Header types

Ok have a question about the difference types of headers. I am looking at long ceramic atm by BBK, my question is there a big difference between long, mid, short/ ceramic, chrome steel etc? I am looking for what might give the best performance. I have heard that longs have better torque. I am still awaiting the completion of my engine to be done. CAN'T WAIT :*burnout*: would have been done sooner but opted to have heads and intake ported and polished lol. Anyways I figure since the engine is out that it would be wise to have the headers installed while its out of the car vs trying to install later with the engine crammed under the hood.

Sorry that i have not been on that much just been busy at Campbell, spending time with my children when ever i can.

v/r
Dan

there is a big difference with long mid short. long tube headers will give you more torque on the low end. short tube headers will give you more torque in the top end. and mid well is mid and its not just the length of the headers its the design and how big the tubes are smaller tubes will be better for the low end and bigger tubes will be better in the top end. i have been told the best headers for street use would be tri "y" [url=example of tri y]http://image.hotrod.com/f/editorials/hot-rod-exhaust-systems/9757453+cr1+re0+ar1/while-conventional-four-into-one-headers-join-all-four-tubes-one-bank.jpg[/url]

sorry i cant get the link to work copy and paste but if i am wrong correct me

There is a pretty good difference in header types. mostly it deals with the airflow and how efficent the air can get out of the engine. As the headers get bigger i.e. mid- long tube headers then you have higher flow and increased power.

Long tube headers will give you best HP gains. You'll lose some low-end torque, but you will gain mid and high end.

As far as the coating/material, they determine the heat transfer and how they add or reduce engine heat. ceramic coated stay the coolest and reduce a good amount of engine heat which adds to the performance value of the header you choose. the other aspect of the coating is of astetic on whether you want them to be chromed or not and if your going for a specific look.

Also you may want to take a look at your mid pipe. If are looking at getting bigger x-pipe or anything like that, because this will detrermine what size of headers you get based on the collectors they have on them where they meet up with your midpipe.

As far as your initial choice, BBK's are crappy. Look at MAC headers, they're cheaper and better overall. And MAC headers are actually made by Hooker.

Hope that helps some! Can't wait to see your car when it's done
T.J.

long tubes vary GREATLY in their exact usage.

ie. you hear 1 1/2", 1 5/8", 1 3/4" primaries, and various collectors.

the fact is, long tubes for one motor are not completely useless for another, but may have peak efficiency at an rpm that doesnt match your combo.

collectors such 2 3/4", 3", 3.5: and 4" all have different torque effects.

in an attempt to avoid pages here, i will illustrate a few ways they work.


primary diameter: a tube of a certain diameter has a peak gas flow velocity where vacuum is achieved. ie. smaller tubes cause velocities for a given gas volume flow, to have higher speed. so by definition smaller diameter primary tubes scavenge at lower rpms.
there is a second effect: pulse tuning. a given pulse for a given tube diameter will arrive at a collector sooner than a larger diameter tube. because the higher gas velocities of the smaller tube. any change in tube diameter causes a low pressure wave that travels down stream and upstream the the speed of sound. so when the pulse reaches the collector, and the collector has larger diameter a low pressure wave travels back to all 4 exhaust ports. tube length is tune for a set rpm where the pulse reaches exactly as the valves open. more.....

collector: collector area determines torque. a larger collector enhances torque. which is the reason and "X" pipe or "H" pipe incrfeases torque. they are in essence increasing collector area. the "X" has additional effects.

a smaller collector enhances HP. if you look in your summitt website at collectors you will notice a delightful design....dynatech's 2 3/4" merged collector that expands to 3" after the merge zone.

get the hp and torque.


so a smaller primary tube for smaller motors, where the tube length matches rpm peak for the motor, with a collector diameter that either enhances torque or stays small for better peak HP.


more....

so Dan,

my advise is to buy the best ceramic header with the smallest tube you can get away with, and slip on collectors from dynatech. big performance gain can be found by adding or taking away primary length. which is what slip ons will let you do. when you get it right weld them. now extensions.........


after the gasses merge in a good collector, they still have heat energy that just gets wasted(free hp) by throwing it in a 2.5" exhaust pipe.

buying collector extensions and spraying a strip of high temp paint, then cutting them where the paint stops burning off, or dyno testing lengths will get the last few dozen hp's. 25 hp is not unusual for extensions that match perfectly.

exhaust diameter......

if a 2" exhaust is better than a 1 3/4", then why is a 3" worse than a 2.5"?

gas velocities for a given engine displacement. if you are running a 454, 460, 502, 512,707shotgun, then you NEED a huge exhaust.

if you have a 281, then 3" will kill torque. and do nothing for hp either.

it all has to do with tube diameter and velocities. 250 ft/sec is the number that comes to mind with exhaust pipe velocities. once you go large enough to drop below that, the piping stops pulling the gasses behind the pulses down the exhaust. it simply stop scavenging.

on a small motor such as a v6 the size can even be smaller. ie. a 2.5l v6 with 2.5" exhaust and x pipe could lose torque over a 2.25" system.


"X" pipe: everyone knows an x pipe is louder than an 'h'. its because the merging pulses cause a large pressure wave that travels down and up the exhaust system. 'h' pipes simply increase collector area for better torque. 'x' pipes enhance torque in the same way, but also enhance HP with low pressure waves at the ports.

you guys will notice on my diminutive exhaust system on my car that it uses 2.5" pipes and no 'h' or 'x'. i still get the scavenging of 2.5" pipes, but sacrifice torque for max hp. my exhaust shifts the rpm band higher. and the spring loaded baffles restrict for 'blow through a straw' torque.



a guy building repro t-bolts uses smaller exhaust pipes to lower the rpm band for more torque.

Ah ok i have a better understanding of it all now thanks for the input. I have been looking also as the hooker headers long tubs also. I will look up mac tonight ans see what they have to offer. Trying to get some of the local auto stores to do competitive pricing lol I love to haggle if I ever can get a chance for a better deal.

I am hopping to be done with the motor soon. I figured i would start there then in time will hit the interior and finely the exterior. I feel sad seeing my body sitting in my driveway engine less lol... She looks all sad LOL

What year stang are you looking to put headers on? Either way ceramic coated longtubes are going to be the best way to go as far as power gains. Also what are you looking to spend on headers?

it will be on a 98 cobra 4v. Trying to stay under 700 on headers.

i strongly recommend1 3/4" for a 3v or 4v. 2.5" collectors and an 'x'.

1 3/4" primaries are a waste unless you're pushing over 600hp. If you're wanting to stay under $700 I'd go with the MAC LTs and get the matching H-pipe.

how is the ground clearance on the MAC LT's when they're installed on a lowered stang (Eibach Sportline)?

i have a MAC O/R H-Pipe, and was thinking about getting the MAC LT's.

Ya your best bet is probably the mac longtubes and I personally like the prochamber as far as the midpipe, but I'm not sure if they make them for your year although I know people who use them on their sn95's.

ok found these on line http://www.hillbankmotorsports.com/product_info.php?products_id=40406 they will be calling me back some time tomorrow to let me know if in stock along with the H pipe. Was going to go X but prefer a deeper sound over the high pitch raspy.

1 3/4 " is not a waste on 'b' heads. they need as much help as possible on the exhaust.

2k6silvergt wrote:Ya your best bet is probably the mac longtubes and I personally like the prochamber as far as the midpipe, but I'm not sure if they make them for your year although I know people who use them on their sn95's.

eh the prochambers are way too loud for me. My MAC O/R H-Pipe and Flowmasters already ticks off the old bitty that lives next door, so a prochamber would not be in my best interest at present time. But the MAC LT's sounds like a plan before long.

MAC doesn't make the prochamber for that year

getbit wrote:MAC doesn't make the prochamber for that year

Ya I didn't think they did, but my buddy was able to get a prochamber to fit on his 98 gt but he has bbk headers.

http://www.headers4u.com/product/MACPC9700/199698_Mustang_Cobra_25_MAC_ProChamber_Stainless_Steel.html

is a prochamber for a 98 cobra

Here is a link also

http://www.headers4u.com/category/150mustang9404.exhaust.xpipeshpipes/

Close but that only works with the stock exhaust manifold.