The truth about headers.

[hooleyboy]

Im going to give this a shot at explaining some info on headers... In my research on this long tube header project I think I found some answers to questions I had about loss of power up top and Lower trap speeds. We've all been on the dyno with our C55 and for me what looks like a stout pull always seems to fade off up top. It left me scratching my head. This would also be seen at the track with lower than expected trap speeds. Anyway what I found was ALL headers currently available that have a merge style collector like a few that lots of us use on the C55 In fact have the wrong firing pattern inside the collector. I've haven't put much thought into the 55K's firing order but it leads me to believe that these headers were never intended to be used on a C55. As the 55K AMG's have a different firing order Q1) What happens when the firing order in a merge collector is wrong? A) All or most headers available for the C55 will make power at some point in the RPM band as they are in most cases a vast improvement over stock. But the flaw with these headers on the C55 is in the way that they fire. IF the header is firing in a "X" pattern it will cause the headers to be unable to scavenge correctly. Our C55 calls for a firing pattern of 1-4-2-3 on the passenger side collector and it should look like this. If it does not look like this the header will have trouble scavenging correctly and efficiently. Q2) what is scavenging? A) It is the headers ability to suck out exhaust gases from the cylinder head under a created vacuum. If a header does not scavenge correctly it looses its ability to suck the gases out of the cylinder head correctly and in most cases you are leaving HP on the table. If it doesn't scavenge correctly you leave it up to the motor to push out the gases with out any help. IF you look back at the rude image. The C55 passenger side fires cylinder 1 first and then as the firing order gets back to the passenger side cylinder 4 fires. You need to have these cylinders next to each other not diagonal from each other. They should fire much like a Gatling Gun... Or in a circular pattern not an X pattern. Kleemann is a prime example of a wrong firing pattern for the C55. Remember the firing pattern should be in a circular pattern. Again the C55 passenger side fireing order is 1-4-2-3. If you look at this Kleemann image you can see based on the firing pattern it brakes the circular pattern needed for optimal scavenging for the C55 Thus leaving HP on the table. I hope this sheds some light on headers for the C55. Its no doubt kind of hard to explain.

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[jturkel]

wow mike. great explanation! can't believe they werent designed properly. i'm sure your headers will truly be something special for the c55 guys.

[C43AMG]

Nice explanation.What type of increase would you expect from a "properly designed" set of headers? 10% increase?

[C43AMG]

In the Kleeman image, #2 and #3 should be reversed, correct ?

[hooleyboy]

Originally Posted by C43AMG

In the Kleeman image, #2 and #3 should be reversed, correct ?

correct.

[eclipsed]

The problem is that our engines are so tight that we cobble up anything that fits. for a header to really work best is they should equal length headers. all runners must be the same length or cylinder gases crash together at the wrong time. I see in your other post those truck headers and see how they twist around each other ensuring proper evacuation of exhaust. Unfortunately on our cars there is no way with the engine bay. In that picture one runner is 4 times shorter than the long one.

[hooleyboy]

Originally Posted by eclipsed

this has been beat to death for many decades. The problem is that our engines are so tight that we cobble up anything that fits. for a header to really work best is they should ALWAYS be whats called equal length headers. all runners must be the same length or cylinder gases crash together at the wrong time. look at old headers from fords and chevys and see how they twist around each other ensuring proper evacuation of exhaust. Unfortunately on our cars there is no way with the engine bay. In that picture one runner is 4-5 times shorter than the long one. reasearch equal length headers.

I know about equal length header. I also know that all the shorty style headers that run merge collectors have a nub for a runner. Thats a problem too. That makes for a double wammy on these Kleemann headers. I believe my design set to hit the market will have one runner 2 inches smaller than optimal. However it would make them impossible to install or you would run the risk of the header collector being set to far under the car and possible hanging to low and could get damaged when driving.

[hooleyboy]

Originally Posted by C43AMG

Nice explanation.What type of increase would you expect from a "properly designed" set of headers? 10% increase?

Its really hard to say if its 10% I would guess 5-8hp If both headers are the same except one have the correct firing pattern.

[RLx02]

Mike, I'm definitely interested to see if you guys can churn out a header designed with our firing order in mind and as close to equal length as possible while still running the cats. The next step for me is the headers as I'm anxious to join the 400hp club (at the crank).

Keep us posted!

[MRAMG1]

Hey Hooley:

First of all I have aplauded you from day one on your GREAT build up

This header game, aka scavenging adventure, might not end up with the gains you are looking for here.

"V-8 and a four-into-one header design (which is about all we race), the header lengths are not super critical from about 28 inches to about 40 inches. If the pipes are between approximately 30 and 38 inches, it will be hard to improve much by juggling these lengths. As a result, valuable time is lost while trying to build a set of headers with totally equal lengths.

As forgiving as the exhaust system's primary lengths may be, the same cannot be said of the secondary or collector length. Depending on the cam and rpm range, the collector should typically be within 12-20 inches to either open air or a large and abrupt change in system cross-sectional area. If you ignore the collector length you could be throwing away as much as 20 lb-ft and 20 hp, even on a relatively mundane engine." Taken for Stockcarracing.com

I have done alot of research myslef with a V-8 pinto MANY years ago when I built a custom set for it, and there is NOT alot to gain with firing order in the collector. The idea behind the vacume created by the collector is do to the hot gas from one primary entering the collecotr. That vacume that it now exhibits is spread equally to the other 3 pipes, and really does NOT change in relation to firing order. All three primaries, not firing will see this vacume. It all falls under physics, aka partial pressures. Reguardless of the order of the primary pipes, at any monemet in time 1 will have a positive wave, aka hot exhaust, and the other 3 will see this partial vacume.

You can make more power by working on the proper collector size and length, than you ever will modifing the oreder of the collector.

I really do wish you luck, and success, but in the end you are going to be putting a TON on money and time for VERY little return. Stop by a NASCAR track, Sprints, etc, and talk with some engine builders if you haven't already done this my friend.

GOOD LUCK

See yeah

[spr]

Makes sense. Hooley you could always make two sets with the different firing orders to kill your curiosity. hehe

[hooleyboy]

Originally Posted by spr

Makes sense. Hooley you could always make two sets with the different firing orders to kill your curiosity. hehe

I will do that. I'll get a set made of mild steel because its dirt cheap and see what happens

[c32AMG-DTM]

Cool idea spr... that's really the best way to A/B test it - mock up a set the same way, minimizing as many variables as possible (i.e. same dia primaries, same collectors, etc.) and just alter the firing order, and see how much (if any) the optimized header picks up on the dyno...

Hooleyboy - thanks for the always valuable input.

[superstar]

Good luck Hooley on your researches!

[FrankW]

good information

[hooleyboy]

After checking my Brothers 2006 CLS55 out I noticed the firing order stamped on the valve covers is the same as the C55.

So if the CLS55 has a firing order of 1-5-4-2-6-3-7-8 as well than every last merge collector style header currently available is made "wrong". Some even go so far to not be equal length and have no regard to the firing order of the engine.

This includes ALL merge collector style headers from Supersprint all the way to kleemann. At least Supersprint is equal length, but I hear all their headers are now made out of Mexico.

here is a pic off a 2006 CLS55

[c32AMG-DTM]

Originally Posted by hooleyboy

After checking my Brothers 2006 CLS55 out I noticed the firing order stamped on the valve covers is the same as the C55.

So if the CLS55 has a firing order of 1-5-4-2-6-3-7-8 as well than every last merge collector style header currently available is made "wrong". Some even go so far to not be equal length and have no regard to the firing order of the engine.

This includes ALL merge collector style headers from Supersprint all the way to kleemann. At least Supersprint is equal length, but I hear all their headers are now made out of Mexico.

Interesting stuff - this include evo, Renntech, VRP, et al. as well?

Given that 55's (N/A too, but especially F/I) have made huge power when upgrading to any of the aforementioned headers, it'll be interesting to see what yours make over and above that. Best of luck!

[hooleyboy]

Originally Posted by c32AMG-DTM

Interesting stuff - this include evo, Renntech, VRP, et al. as well?

Given that 55's (N/A too, but especially F/I) have made huge power when upgrading to any of the aforementioned headers, it'll be interesting to see what yours make over and above that. Best of luck!

I tell you what, It leads me to believe VRP's logs and AMS might be a good design. They done have to worry about firing order because the dont have a merge style colector.

[Vadim @ FD]

Mike, great theory!

However, two problems on a stock C55 engine. Not enough compression and not enough cam timing to where header tuning will have enough effect on HP to be worth the expense of making a very specifically tuned header.

Not to mention an intake manifold tuning that is designed to cover 2000-6000 rpm.

And I am not even going to mention the noise and smog issues with a true racing setup.

[Vadim @ FD]

It leads me to believe VRP's logs and AMS might be a good design.

Yes, the HEMs are very good at evacuating exhaust, not at tuning for a particular RPM range.

The problem with AMS, is that they are an exact copy of a stock manifold, down to the primary pipe and exhaust flange diameter. Except stock manifold is T409 and will last longer.

[c32AMG-DTM]

Originally Posted by Vadim @ FD

Mike, great theory!

However, two problems on a stock C55 engine. Not enough compression and not enough cam timing to where header tuning will have enough effect on HP to be worth the expense of making a very specifically tuned header.

Not to mention an intake manifold tuning that is designed to cover 2000-6000 rpm.

And I am not even going to mention the noise and smog issues with a true racing setup.

So, to surmise your post, "great in theory but likely won't provide practical real-world 'cost/benefit' returns" - is that fair?

[hooleyboy]

Originally Posted by Vadim @ FD

Mike, great theory!

However, two problems on a stock C55 engine. Not enough compression and not enough cam timing to where header tuning will have enough effect on HP to be worth the expense of making a very specifically tuned header.

Not to mention an intake manifold tuning that is designed to cover 2000-6000 rpm.

And I am not even going to mention the noise and smog issues with a true racing setup.

Maybe I'm misunderstanding you. 11:1 is not enough compression? There are cars with the same or slightly less the 11:1 that benefit greatly from Longtube headers. I know with a long tube header you can add more ignition when tuning over a standard shorty. Most NA intake manifolds on Ford 3 vales motors and LS GM engine see great benefits form long tubes that have an RPM range in that ball park. Jturkel can attest that Longtube headers on his friends LS2 motor made it come alive and that is on a car with no tune. I've raced that car and driven in it its a beast.

[jturkel]

Originally Posted by hooleyboy

Jturkel can attest that Longtube headers on his friends LS2 motor made it come alive and that is on a car with no tune. I've raced that car and driven in it its a beast.

oh yah....on brocks car (which is an LS1 btw). we were even before his headers. he puts on longtubes, pulls 2-3 cars from 40-140 (i have vids)....i upgraded from code3 to 185 and got my car dyno tuned (it was already tuned, but just did some refinement)....and we are almost even....he still pulls a little bit actually uptop.

[hooleyboy]

Originally Posted by jturkel

oh yah....on brocks car (which is an LS1 btw). we were even before his headers. he puts on longtubes, pulls 2-3 cars from 40-140 (i have vids)....i upgraded from code3 to 185 and got my car dyno tuned (it was already tuned, but just did some refinement)....and we are almost even....he still pulls a little bit actually uptop.

Brock's car is fast up top no doubt.

[MRAMG1]

Hey Hooley:

Okay, I came up with an idea for you to be able to bench prove your collector idea without actually having to install them on a car. Get a MagnaHela gauge, aka a VERY sensitive vacuum/pressure gauge for about $150.00. I use them for checking scuba regulators and anemometers. Build two collectors, one with your idea and the other a stocker or any other manufacturers collector, aka out of phase. Attach a blower to one of the primaries and read the vacuum across the others. See if there is ANY difference, aka a stronger vacuum signal like you think. Good luck, but I really don’t think you are going to see any difference here.

Atleast this way you don’t have to install them twice.

See yeah