S40 T5 Baclpressure ?
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Junior Member
Joined: Nov 2011
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S40 T5 Baclpressure ?
Hi
I was surfing the internet for a proper performance exhaust system for my 2008 Volvo s40 T5 and would like some advice please. Seems that mostly a 76mm (3") downpipe is used and then the rest of the system is reduced to 63mm and the cat is also removed and replaced by a catfooler. I have however came across 2 chaps that said they have experienced boostcontrol problems after installing the 76mm downpipe. Apparently the size of the downpipe helps to control the amount of boost ? I was also advised to do the downpipe and catfooler but to not replace the backbox to keep the backpreassure correct by some others ?
My goal is to get more power and would like some of the forums expertise please.
I was surfing the internet for a proper performance exhaust system for my 2008 Volvo s40 T5 and would like some advice please. Seems that mostly a 76mm (3") downpipe is used and then the rest of the system is reduced to 63mm and the cat is also removed and replaced by a catfooler. I have however came across 2 chaps that said they have experienced boostcontrol problems after installing the 76mm downpipe. Apparently the size of the downpipe helps to control the amount of boost ? I was also advised to do the downpipe and catfooler but to not replace the backbox to keep the backpreassure correct by some others ?
My goal is to get more power and would like some of the forums expertise please.
Well you want to eliminate back pressure, but not completely.
What tune are the guys who you are talking to using? if it's a stock that means they have other issues and it's not the DP's fault.
On the other hand i am soon making custom 3inch DP's.
What tune are the guys who you are talking to using? if it's a stock that means they have other issues and it's not the DP's fault.
On the other hand i am soon making custom 3inch DP's.
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Joined: Dec 2005
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From: NOYB
You want some backpressure but not a lot. So install a straight through desgin free flowing muffler like Magnaflow or BORLA is what your going to want to look into & or an equivalent.
As for the 3" downpipe to control boost I have never heard of this. It's a metal pipe it doesn't control boost period. Your ECU and wastegate do that. Now it may help it boost a little sooner (Spool Time) . But that is only because more airflow can get through. Your not going to gain "BOOST" by adding a downpipe. You'll gain HP and performance but if you want more "BOOST" you need a Boost Controller and or an ECU upgrade (IPD USA, BSR, RICA, SPEEDTUNING USA, UPSOLUTE...).
When you do the downpipe and catback system you want mandrel bends for a free flowing exhaust crush bends will hinder performance.
As for the 3" downpipe to control boost I have never heard of this. It's a metal pipe it doesn't control boost period. Your ECU and wastegate do that. Now it may help it boost a little sooner (Spool Time) . But that is only because more airflow can get through. Your not going to gain "BOOST" by adding a downpipe. You'll gain HP and performance but if you want more "BOOST" you need a Boost Controller and or an ECU upgrade (IPD USA, BSR, RICA, SPEEDTUNING USA, UPSOLUTE...).
When you do the downpipe and catback system you want mandrel bends for a free flowing exhaust crush bends will hinder performance.
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