Headers Lesson
Thread Starter
|
Registered User
Joined: Mar 2004
Posts: 1,116
Likes: 0
From: Memphis
Headers Lesson
I would like a short lesson on headers if any one knows what they are talking about.
Pros and cons. Why do they work? How does equal length improve anything? Ceramic vs. SS? What implications does "longer" have? Do "short" headers have any advantage? What brands are recommended for the G and why? Why doesn't one want headers if they are going turbo? What are the supercharger and nitrous implications? Do the inside diameters vary?
I've seen DC headers from $450 and the Nismo and Crawford headers in the low thousand range. Why the big price difference?
Any thoughts would be appreciated, particularly factual or firsthand experiences controlling for conditions.
2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way
Pros and cons. Why do they work? How does equal length improve anything? Ceramic vs. SS? What implications does "longer" have? Do "short" headers have any advantage? What brands are recommended for the G and why? Why doesn't one want headers if they are going turbo? What are the supercharger and nitrous implications? Do the inside diameters vary?
I've seen DC headers from $450 and the Nismo and Crawford headers in the low thousand range. Why the big price difference?
Any thoughts would be appreciated, particularly factual or firsthand experiences controlling for conditions.
2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way
Registered User
Joined: May 2004
Posts: 233
Likes: 0
From: Texas
Re: Headers Lesson
"Pros and cons. Why do they work?"
Just like your exhaust upgrades, they provide more and better flow, due to increased size of pipes and mandrel bends. The down side, if you consider it such, is that they will result in a louder exhaust note when combined with a free-flowing exhaust.
"How does equal length improve anything?"
Just an educated guess here, but equal exhaust scavenging is a likely benefit, which results in better power production and uniform temps. among all cylinders (providing other factors aren't contributing to different cylinder temps.)
"Ceramic vs. SS?"
Ceramic-coated headers are going to keep the heat within the headers better, which result in better exhaust scavenging and, in return, better power production. You can get headers coated on just the outside or get them coated on the inside as well, which is the recommended route. Slightly lower under-hood temps. are also a benefit with ceramic-coated headers. SS headers look great, at first, but will gernerally turn colors as they go through several heat cycles. Nothing too bad, but you'll get that blue'ish hue instead of crystal clear polished stainless. IMO, the ceramic-coated headers are going to be a more practical choice, but the SS headers should add what I consider to be a better quality exhaust note. It's not going to be a huge difference, but enough for some to notice and have a preference.
"What implications does "longer" have? Do "short" headers have any advantage?"
Short are going to fit in tighter locations, which is always a benefit, but long headers generally offer equal flow from each cylinder due to the equal length of each primary exhaust tube. Today, you can usually find equal-length shorty headers for most applications, which is a great solution for street cars.
"What brands are recommended for the G and why?"
You got me on that one.
"Why doesn't one want headers if they are going turbo?"
It's a waste of money because you'll need an exhaust manifold that has a flange mount for the turbo. Turbos are driven by the exhaust.
"What are the supercharger and nitrous implications? Do the inside diameters vary?"
Never messed with nitrous, but a supercharger is going to benefit from better headers just as a turbo benefits from a bigger exhaust. Because the supercharger isn't mounted to an exhaust manifold, the headers are what you'd need.
"I've seen DC headers from $450 and the Nismo and Crawford headers in the low thousand range. Why the big price difference?"
I'd have to look into these further to be certain, but I believe the DC headers are going to be mild steel and ceramic coated, while the higher priced headers are generally stainless steel.
Maybe someone else can touch on the pros and cons of mild-steel over stainless.
And sorry for the long-winded post. I'm bad about those.
Future G35C Owner... ...Never too soon to think about modifications!!
Just like your exhaust upgrades, they provide more and better flow, due to increased size of pipes and mandrel bends. The down side, if you consider it such, is that they will result in a louder exhaust note when combined with a free-flowing exhaust.
"How does equal length improve anything?"
Just an educated guess here, but equal exhaust scavenging is a likely benefit, which results in better power production and uniform temps. among all cylinders (providing other factors aren't contributing to different cylinder temps.)
"Ceramic vs. SS?"
Ceramic-coated headers are going to keep the heat within the headers better, which result in better exhaust scavenging and, in return, better power production. You can get headers coated on just the outside or get them coated on the inside as well, which is the recommended route. Slightly lower under-hood temps. are also a benefit with ceramic-coated headers. SS headers look great, at first, but will gernerally turn colors as they go through several heat cycles. Nothing too bad, but you'll get that blue'ish hue instead of crystal clear polished stainless. IMO, the ceramic-coated headers are going to be a more practical choice, but the SS headers should add what I consider to be a better quality exhaust note. It's not going to be a huge difference, but enough for some to notice and have a preference.
"What implications does "longer" have? Do "short" headers have any advantage?"
Short are going to fit in tighter locations, which is always a benefit, but long headers generally offer equal flow from each cylinder due to the equal length of each primary exhaust tube. Today, you can usually find equal-length shorty headers for most applications, which is a great solution for street cars.
"What brands are recommended for the G and why?"
You got me on that one.
"Why doesn't one want headers if they are going turbo?"
It's a waste of money because you'll need an exhaust manifold that has a flange mount for the turbo. Turbos are driven by the exhaust.
"What are the supercharger and nitrous implications? Do the inside diameters vary?"
Never messed with nitrous, but a supercharger is going to benefit from better headers just as a turbo benefits from a bigger exhaust. Because the supercharger isn't mounted to an exhaust manifold, the headers are what you'd need.
"I've seen DC headers from $450 and the Nismo and Crawford headers in the low thousand range. Why the big price difference?"
I'd have to look into these further to be certain, but I believe the DC headers are going to be mild steel and ceramic coated, while the higher priced headers are generally stainless steel.
Maybe someone else can touch on the pros and cons of mild-steel over stainless.
And sorry for the long-winded post. I'm bad about those.
Future G35C Owner... ...Never too soon to think about modifications!!
Thread Starter
|
Registered User
Joined: Mar 2004
Posts: 1,116
Likes: 0
From: Memphis
Re: Headers Lesson
Thanks alot Ron. Great comments.
I just got off the phone with Doug (yeahhh my plenum is on the way!!!!!) and he says that his are the longest out there. At 26" they are perfect for mega low end torque and high end HP. His are SS and powder coated. He says the rest are up to an inch or two non-equal length and way too short. His philosophy is that if you're going to spend 6-8 hours putting something on, it better be the optimal it can be. He said he tried 28" but it wouldn't fit, no way, no how.
He's convinced me enough to remain with my choice to stick with the Crawford headers when the time comes, but after then plenum, I'm not doing anything else until the TS ECU becomes available for the 04.5 Coupe sometime in the next month or two.
Crawford also mentioned that TS is working on an ECU flash specifically tuned to the Crawford total package. I'm all over that, and after it's available my current plan is headers, Crawford cats, and a Fujitsubo exhaust. Then I'm done....that is until I find a lightweight wheel...Nismo?
Interesting to note: He's a firm believer that the stock air intake is the best. He says the CAIs on the market now will cost HP on the Z for sure. He hasn't tested the G yet but he felt pretty strongly about it.
2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way
I just got off the phone with Doug (yeahhh my plenum is on the way!!!!!) and he says that his are the longest out there. At 26" they are perfect for mega low end torque and high end HP. His are SS and powder coated. He says the rest are up to an inch or two non-equal length and way too short. His philosophy is that if you're going to spend 6-8 hours putting something on, it better be the optimal it can be. He said he tried 28" but it wouldn't fit, no way, no how.
He's convinced me enough to remain with my choice to stick with the Crawford headers when the time comes, but after then plenum, I'm not doing anything else until the TS ECU becomes available for the 04.5 Coupe sometime in the next month or two.
Crawford also mentioned that TS is working on an ECU flash specifically tuned to the Crawford total package. I'm all over that, and after it's available my current plan is headers, Crawford cats, and a Fujitsubo exhaust. Then I'm done....that is until I find a lightweight wheel...Nismo?
Interesting to note: He's a firm believer that the stock air intake is the best. He says the CAIs on the market now will cost HP on the Z for sure. He hasn't tested the G yet but he felt pretty strongly about it.
2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way
Registered User
Joined: Oct 2003
Posts: 749
Likes: 0
From: Toronto
04 G35 Coupe 6MT Gold Brembo’s
Re: Headers Lesson
Yeah, thanks Ron for the post on headers.
Hey Todd,
When you spoke with Doug did he mean the stock intake was best WITH the Crawford plenum? Or without too?
I figure he means the stock intake prevents the car from running too lean as it might with the plenum plus cats, PLUS aftermarket CAI... right?
I'm ordering a Crawford too, but haven't spoken to Doug. Is that what you understood him to mean when he said that?
(In any case, even if the car runs lean, the ECU reprogram should take care of that, I figure.)
2004 G35C 6MT + Nav, Silverstone
Hey Todd,
When you spoke with Doug did he mean the stock intake was best WITH the Crawford plenum? Or without too?
I figure he means the stock intake prevents the car from running too lean as it might with the plenum plus cats, PLUS aftermarket CAI... right?
I'm ordering a Crawford too, but haven't spoken to Doug. Is that what you understood him to mean when he said that?
(In any case, even if the car runs lean, the ECU reprogram should take care of that, I figure.)
2004 G35C 6MT + Nav, Silverstone
Re: Headers Lesson
How is the 04.5 coupes ECU differnt then the 04? I've never heard of an 04.5???
Kevin
----------------------------------------------------------------
04 Diamond Graphite Coupe - FULLY loaded
Windows up with OEM Remote
RE Short Shifter // Z Tube
Kevin
----------------------------------------------------------------
04 Diamond Graphite Coupe - FULLY loaded
Windows up with OEM Remote
RE Short Shifter // Z Tube
Trending Topics
Registered User
Joined: Jun 2002
Posts: 378
Likes: 0
From: Tennessee
Re: Headers Lesson
Great input.
I believe the materials used to make the headers determine how long they last before they crack. Mild steel headers will crack soonest. Stainless steel headers last longer. Cast iron (!) would last the longest, but are probably not practical. I'd default to SS.
Equal length, mandrel-bent tubes ensure that each pulse of exhaust is directed to the tail-pipe unimpeded by another adjacent pulse. The equal length tubes line the pulses up, one behind the other, to minimize back-pressure and maximize scavenging. Less back-pressure probably allows the engine to run cooler, too...
The engine exhales more freely with headers, which, in turn, allow it to inhale more freely. Each cylinder charge is cleaner, allowing the engine to make more power.
'03 G35s 5AT, Garnet Fire/Willow
Staggered 18" SSR GT1/Bridgestone PP S03
Eibach Springs/Sways, Stillen 2-pc BBK
Stillen Intake & SS Cat-Back Dual Exhaust
I believe the materials used to make the headers determine how long they last before they crack. Mild steel headers will crack soonest. Stainless steel headers last longer. Cast iron (!) would last the longest, but are probably not practical. I'd default to SS.
Equal length, mandrel-bent tubes ensure that each pulse of exhaust is directed to the tail-pipe unimpeded by another adjacent pulse. The equal length tubes line the pulses up, one behind the other, to minimize back-pressure and maximize scavenging. Less back-pressure probably allows the engine to run cooler, too...
The engine exhales more freely with headers, which, in turn, allow it to inhale more freely. Each cylinder charge is cleaner, allowing the engine to make more power.
'03 G35s 5AT, Garnet Fire/Willow
Staggered 18" SSR GT1/Bridgestone PP S03
Eibach Springs/Sways, Stillen 2-pc BBK
Stillen Intake & SS Cat-Back Dual Exhaust
Re: Headers Lesson
ok, once and for all, the stock intake is the best for anything and everything.
G35s6mt/TSecu/350Z Springs&Struts/K&Nfilter+Z-tube/StillenDualExhaust /6WireGroundKit/KinetixHighFlow
G35s6mt/TSecu/350Z Springs&Struts/K&Nfilter+Z-tube/StillenDualExhaust /6WireGroundKit/KinetixHighFlow
Registered User
Joined: Jul 2002
Posts: 587
Likes: 0
From: Orlando
Re: Headers Lesson
nutty, did you mean intake or exhaust? Or were you kidding?
Stock intake may be better for some reasons, but not for sound. Or looks.
imho.
2004 G35C 6MT Black. I stare. And I am content.
Stock intake may be better for some reasons, but not for sound. Or looks.
imho.
2004 G35C 6MT Black. I stare. And I am content.
Registered User
Joined: Feb 2004
Posts: 8,269
Likes: 0
Re: Headers Lesson
DED,
Since his sig has "K&N filter + Z-tube" listed in it, I believe he is referring to the headers. I'd also guess he is not referring to the plenum, because if he is, he'd be absolutely nuts!!! [img]/w3timages/icons/smile.gif[/img]
300bhp??? We'll see... 5-22-2004
Since his sig has "K&N filter + Z-tube" listed in it, I believe he is referring to the headers. I'd also guess he is not referring to the plenum, because if he is, he'd be absolutely nuts!!! [img]/w3timages/icons/smile.gif[/img]
300bhp??? We'll see... 5-22-2004
Thread Starter
|
Registered User
Joined: Mar 2004
Posts: 1,116
Likes: 0
From: Memphis
Re: Headers Lesson
Meta,
Doug does not like any of the aftermarket intakes (I'm NOT referring to the Z tube) and he is convinced that there is a ram air effect the stock box creates.
Knowing what I do about ram air, I'd love to debate this with Doug or anyone else over a beer and a pool table. Ram air is an effect that happens only at a select RPM range. It will add some ponies in one small range. A CAI however, can potentially reduce the temperature of the air. Proper resonance can also help. I'm gambling that Nismo has done their homework and I'm trying the Nismo CAI this weekend. I'm going to test my hypothesis that cold air trumps ram air. I also doubt that there is even a clear and straight enough path on the G to even claim 'ram air'. By the time the air hits the stock box, it's not exactly "ramming". It's gone through a radiator and made several turns by the time it gets to the throttle body.
Doug was referring to the Z, which already has the Z tube on it. So his preference, on the Z anyway, is to leave the stock airbox on it. I'm extrapolating his reasoning to assume that his preference on the G (with or without the plenum) would be to use the Z tube with the stock airbox.
Doug seems to be a practical old salt that learns by doing and testing. I don't know how well he controls for conditions but he does have years under his belt. Being the "trust but verifier" that I am, I'm going to see for myself in controlled conditions with my G Tech Comp. I'll post my observations when I'm done this weekend.
He seemed to think the G has plenty of fuel to avoid a lean condition, but he did advise that once I started playing with the exhaust, I better flash the ECU. He seemed suprised when I told him that there was NO T/S ECU AVAILABLE for the 2004.5. T/S has told me it's in Japan being decoded and to check back with them in a month. Doug told me that he is working with T/S on a flash specific to the "Crawford total package". I am going with the "total package" and putting on the Fujitsobu exhaust (cat back) as well.....then I'm off to find the lightest wheel that's the same dimensions as stock (any ideas on this part?).
2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way
Doug does not like any of the aftermarket intakes (I'm NOT referring to the Z tube) and he is convinced that there is a ram air effect the stock box creates.
Knowing what I do about ram air, I'd love to debate this with Doug or anyone else over a beer and a pool table. Ram air is an effect that happens only at a select RPM range. It will add some ponies in one small range. A CAI however, can potentially reduce the temperature of the air. Proper resonance can also help. I'm gambling that Nismo has done their homework and I'm trying the Nismo CAI this weekend. I'm going to test my hypothesis that cold air trumps ram air. I also doubt that there is even a clear and straight enough path on the G to even claim 'ram air'. By the time the air hits the stock box, it's not exactly "ramming". It's gone through a radiator and made several turns by the time it gets to the throttle body.
Doug was referring to the Z, which already has the Z tube on it. So his preference, on the Z anyway, is to leave the stock airbox on it. I'm extrapolating his reasoning to assume that his preference on the G (with or without the plenum) would be to use the Z tube with the stock airbox.
Doug seems to be a practical old salt that learns by doing and testing. I don't know how well he controls for conditions but he does have years under his belt. Being the "trust but verifier" that I am, I'm going to see for myself in controlled conditions with my G Tech Comp. I'll post my observations when I'm done this weekend.
He seemed to think the G has plenty of fuel to avoid a lean condition, but he did advise that once I started playing with the exhaust, I better flash the ECU. He seemed suprised when I told him that there was NO T/S ECU AVAILABLE for the 2004.5. T/S has told me it's in Japan being decoded and to check back with them in a month. Doug told me that he is working with T/S on a flash specific to the "Crawford total package". I am going with the "total package" and putting on the Fujitsobu exhaust (cat back) as well.....then I'm off to find the lightest wheel that's the same dimensions as stock (any ideas on this part?).
2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way
Thread Starter
|
Registered User
Joined: Mar 2004
Posts: 1,116
Likes: 0
From: Memphis
Re: Headers Lesson
DED,
I'm pretty sure the Z tube is what's giving us a great deal of that addictive sound we all like. There is another resonator on the stock box and I'm sure that's contributing, but I'm not willing to trade even 1 HP for that growl.
I think Nutty, Doug, and a few others may be onto something by sticking with the stock over the JWT. It's definitely hotter air than the stock filter, but being the doubting Thomas that I am, I couldn't help but give the Nismo CAI a shot at it.
Meta,
One more thing. The cone type filters, according to Q45Tech (Dennis) may be creating some type of vortex (I forget the exact word he used) directly behind it (right where the MAF is) which "tricks" the MAF into thinking there is less air than there really is, thereby sending a signal to the ECU to send less fuel. In other words, it tricks a lean condition, thereby making more power (holding everything else constant). Of course, too lean, will not make more power but given the natural state of the G (with no Crawford plenum) is overly rich, that may explain why taking the JWT off made the Crawford plenum work better.
It's finally all starting to click with me on my understanding of this car and one things for sure, if I'm going any further after the intake and plenum, I'm doing the ECU reflash first.
2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way
I'm pretty sure the Z tube is what's giving us a great deal of that addictive sound we all like. There is another resonator on the stock box and I'm sure that's contributing, but I'm not willing to trade even 1 HP for that growl.
I think Nutty, Doug, and a few others may be onto something by sticking with the stock over the JWT. It's definitely hotter air than the stock filter, but being the doubting Thomas that I am, I couldn't help but give the Nismo CAI a shot at it.
Meta,
One more thing. The cone type filters, according to Q45Tech (Dennis) may be creating some type of vortex (I forget the exact word he used) directly behind it (right where the MAF is) which "tricks" the MAF into thinking there is less air than there really is, thereby sending a signal to the ECU to send less fuel. In other words, it tricks a lean condition, thereby making more power (holding everything else constant). Of course, too lean, will not make more power but given the natural state of the G (with no Crawford plenum) is overly rich, that may explain why taking the JWT off made the Crawford plenum work better.
It's finally all starting to click with me on my understanding of this car and one things for sure, if I'm going any further after the intake and plenum, I'm doing the ECU reflash first.
2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way
Registered User
Joined: Feb 2004
Posts: 8,269
Likes: 0
Re: Headers Lesson
-fish,
this is a quote from Jason at Performance Nissan over on Fresh Alloy...
<blockquote><font class="small">In reply to:</font><hr>
the DC Headers are actually pretty nice... I just got a few of them and have been inspecting them... better quality welds and bends then another company's headers out there...
but... my favorite are still the NISMO when it comes to pipe diamater and quality...
next would be the Crawford but the fact that the motor has to be lifted off its mounts does not appeal to me on the install... neither does the cost...
stillen and dc sports are the next ones i would pick...
borla are last on my list simply because they are not equal length...
--------------------
Jason ph.6263053000x221
AIM - PerformanceNISMO
Yahoo - MyNismoParts
<hr></blockquote>
Here's the link if you want to verify the comment. It is the 8th post, FYI...headers
300bhp??? We'll see... 5-22-2004
this is a quote from Jason at Performance Nissan over on Fresh Alloy...
<blockquote><font class="small">In reply to:</font><hr>
the DC Headers are actually pretty nice... I just got a few of them and have been inspecting them... better quality welds and bends then another company's headers out there...
but... my favorite are still the NISMO when it comes to pipe diamater and quality...
next would be the Crawford but the fact that the motor has to be lifted off its mounts does not appeal to me on the install... neither does the cost...
stillen and dc sports are the next ones i would pick...
borla are last on my list simply because they are not equal length...
--------------------
Jason ph.6263053000x221
AIM - PerformanceNISMO
Yahoo - MyNismoParts
<hr></blockquote>
Here's the link if you want to verify the comment. It is the 8th post, FYI...headers
300bhp??? We'll see... 5-22-2004
