With all the Header talk.. headers 101 heading in the rite direction

[Justincredible]

****WOW good read dyno info below on actual headers this was what we were talking about over a year ago***


I decided to do what research I could on this to come to my own conclusion.
I was able to get ahold of some S8 headers as a reference to ours.

Notice how the S8 header has individual runners for each cylinder much like the RS4. Our headers end up sharing one of the runners.

The S8 has 360 hp and 317tq max power 7000. The S8 has some changes over the S6 that seems to have about the same power rating as us. cams intake throttle body and from what I understand the headers.

This is not to say that headers are going to make any difference. I am just sharing info I found.

[DeatschWerks]

This is not to say that headers are going to make any difference. I am just sharing info I found.

I think it is fair to say headers WILL make a big difference. I can't belive there are SC kits out there but no headers! i want headers!

[S4J]

Dam that manifold look ugly and inefficient. I'd like to see the inside of ours. Thanks for sharing.

[Captain Insano]

Thanks for posting this. I am one of the folks that started a thread and was wondering about headers and why nobody has done these with the exception of a guy in South Africa and one guy that is building his engine....
http://www.audizine.com/forum/showthread.php?t=236990

Alot of good opinions in that thread and also some folks that actually tune Audis for a living which I'm glad we got some feedback from somebody that I would consider an expert.

I agree that headers should increase power, but I do wonder how much. If it's only 10 hp then not worth messing with imho. If I could get 20+ hp out of them I might actually consider it (many think that's crazy - just a matter of opinion). My theory is, if I could get 380+ hp NA with exhaust (including headers) and chip modding I like the idea of that. It appears to me that DP/Catback exhaust and chipping is only yielding around 360 at teh crank - people let me know if that's off.

Another thing going on here, people will now be thinking since a SC kit is available, why mess with headers??? FI is cool and all, but I'm not a huge fan of doing FI on cars that are OEM NA cars. I know alot of people would vehemently disagree with that too, but again, just a personal opinion.

One conclusion that was drawn in another thread that answers one of my original questions (and I agree with this answer), the RS4 header will not fit on an S4 block... Which sucks.

[Justincredible]

If you look over the entire car platform. Most cars do very well with the addition of headers. But the difference will all depend on how well the initial design was.

Here is a pic of ours. Don't be fooled into thinking it looks bigger it is just a much closer pic. the actual collector area is smaller than in the S8 and you can see there is only 3 collection points not 4.



same look from the side view as the other ones.

[Justincredible]

Well I took a good solid year to get here and here are some updates.

A few things I was looking at. We have run time and time again about how we would love to get RS4 performance out of our S4's. Lets take a look at ONE of the different parts a RS4 has over us. How about we look at the headers and the differences...we know what our headers (manifolds) look like what is the next best option for us. Headers

JHM Full length top.......RS4 stockers bottom




The bottom headers are the RS4's. They use a tri Y idea. This was used several years ago to help save space while trying to still get the benefits of the full length header Idea.

While the RS4 dominates us in Hp it falls well short of handing us much of a loss in the Tq category as the RS4 only has 15tq more then we do.

To get the Hp out of the motor you need big ability to flow and to make sure the flow path is fixed long enough to gain proper and exhaust velocity. While the stock manifolds we have use smaller ports off the head both the RS4 and JHM headers use a almost port matched opening to assure your getting unrestricted flow out of the heads at higher RPM's



The end result of all this is better TQ and hp up top. Here is a Dyno sheet from a stock Automatic and a JHM header automatic car....

Notice the TQ comes in WAY sooner and holds over 40tq TO THE WHEELS for quite some time. Even in the higher RPM's where Tq usually gets hurt its making 14-18tq more then was the case stock.



For those of us that Might not know. Headers on average give about 20-50 more ft lbs of TQ and 20-50 hp depending on the apps. The LS1 we have been talking about will get the same results we do. Ive seen several mustangs with the 4valve do quite the same as us.

after a long thought about it I made the plunge and got the headers..

I installed them my self. I only ran into an issue cause I didn't have a stock fitting or stock location cat back. I had a custom cat back... So I needed to get my exhaust cut and adjusted to fit the headers. This is not something you would have to do if you have a stock fitting cat back

LOADING PIC"S NOW

[cjperformance]

i'd love to do headers...pulling the motor out is whats stopping me..

i need a nitro kit

[ginkof]

im going to do headers when i hit 100k miles when the timing chains and stuff back there have to be replaced... hopefully by then there will be some info/parts floating around the forums about cams, intake manifolds, port/polish stuff/ high 9K+ revving motors... All that fun stuff! Im only at 53k miles now, so i figure i have another 3-4 years!

[Justincredible]

So after pulling the motor. The headers install quite well and are well thought out. The tubes are very close to the same length but they are also routed in such a fashion that the bolts are still easy to get to.




A close up one.



There are a lot of bends and turns to make these work. But there still is just enough room for motor rock just encase. Its hard to tell from this pic but there still is a good amount of room left between the frame rail




Now for some clips of the headers. The thing to know is that the headers don't make the car any louder. The headers actually make the exhaust tighter and more crisp. Its responsive now with not the back burble when you get off the throttle (exhaust reversion). You would think with the headers the car was louder. Not the case its actually not so much quieter but more refined if you know what I mean.

This is starting it for the first time. You can hear my power steering pump towards the end as it was getting the air out of it and had a little whine

http://www.flickr.com/photos/justinc...99/3765018004/

Now to further explain what Im talking about with the headers. One of the things you can hear and make out is the reversion from the stock to the eliminated reversion on the headers

you can hear the burble (15 sec) and the on throttle rev up.
http://www.youtube.com/watch?v=kd5-fN1gHkI


Then with the headers, listen to how crisp the throttle is and how the off throttle doesn't burble, but just hold and fall
http://www.youtube.com/watch?v=un_6KEnfISk

Are headers a big difference over Dp's.......its a total different ball game, it took longer for the power to come on with the Dp's then it does with the headers. The power was shifted and the tq was worth the switch.

The free rev of the motor is cleaner and quicker and the Dp drone, gone the tuned headers take the drone right out. I can't speak for every cat back but the cat less Dp's and the auto were not so great at certain RPM's when it came to drone. Now its not an issue

[teknostar]

Justin, those bottom two youtube links do not seem to be working.

[sakimano]

here is his youtube page. the user had a few extra ... added in the links for some reason


http://www.youtube.com/user/dxhs2000

[brad65ford]

Damn I've always wanted l/t's for this car.

[charliemike]

Damn. I've been thinking about putting together a list of things that can be done at the same time when the engine gets pulled.

* Clutch/Flywheel
* Headers
* Timing guides/tensioners

Anything else we should consider? It'd be nice if it was in one place so that if someone needs to pull the engine, there's an easy list of stuff they can consider doing to save labor.

[brad65ford]

Damn. I've been thinking about putting together a list of things that can be done at the same time when the engine gets pulled.

* Clutch/Flywheel
* Headers
* Timing guides/tensioners

Anything else we should consider? It'd be nice if it was in one place so that if someone needs to pull the engine, there's an easy list of stuff they can consider doing to save labor.

Damn that looks expeniseve!

[charliemike]

Damn that looks expeniseve!

LOL, I just priced out everything I'd want to do when my car wears out its OEM parts and it was just shy of $10k

That doesn't include the new seat covers I'm probably going to need to get in 2-3 years as well ($2500 at least).

Plus labor ...

I need a second or third job :)

[brad65ford]

LOL, I just priced out everything I'd want to do when my car wears out its OEM parts and it was just shy of $10k

That doesn't include the new seat covers I'm probably going to need to get in 2-3 years as well ($2500 at least).

Plus labor ...

I need a second or third job :)

I love this car, but dude it aint worth it, no way. It just doesn't make sense all that money needed

[charliemike]

I love this car, but dude it aint worth it, no way. It just doesn't make sense all that money needed

It's not crazy stuff like a supercharger. It's all stuff that will likely need to be replaced at some point or might be a worthwhile upgrade:

Headers - $2500
Crank Pulley - $300
Clutch/Flywheel - $1500
Timing Chain Guides - ??
Coilovers - $1200
Cayenne Brakes - $1725
Magnaflow - $400
Motor Mount - $170
Rear Diff Mount - $209
Solid Linkage Upgrade - $189
Short throw shifter - $265
4:1 Center Diff - $350
Control Arms - $600

If I end up keeping the car a long time, I could see a lot of this stuff being worth getting. The list is from JHM's site, BTW.

But then again, if I don't keep it I'll put that $10k into a B8-something.

[beemercer]

Great job collecting all the pertinent information and pictures on the header discussion. It'll be a nice resource to point the noobish ones towards.

[justinperkins]

I'm still learning, so bear with me, but the headers you installed basically take the place of our headers+DPs, correct? I have seen people quote that piggies would yield about 10 HP and the same could be said for performance headers (that don't encompass the factory DPs), if you add them together then your 20-30 HP gain seems totally reasonable.

[beemercer]

I'm still learning, so bear with me, but the headers you installed basically take the place of our headers+DPs, correct? I have seen people quote that piggies would yield about 10 HP and the same could be said for performance headers (that don't encompass the factory DPs), if you add them together then your 20-30 HP gain seems totally reasonable.

Yeah the exhaust tract goes like this stock (I highlighted problems with the stock setup):
The exhaust side of the heads ->
The stock log manifold (uses shared runners, unequal length runner, tubing inlets are smaller than head exhaust ports, small primary diameters, no real collector) ->
The stock downpipes (small 2.125" diameter?, 2 catalytic converters per pipe, tight bends and generally restrictive design, one of the catalytic converters is in the precat position immediately behind the manifold flange ) ->
The stock catback (small 2.125" diameter, center resonator doubles as a crossover less than ideal design, large restrictive mufflers, strange flattened section of piping before the mufflers)

The typical aftermarket fullback setup goes like this (advantages over stock in parenthesis now):
The exhaust side of the heads ->
The stock log manifold ->
The aftermarket downpipes (larger 2.5" diameter, smoother bends, one catalytic converter per pipe instead of two, with some DP's [Fast intentions] the singular catalytic converter is located further downstream others have it in the precat position which is less than ideal)
OR
The piggie pipe (same as the stock DP just with either the precat or both cats removed) ->
The aftermarket catback (2.25" - 2.5" piping allows for greater exhaust flow [2.5" is preferable since it allows greater room to grow], smoother bends throughout the system, proper crossover design [x-pipe will allow for better high rpm exhaust scavenging], less restrictive mufflers and resonators, elimination of flattened section)

Finally there are the header cars:
The exhaust side of the heads ->
The JHM longtube headers (eliminates the stock exhaust manifold and the downpipes combining them into one, larger primary diameters support greater high rpm flow and consequentaly high end power, equal length runners combined with a tuned collector design work to provide extra exhaust scavenging [I won't go into how this increases power it is pretty involved]) ->
The aftermarket catback (2.25" - 2.5" piping allows for greater exhaust flow [2.5" is preferable since it allows greater room to grow], smoother bends throughout the system, proper crossover design [x-pipe will allow for better high rpm exhaust scavenging], less restrictive mufflers and resonators, elimination of flattened section)

As far as how exactly the headers help to create more power it is very very involved. Like I've said a million times header design is not some black magic of combining exhaust bends, trial and error, and chicken sacrifice; there are scientifically derived design parameters to follow based on desired power range and engine displacement. JHM did their homework and followed these guidelines exactly, and that's how they created a header setup that produces extra power in the midrange as well as the topend (they could've made a race header tha optimized power from 5k rpm and up, but chose to focus on 3k and up). So basically when they say it is a tuned equal length header, it means that the primary length and diameter, secondary length and diameter, collector design and length, and bend styles were all carefully chosen to bolster power in the midrange.



Some good reading over here btw
-Performance Tune Questions
-Piggie Pipes and CEL avoidance

[drew]

wow, for a factory part, those rs4 headers look pretty damn good

[brad65ford]

wow, for a factory part, those rs4 headers look pretty damn good

I agree I'd be happy with those than the stockers.

[justinperkins]

... lots of great info ...

Some good reading over here btw
-Performance Tune Questions
-Piggie Pipes and CEL avoidance

Indeed. I've read the piggie pipes and CEL thread, got some good info from it as well as Justincredible's "removing your DPs" thread. Your epic pasted post in the "Performance Tune Question" is an invaluable resource. I found it interesting the that Milltek DPs place the main (and only) cat in the OEM pre-cat position. Considering all that you have posted, it basically means that that is a bad design on their part. Have they since changed this design or are there plans to do so? Like you have said "... the reason why the pre-cat present in both the unmodified stock downpipes and catted aftermarket downpipes are such performance robbers" and you drove the point home by removing the cats from your Milltek DPs.

for the info

[beemercer]

Indeed. I've read the piggie pipes and CEL thread, got some good info from it as well as Justincredible's "removing your DPs" thread. Your epic pasted post in the "Performance Tune Question" is an invaluable resource. I found it interesting the that Milltek DPs place the main (and only) cat in the OEM pre-cat position. Considering all that you have posted, it basically means that that is a bad design on their part. Have they since changed this design or are there plans to do so? Like you have said "... the reason why the pre-cat present in both the unmodified stock downpipes and catted aftermarket downpipes are such performance robbers" and you drove the point home by removing the cats from your Milltek DPs.

for the info

I appreciate the kind words it makes it easier to type out massive posts. My supposition is that most of these aftermarket exhaust manufacturers retained the pre-cat position rather than main-cat position in order to keep the catalytic converters operating as factory as possible. By that I mean
-The motor warms up as quickly as stock. The precats are a large, heavy chunk of high heat capacity metal closest to the heads that will trap large quantities of heat near the head allowing cylinder temperatures to increase at a greater rate than a main-cat positioned DP.
-On the same page as warming the motor up quickly a pre-cat positioned catalytic converter will get up to operating temperature faster and begin operating in its intended purpose faster than a mid-mounted or bottom mounted catalytic converter.

That being said I stand by my assertion that from a performance standpoint any downpipe with the catalytic converter located near the exhaust manifold flange is an inferior design. Talk to the guys at fast intentions or old-school american muscle exhaust designer and they will tell you that placing the first major exhaust restriction that close to the heads is horrific for the flow characteristics; and that is on top of the performance impact of trapping heat that close to the combustion chambers.

I just checked the milltek site and they are still making 2.25" pre-cat positioned DP's, and it'll probably never change since the B8S4 is coming out and they'll soon shift their focus. Really the only option for aftermarket downpipes with proper catalytic converter placement is the fast intentions downpipes.

[1FastS4.Com]

Here is a pic of the R8 headed took at the R8's launch...

[beemercer]

Here is a pic of the R8 headed took at the R8's launch...

Terrific photo there. I'm trying to make sense of them, did you see if it was a Tri-Y? Or was there a collector?

Edit: definitely looks like a tri-y, decent design for a shorty header. Look down below the third cylinder from the front and you can see the first y in back and then the second y in the foreground to the right a bit.

[DuncanC]

I took a look at them at the dealer and they looked to be a Tri Y setup. They really are a work of art. The whole car is.

[beemercer]

I took a look at them at the dealer and they looked to be a Tri Y setup. They really are a work of art. The whole car is.

It really is, definitely a modern classic.

[Justincredible]

I took a look at them at the dealer and they looked to be a Tri Y setup. They really are a work of art. The whole car is.

This once again makes me feel better about the long tubes we have. You can see when Audi goes for all out performance that they look some what like our JHM headers.

If you look close its a semi Try Y. You can see what looks to be the 02 sensor in what looks like it would be some sort of collector. It looks like a cat it not too far back form there. Given the space allocated the Tri Y was about the only way to go from a manufacturing stand point if you ask me, that space looks small.

[EvoRam]

****WOW good read dyno info below on actual headers this was what we were talking about over a year ago***


I decided to do what research I could on this to come to my own conclusion.
I was able to get ahold of some S8 headers as a reference to ours.

Notice how the S8 header has individual runners for each cylinder much like the RS4. Our headers end up sharing one of the runners.

The S8 has 360 hp and 317tq max power 7000. The S8 has some changes over the S6 that seems to have about the same power rating as us. cams intake throttle body and from what I understand the headers.

This is not to say that headers are going to make any difference. I am just sharing info I found.

I know, I know...holy 10 years later thread revival!!! Not that anyone cares...but I am having a set of these modified to fit my B7 S4. I found out when I had the timing service done that they don't bolt directly on b/c of the dp flange orientation but they have the same mani-to-head gasket. Just have to rotate the dp flanges to clear the rear covers. I got the manifolds for cheap a couple of years back and having a friend finally modify them for next to nothing so I am not in it that much $$$.

[Dashiki]

Where did you find the headers? How much? I’m looking to do a pair of these in the coming months when I pull motor for timing maintenance

[roboto_1337]

How much money? Like cheaper than XS power headers?


Sent from my iPhone using Audizine

[Jdsb6s4]

are we talking about part #0772530340 ? audi s8 headers interesting. I would love to see before and after dyno numbers before even considering

[q_dubz]

I've seen em go for $200 so...CHEAP

[Jdsb6s4]

I've seen em go for $200 so...CHEAP

I just ordered the JHM headers...wooohoo!

[roboto_1337]

Congrats! I’m wondering if anyone has any experience with the XS Power headers on a 6MT.... good/bad/indifferent. If anyone has installed these I’d love to hear their thoughts.


Sent from my iPhone using Audizine

[EvoRam]

Where did you find the headers? How much? I’m looking to do a pair of these in the coming months when I pull motor for timing maintenance

My set I found from Specialized German in California.

are we talking about part #0772530340 ? audi s8 headers interesting. I would love to see before and after dyno numbers before even considering

Part # ends in 'J'. The idea is more based on exhaust scavenging and keeping turbulence low by keeping the runners as separate as possible instead of merging them like the B6/B7 manifolds.

I've seen em go for $200 so...CHEAP

I got mine dirt cheap a couple years back. About $50 shipped iirc.

[EvoRam]

Finally got them rotated. Waiting to receive them back.

Teaser:

[Jdsb6s4]

I’ll give you some header talk... My JHM mid length headers arrive tomorrow. I’ll post a follow up soon :)

[Mr.Wrong]

Finally got them rotated. Waiting to receive them back.

Teaser:

Have you considered B7 RS4 headers?