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-   -   long tubes or shorties?? (http://www.ramforumz.com/showthread.php?t=119544)

Dodge Boy13 08-17-2012 12:18 AM

long tubes or shorties??
 
hey im looking into headers for my 98 5.2l just looking for some suggestions as to the similarities and differences and which would be better and brands

thanks:smiley_thumbs_up:

ArtNJr 08-19-2012 06:25 AM

1 Attachment(s)
Quote:

Originally Posted by Dodge Boy13 (Post 867582)
hey im looking into headers for my 98 5.2l just looking for some suggestions as to the similarities and differences and which would be better and brands

Dyno tests conclusively show that headers with less than 30" long primary tubes do not make anywhere near as much power as headers with 30" or longer primary tubes. Also, the tube diameter needs to be the same as the exhaust port to speed exhaust gasses out -- large tube headers are ONLY for engines designed to run high rpms all the time, are supercharged, etc. -- large tube headers just kill low-end power on a normally-aspirated engine without serious head work, cam, etc.

And the small valves / combustion chambers on the 318 engine require small tube but long length header tubes -- 32" long for best HP, 36" long for best torque. Then add a NASCAR style X pipe in the middle of the exhaust system to balance out the uneven firing order of each bank of cylinders -- more HP & torque both & better fuel mileage too.

The engine itself is an "even-fire" engine, firing every 90 of crankshaft rotation, but if you look @ the firing order, 1-8-4-3-6-5-7-2, you will see that the exhaust pulses coming out of the right head & the left head are uneven. Just consider what's coming out of the left head in terms of engine firing order: 1 - - 3 - 57. Cylinder 5 "robs" air from cylinder 7 since they fire one right after the other & #7 tends to run lean. On the other side, #8 "robs" air from #4 since they fire one right after the other, but the 5-7 problem is worse.

How do you fix that? Better intake manifold & headers which are designed to equalize the amount of air (fuel mixture on a carbureted engine) which goes into each cylinder & it can get VERY complicated. But headers with small diameter tubing (same size as the exhaust ports) & at least 30" long will make a major difference in how the engine runs. (Best way to go is a 4-2-1 setup on each side). And although the X pipe is the best way to go, if you just put an H pipe in that'll make a big difference -- a piece of pipe which goes from the left exhaust to the right, after the headers & before the mufflers.

Not trying to "toot my own horn" here, but I'm an engineer who's designed & made exhaust systems for over 40 years & have been to the dyno many, many times, so I know what works, what doesn't & why. (My diesel truck has an exhaust of my own design that out-flows anything on the market for that engine).

Any of the name brands will work well -- as long as they're designed as I described -- the big-name companies have put a lot of work into their products. And I'll give a shout-out to Bassani exhaust as owner Darrell Bassani made the pipes for my Land-Speed-Record Harley-based engine, based on a combination of my design & his CAD-CAM equipment -- I don't have CAD-CAM (computer-aided design / computer-aided manufacturing) programs like he does.

But I asked him to make the pipes too long on purpose because we were going to cut 'em back on the dyno anyway -- look @ the dyno chart's HP / torque curves, cut off an inch (or less) & run the bike again. I knew where I wanted my peak HP to be (7200 rpm) so we just cut the pipes back a little @ a time until they dyno showed peak HP @ 7200. They ended up being within 1/2" of my calculations ;-) But @ the Bonneville salt flats, 1/10th of a mph can be the difference between getting a record or not (got 3).

So anyway, Bassani, Doug Thorley, Hooker, etc. all make good products & there's a LOT of engineering that goes into them. Just remember small diameter & 30" long (or more) for your truck & an X pipe or an H pipe in the exhaust after the header collectors & before the mufflers (doesn't really matter where you put it). "Been there, done that, got the T-shirt" :smileup:

crusher 08-19-2012 08:14 AM

long tube = more power in most of the time but also hardder to install most of the time

short tube = easier install most of the time but less power

ive seen long tube in two pieces for mustang, dont know if they make it for the truck nor do i remember the cie that made it, but since it was in two pieces it was easier to install and had the same total lenght that the one piece headders,. and the exact same shape.

dean98ram1500 11-24-2012 09:07 PM

long tube your gonna get the most power in the mid- high rpm range and a better sound as shorties will be easier to install, no need to take out the engine, but more torque

HammerHead 05-07-2014 07:24 PM

Quote:

Originally Posted by ArtNJr (Post 868933)
Dyno tests conclusively show that headers with less than 30" long primary tubes do not make anywhere near as much power as headers with 30" or longer primary tubes. Also, the tube diameter needs to be the same as the exhaust port to speed exhaust gasses out -- large tube headers are ONLY for engines designed to run high rpms all the time, are supercharged, etc. -- large tube headers just kill low-end power on a normally-aspirated engine without serious head work, cam, etc.

And the small valves / combustion chambers on the 318 engine require small tube but long length header tubes -- 32" long for best HP, 36" long for best torque. Then add a NASCAR style X pipe in the middle of the exhaust system to balance out the uneven firing order of each bank of cylinders -- more HP & torque both & better fuel mileage too.

The engine itself is an "even-fire" engine, firing every 90 of crankshaft rotation, but if you look @ the firing order, 1-8-4-3-6-5-7-2, you will see that the exhaust pulses coming out of the right head & the left head are uneven. Just consider what's coming out of the left head in terms of engine firing order: 1 - - 3 - 57. Cylinder 5 "robs" air from cylinder 7 since they fire one right after the other & #7 tends to run lean. On the other side, #8 "robs" air from #4 since they fire one right after the other, but the 5-7 problem is worse.

How do you fix that? Better intake manifold & headers which are designed to equalize the amount of air (fuel mixture on a carbureted engine) which goes into each cylinder & it can get VERY complicated. But headers with small diameter tubing (same size as the exhaust ports) & at least 30" long will make a major difference in how the engine runs. (Best way to go is a 4-2-1 setup on each side). And although the X pipe is the best way to go, if you just put an H pipe in that'll make a big difference -- a piece of pipe which goes from the left exhaust to the right, after the headers & before the mufflers.

Not trying to "toot my own horn" here, but I'm an engineer who's designed & made exhaust systems for over 40 years & have been to the dyno many, many times, so I know what works, what doesn't & why. (My diesel truck has an exhaust of my own design that out-flows anything on the market for that engine).

Any of the name brands will work well -- as long as they're designed as I described -- the big-name companies have put a lot of work into their products. And I'll give a shout-out to Bassani exhaust as owner Darrell Bassani made the pipes for my Land-Speed-Record Harley-based engine, based on a combination of my design & his CAD-CAM equipment -- I don't have CAD-CAM (computer-aided design / computer-aided manufacturing) programs like he does.

But I asked him to make the pipes too long on purpose because we were going to cut 'em back on the dyno anyway -- look @ the dyno chart's HP / torque curves, cut off an inch (or less) & run the bike again. I knew where I wanted my peak HP to be (7200 rpm) so we just cut the pipes back a little @ a time until they dyno showed peak HP @ 7200. They ended up being within 1/2" of my calculations ;-) But @ the Bonneville salt flats, 1/10th of a mph can be the difference between getting a record or not (got 3).

So anyway, Bassani, Doug Thorley, Hooker, etc. all make good products & there's a LOT of engineering that goes into them. Just remember small diameter & 30" long (or more) for your truck & an X pipe or an H pipe in the exhaust after the header collectors & before the mufflers (doesn't really matter where you put it). "Been there, done that, got the T-shirt" :smileup:

Thank you so much for the well written info. Could you please help me as I am a newbie and need your advice. I want a complete new exhaust system from the block to the tail pipes and want maximum torque and HP. I have no idea what the size of the outlet into the header is from the block and want to buy the right system one time. Any and all advice would be greatly appreciated. :smileup:


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