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Discussion Starter #1
Can adding a 3 inch downpipe without adding the exhuast still gain more power? I'm really not looking to add more loud exhuast note to my car
 

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you will get some form of free-er flow. slightly improved mid range punch. you'll notice it better if you have at least a stage 1 software. but it won't be efficient use of your $.
you could remove one of the resonators or the stuffing in the rear muffler. but still its not the best flow, even if its improved.

importantly, try it out and you might just be pretty pleased with the results.
 

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Discussion Starter #5
Well the thing is i removed the resonator out from the exhuast system. No resonator plus the twin sport pipe exhuast i like it alot. Is the size of the stock pipings 2.25 or 2.5?
 

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You really need the software to get the gains out of the downpipe. Some have run the downpipe and 2.5" exhaust without software and have not reported any noticeable gains.
 

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Saba,

I am also wondering, on stock software, since there is going to be less pressure, or rather free-er flow with the DP and Cat back, torque might be the same, but the mid-high rev range will be slightly more responsive. When you say there is no difference, do you mean across the board, that nothing has changed?

Did that to a local linear and it seems to be working fine. It doesn't have the same feel as a stage 1, but its 1/2 step better than stock. Of course, being not optimised, there will be some loss of low end.

Thanks
 

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the only way of getting a true gain in an intake. Is having cooler air entering the vehicle. Since vehicles combust better with cold O2 . The basic air intakes ive seen going for $200-300 are a total waste of money. Since they honestly dont do anything but add a bigger cone at the end.

Intakes are pointless IMO.
 

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There will be no gain at all if you dont upgrade the rest of the system too. the system is only as free flowing as its most restrictive point. its simple physics. think of the bottleneck effect. example: two milk bottle's, one can hold a pint of milk, the other, two. Both have the same size opening out of which to pour the milk..... which flows faster? neither, the openings are the same size and will only let a certain quantity flow through it regardless of the bottle size(unless you start to take things like gravity into account and stuff but thats going to far for this example)! If your going to do it, do all of it or your just wasting money. and dont use one of them cheap custom places either. you can buy quality perfomance full systems which include racing catylist that arn't much noiser than stock systems. you get what you pay for when it comes to exhausts.
 

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WooSAABy said:
There will be no gain at all if you dont upgrade the rest of the system too. the system is only as free flowing as its most restrictive point. its simple physics. think of the bottleneck effect. example: two milk bottle's, one can hold a pint of milk, the other, two. Both have the same size opening out of which to pour the milk..... which flows faster? neither, the openings are the same size and will only let a certain quantity flow through it regardless of the bottle size
That's an excellent example, and actually gives credence to the practice of going with a larger downpipe. In your example, the bottles are emptying into an infinite space -- the open air -- but what if one was emptying into a fire hose and the other into a drinking straw?

In many turbo systems, the turbine housing (the part spun by the exhaust) and the part directly aft of it (the downpipe) are the pinch point for the expelled gasses trying to flow past the spinning turbine blades. Enlarging the downpipe enables gasses to flow away from the blades faster, which helps both initial spool and top end.

Since most of the 9-3SS models have relatively small turbos, spool is already pretty fast so you might not see much gain there....but the downpipe is the foundation mod for serious power.

If your going to do it, do all of it or your just wasting money. and dont use one of them cheap custom places either. you can buy quality perfomance full systems which include racing catylist that arn't much noiser than stock systems. you get what you pay for when it comes to exhausts.
Getting a full 3" exhaust would be ideal, but unless you're changing the turbo too..and programming...and fueling..and intake...you're just wasting money. Just the downpipe is fine for a start, especially since most spool/top end gains will happen there...but you're right that better flowing exhausts should be next in line.
 

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Discussion Starter #13
How much louder will our rides be with the stage 3 upgrade with the downpipe and exhuast. I really dont want the extra loud noise. Just the extra boost in ponies
 

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mike saunders said:
That's an excellent example, and actually gives credence to the practice of going with a larger downpipe. In your example, the bottles are emptying into an infinite space -- the open air -- but what if one was emptying into a fire hose and the other into a drinking straw?

In many turbo systems, the turbine housing (the part spun by the exhaust) and the part directly aft of it (the downpipe) are the pinch point for the expelled gasses trying to flow past the spinning turbine blades. Enlarging the downpipe enables gasses to flow away from the blades faster, which helps both initial spool and top end.

Since most of the 9-3SS models have relatively small turbos, spool is already pretty fast so you might not see much gain there....but the downpipe is the foundation mod for serious power.



Getting a full 3" exhaust would be ideal, but unless you're changing the turbo too..and programming...and fueling..and intake...you're just wasting money. Just the downpipe is fine for a start, especially since most spool/top end gains will happen there...but you're right that better flowing exhausts should be next in line.
Thanks mike, thats what I meant, but not in so many words.


I've got a full 3" exhuast, great for highway drives, but the one thing I dont like about it is the shortening of the torque/power the rev range, and the turbo lag I get. Its deafening to the rear seat passenger, and at that bass tone, it wipes out some of the words that they are saying in the back seat. resonance they call it?

But when it pulls.... it pulls........... and pulls........ and pulls........
 
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