Equal Length Exhaust Manifold?

[ProjectGSX]

What are the pros and cons of an equal length exhaust manifold?

[WanneBe]

Pros:
Equal legnth tubing puts exhaust pulse right inline, so that the exhaust doesn't collide with itself like in a manifold.
More efficient (see above)
Cons:
Expensive?

I can't think of too many cons. Hopefully somebody more knowledgable finds this thread worth noting in. That seems to be a problem on this board.

[V8SpankR]

I hear the headers are prone to cracking,the stock ones (95+) are very durable and still your best bet for the $$$.

[Cooter]

on a turbo car the gains from an equal legnth exhaust manifold are minimal... the exhaust pulses run into a huge wall (turbine wheel) anyway... so there's not really an advantage unless your at the point where you need to squeeze every last hp out of your car... the money, in most cases, is better spent elsewhere... the gains that you get from most aftermarket headers are from increased flow due to larger pipe diameter, smoother bends and full radius bends...

Cooter
http://www.sound-performance.com

[redgsturbo]

Actually to quote "Turbochargers" (see left column.. a long time bowl read of mine): "intake and exhaust tuning is just as important on a turbocharged engine as on a naturally aspirated one" this is a caption describing an equal length header going to a high output turbo application. Wait!! Theres more : "One of the biggest misconceptions is that ram tuning is not important on a turbocharged engine. Through extensive testing, I've found that a turbocharged engine responds to a tuned inlet and exhaust system and large-port cylinder heads as much as a naturally aspirated engine." They also highly recommend dual port turbos and manifolds as while they didn't increase power on a 640hp 2.0 liter BMW-Mclaren race engine they made lag "all but disappear". This same engine experience a 60hp gain from 540 when switching to equal length headers.

[Redkin]

Are there tuner headers available?

[redgsturbo]

I think that is more of a custom made thing... I have never seen a tuned exhaust mani for eclipses

edit: and if anybody is gonna hang me on those numbers up there 540 + 60 =600... that additional 40 hp is from cam adjustment after the exhaust tuning was realized

[Edited by redgsturbo on 07-18-2001 at 08:20 PM]

[Cooter]

i'm sorry, i should have been more clear....

any improvements that are made to the effieciency of the intake and exhaust tract are beneficial... sure the manifold got 60 hp..... and i didn't see that article... but getting 60 more hp out of a 540hp motor isn't that hard.... relatively speaking...and 11% gain... something like a custom built header is not generally done because of the cost and the few ppl that actually mod their cars enough to get respectable gains from something that they have to invest that much money and time in.... hence 'the money is usually best spent elsewhere' an 11% gain one a typical bolt ons car will net you only 3.3hp... assuming your average bolt ons car makes 300hp... is it worth the $600 for the manifold? $600 can buy you more hp with different parts.. at that point... hence the 'unless your at the point where you need to squeeze every last hp out of your car' statement.. hope that clears things up...

Cooter
http://www.sound-performance.com

[redgsturbo]

you forgot one decimal place man... on a 300hp car 11% increase is 33 hp... worth $600 at that point.

[blunttwister]

a local machine shops makes them
Max Rev:
dont know the price, but they do extremely good work. they are more of a custom shop, but i have seen there work up close and is second to none. they build monsters.

<<<you forgot one decimal place man... on a 300hp car 11% increase is 33 hp... worth $600 at that point.>>

you wont get the same % gain from tuned header as a 540 hp car does. ex flow is more important in a 540hp car than a 300 hp car.
quick example:
a 3inch turbo back could make over 100hp difference on a 500hp car(w/stock ex), but on your 250hp car is not going to give you 50hp. see what i'm saying?

[Cooter]

*feels stupid*

okay.. i'm sorry about that...thought that looked fishy but i was in a hurry.. blunttwister is right though, a 33hp increase is not realistic on a 300 hp motor..

Cooter
http://www.sound-performance.com

beware of white supras....

[redgsturbo]

no its not.. and its not as cost efficient as a turbo upgrade, but how much are people *really* paying for 5 and 10hp chunks on cars.. realisticly i wouldn't be suprised if a tuned header system on a 300hp car netted 20hp or so. the "tuning" of the factory exhaust manifold is horrid. Some runners are almost twice as long as others. Keep in mind that the exhaust gas pulsastions would be more evenly distributed which would make a big difference in spoolup.. (think of the idea behind axially divided turbos. same principle is being applied here) so lets say you get no power gain.. but you spool 750rpm sooner? People pay so much and a lot more for porting. Anyways, I never meant to attempt to predict what a tuned header system's hp increase would amount to... I just meant to dispel the thought that tuned exhaust doesn't matter for turbo cars.

[Boostspike]

doesn't HKS make DSM manifold....??? i know a shop in NY (forgot the name of it) who does custom manifold.. but they're stainless steel not cast iron (like our OEM).. stainless will crack after a while right??

[redgsturbo]

Its not as durable as a thick ass cast manifold, but if you are at that level I don't think you are really hoping for unreal mileage from the car

[reptiles]

I remember the Archer brothers once provided a tuned stainless header system with a lifetime guarantee. They don't seem to provide that anymore.

Such custom headers are for dedicated track vehicles that only do a few hundred miles/year (in 1/4 mile increments.)

To put a tuned header on a street car and expect it to last for tens of thousands of miles is unrealistic.

Even the titanium custom made headers crack on street cars.

Maybe someday someone will make a CAST titanium equal-length, tuned header for us.... but generally we're a cheap bunch of hobbyists :) so I would expect it.

Cheers,
Mark Miller
http://PhillyDSM.com

[dyezak]

Anyone with a tube bender can fab up a custom equal length turbo manifold...and it will improve HP. But you might as well get a tuned equal length for the same $$. Tuned pipes not only keep the exhaust pulses from colliding, they make maximum efficency of the collector (which is very important on a turbo car).

Example (the numbers represent a collector where the runners are meeting, the numbers correspond with the cylinder numbers):

12 14
34 23

Which one of the configurations is correct for maximum HP? The first one listed is...but why? Well cyl #1 and #4 fire together, so their exhaust puleses match. When they come together in the collector you want to have them caddy-corner from each other, not side by side. If they were side by side one half of the collector would have a high velocity moving exhaust flow with a dead spot on the other side of the collector. This situation would enable boyle's law and create a turbulant air mass that wouldn't flow well. But if you had them caddy-corner, you would split the flow equally across the collector and essencially eliminate this effect.

[WanneBe]

Sport compact car did an article on the 600HP Bozz Lancer. Now I know there are a who slew of differences between the US DSMs and the Jap. Lancer, but it had equal length header from HKS. (Correct me if I'm wrong, I don't have the article right now) But among the other mods, a properly tuned header hsa got to be worth some level og significant power.

[dsm4eva]

Archer did in fact make/sell the stainless headers, and yes they were very prone to cracking but they also used the wrong material to make them, 304L CRES. High temps, carbon, and 304 don't mix, it causes the material to leech out chromium and the net effect is the weld becomes brittle and cracks.

Titanium and 321 CRES are the materials of choice for a dedicated racer, but then again, they have budgets larger than the GDP of 3rd World Countries so they can use these materials. For us, the best alternative is to use a mild carbon steel (for economic value) and have the header Jet Hot coated. This coating is an organic/ceramic plating that will offer significant heat and corrosion protection. Plating the exterior is all that is required but plating the interior will keep heat rejection even lower (its a good thing). The coating needs to be reapplied at a certain service interval, something like 4-5 years, otherwise you lose that buffer of protection. Also, the mild steel welds will need to be touched up every few years.

One thing that will help your headers live a longer life is adequate bracketry and gussets. The less weight you are asking the tube welds to carry, the less force is on the weld, the longer the weld will last. Its an easy correlation.

[4G63Rydah]

Originally posted by dyezak
Well cyl #1 and #4 fire together, so their exhaust puleses match.

Umm...the only thing that fires together for cylinders #1 and #4 is the spark. But we have a waste spark system where coil 1 will fire when it's needed and coil 2 will fire when it's needed. This works out fine because when #1 is on it's compression stroke #4 is on it's exhaust stroke so firing the #4 spark at the same time won't do nothing. There's no gas to burn.

But I do agree with you that equal-length isn't necessarily the same as tuned. I don't know how much HP you are going to gain from tuned headers but I'm sure the combination of improved spool-up and increased HP (however much it is) on a 400HP+ engine would make the tuned headers well worth it.

[GSXXXguy]

so where can I get one of these "headers" that you guys are talking about and what are we looking at as far as cost goes?

[turbo21psi]

I might need a custom manifold done for a turbo w/ a split housing. Which 2 runners should I combine for each collector to maximize turbo spool-up? I heard that 1&4 and 3&2 together should be used. Is that correct? It kind of disagrees w/ the previous post about what runners to mix.

[widebody]

one of my sponsors can make them, email me for that info. South florida performance makes them and from what i have seen they are decent. Wright touch also makes them to mount up the 25g but should be able to work on just about any turbo (just weld on a diff flange). When i called archer up to see if they would still make theirs they told me if i could get an order for 20 or more at 800 a pop, they don't want to make them mainly because they couldn't make any money off them (kept cracking and having to be replaced under warrenty) which i can totally understand. Mine i bought all the stainless for it and a sponsor is mocking it up to be shipped out and welded all total i spent about 300 in stainless pipe and flange material.

[NosLaser]

First off, Dyezak, I must say you know your shit. I am SO GLAD to see that there is someone who actually belongs on the ADVANCED technical section.

Bill, you are doing it again...

<<<Umm...the only thing that fires together for cylinders #1 and #4 is the spark. But we have a waste spark system where coil 1 will fire when it's needed and coil 2 will fire when it's needed. This works out fine because when #1 is on it's compression stroke #4 is on it's exhaust stroke so firing the #4 spark at the same time won't do nothing. There's no gas to burn.>>>

Let me ask you a simple question...have you ever had the head off the car? Which two pistons do you see at bottom dead center, and which two are at top dead center? Cylinders 1 and 4 are in time, and 2 and 3 are in time. What a WASTED spark ignition means, is that it will fire TWICE, once on the power stroke, once on the exhaust stroke. The "wasting" of the spark means that obviously, spark does nothing on the exhaust stroke. Cylinder's number 1 and 4 FIRE AT THE SAME TIME, and 2 and 3 FIRE AT THE SAME TIME (for nit-pickers, they are VERY slightly off, but so slightly it would be hard to measure with even measuring tools; it's determined by wire length, resistance, etc. but for arguments sake, they fire at the same time). That goes for exhaust, intake, etc etc. The theory Dyezak was talking about WORKS...and works for all 4 cylinder cars. You guys should pay more attention at least to him, if you won't listen to me. Tuned headers basically increase the scavenging affect from one cylinder to the next. As simply put as possible, how this theory works is when a cylinder fires, it sends an exhaust pulse into the exhaust (manifold/header) This exhaust pulse creates a vacuum, and basically you are going to try to team THIS exhaust tube with the NEXT exhaust pulse inline to fire. If this is done at the right distance (this distance is the actual part you would "tune" on a header), when the exhaust valve opens on the next cylinder, the vacuum caused by the exhaust pulse before it will help "scavange" all of the exhaust out of the combustion chamber. It gets more complicated than this, and actually incorporates variables such as how sound waves travel, but I don't want to confuse anyone. I hope this helps you understand the reason to run tuned headers. You are "tuning" to increase the scavenging affect. Bill...you are striking out dude. Do you really work on people's cars?

[Van]

Originally posted by NosLaser
Bill, you are doing it again...
Bill...you are striking out dude. Do you really work on people's cars?

WhoTF are you talking about?! You seem a little confused on this, at least make sure you get the names right.

[Van]

Originally posted by NosLaser
Let me ask you a simple question...have you ever had the head off the car? Which two pistons do you see at bottom dead center, and which two are at top dead center? Cylinders 1 and 4 are in time, and 2 and 3 are in time. Cylinder's number 1 and 4 FIRE AT THE SAME TIME, and 2 and 3 FIRE AT THE SAME TIME (for nit-pickers, they are VERY slightly off, but so slightly it would be hard to measure with even measuring tools; it's determined by wire length, resistance, etc. but for arguments sake, they fire at the same time).

LOL! Umm, the pistons may be in time in your example but they most certainly DO NOT FIRE **on compression** AT THE SAME TIME, the valves have some say so there...ever look at your cams really close?!
#1 is at TDC about to head down on power stroke. #4 just came up on exhaust stroke (dead spot) and will next head down on intake stroke, while #1 is on the power stroke down. When they come up together again, #4 is on compression stroke approaching TDC about to fire, while #1 comes up on the exhaust stroke.
AND, just for good measure #3 fired in between #1 and #4 cylinders just to keep things smooth. Anybody want to guess when #2 is gonna fire? :eek: Because it sure ain't at the same time #3 fired. Basic automotive fundamentals of a four cylinder, four stroke engine...

Now please withdraw foot from mouth... Wasted spark is not the same as tdc compression spark, 4G63Rydah had it right. They, #1 and #4, get spark pulse at the same time and one is a wasted spark, but NOT tdc compression spark.

[Nick 92 TSi AWD]

Um the 4G63 is a four stroke engine. It fires 1 cylinder every 180 degrees of crank rotation. That would make 720 total degrees, which would be a four stroke engine.

Before you flame people you should at least have some sort of f*cking clue as to how a engine works.

[4G63Rydah]

Thank you very much Van. I'm glad someone else posted here that knows what they're talking about.

NosLaser...

Let me ask you a simple question...have you ever had the head off the car? Which two pistons do you see at bottom dead center, and which two are at top dead center?

Let me ask YOU a simple question...have you ever had the valve cover off the car when cylinder number one is at top dead center? Next time you do, look at the intake and exhaust lobes on both cylinder #1 and cylinder #4. Picture in your head the cams turning. What's about to happen with each cylinder?? Hmmm... Seems to me that both intake and exhaust valves are about to remain closed on #1 and that intake valves are about to open on #4. Wonder what that could mean?? Could it be that #1 is about to start it's power stroke and #4 is about to start the intake stroke??

[redgsturbo]

wow... lets tone down the angst and stuff here.. this started as a "would a turbo car benefit from a E.L.E.M." and now its a "you don't know sh*t" party.

<~~ I don't wanna be a moderator again.. but i will if i have to

[NosLaser]

Lord...you all are hopeless..

Here's an ANIMATION of how a 4 cylinder engine works for the children:

http://www.howstuffworks.com/engine-inline.htm

Look at that picture really hard, and tell me how many times you see #3 just jump in there "for good measure."
Very close to getting off this board if I'm going to continue to be challenged by idiots...

[Redkin]

That was a great animation, but you're missing the upper half of the engine! I think that matters somewhat too...

[NosLaser]

<<<That was a great animation, but you're missing the upper half of the engine! I think that matters somewhat too...>>>

What that "great animation" was showing is how #'s 1 and 4 are in time, and 2 and 3 are in time ON EVERY 4 CYLINDER ENGINE!!!! I don't know how much more I need to dumb it down for you guys. Instead of TRYING to be assholes, sit back and LEARN something.

[Redkin]

I really think you need re-read the last comment Van made. Yea, the crank may rotate the pistons at the same time, but the pistons don't have the same power stroke...

[MoBoost]

Aslan, you might know "some" stuff, but not knowing how a four stroke motor works, is just ... plain shame. http://library.thinkquest.org/C006011/english/sites/mehrzylinder.php3?v=2

Edited : I hoped it was all misunderstanding. Glad it was resolved. FYI : 4G63 firing order is 1-3-4-2

[Edited by MoBoost on 08-27-2001 at 02:37 PM]

[NosLaser]

Here is an animation of the bottom end with the camshaft...notice a difference? I didn't think so.. 1 and 4 at the same time, 2 and 3 at the same time. God you people make my head hurt.

http://www.howstuffworks.com/engine-cam.htm

MoBoost...you disappoint me. Quit being a follower like Nick and look it up for yourself. You should know who to trust by now dude.

[Redkin]

Alright, your 'Animation' *shows* you #4 and #1 cylinders firing at the same time. Now, may I ask you, was this 'Animation' generated from a 4g63 engine? Is this true to life, or is it oversimplified so the 'concept' can be easily understood? Now it has been several months since I've had my cylindeer head off, but from what I can remember, that's not what my camshaft looked like. I think you need to examine the actual cam a little better and stop referring to pretty pictures.

http://www.extrememotorsports.com/g1cat/hks262-l.jpg

Very disappointing...

[greenstreak]

Alright, I'm here to learn like the rest of you guys. NOSLaser, could you please respond to Van's post concerning the statement that the crank may rotate the pistons in the same time (1&4, 2&3) but the common rotating pistons are not on the same power stroke. I believe that is what is being contested here at this point in relation to the tuned/equal length manifold discussion.

[NosLaser]

<<<Alright, your 'Animation' *shows* you #4 and #1 cylinders firing at the same time. Now, may I ask you, was this 'Animation' generated from a 4g63 engine?>>>

Dude, I honstly hope you are joking... You think that the laws of physics cease to exist on a 4G63??? It's the SAME FOR EVERY SINGLE INLINE 4 CYLINDER ENGINE IN THE WORLD!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! God people!!!!!!!!!

[NosLaser]

<<<but the common rotating pistons are not on the same power stroke.>>>



[Edited by NosLaser on 08-27-2001 at 11:55 AM]

[Redkin]

Ugh...Did you happen to check the photograph of the actual camshaft? The lobes are opposite each other! Look at the pic! Maybe you posses some extremely higher intellect than I, in which case, explain to me how two cylinders firing 180 degres of each other have the same power stroke time?

[mark93]

Here is the right version of how a 4cyl. engine works
http://home.s-planet.de/kwode/vmotor/v_zylinde.html

[dsm93talon]

I've found a way to make everyone understand... NOSLaser, this is how to dumbify it for everyone. And I must add my opinion as well... 2 cylinders DO NOT fire at the same time, nor do they fire CLOSE to time with each other.

Granted, the diagrams do not show the full cycle from 4 firing, through 1, 2 and then 3... but it does give a GREAT idea of how it REALLY works. Hopefully we can get back on topic now.

http://albums.photopoint.com/j/View?u=1598847&a=13483075&p=53442252&Sequence=0&res=high
http://albums.photopoint.com/j/View?u=1598847&a=13483075&p=53442253&Sequence=0&res=high
http://albums.photopoint.com/j/View?u=1598847&a=13483075&p=53442414&Sequence=0&res=high
http://albums.photopoint.com/j/View?u=1598847&a=13483075&p=53442256&Sequence=0&res=high

Hope it helps to educate SOME of you ;)

[mark93]

There is no reason to dumbify it. You just need to get the facts and get them right,there is no reson to bash people and call them stupid.I come on this forum to learn more about my car. It just pisses me off to see some people come on here and act like GOD!! This was an interesting topic till that started.

[NosLaser]

Okay, I re-read everything. First, I thought that 4g63rydah was Bill Marino for a second (notice what time I posted my response) so I apologize to Bill for that. Secondly, I mis-understood what he said...I thought he said something along the lines of 1 and 4 are not in time as far as tdc/bdc and 2 and 3 are not in time. Van is right about the different strokes; I was on a completely different tangent and I apologize. If you look at my first post, I almost repeat what 4g63rydah said. Again, I apologize for that, I was in a bad mood and very tired, and awake at 2am on a Sunday night/morning. I thought he said something completely different.

[dsm93talon]

being awake @ 2am sure will do that to ya ;)

[Rdy2race]

Originally posted by NosLaser
First off, Dyezak, I must say you know your shit. I am SO GLAD to see that there is someone who actually belongs on the ADVANCED technical section.

Bill, you are doing it again...
. Bill...you are striking out dude. Do you really work on people's cars?

Ummmm DICK. ( isn't your name Rich? )

yes you DICK have you seen me reply to this NEARLY usless thread ( at this point when you comment was made. )

Let me restate your new name

_ _ _ _

fill in the blanks.


Okay, I re-read everything. First, I thought that 4g63rydah was Bill Marino for a second (notice what time I posted my response) so I apologize to Bill for that. Secondly, I mis-understood what he said...I thought he said something along the lines of 1 and 4 are not in time as far as tdc/bdc and 2 and 3 are not in time. Van is right about the different strokes; I was on a completely different tangent and I apologize. If you look at my first post, I almost repeat what 4g63rydah said. Again, I apologize for that, I was in a bad mood and very tired, and awake at 2am on a Sunday night/morning. I thought he said something completely different.
__________________
Aslan
92 Laser RST
"NosLaser"


Ok that is fine but maybe you should edit your post then,. I take offence to things like that and making a comment about my knowlage and my business. TRUST me I know A LOT more then you and I am not braging here but this thread was ANSWERED A LONG TIME AGO. Get it on track or it's getting locked. If your going to talk about the 4 strokes of a motor bring it to gen tech it DOES NOT belong in Adv tech never the less in a thread about manifolds!!!

BM- (Pissed off)
NOS LASER Be on your BEST behavior I will be looking...
have a GREAT day!@!!@!!!@!!!


[Edited by Rdy2race on 08-27-2001 at 12:57 PM]

[NoAvail]

***mental note***
...highly intelligent people first must understand exactly what it is that they are about to respond to, then they can be sure that they won't sound like a complete dumb ass when they make insulting responses...

[Van]

Originally posted by NosLaser
Okay, I re-read everything. I was on a completely different tangent and I apologize.

Nuf said.
Now it takes a real man to come back and publicly state he was wrong on something.
IMHO, this ISN'T about bashing Aslan or any such dumb bs. It's more about clarifying a misunderstanding that *could* happen when we look at the concept of wasted spark and tuned, equal length exhaust runners, etc.
There are many new dsm'rs out there that do not know some of this stuff and might read this thread. My previous post was to clarify the misinformation for others, not bash Aslan. Sorry if it seemed that way.
I personally would value Aslan's input on some things, as should others... Do your research and look for many opinions/experiences that support the same thing, not just one guy's. After all, he might've misread something in your question or be having a bad day. It happens.
The moderating team would appreciate it if you edited out some of your own comments Aslan. ;)

[gsxalex]

I've been highly consitering fabing my own ELEM but i am not sure on the correct way to measure and cut the tubing. Obviously a straight piece of 8 in pipe is 8 in, but how would you make the calculations for an 8 in "S" bend? since the inner wall radius and outer wall radius are very different in length. My assumption would be that you need to average these two radiuses and base calculations off of this "center" radius. Anyone know where i can find this info? and what type or what grade metal would be ideal for tubing and flanges?

[Redkin]

So...with all that said from everyone...is there someone who can provide a synopsis to answer the original intent of this thread? I initially tuned in because I think it is a relevant question. This obviously took a turn for the worse, but there has to be some redeeming value from it. Is is safe to say that tuned/equal-lenght/tuned&equal-length headers offer some benefit? That's what I got from relevant posts. Anyone?

[NosLaser]

Read my post on the first page and it explains the reason for a tuned header, and what exactly you are tuning for. (Ignore the whole tangent about 4 strokes, etc. and you'll see I did answer the question at hand)

** admin edit **
I'd advise us to not get the bs started again Aslan, ok.
Thanks. Let's talk headers instead.

[Edited by Van on 08-27-2001 at 01:17 PM]

[dsm4eva]

You need to calculate the length using the arc lengths of your bent sections. (e.g. using the centerline of the arc)

http://forum.swarthmore.edu/~sarah/hamilton/ham.seeing.cutting.html

[Rdy2race]

to sum it up...

yes a tuned head will make a change in the total power output of a motor. Now where this peak takes place and how broad the gain is, this is all set in the "tuning" of the headder. The gains can be from a shorter spool time to a power peak. Trade off's for both are something that should not be overlooked. If you study header design you will see the wide available options you have for a headder. From short and fat to long and thin they all do different things as the "tunning" of the headder was done for different reasons.

No down side can be seen othen then the following
Cost

Size ( most of the time they will need to be MUCH larger then stock and eats up room)

life span ( headders are made for race cars, race cars are expected to be over looked all the time and problems delt with. Also race cars are not expected to see the street and deal with Potholes and a rough ride surface. This makes cracking the welds a ongoing problem for street/strip car. But then again it IS a race car right? =-)

[dsm4eva]

The problem I'm having is calculating the ideal length for the tubes. I understand that you can only really 'tune' the header for a RPM band, and I'm targeting the WOT range for ideal power generation (as Bill stated, its a race car :)). Everything I can find is to calculate header lengths, tube diameters, and collector length for n/a cars. Its a turbo engine, I don't need no stinkin' horn! So that leaves me with this problem, how long should they be?!?

[widebody]

that is what i was wondering it would seem that the longer the tube the higher in the rpm band it would be effective.

[Rdy2race]

I really have no info infront of me to work off of but some super basic rules. Please correct me if I am wrong as this is off the top of my head.

Longer = Higher power peak RPM
shorter = Lower RPM power peak ( shorter with in reason. I don't want to get in to " What if we put the turbo on the head!!!" kind of thread. :D

4-1 = most gain on peak
4-2-1 = broad power band gain, midrange

For us being a 4 banger I feel that 4-1 is best and longer is better since we lack the monster torque that other motors make we need to make this up in RPM's Moster RPM's is the only thing that will sub for pure twisting power (torque)

Let us know what you come up with

BM-

[dsm4eva]

You're right on there Bill, its the same principle of changing intake runner length to move torque peaks around, HOWEVER, I cannot find good info out there that is empirical data for turbo engines. I can find a sh!t load for V8 headers, but we know that just isn't the same. Everything I've found for 4-cyl turbo engines have lengths around 14-18", but WHY?!? and which one do I want based on my RPMs?

[MoBoost]

That's an interesting point. How does the length of the header affect the performance?
I can see that ELEM brings a very balanced exhaust pulse to the turbo wheel.
What I don't understand how the length itself plays the role. Do antiwaves come in play? Resonance? Sound waves? In my mind the shorter is the header the better - gases are hotter, velocity is higher, etc.... but appearently it's not as simple.
Somebody with the "knowledge", please enlight :)

P.S. Aslan : no hard feelings, I know how you get "pissed" as somebody's stubborn stupidity, but as you see, there is a danger of blowing up a misunderstanding out of proportion (as it happened here).

[dsm4eva]

A well designed header not only relieves the backpressure, but goes one step further and creates a vacuum in the system, as has been stated before. When the next cylinder's exhaust valve opens, the vacuum in the system pulls the exhaust out of the cylinder. This is what the term "Scavenging" means and is why we desire to design the system properly instead of creating a ‘log style’ manifold.

There are many design criteria that must be established prior to constructing the header. The first consideration is the proper tube diameter. You might think "Bigger is Better", but this is not the case. The smallest cross-sectional area that will flow enough air to handle the engine's displacement at your desired RPM target should be used. The smaller diameter will generate the increased air velocity that will help scavenge at lower RPMs. If too small a cross-sectional area is used, the engine will out-flow the header fairly early. The solution to this situation would require bumping the tube diameter one size larger. The second consideration is the proper tube length. The length directly controls the power band vs. engine RPM. Longer tube lengths pull the torque down to a lower RPM range, while shorter tubes move the power band up into a higher RPM range.


Quoted from a Header builder for n/a V8s.

Engines that Red Line at 10,000 R.P.M. would need short tube lengths about 26" long. Engines that are torquers and Red Line at 5,500 R.P.M.s would need a tube length of 36". This is what is meant by the term "Tuned Length". The tube length is tuned to make the engine operate at a desired R.P.M. range.
The third consideration is the collector outlet diameter and extension length. This is where major differences occur between four cylinder engines and V-8 engines. The optimum situation is the four cylinder because of it's firing cycle. Every 180 degree of crankshaft rotation there is one exhaust pulse entering the collector. This is ideal timing because, as one pulse exits the collector, the next exhaust valve is opening and the vacuum created in the system pulls the exhaust from the cylinder. In this ideal 180 degree cycling the collector outlet diameter only needs to be 20% larger than the primary tube diameter. (Example: 1 3/4" primary tubes need a 2" collector outlet diameter.) The rule of thumb here is two tube sizes. This keeps the velocity fast to increase scavenging, especially at lower R.P.M.s. Going to a larger outlet diameter will hurt the midrange and low R.P.M. torque.


The amount of straight in the collector extension can move the engines torque up or down in the R.P.M. range. Longer extension length will pull the torque down into the midrange. Larger diameter collectors cause a tremendous drop in air velocity, resulting in less scavenging through the entire RPM range. Exhaust cams with extended valve timing will help the exhaust cycling. However, this results in valve timing overlap (Intake and Exhaust valves both open at T.D.C.) which causes a "Reversion"cycle in the exhaust. When this happens, exhaust actually backs up into the cylinder causing intake air to be pushed back out the intake. Proper head porting and flow bench values are required when designing the header and/or considering doing any serious exhaust ‘bowl work’.

Unfortunately, my problem of finding good engineering data or design criteria for turbo headers is still definitely lacking. However, I’m getting closer everyday to a solution.

[Redkin]

I hope I don't get chewed out for this, but I remember in a SCC Mag a few years ago, some kid turbocharged an Accord with tuned headers and got amazing results. I'll have to search for the magazine when I get home and I'll post something if I find anything. It was a wild looking header, with the runners heading out to the passenger side where they met the turbo. Just thought it might help someone remember reading that article too.

[gsxalex]

Sounds like it would be pretty beneficial to match some good cams to the ELEM.

To answer the question of exactly how the length affects power in different rpm bands: The exhaust pulses are the same type of wave as a sound wave. They are made up of compression pulses with vacuum in between. As previously stated these pulses travel at different velocities depending on the diameter of the runners. As each pulse reaches the collector it will send a vacuum wave back down the other runners.
The length and diameter of the runners will determine how long it takes for this vacuum wave to travel out of the combustion chamber, to the collector, and back up the other runners.
The vacuum wave will have a peak effectivness when the cylinder it is effecting is just opening the exhaust valves as the vacuum wave arrives. This vacuum wave will help to pull the cumbustion exhausts out of the combustion chamber.
Since the compression/vacuum waves travel at a constant velocity depending on the given tube diameter, you must adjust the length of the tubes to change what rpm is conincidental to when these waves arrive back at the cylinder head.

Make sense?

Im not sure how much effect it would have, but i think it is possible that the compression wave can be made to allign with the exhaust cycle of the cylinder and actually hinder performance by causing high pressure as the valves open and preventing the exhaust gases from easily escaping

[dsm4eva]

Oops forgot the whole development of the standing-wave inside the header bit.. Thanks. Also, have you found any equations to calculate, based on cross-sectional area and RPMs, a length that will be ideal for a low pressure trough?

[Nick 92 TSi AWD]

On a na car the thing that helps the low to midrange torque is venturi waves. I'm not the expert on this (not carring about na cars, never looked into it) but it is some type of harmonic backwave that flows back into the combustion chamber. It is NOT backpressure though. Supposedly a perfectly designed header for a na motor will have almost no backpressure, but keep the low end torque due to the venturi waves.
How much does this apply to turbo cars? Not a clue.

Here's something for you guys to look at though:
http://www.pics.dsm.org/files/don_greendwood_turbo_header_1.jpg

[GSXXXguy]

OK, so how much are those and is there a big benefit to using them? And what about cracking. The welds look small...or weak.

[DSMDragger]

Here is an example of a stainless manifold on the BOZZ Speed Lancer EVO 5...

http://home.earthlink.net/~syth3/sema5.jpg

[DSMDragger]

Here is Gary Gardellas ECHO Civic Stainless header..
SEMA 2000

http://home.earthlink.net/~syth3/sema14.JPG

[DSMDragger]

One of the most beautifully done manifolds I have seen in person..
Gary Gardellas Race Civic
SEMA 2000 Las Vegas

http://home.earthlink.net/~syth3/sema12.JPG

[DSMDragger]

Bozz Speed Lancer

stainless manifold
HKS GT3540 Ballbearing Turbo
600HP+
4inch intake with HKS Filter

http://home.earthlink.net/~syth3/sema6.jpg

[DIMO]

I've always wondered about this when i had my eclipse, but all the shops told me that its a waste of money unless your making big power, but isn't it also to smooth the exhaust going into the turbo which should help with spool-up, I know they make quite of bit of power in my car. Oh yeah the venturi waves (harmonics) act as a way to pull more air in the engine as well as help exhaust flow out, this would not work on a turbo car because air is being forced into the engine as well as the turbo block harmonics made by the air flowing into the engine...On na cars part of the science of intakes and pipes with the sound they create, those sound waves help draw air into the engine but this help is very minimal though

[Edited by DIMO on 10-05-2001 at 06:14 AM]

[Rogue_Ant]

Originally posted by Nick 92 TSi AWD

http://www.pics.dsm.org/files/don_greendwood_turbo_header_1.jpg

Looks nice, but the welds are icky.

Rogue

[TSi92]

Originally posted by redgsturbo
[B]I think that is more of a custom made thing... I have never seen a tuned exhaust mani for eclipses

The HKS t4 exhaust manifold has equal lenght runners. Nut it will only fit a t4 turbine housing.

[tworbtalon21]

was anybody at Bushur Racing for the dyno shootout back in July?
Kevin Lawson has a 91 awd talon with a BR57 (t3/t4) turbo on his car with what looked like an equal length manifold. I believe it was cast iron and jet hot coated, which he says wears off after a few heat cycles but the manifold itself looked pretty stout. He put 603 horsepower to the wheels with no nitrous, which is actually more power than Dave Bushurs 7 sec car makes off nitrous. just thought I'd bring it up.

[16g-95GSX]

From my reading, please excuse me if I havent had as much experience as some of you, but from my reading at most a turbo should have 3 runners funneling into it directly. Ideally on a 4cyl engine you should have a pulse convertor exhaust manifold to ensure a steady stream of exhaust pulses and not have them collid. This will explain why a TT'd 6cyl is ideally a better setup than a turbo'd 4cyl with a 4-1 exhman. Again this is just from my reading, and a divided turbine housing also helps this out as well.

[Rogue_Ant]

Why 3 runners? This doesn't make sense (at least not to me).
If you have 4 runners they don't collid, if you have equal length runners.
The best is to have none of the exhaust pulses collect until they are in the turbine housing (nearly impossible to do). This is why divided housings with properly engineered header will help spool and performance, because you can atleast keep half of the runners seperated.
Obviously more cylinders is (generally) better, since the amount of time between pulses is less.

Rogue

[GSXMonster]

http://www.dnperformance.com/Images/header02.JPG
http://www.dnperformance.com/Images/header04.JPG

DNP makes them... $499
http://www.dnperformance.com/eclipse.html

[Wreckleford]

Anyone ever used one of these? That's the best price I have ever seen for a stainless manifold.

[marshall]

that is amazing, 499...if you've never tried to make a tubular 4G63 exhaust manifold it's pretty hard to imagine the amount of time involved in putting one together...to do all that work AND use quality material for under 500 bucks seems like an excellent deal.

marshall

[Mike'sGSX64]

That manifold from DNP is nice but only comes with a 14 day warranty. I e-mailed them and they said that they weld on extra suports on the tubing where it meets the flange to the head.

The manifold from SFP has a 3 year warrranty agaisnt cracking. I like there design better by mounting the wastegate off the collector and their manifold is $475.

www.sfp.net

[import_power22]

just so you guys know. AGP makes an equal length, cast manifold that will allow mitsu turbos to bolt directly to it. Coost is $575. Visit www.agpturbo.com

[GSXMonster]

The one AGP sells has a T4 flange on it. Or is it not listed on the site?
Rob

[1_vicious_gsx]

I have an equal length header made by DN Performance (http://www.dnperformance.com) and I like it alot. I put it on at the same time I installed my TurboTrix S/S o2 housing. I get full boost (20psi) before 3000rpm on my stock 16g (unported/unclipped). My best e.t. was 13.14 @ 102.81 mph before the change, my car has now gone 12.62 @ 111.12 mph. , but My EGT is only @ 805 deg c, which means I still have plenty of power to extract. Fit was perfect. No leaks. Can't say which gave the most improvement (header or o2 housing), but it works for me.
:happy:

[1_vicious_gsx]

OOOOPS, I forgot to show it. Here's a picture of mine installed.
http://images.cardomain.com/installs/225000-225999/225656_24_full.jpg

[1 FAST 2.0]

Where did you buy that ^^^^^ Header from??? How long has it been on your car? Could you post a link to the site you got it from? I have a Buschur t3/t4 will they make the flange for that turbo? Right now I have the Turbonetics manifold but I am looking to upgrade.
Thanks,
Tim

[1_vicious_gsx]

Originally posted by 1 FAST 2.0
Where did you buy that ^^^^^ Header from??? How long has it been on your car? Could you post a link to the site you got it from? I have a Buschur t3/t4 will they make the flange for that turbo? Right now I have the Turbonetics manifold but I am looking to upgrade.
Thanks,
Tim
I got it from DN Performance (http://www.dnperformance.com). Been on the car about 1-2 months. They do offer a T3 flange header. See my post above this one for more info.

Thanks, Mike.

[1 FAST 2.0]

Sorry I must have looked right over that post.

[kris]

So now that we understand the reasons for an elem manifold can we discuss the options available?

Most of us will not choose to get a manifold that needs to have the welds touched up, re-jet coating every XX amount of time, or even the possibility of cracking over time. In addition, since fabricating a peice is out of most of our capabilities, it would seem that buying a manifold from a vendor is the best option.

The apparent choices are:
DN Performance - good looks, tubular - 500
South Florida Performance - anybody got a pic?, tubular - 475
Archer (probably not worth considering, but they had a great warranty back in the day)
AGP - apparently only for t4's,cast - 575
HKS (cast, and more expensive) - AGP lists these as no longer being in production.
Buschur t3/t4 - cast, mount for ext. wg or egt - 475
buschur t4 - looks just like agp's - 575 (same price too)

I contacted SFP several months ago and there price was 500 with a 2 year warranty. Watch out for falling prices...

I also noticed that Magnus is currently working on their own version. I called Marco and he told me that they'll probably have something to show by the start of the new year for less than 800. I've got their Intake Manifold and judging from that, I'd expect big things from Magnus, because that intake is fantastic.

I also remember seeing Sheppard's car at the SO and he had a cast manifold. Did anybody else see it? I'm not sure what manufacturer it was.

I know vicious likes his manifold, but how long have you had it on the car and the big question is will it hold up? Time will tell.

For me, with a solid 12 second daily driver with a 16G (maybe I'll go bigger someday), I doubt the benefit for a high dollar peice will ever be there, but I'm still interested in following the developments.

[DCJ98GST]

Originally posted by 1_vicious_gsx
I have an equal length header made by DN Performance (http://www.dnperformance.com) and I like it alot. I put it on at the same time I installed my TurboTrix S/S o2 housing. I get full boost (20psi) before 3000rpm on my stock 16g (unported/unclipped). My best e.t. was 13.14 @ 102.81 mph before the change, my car has now gone 12.62 @ 111.12 mph. , but My EGT is only @ 805 deg c, which means I still have plenty of power to extract. Fit was perfect. No leaks. Can't say which gave the most improvement (header or o2 housing), but it works for me.
:happy:

That is a pretty significant gain with the header and the O2 housing. Is that with an external or internal dump O2 housing? What was spoolup before the change?

[1_vicious_gsx]

kris brings up some valid points that everyone should consider. What is the objective for your car? For me it's show & go, which means that every part I consider adding or replacing on my car has to pass a list of requirements;

1st. will it improve performance
2nd. what else would have to be changed or modified to install it
3rd. quality of the contruction & durability
4th. will it add weight or lighten the car
5th. will it add to the theme (appearance) of what my car is about

The DN Performance header meets "MY" requirements very well for "ME". Could there be a better header (better flow, better construction), possibly. Would it be worth the extra $$$ some builders are asking for, probably not.

These forums are for us, as DMS'ers, to discuss what works and what doesn't. I find some, if not most of the info I read in these forums to be based on opinions instead of facts. I'M NOT FLAMING ANYBODY BY SAYING THAT!!!. Just keep it in mind. It's "MY" OPINION that the DN Performance header would more than meet the needs of anybody considering it.

As far as the issue of cracking, my header is too new to tell you. If it does crack, I will fix it. Just as I would with anything else that would go wrong on my car. But keep in mind that the factory cast manifold cracks also, mine was when I took it off my '99 model. And I do believe it is harder to repair a cast manifold vs a header, if it can be repaired at all.

If all you are worried about is pure longevity of you car's powertrain then leave it stock. If you are going for performance, you better be prepared to repair or replace parts on some kind of a regular basis when they break or wear out. A good example of this would be running an automatic trans vs a standard. We all know automatics would be easier on the driveline and more consistant at the drag strip, but we would rather run a 5-speed because it will go faster, knowing we will eventually break something or wear the clutch out and have to replace it. It's no different for anything else on the car when you alter it.

So just ask your self "will it work for me"?
Thanks, Mike.

[1_vicious_gsx]

Originally posted by DCJ98GST


That is a pretty significant gain with the header and the O2 housing. Is that with an external or internal dump O2 housing? What was spoolup before the change?
Internal dump back into the o2 housing. My spool up improved slightly, about 100-200rpm . No more boost creep. It will hold rock steady as low as 8psi up to a solid 20psi. Instant boost between shifts.

[1_vicious_gsx]

Originally posted by 1_vicious_gsx

Internal dump back into the o2 housing. My spool up improved slightly, about 100-200rpm . No more boost creep. It will hold rock steady as low as 8psi up to a solid 20psi. Instant boost between shifts.
I believe I picked up the biggest gain in the upper rpm range through better flow, which is evident by the mph.

[99GSTRaptor]

1_vivious_gsx,

I know you haven't had the manifold long enough to comment on cracking, but what about tapping for an EGT guage??

Have you done that? I couldn't tell from your pics. I'm very interested in the manifold, but there are only two things that I am worried about:

1. Premature cracking
2. Ability to tap or reliably attach an EGT guage

Correct me if I'm wrong, but I believe the material that the stainless is too thing to reliably tap into. So I'm assuming only a weld would work for the EGT?

Let me know if you have an EGT with this manifold and what you did.

Thanks,
Eric

[marshall]

my autometer egt came with a clamp for using the probe in thin wall tubing. just drill the hole and clamp it on, no need to tap it.

marshall

[99GSTRaptor]

I have the 60mm Greddy peak/warning guage and haven't installed it yet, but the last time I looked I don't remember seeing a clamp. I might be wrong, but I dont think there is.

If not, where could I pick something like that up at so that I could install the EGT.

Eric

[marshall]

www.aircraftspruce.com

[1_vicious_gsx]

Originally posted by 99GSTRaptor
1_vivious_gsx,

I know you haven't had the manifold long enough to comment on cracking, but what about tapping for an EGT guage??

Have you done that? I couldn't tell from your pics. I'm very interested in the manifold, but there are only two things that I am worried about:

1. Premature cracking
2. Ability to tap or reliably attach an EGT guage

Correct me if I'm wrong, but I believe the material that the stainless is too thing to reliably tap into. So I'm assuming only a weld would work for the EGT?

Let me know if you have an EGT with this manifold and what you did.

Thanks,
Eric
If you look closely at this pic. To the right of my oil dip stick you will see a brass plug. That is wear I tapped for the EGT. I had to get a new EGT fitting for my probe which has been installed since this pic was taken. I tapped into the #1 runner where it gets wider at the port. I just drilled and tapped it prior to installation. Worked like a charm. Just don't over tighten it. Snug will do it. I have not had any problems with it. I think the issue of cracking is being talked about too much, just like "crankwalk". Either it will happen or it won't. If it does crack just fix it, it's not the end of the world. It's "luck of the draw" on who gets a piece that will fail or not. Any header could crack, no matter who makes it or the design. Cast manifolds crack too. I guess I need to post a better pic since I get this question alot.
http://images.cardomain.com/installs/225000-225999/225656_24_full.jpg

[99GSTRaptor]

Thanks 1_Vicious_GSX and marshall.

I appreciate all of the help that people offer...it really does help people out...at least for me it does.

I guess I agree with your point on the cracking, too. Either you get the manifold and deal with it when/if it arises or just sit there and never get anything and just wonder what if....

One last question and I will leave you alone. I believe someone else that uses this manifold gave the bolt sizes for the flange to the turbine housing. Since this flange is thin and tubes arranged the way they are, you need shorter bolts.

Do you remember the sizes of the bolts you used? If I remember correctly, I think someone actually used two different sized bolts for the "front" and "back" of the flange.

Thanks again,
Eric

[1_vicious_gsx]

Originally posted by 99GSTRaptor
Do you remember the sizes of the bolts you used? If I remember correctly, I think someone actually used two different sized bolts for the "front" and "back" of the flange.

Thanks again,
Eric
That was me. I had another post about this header some where in the forums.
2 bolts for the front are 10 x 12.5 x 30mm
2 bolts for the rear are 10 x 12.5 x 40mm

Hope this helps.