3" Headers on a N/A 5.5g?
10-21-2012, 01:49 PM
#1
3" Headers on a N/A 5.5g?
Would headers with a 3" yipe section create enough back pressure if running N/A? I have a 3" testpipe , 3" catback and a 3.5" intake already. I have no plans of going boost or spray. I know the car will go very rich but I have a VAFC2 to correct it.
The header setup is VERY similar to Cattmans with runners being I think, 10-13"
EDIT: Mod list is here: http://forums.maxima.org/1-4-1-8-mil...to-maxima.html
The header setup is VERY similar to Cattmans with runners being I think, 10-13"
EDIT: Mod list is here: http://forums.maxima.org/1-4-1-8-mil...to-maxima.html
Last edited by nishfish871; 10-21-2012 at 09:02 PM.
10-21-2012, 06:28 PM
#2
I think very very unnecessary without other mods first, like cams and ability to truly tune the car. Otherwise, I'd expect little to no gain. Unless you consider noise/volume a gain, then I suspect there will be more of that than in the performance area. But, I'd be interested in before and after dynos. Just think your time and money could be better spent elsewhere.
10-21-2012, 07:51 PM
#3
I dont think you want to do that. Most exhaust systems are built with opposite theory in mind, especially Nissan cars. The idea is to have the smallest diameter pipes early and open up as they travel to the rear. I wouldnt go bigger than 2.5" for a N/A car. A 3" cat-back is one thing but not on the y-pipe
10-21-2012, 08:20 PM
#4
Well I'm gonna put in my 2 cents! If you could build a copy of Cattman's header Ypipe utilizing a 3" collector do it ...just as a test.....I think you would see gains on the track but on the streets during normal driving the driveability maybe sacrificed.....
10-21-2012, 08:28 PM
#5
With an oversized flex I think that is enough. I would personally like to have a 2.5" Y-pipe but the 2.25" is fine and allows it to open up as it goes back.
^Picture of this 3" header cattman made? I wasnt aware he made any larger than 2.5" ID
^Picture of this 3" header cattman made? I wasnt aware he made any larger than 2.5" ID
10-21-2012, 08:59 PM
#7
I'm looking for what is gained over the original 2.5" cattman and this one. And do not take cams out the question. I wonder if any 350z guys run 3" after the collectors N/A.
10-22-2012, 04:38 AM
#8
It will only help. Assuming you have a way to tune, less back-pressure is almost always better.
I have hotshots with a 3" y-pipe (actually stock hotshot y-pipe with the collector replaced with a 3" oval to circular pipe), (Full 3" from the y-pipe to the tips) and my car seems to run pretty well with it.
There are all motor k-series Honda's running 3" exhaust making like 220whp lol.
People gained power switching from a 2.5" catback to a 3" catback, so I would assume increasing the y-pipe size would help in a similar way.
I have hotshots with a 3" y-pipe (actually stock hotshot y-pipe with the collector replaced with a 3" oval to circular pipe), (Full 3" from the y-pipe to the tips) and my car seems to run pretty well with it.
There are all motor k-series Honda's running 3" exhaust making like 220whp lol.
People gained power switching from a 2.5" catback to a 3" catback, so I would assume increasing the y-pipe size would help in a similar way.
10-22-2012, 08:01 AM
#10
Just buy it already! lol
...and gains will be had for you regardless since you're eliminating the precats. In the end, you're gonna yearn for more and probably go nitrous anyway...you know it, Nish!
hahaha
...and gains will be had for you regardless since you're eliminating the precats. In the end, you're gonna yearn for more and probably go nitrous anyway...you know it, Nish!
hahaha
10-22-2012, 09:56 AM
#11
I say go for it. http://forums.maxima.org/dyno-discus...f-set-ups.html
10-22-2012, 02:07 PM
#13
i was working toward that at one point. dude said that he would have to drop the piping down further under the car to make the loop. They offered an unequal length setup that would have been in three and about half of the price :/
I do have another local that can make one for you pretty cheap in comparison to MBS (*Mandrel Bent Solutions*), he just made one for a 4th gen for under 300. (Ypipe that is)
10-22-2012, 04:55 PM
#18
The comparison would be pointless, exhaust is completely different. But yes, there's a ton of 3"y pipes on 350s, the diff is th z basically has dual exhaust until the y pipe which is way back under the driver seat. Apples/oranges
10-22-2012, 05:44 PM
#19
As far as the specifics of the Y pipe setup, I am assuming if you go to 3" Y pipe, you'll be installing a new Collector as well?
All of this does seem silly without Cams, though, just my $0.02, with little experience.
The truth is, no one can tell you if it's good/bad, but given what we know about your current mods, I'd say it's too big without cams, but if cams are coming, you can deal with the low-end power loss until cams, maybe.
Given your N/A, have you considered long-tube headers instead of this?
All of this does seem silly without Cams, though, just my $0.02, with little experience.
The truth is, no one can tell you if it's good/bad, but given what we know about your current mods, I'd say it's too big without cams, but if cams are coming, you can deal with the low-end power loss until cams, maybe.
Given your N/A, have you considered long-tube headers instead of this?
10-22-2012, 08:51 PM
#20
As far as the specifics of the Y pipe setup, I am assuming if you go to 3" Y pipe, you'll be installing a new Collector as well?
All of this does seem silly without Cams, though, just my $0.02, with little experience.
The truth is, no one can tell you if it's good/bad, but given what we know about your current mods, I'd say it's too big without cams, but if cams are coming, you can deal with the low-end power loss until cams, maybe.
Given your N/A, have you considered long-tube headers instead of this?
All of this does seem silly without Cams, though, just my $0.02, with little experience.
The truth is, no one can tell you if it's good/bad, but given what we know about your current mods, I'd say it's too big without cams, but if cams are coming, you can deal with the low-end power loss until cams, maybe.
Given your N/A, have you considered long-tube headers instead of this?
I guess I have no choice...cams would have to be the next mod or custom UIM.
I will wait for a few others to chime in before I make a decision.
And who can produce long-tube headers for under $1k?
10-22-2012, 10:28 PM
#23
10-22-2012, 11:41 PM
#24
i was working toward that at one point. dude said that he would have to drop the piping down further under the car to make the loop. They offered an unequal length setup that would have been in three and about half of the price :/
I do have another local that can make one for you pretty cheap in comparison to MBS (*Mandrel Bent Solutions*), he just made one for a 4th gen for under 300. (Ypipe that is)
10-23-2012, 04:56 AM
#25
Just pointing out...everyone and their mother swore that 2.5" exhaust was 'best' and produced most power, and that a larger exhaust would only cause losses by flowing too much. Hell there were countless scientific reasoning Internet links to back up those claims. 
Then the 3" exhaust catbacks started production and all of a sudden people noticed gains over the 2.5" setup.
Y'all do know that once people thought the earth was flat?...crazy huh?
Then the 3" exhaust catbacks started production and all of a sudden people noticed gains over the 2.5" setup.
Y'all do know that once people thought the earth was flat?...crazy huh?
Last edited by MrEous; 10-23-2012 at 04:59 AM.
10-23-2012, 09:57 AM
#27
The header and ypipe is sold as a unit, like Cattmans. They are basically 3" Cattman headers since his welder made them. So after having all boltons possible (except lw pully), a 3" setup is still pointless...interesting.
I guess I have no choice...cams would have to be the next mod or custom UIM.
I will wait for a few others to chime in before I make a decision.
And who can produce long-tube headers for under $1k?
I guess I have no choice...cams would have to be the next mod or custom UIM.
I will wait for a few others to chime in before I make a decision.
And who can produce long-tube headers for under $1k?
As long as theres a nice transition to the 3" with a proper collector.
The age old thing, it's not about pressure, it's about flow, more precisely, velocity. In rough rules, you want properly 'tuned' and sized Headers with long tubes on an N/A car, then after that you want the exhaust pretty much as open as possible. there is a point where you don't gain any more and are wasting your money and time though, I would like to guess that 3.5" is that line on the Maxima for the rest of hte exhaust. But it's fairly unreasnable to try and fit 3.5" piping, let alone the cost of it.
11-10-2012, 08:35 PM
#33
No before and after. I really don't think I'll be loosing any low end with the 3" ypipe section.
To get one made from Cattman...it will be expensive and that's an understatement.
To get one made from Cattman...it will be expensive and that's an understatement.
Last edited by nishfish871; 11-10-2012 at 08:37 PM.
11-11-2012, 06:55 AM
#36
11-11-2012, 09:09 AM
#38
Just pointing out...everyone and their mother swore that 2.5" exhaust was 'best' and produced most power, and that a larger exhaust would only cause losses by flowing too much. Hell there were countless scientific reasoning Internet links to back up those claims.
Then the 3" exhaust catbacks started production and all of a sudden people noticed gains over the 2.5" setup.
Y'all do know that once people thought the earth was flat?...crazy huh?
Then the 3" exhaust catbacks started production and all of a sudden people noticed gains over the 2.5" setup.
Y'all do know that once people thought the earth was flat?...crazy huh?