2.25 or 2.5 exhaust?
02-19-2011, 07:02 AM
#81
The cross sectional area of a pipe is radius squared times Pi. I will do the math
2.25" pipe has a little more than 25% more area than a 2" pipe. (26.5%)
2.5" pipe has a little more than 50% more area than a 2" pipe. (56.25%)
3" Pipe has 125% more area than a 2" Pipe.
I currently need a new cat back exhaust, my original rusty I30 muffler is peeling a away like an onion and had developed a small leak that imagine is only going to get worse.
I have been trying to research exhaust, it seems like catback exhaust gains are minimal. I am wonder if since I have an 00VI and Y-Pipe if I will see any gain when I replace the exhaust.
2.25" pipe has a little more than 25% more area than a 2" pipe. (26.5%)
2.5" pipe has a little more than 50% more area than a 2" pipe. (56.25%)
3" Pipe has 125% more area than a 2" Pipe.
I currently need a new cat back exhaust, my original rusty I30 muffler is peeling a away like an onion and had developed a small leak that imagine is only going to get worse.
I have been trying to research exhaust, it seems like catback exhaust gains are minimal. I am wonder if since I have an 00VI and Y-Pipe if I will see any gain when I replace the exhaust.
Last edited by dgoodhue; 02-21-2011 at 08:36 AM.
03-08-2011, 09:03 PM
#83
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Sorry to resurrect (SP?) an old thread but I just wanted to update anyone that was intrested, I ordered all my 3" pipes that I will need and I decided to rid myself of the cat, so it's going to be straight 3" from the y back. Also, I am going to be getting a different y pipe. I will post pix as the stuff comes.
03-08-2011, 09:08 PM
#84
Sorry to resurrect (SP?) an old thread but I just wanted to update anyone that was intrested, I ordered all my 3" pipes that I will need and I decided to rid myself of the cat, so it's going to be straight 3" from the y back. Also, I am going to be getting a different y pipe. I will post pix as the stuff comes.
03-08-2011, 10:16 PM
#87
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Yea sorry lol. I have a test pipe, 24.5" long resonator, and a muffler with an adjustable silencer. I ment to say it's 3" all the way through instead of just the cat back. I should have cleared that up. Sorry
03-08-2011, 10:31 PM
#88
Wow!!!! Will this be a multi-flanged, 2 or 3 piece exhaust system ? Or a 1 piece all welded together system? Stainless or Aluminized? Can't wait to see your pics!!!!!!!
Here's my 3rd Gen 2.5" catback
Here's my 3rd Gen 2.5" catback
Last edited by CMax03; 03-08-2011 at 10:34 PM.
03-09-2011, 06:24 AM
#90
03-09-2011, 06:42 AM
#91
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Location: Worcester, MA
Posts: 4,011
The cross sectional area of a pipe is radius squared times Pi. I will do the math
2.25" pipe has a little more than 25% more area than a 2" pipe. (26.5%)
2.5" pipe has a little more than 50% more area than a 2" pipe. (56.25%)
3" Pipe has 125% more area than a 2" Pipe.
I currently need a new cat back exhaust, my original rusty I30 muffler is peeling a away like an onion and had developed a small leak that imagine is only going to get worse.
I have been trying to research exhaust, it seems like catback exhaust gains are minimal. I am wonder if since I have an 00VI and Y-Pipe if I will see any gain when I replace the exhaust.
2.25" pipe has a little more than 25% more area than a 2" pipe. (26.5%)
2.5" pipe has a little more than 50% more area than a 2" pipe. (56.25%)
3" Pipe has 125% more area than a 2" Pipe.
I currently need a new cat back exhaust, my original rusty I30 muffler is peeling a away like an onion and had developed a small leak that imagine is only going to get worse.
I have been trying to research exhaust, it seems like catback exhaust gains are minimal. I am wonder if since I have an 00VI and Y-Pipe if I will see any gain when I replace the exhaust.
03-09-2011, 04:03 PM
#94
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03-10-2011, 06:36 PM
#95
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Got my bends today. Should be getting the res, test pipe, and exhaust tomorrow. Figured I'd upload the bends. I never thought I's be so happy to see pipes lol. They came with some kinda wierd slippery stuff on them, had to wipe them down before taking pix
45s
90s
Opening
45s
90s
Opening
03-10-2011, 06:59 PM
#96
yea i got a 2.5in megan cat back and it didnt kill torque at all, it defintly shows a little more power.. go with 2.5. My brother just bought a muffler for his 4th gen and mineke did a 2.25 mandrel bend, so if you do go 2.25, mandrel bend will have no resonators like catbacks have, which may lag more.
03-10-2011, 07:58 PM
#97
The existence of resonators in exhausts/catbacks do not depend on the size of the piping you use. Blame the installer and/or owner if they don't have a resonator, not the size of the piping.
What does the lack of a resonator have to do with lag?
What does the lack of a resonator have to do with lag?
03-10-2011, 08:48 PM
#98
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either way idk where the lag is coming from?
03-11-2011, 12:06 PM
#99
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Proof? All i got is butt dynos lol.
but are u guys saying im wrong? bigger pipe means lower exhaust velocity in the low rpm.
And hey, im not saying to not get the larger pipe. Its all about the top end anyway. There is plenty of low end on these cars for everyday driving.
but are u guys saying im wrong? bigger pipe means lower exhaust velocity in the low rpm.
And hey, im not saying to not get the larger pipe. Its all about the top end anyway. There is plenty of low end on these cars for everyday driving.
03-11-2011, 12:43 PM
#101
Proof? All i got is butt dynos lol.
but are u guys saying im wrong? bigger pipe means lower exhaust velocity in the low rpm.
And hey, im not saying to not get the larger pipe. Its all about the top end anyway. There is plenty of low end on these cars for everyday driving.
but are u guys saying im wrong? bigger pipe means lower exhaust velocity in the low rpm.
And hey, im not saying to not get the larger pipe. Its all about the top end anyway. There is plenty of low end on these cars for everyday driving.
03-11-2011, 01:10 PM
#102
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I gave my opinion solely based on the fact flow = velocity x cross sectional area. The flow curve is exactly that, a curve so there is a point here u have optimum exit velocity for 3" pipe. That could be at 5000 rpm or 4000 rpm or even 3000 rpm. I would be very surprised if that point was any lower than 3000 rpm. Which means the engine is actually working harder at these lower RPMs. Also if that point was so low then Nissan would have supplied a bigger diameter stock pipe, like larger truck engines have.
Again, the max has enough low end power for everday use even with bigger exhaust piping. AND u make up for the loss with the increased HP up top. THats why, in the end, its actually worth it gettin the 3", if u are looking to get every ounce of power out of your car. But this only for some cars. I think a small 4cyl engine would lose power if it was using 3" piping. THe car jus doesnt produce enough exhaust gas to warrant 3". But maybe a large 4cyl could? Idk. You wd have to meausre the exhaust velocity across the entire RPM band to make an informed decision.
And like always, Who needs low end torque if u cant even put most of it to the front 2 wheels. Burnouts and low end is for drag racing.
If anyone is looking to get the most HP out of the car then they shd jus get 3" piping. The next best thing is to get 2.5" piping. This is assuming, the goal is to get the most HP out of the car.
03-11-2011, 05:31 PM
#103
I have a 3" on my 2003 and It's not quite as linear response wise as the OEM system with throttle inputs in the first 1/4"-1/2" of accelerator pedal movement...but for damn sure 1/2" to WOT is A KILLER!!!!! The low range rpm is no slouch.....but 3K on up is like an orgasmic event....I can usually leave a stop sign like an old lady and roll into the throttle (that's not flooring it either!!!) and break the tires loose just before the 1-2 gear change with an A/T.... It never did that before with the 2.5" Cattman and definitely not with the 2" OEM (Choker)!!!!
03-11-2011, 05:40 PM
#104
I know I'm really impressed with Aaron's beast and it's 3" Cattman....That guy is shredding his tires in 1st, 2nd and not just chirping in 3rd but loosing traction.....Yes there's alot of Mid to upper Rpm power gain but low rpm driveability is still awesome and increasing your intake tract size (dia.) from the filter>MAF>TB will make it even more responsive.....Remember the Intake valve is always bigger than the exhaust valve.....
03-11-2011, 09:23 PM
#109
I dont have the 3" so i cant and wont speak on it. If the 3" guys say its the same or better down low then i wd be a lil skeptical but u guys have the equipment so u tell us how the car responds.
I gave my opinion solely based on the fact flow = velocity x cross sectional area. The flow curve is exactly that, a curve so there is a point here u have optimum exit velocity for 3" pipe. That could be at 5000 rpm or 4000 rpm or even 3000 rpm. I would be very surprised if that point was any lower than 3000 rpm. Which means the engine is actually working harder at these lower RPMs. Also if that point was so low then Nissan would have supplied a bigger diameter stock pipe, like larger truck engines have.
Again, the max has enough low end power for everday use even with bigger exhaust piping. AND u make up for the loss with the increased HP up top. THats why, in the end, its actually worth it gettin the 3", if u are looking to get every ounce of power out of your car. But this only for some cars. I think a small 4cyl engine would lose power if it was using 3" piping. THe car jus doesnt produce enough exhaust gas to warrant 3". But maybe a large 4cyl could? Idk. You wd have to meausre the exhaust velocity across the entire RPM band to make an informed decision.
And like always, Who needs low end torque if u cant even put most of it to the front 2 wheels. Burnouts and low end is for drag racing.
If anyone is looking to get the most HP out of the car then they shd jus get 3" piping. The next best thing is to get 2.5" piping. This is assuming, the goal is to get the most HP out of the car.
I gave my opinion solely based on the fact flow = velocity x cross sectional area. The flow curve is exactly that, a curve so there is a point here u have optimum exit velocity for 3" pipe. That could be at 5000 rpm or 4000 rpm or even 3000 rpm. I would be very surprised if that point was any lower than 3000 rpm. Which means the engine is actually working harder at these lower RPMs. Also if that point was so low then Nissan would have supplied a bigger diameter stock pipe, like larger truck engines have.
Again, the max has enough low end power for everday use even with bigger exhaust piping. AND u make up for the loss with the increased HP up top. THats why, in the end, its actually worth it gettin the 3", if u are looking to get every ounce of power out of your car. But this only for some cars. I think a small 4cyl engine would lose power if it was using 3" piping. THe car jus doesnt produce enough exhaust gas to warrant 3". But maybe a large 4cyl could? Idk. You wd have to meausre the exhaust velocity across the entire RPM band to make an informed decision.
And like always, Who needs low end torque if u cant even put most of it to the front 2 wheels. Burnouts and low end is for drag racing.
If anyone is looking to get the most HP out of the car then they shd jus get 3" piping. The next best thing is to get 2.5" piping. This is assuming, the goal is to get the most HP out of the car.
Leaking y-pipe+stock cat.
Leaking Y-pipe+3" Catback
OBX 3.5 Headers+3" Catback.
All 3 had tq down low (or so I thought at the time), each step up I gained more low end, to the point where shifting @ 2k is almost more than enough to keep up with traffic, also cash I'd like to see a dyno with a 2.5" putting down more tq than me before 3k, then I can give your argument some weight.
Now if you were following the 3" thread on the 5th gen forum, you would realise cmax03 was taking the EXACT same postion you were, even after dyno's were posted, because his theory was that even though @ WOT the car is obviously making more power @ all rpms, CMax was thinking that part throttle would be affected the most, and he is concerned more about part throttle response than wot because he doesn't drive his own maxima that much anymore
, mostly the fam drives his, so part throttle response couldn't lag one bit behind stock or he'd hear complaints. For him to back the 3" means a lot more than you think.Sidenote: the reason why I call it the leaky Y is because after many complaints and compliments, my car certainly did not perform like your everyday I/Y maxima, and I've just resorted to calling it the "Leaky Y Setup" cause it's done quite a few things I/Y maximas shouldn't have....
I have a 3" on my 2003 and It's not quite as linear response wise as the OEM system with throttle inputs in the first 1/4"-1/2" of accelerator pedal movement...but for damn sure 1/2" to WOT is A KILLER!!!!! The low range rpm is no slouch.....but 3K on up is like an orgasmic event....I can usually leave a stop sign like an old lady and roll into the throttle (that's not flooring it either!!!) and break the tires loose just before the 1-2 gear change with an A/T.... It never did that before with the 2.5" Cattman and definitely not with the 2" OEM (Choker)!!!!
I know I'm really impressed with Aaron's beast and it's 3" Cattman....That guy is shredding his tires in 1st, 2nd and not just chirping in 3rd but loosing traction.....Yes there's alot of Mid to upper Rpm power gain but low rpm driveability is still awesome and increasing your intake tract size (dia.) from the filter>MAF>TB will make it even more responsive.....Remember the Intake valve is always bigger than the exhaust valve.....
That's definitely one of the 3.5 autos I dream to keep up with, I hope you can take it to the track on the 16th, I hope my extra 2 gears can make that dream happen.How much is this costing you? Keep us up to date w/ prices!
Last edited by aackshun; 03-11-2011 at 09:29 PM.
03-11-2011, 09:36 PM
#110
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All the piping thus far has cost alittle more then $200. I should be getting a 2.5 ypipe for $40 but have to fix the flex pipe. At the end of it all, I should be paying less or just as much as the cattman catback with alot more mods.
03-11-2011, 09:39 PM
#111
You my friend are doing it right, saving money is where it's @.
03-12-2011, 12:15 AM
#112
All 3 had tq down low (or so I thought at the time), each step up I gained more low end, to the point where shifting @ 2k is almost more than enough to keep up with traffic, also cash I'd like to see a dyno with a 2.5" putting down more tq than me before 3k, then I can give your argument some weight.
Agreed, looks like a set of altima headers would go great with this budget setup.
03-12-2011, 01:14 AM
#113
I'm curious whether the piping is Stainless steel or aluminized steel?
03-12-2011, 12:23 PM
#114
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@aackshun, thanks man. It took me a while to do all my research and money balancing to figure out the least expensive way
@shmelly, I assume you mean the 3.5 Altima. What kinda benefits would that have?
@CMax, the test pipe, muffler, and resonator are 309 SS. And the pipes are 409 SS.
@shmelly, I assume you mean the 3.5 Altima. What kinda benefits would that have?
@CMax, the test pipe, muffler, and resonator are 309 SS. And the pipes are 409 SS.
03-12-2011, 03:01 PM
#115
Yes, the generic 3.5 Altima headers. They are nearly identical to the Hotshot headers that a number of people consider as the best headers, if not one of the best available for the maxima. They are very affordable if you can find someone to make you a custom y pipe and relocate a flange or two for a reasonable price. Heres my thread on these headers: http://forums.maxima.org/all-motor/6...-knockoff.html
03-13-2011, 12:35 AM
#120