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#3382104 - 05/27/14 11:07 AM Re: Why Aren't Headers Standard Equipment? [Re: fdcg27]
supton Offline


Registered: 11/09/08
Posts: 4907
Loc: NH
Originally Posted By: fdcg27
Originally Posted By: supton
How many cars "need" headers? A few hp gain at an rpm that few use.


How many cars "need" more than four cylinders and two liters of displacement?
It isn't always or even usually about need, it's about want.


I won't disagree with you, my contention is with the OP. I don't need 2-3 more hp at the cost of reliability/durability/initial purchase price. I don't want much less "need" headers.
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#3382113 - 05/27/14 11:14 AM Re: Why Aren't Headers Standard Equipment? [Re: artificialist]
zzyzzx Offline


Registered: 05/18/12
Posts: 1703
Loc: Baltimore, Maryland, USA
Originally Posted By: artificialist
Some cars left the factory with pipes that are similar to headers. The 2.2 and 2.3 engine found in Honda Accords are built that way.


My 1995 Ford Escort looks like this as well.

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#3382157 - 05/27/14 12:10 PM Re: Why Aren't Headers Standard Equipment? [Re: circuitsmith]
rslifkin Offline


Registered: 06/27/10
Posts: 2218
Loc: Stamford, CT / Rochester, NY
Originally Posted By: circuitsmith
Tube headers make more noise under the hood as well as at the tailpipe end.

Tube headers extract and cool the exhaust gases from the cylinder more quickly.
That increases HC emissions and makes the cat converter take more time to warm up.


Headers aren't necessarily louder. On my Jeep, the under-hood noise is about the same as it was with the stock cast iron manifolds. Tailpipe noise actually dropped a hair when I put the headers on.

It does throw a little more heat into the engine bay, however. In my case, the headers allow the piping to be routed a bit differently than how the factory handled things, terminating the y-pipe further forward and allowing the cat to be moved closer (which led to it lighting off faster than stock and taking less drive time to become non-smelly) as well as making space to add a resonator where the cat originally sat to quiet it down further.
_________________________
1998 Jeep Grand Cherokee 5.9 Limited with Heads/Cam/Headers/Exhaust/Tune/Shift Kit (175k miles, bought with 100k)
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#3382688 - 05/28/14 02:20 AM Re: Why Aren't Headers Standard Equipment? [Re: OVERKILL]
Scott_Tucker Offline


Registered: 12/31/09
Posts: 872
Loc: Santa Cruz, Ca.
I worked for Dinan Engineering when the E39 M5 was new. Our headers increased power almost 40 HP. The stock manifolds are extremely restrictive and are designed for emissions only.
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#3383142 - 05/28/14 02:24 PM Re: Why Aren't Headers Standard Equipment? [Re: JerryBob]
Doublehaul Offline


Registered: 05/19/14
Posts: 22
Loc: Mi.
Having owned several drag/race cars in the past its been my experience that headers are more likely to warp, crack, rust out and be a PITA than a cast manifold.

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#3383313 - 05/28/14 05:40 PM Re: Why Aren't Headers Standard Equipment? [Re: OVERKILL]
dailydriver Offline


Registered: 03/14/06
Posts: 7071
Loc: Bucks County, Pa.
Originally Posted By: OVERKILL
Originally Posted By: dailydriver
Originally Posted By: OVERKILL
Stock M5 exhaust (foreground):



You'll note the cats are a fair ways back from the headers, which I would categorize as "mid length", as they aren't shorties and they aren't long-tubes either.


Does Bimmer play with the timing/firing order/etc. in order to get the catcons to light off, like Mazda does with the high compression skyactivs??

Yes, those are about mid lengths, but it perplexes me that they did not put the catcon right at the flange of the header (already quite far away from the exhaust port) for faster/more efficient light off, and instead put it way back in the connecting/intermediate pipe. ???

I am guessing that unibody/subframe clearance and interference problems are the reason?


Subframe and transmission.

The engine has a big electric air pump that runs for a bit on cold start, I assume to aide in lighting off the cats.


Yes, it would HAVE TO BE a VERY 'high flow' air pump in order to help light off catcons that far away from the exhaust ports. wink
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#3383375 - 05/28/14 06:31 PM Re: Why Aren't Headers Standard Equipment? [Re: Scott_Tucker]
OVERKILL Online   content


Registered: 04/28/08
Posts: 26463
Loc: Ontario, Canada
Originally Posted By: Scott_Tucker
I worked for Dinan Engineering when the E39 M5 was new. Our headers increased power almost 40 HP. The stock manifolds are extremely restrictive and are designed for emissions only.


I don't recall the gains, from many posts on m5board, being that high for the headers alone shrug

Maybe for the entire exhaust system? They have that squished crossover pipe, the resonator, and the massive quad mufflers. I'm sure that stuff is restrictive. But I don't find the stock headers look that bad quite frankly. Not compared to the rest of the exhaust system anyways.
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#3385087 - 05/30/14 05:55 PM Re: Why Aren't Headers Standard Equipment? [Re: OVERKILL]
dailydriver Offline


Registered: 03/14/06
Posts: 7071
Loc: Bucks County, Pa.
Originally Posted By: OVERKILL
Originally Posted By: Scott_Tucker
I worked for Dinan Engineering when the E39 M5 was new. Our headers increased power almost 40 HP. The stock manifolds are extremely restrictive and are designed for emissions only.


I don't recall the gains, from many posts on m5board, being that high for the headers alone shrug

Maybe for the entire exhaust system? They have that squished crossover pipe, the resonator, and the massive quad mufflers. I'm sure that stuff is restrictive. But I don't find the stock headers look that bad quite frankly. Not compared to the rest of the exhaust system anyways.


It is close to that figure (40 rwhp) on LSxes for long tubes (at least the best ones) alone, as long as it is TUNED as well. wink
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Fram Ultra filter
Synpower 75W-140/4oz. XL-3
Red Line D4 in the T56

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#3385986 - 06/01/14 12:35 AM Re: Why Aren't Headers Standard Equipment? [Re: OVERKILL]
Scott_Tucker Offline


Registered: 12/31/09
Posts: 872
Loc: Santa Cruz, Ca.
Originally Posted By: OVERKILL
Originally Posted By: Scott_Tucker
I worked for Dinan Engineering when the E39 M5 was new. Our headers increased power almost 40 HP. The stock manifolds are extremely restrictive and are designed for emissions only.


I don't recall the gains, from many posts on m5board, being that high for the headers alone shrug

Maybe for the entire exhaust system? They have that squished crossover pipe, the resonator, and the massive quad mufflers. I'm sure that stuff is restrictive. But I don't find the stock headers look that bad quite frankly. Not compared to the rest of the exhaust system anyways.


Since Dinan only produces their parts in 'stages' you generally wouldn't buy just the headers. The whole 5 stage package produce an additional 70 HP. I can tell you that the headers were the single biggest improvement and they added about 40 HP just by themselves.

We kept the squished pipe because it was there for a reason and eliminating it didn't add any usable power. It was their to smooth out exhaust flow in the pipe and eliminating would result in check engine lights due to turbulence near the O2 sensor.

The stock manifolds were incredibly restrictive with unequal tubes of improper length. The Dinan headers are equal length tubes of the proper diameter made of extremely high quality stainless steel and jet coated. It is built up from weld els which means the diameter of the pipes is consistent throughout the header.

The muffler weren't all that restrictive.
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#3386557 - 06/01/14 09:14 PM Re: Why Aren't Headers Standard Equipment? [Re: Scott_Tucker]
OVERKILL Online   content


Registered: 04/28/08
Posts: 26463
Loc: Ontario, Canada
Originally Posted By: Scott_Tucker
Originally Posted By: OVERKILL
Originally Posted By: Scott_Tucker
I worked for Dinan Engineering when the E39 M5 was new. Our headers increased power almost 40 HP. The stock manifolds are extremely restrictive and are designed for emissions only.


I don't recall the gains, from many posts on m5board, being that high for the headers alone shrug

Maybe for the entire exhaust system? They have that squished crossover pipe, the resonator, and the massive quad mufflers. I'm sure that stuff is restrictive. But I don't find the stock headers look that bad quite frankly. Not compared to the rest of the exhaust system anyways.


Since Dinan only produces their parts in 'stages' you generally wouldn't buy just the headers. The whole 5 stage package produce an additional 70 HP. I can tell you that the headers were the single biggest improvement and they added about 40 HP just by themselves.

We kept the squished pipe because it was there for a reason and eliminating it didn't add any usable power. It was their to smooth out exhaust flow in the pipe and eliminating would result in check engine lights due to turbulence near the O2 sensor.

The stock manifolds were incredibly restrictive with unequal tubes of improper length. The Dinan headers are equal length tubes of the proper diameter made of extremely high quality stainless steel and jet coated. It is built up from weld els which means the diameter of the pipes is consistent throughout the header.

The muffler weren't all that restrictive.


good to know!
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02 Expedition
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#3386683 - 06/02/14 01:01 AM Re: Why Aren't Headers Standard Equipment? [Re: OVERKILL]
SuzukiGoat Offline


Registered: 02/04/13
Posts: 389
Loc: Louisiana
On my vehicles, the cast manifolds are works of art. So intricate and beautiful that they crack at the fourth exhaust port. Given the age, replacement isnt an option. I run long tube headers. They sound better, little else can be said for them.
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1996 Geo Tracker Auto 4x4 Denso VNG 10w30. 120k.

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#3391431 - 06/07/14 12:06 PM Re: Why Aren't Headers Standard Equipment? [Re: JerryBob]
Now Offline


Registered: 03/19/14
Posts: 10
Loc: Alabama
Dear moderators, please forgive me for posting this horrible video. I have this terrible problem. When I hear the word "Header" I think red hot glowing.

http://www.youtube.com/watch?v=qyQi4js2fn0
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#3392014 - 06/08/14 08:50 AM Re: Why Aren't Headers Standard Equipment? [Re: JerryBob]
Cujet Offline


Registered: 02/15/03
Posts: 4188
Loc: Jupiter, Florida
I fly a 4cyl 200HP Cessna Cardinal RG. It originally came with one muffler per side, with a single tailpipe. Not exactly a tuned exhaust.

I recently purchased a "powerflow" exhaust, which is simply a tuned 4-into-1 header, with very long primary tubes, tuned for the LOW RPM of aircraft engines.

The difference in performance has been significant. I have no way to measure HP, but I can measure rate of climb and service ceiling. I gained about 300 feet per min rate of climb. Also gained about 1500 feet service ceiling.

It also increased my fuel consumption. More HP requires more fuel.

Contrary to claims about increased economy, I do not see any practical flight conditions where I can achieve better fuel economy. Put another way, a given amount of HP requires a given amount of fuel. The restrictive stock exhaust simply limited the maximum output of the engine, but when the throttle is reduced, to a given output, fuel flow matches the work required.
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Turbo's rule.

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#3392085 - 06/08/14 10:30 AM Re: Why Aren't Headers Standard Equipment? [Re: JerryBob]
Jarlaxle Offline


Registered: 02/02/12
Posts: 4141
Loc: New England
On a plane, sure...but I have seen MPG gains from free-flow exhaust!
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1979 Coupe de Ville, 542 stroker, Super Tech 15W40, AC Delco
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2012 Suzuki AN400A, M1 10W-40, Caltric

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#3392537 - 06/08/14 08:52 PM Re: Why Aren't Headers Standard Equipment? [Re: Jarlaxle]
Garak Offline


Registered: 12/05/09
Posts: 11644
Loc: Regina, Saskatchewan, Canada
Airplane engines are a little different, though. They are a wonderful example of an ICE turning something and adjusting output based solely on throttle and mixture (yes, Cujet, I know about variable pitch props, I'm just simplifying). No transmissions, gearing, or computer controlled injection. wink

Most of the textbook stuff one reads on ICE theory fits much more closely to the airplane engine than what we see in a car these days. Most of us certainly have seen improvements in various vehicles thanks to exhaust.
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Plain, simple Garak.

2008 Infiniti G37 coupe - Mobil Delvac 1 ESP 5w-40, Hastings LF113
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