my 3in problem - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

s13winder · 11-11-2003, 10:10 PM

I own a 89 240sx with a 97 ka24de swap. I am currently running the apex N1 exhaust. already am i not matching up with the OEM piping to my exhaust so im not getting full potential of the car. Now is there anyway, or anyone that makes 3in headers for the KA, or would i just be better off running hot shot headers, then running with a 3in downpipe then the 3in strait pipe? im kinda lost. so if anyone here can help, id be greatly appreciatd. Thank ya much!

Evil S14 · 11-11-2003, 10:24 PM

why would you need that big of piping? you wont have any backpressure and ur car will feel like ass

knightrider · 11-11-2003, 10:28 PM

ur apex n1 exhaust is made for a turbo car, hence the 3 in piping, if u run 3 in piping, ur car will have no backpresure, since it is normally aspirated, and will have no low end power at all, bigger is not always better in the case of NA engines,

s13winder · 11-11-2003, 10:32 PM

alrite, sounds understandable. Thanks!

holisticbeatz · 11-11-2003, 10:43 PM

Quote:

Originally posted by Evil S14
why would you need that big of piping? you wont have any backpressure and ur car will feel like ass

Quote:

Originally posted by Evil S14
why would you need that big of piping? you wont have any backpressure and ur car will feel like ass

If you guys aren't going to answer his question, then why bother replying?

Quote:

Originally posted by s13winder
I own a 89 240sx with a 97 ka24de swap. I am currently running the apex N1 exhaust. already am i not matching up with the OEM piping to my exhaust so im not getting full potential of the car.

If I understand this correctly, you own an 89 S13 with a S14 KA24DE swap and the APEXi N1 isn't lining up with the OEM piping? A simple solution would be to take your car in to a muffler shop and have them hack/weld/flange it for you so it'll fit.

Quote:

Now is there anyway, or anyone that makes 3in headers for the KA, or would i just be better off running hot shot headers, then running with a 3in downpipe then the 3in strait pipe? im kinda lost. so if anyone here can help, id be greatly appreciatd. Thank ya much!

I'm assuming your KA is naturally aspirated, so with that in consideration, it'll be a good idea not to use a 3 inch downpipe or custom 3 inch headers. My advice, get Hotshot headers and have a muffler shop install custom exhaust piping for you.

misnomer · 11-12-2003, 12:20 AM

I think what he means is matching the 2 or 2.25" factory header (dunno what the size is) to a 3" exhaust is causing him concerns with performance.

There are more than enough threads on these forums about scavenging and exhaust pipe sizes. Do a quick search for "Scavenging" or "Backpressure" and you'll find what I just did :P

To summarize: for N/A, too big a pipe sucks. Basically, with a big pipe, it may flow more air, but as the exhaust gasses enter that greater volume, it cools and slows down. Anyhow, for a 2.4 liter, NA engine, 3" really is just too big. And for the record, backpressure is bad, mmkay? :P It's just a common side effect of scavenging. "Full Potential" of the car would be shorter diameter pipe all the way back.

Bigger headers may help, but they will also make your car really freaking loud. About the best thing I can think of for you may be a 2.whatever inch to 3" pipe that will steadily open up to your N1. . . It's a compromise that will help reduce turbulance (won't help the cooling effect). You won't find a 3" header-- at least there are none I have heard of. There is no advantage to it.

If you were planning to turbocharge the car in the near future, disregard everything I said.

s13winder · 11-12-2003, 12:29 AM

alrite. Thanks for your time guys. its greatly appreciated. I guess ill go with the NA setup and stick with 2.5 at the most..hot shots, 2.5 strait pipe, and i am trading my friend for his HKS exhaust so it'll be 2.5 al lthe way. Thanks again for your help. Explained alot.

Evil S14 · 11-12-2003, 10:03 AM

Quote:

Originally posted by holisticbeatz
If you guys aren't going to answer his question, then why bother replying?

its not like my post was completely irrelevant, if someone asked you if it was possible to run their car off of moonshine would you rather tell them "yes" and answer the question or tell them "thats not such a good idea..." so they actually learn something

bad analogy, but you get the point

twitchy · 11-12-2003, 12:14 PM

i found half inch oversize plumbing really woke up the top end

11-11-2003, 10:10 PM	#1
s13winder Join Date: Nov 2003 Location: Villa Park, CA Posts: 7 Trader Rating: (0) Feedback Score: 0 reviews	my 3in problem I own a 89 240sx with a 97 ka24de swap. I am currently running the apex N1 exhaust. already am i not matching up with the OEM piping to my exhaust so im not getting full potential of the car. Now is there anyway, or anyone that makes 3in headers for the KA, or would i just be better off running hot shot headers, then running with a 3in downpipe then the 3in strait pipe? im kinda lost. so if anyone here can help, id be greatly appreciatd. Thank ya much!

11-11-2003, 10:24 PM	#2
Evil S14 Zilvia Addict Join Date: Dec 2001 Location: Indianapolis/Bloomington Age: 41 Posts: 610 Trader Rating: (0) Feedback Score: 0 reviews	why would you need that big of piping? you wont have any backpressure and ur car will feel like ass __________________ image exceeds forum limit -Moderation

11-11-2003, 10:28 PM	#3
knightrider Zilvia Addict Join Date: Jan 2003 Location: san diego Age: 41 Posts: 618 Trader Rating: (0) Feedback Score: 0 reviews	ur apex n1 exhaust is made for a turbo car, hence the 3 in piping, if u run 3 in piping, ur car will have no backpresure, since it is normally aspirated, and will have no low end power at all, bigger is not always better in the case of NA engines, __________________ Drift_ Into A Mountain Jim Wolf Technology Stock CA18DET-SR T25-greddy FMIC-JWT SR Lightened FLywheel-300zxTTclutch-SR20DET JWT tuned Ecu

11-12-2003, 12:20 AM	#6
misnomer Nissanaholic! Join Date: Jul 2001 Location: Nevada Posts: 2,293 Trader Rating: (0) Feedback Score: 0 reviews	I think what he means is matching the 2 or 2.25" factory header (dunno what the size is) to a 3" exhaust is causing him concerns with performance. There are more than enough threads on these forums about scavenging and exhaust pipe sizes. Do a quick search for "Scavenging" or "Backpressure" and you'll find what I just did :P To summarize: for N/A, too big a pipe sucks. Basically, with a big pipe, it may flow more air, but as the exhaust gasses enter that greater volume, it cools and slows down. Anyhow, for a 2.4 liter, NA engine, 3" really is just too big. And for the record, backpressure is bad, mmkay? :P It's just a common side effect of scavenging. "Full Potential" of the car would be shorter diameter pipe all the way back. Bigger headers may help, but they will also make your car really freaking loud. About the best thing I can think of for you may be a 2.whatever inch to 3" pipe that will steadily open up to your N1. . . It's a compromise that will help reduce turbulance (won't help the cooling effect). You won't find a 3" header-- at least there are none I have heard of. There is no advantage to it. If you were planning to turbocharge the car in the near future, disregard everything I said. __________________ Rowsdower saves us and saves all the world!

11-12-2003, 12:14 PM	#9
twitchy Zilvia FREAK! Join Date: Apr 2003 Location: Ontario Posts: 1,579 Trader Rating: (0) Feedback Score: 0 reviews	i found half inch oversize plumbing really woke up the top end __________________ Who the hell needs a sig anyhow

11-11-2003, 10:32 PM	#4
s13winder Join Date: Nov 2003 Location: Villa Park, CA Posts: 7 Trader Rating: (0) Feedback Score: 0 reviews	alrite, sounds understandable. Thanks!

11-12-2003, 12:29 AM	#7
s13winder Join Date: Nov 2003 Location: Villa Park, CA Posts: 7 Trader Rating: (0) Feedback Score: 0 reviews	alrite. Thanks for your time guys. its greatly appreciated. I guess ill go with the NA setup and stick with 2.5 at the most..hot shots, 2.5 strait pipe, and i am trading my friend for his HKS exhaust so it'll be 2.5 al lthe way. Thanks again for your help. Explained alot.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode