2.5" > 3" Exhaust Piping... Turbo Application! - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

EchoOfSilence · 01-23-2005, 08:03 PM

I was reading this... and i was really surprised because it actually made sense. has anyone else read this?

sorry for the cross-forum reference guys

Exhaust diameter discussion on fresh alloy

Basically what it says is that on a turbo app the 3" downpipe is best because of the fact that the pressure differential across the turbine is higher with it, therefore higher turbine. then 2.5" piping to the back because of less heat loss and therefore higher exit velocity.

so therefore 3" downpipe, 2.5" piping out is best for turbo system.
What do you guys think?

sr240mike · 01-23-2005, 08:23 PM

It looks like they debated in enough already. I say 3" all the way back with mandrel bends for smooth flow. I could be wrong but I would leave it to a dyno to decide the truth.

007jpang · 01-23-2005, 08:31 PM

what's the best application for NA?

EchoOfSilence · 01-23-2005, 08:33 PM

N/A would be no bigger than 2.5" all the way.

***S14DB*** · 01-23-2005, 08:54 PM

My N/A is 3" now and is better than my 2.5" on the butt and real dyno. So, I'll keep it. I can sell you my 2.5" but no one wants to put there money where their mouth is.

...and that thread is from 2001... Some of those people have changed there mind when they got a 3" on the dyno.

wootwoot · 01-23-2005, 09:37 PM

Turbo acts best from no back pressure at all. Simple as that. For n/a it depends on which engine it is. KA's are strange and seem to like 3'' exhaust even in n/a form

twong85 · 01-23-2005, 11:51 PM

Wow that thread is old. Maybe you should search for more recent topics on that forum that are backed by some dyno sheets.

nlzmo400r · 01-24-2005, 02:58 PM

its not that KAs are strange, its just a 2.4 liter engine is going to react a lot different than a b16 that runs on 3". Its all displacement difference.

wootwoot · 01-24-2005, 03:57 PM

^^^^ no

Different engines have different exhausts that work well with them. For example the vr6(2.8l) works better with a 2.5'' then any other set up and some like the lower torque that the 2.25'' gives it. Different engines do different things.

***S14DB*** · 01-24-2005, 05:09 PM

Quote:

Originally Posted by wootwoot

^^^^ no

Different engines have different exhausts that work well with them. For example the vr6(2.8l) works better with a 2.5'' then any other set up and some like the lower torque that the 2.25'' gives it. Different engines do different things.

The VR6 is a weird engine to begin with...

My car, I/H/E:

EchoOfSilence · 01-24-2005, 06:19 PM

woah wtf

that is some flat shit.

01-23-2005, 08:03 PM	#1
EchoOfSilence Nissanaholic! Join Date: Aug 2003 Location: Los Angeles/Berkeley, CA Posts: 2,238 Trader Rating: (1) Feedback Score: 1 reviews	2.5" > 3" Exhaust Piping... Turbo Application! I was reading this... and i was really surprised because it actually made sense. has anyone else read this? sorry for the cross-forum reference guys Exhaust diameter discussion on fresh alloy Basically what it says is that on a turbo app the 3" downpipe is best because of the fact that the pressure differential across the turbine is higher with it, therefore higher turbine. then 2.5" piping to the back because of less heat loss and therefore higher exit velocity. so therefore 3" downpipe, 2.5" piping out is best for turbo system. What do you guys think? __________________ Petition Nissan to Make the IDx on http://IDxClub.co !

01-23-2005, 08:23 PM	#2
sr240mike Zilvia FREAK! Join Date: Apr 2004 Location: California, Norcal biiaatch Posts: 1,185 Trader Rating: (0) Feedback Score: 0 reviews	It looks like they debated in enough already. I say 3" all the way back with mandrel bends for smooth flow. I could be wrong but I would leave it to a dyno to decide the truth. __________________ TWO IN THE COOT, ONE IN THE POOT

01-23-2005, 08:33 PM	#4
EchoOfSilence Nissanaholic! Join Date: Aug 2003 Location: Los Angeles/Berkeley, CA Posts: 2,238 Trader Rating: (1) Feedback Score: 1 reviews	N/A would be no bigger than 2.5" all the way. __________________ Petition Nissan to Make the IDx on http://IDxClub.co !

01-24-2005, 02:58 PM	#8
nlzmo400r Zilvia FREAK! Join Date: Oct 2003 Location: louisiana Posts: 1,248 Trader Rating: (0) Feedback Score: 0 reviews	its not that KAs are strange, its just a 2.4 liter engine is going to react a lot different than a b16 that runs on 3". Its all displacement difference. __________________ 'my drinking team has a racing problem' [email protected] - gt32 .6bar

01-24-2005, 06:19 PM	#11
EchoOfSilence Nissanaholic! Join Date: Aug 2003 Location: Los Angeles/Berkeley, CA Posts: 2,238 Trader Rating: (1) Feedback Score: 1 reviews	woah wtf that is some flat shit. __________________ Petition Nissan to Make the IDx on http://IDxClub.co !

01-23-2005, 08:31 PM	#3
007jpang Zilvia Junkie Join Date: Jan 2004 Location: Daly City/ San Jose Posts: 495 Trader Rating: (0) Feedback Score: 0 reviews	what's the best application for NA?

01-23-2005, 08:54 PM	#5
*S14DB* AFC #1 Join Date: Oct 2003 Location: 昨晩あなたのお母さんの家 Posts: 20,181 Trader Rating: (3) Feedback Score: 3 reviews	My N/A is 3" now and is better than my 2.5" on the butt and real dyno. So, I'll keep it. I can sell you my 2.5" but no one wants to put there money where their mouth is. ...and that thread is from 2001... Some of those people have changed there mind when they got a 3" on the dyno.

01-23-2005, 09:37 PM	#6
wootwoot Post Whore! Join Date: Jan 2004 Location: sarasota florida biatch Age: 39 Posts: 3,850 Trader Rating: (0) Feedback Score: 0 reviews	Turbo acts best from no back pressure at all. Simple as that. For n/a it depends on which engine it is. KA's are strange and seem to like 3'' exhaust even in n/a form

01-23-2005, 11:51 PM	#7
twong85 Zilvia Member Join Date: Apr 2004 Location: Monterey Park, CA Age: 39 Posts: 155 Trader Rating: (0) Feedback Score: 0 reviews	Wow that thread is old. Maybe you should search for more recent topics on that forum that are backed by some dyno sheets.

01-24-2005, 03:57 PM	#9
wootwoot Post Whore! Join Date: Jan 2004 Location: sarasota florida biatch Age: 39 Posts: 3,850 Trader Rating: (0) Feedback Score: 0 reviews	^^^^ no Different engines have different exhausts that work well with them. For example the vr6(2.8l) works better with a 2.5'' then any other set up and some like the lower torque that the 2.25'' gives it. Different engines do different things.