their opinion the mounting bracket wasn't quite in the right place. It's a PDUK pipe, could be transmitting noise into the cabin via the streached mountings.
It does seem likely, so ignore my post as the noise is probably unique to me!
The performance gains are undeniable, & the bellow is only when giving it some serious pedal.

Regards,
Jon
 

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I had the Mongoose cat back and then added the downpipe and sports cat. Definately a bit more noise but the improvement was noticeable

Chris
 

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jon

i have pduk downpipe and 100cpi cat...but standard tail

there is very little cabin noise apart from the annoying whislte from the cias

maybe its just you?
 

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QUOTE(JayGee @ 7 Jan 2010, 02:07 PM) <{POST_SNAPBACK}>The noise is definately coming from the other side of the fire-wall or at least that's what it seems.
I have got a Mongoose cat-back, very pleased with that (looks nice, not too loud, not a performance mod though).

Profile fitted the down-pipe & I've just remembered they did say that it was very tight on the mounting rubbers,
in their opinion the mounting bracket wasn't quite in the right place. It's a PDUK pipe, could be transmitting noise into the cabin via the streached mountings.
It does seem likely, so ignore my post as the noise is probably unique to me!
The performance gains are undeniable, & the bellow is only when giving it some serious pedal.

Regards,
Jon

I have seen a couple of downpipes that had holes in the flexi section Jon but if yours was like it from new maybe its the mountings as you have suggested?
 

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QUOTE(fishface31a @ 7 Jan 2010, 02:47 PM) <{POST_SNAPBACK}>
I have seen a couple of downpipes that had holes in the flexi section Jon but if yours was like it from new maybe its the mountings as you have suggested?


I've got an oil change due as soon as the weather improves (got my magnetic sump plug today).
Will have a look when I've got the under tray off. Cheers guys.

So, if you can have the gains without the racket, do both pipe & 100 cell cat, definately.
 
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