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headers and drag times

This is a discussion on headers and drag times within the External Engine forums, part of the LSx Technical Help Section category; Quote: Originally Posted by Wikid NaSSty Also, longtubes can actually cause you to lose a little but of low end ...

  1. #21
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    Quote:
    Originally Posted by Wikid NaSSty
    Also, longtubes can actually cause you to lose a little but of low end TQ but they usually make up for it in the mid to uper RPM's.


    You have your understanding of long tube headers backwards. Long tubes create much more torque lower in the RPM range than shorty headers or the stock castings. Shorty headers create power well in the upper RPM's. Long tube headers give you a a much better performance boost all around. The mistake some people make is that they put to large a header on their mostly stock engine and expect an insane improvement in HP...An over sized set of headers will actually decrease your performance in many situations. Go do the CNC ported heads, the bigger cam, better breathing LS6 or FAST intake, better breathing throttle body, etc...etc...You need all of these things to make a trick pair of headers do their job. Remember, your engine is nothing more than an air pump...get it to breath in alot of air and exhale alot of air..and you'll go faster.
    why did my tq and power band move up in the rpm range??
    i have dyno pulls that show before and after header pulls.
    I did not say that longtubes decrease tq. in all cases but I have noticed that it is common that longtubes can actually decrease or not change low end torque values. My experience is that a little exhaust backpressure often helps build low end torque. I experienced the same nhraformula did in that my tq and power band moved up, causing little or even slightly negative change in tq. in the lower rpm range. I also have a basically stock ls1 with stock heads, compression, and intake manifold like most people on here have. I am not dismissing your opinion as wrong but for a stock engine on a stock tune and not seeing any low end torque increases.......it did't surprise me at all. There is also a lot more to an engine than air in/air out. An engine is a lot more than an air pump......it is actually a reverse heat pump and its efficiency depends on much more that the air you can cram into it.

  2. #22
    Quote Originally Posted by nhraformula View Post
    why did my tq and power band move up in the rpm range??
    i have dyno pulls that show before and after header pulls.
    Because you have a junk comparison. Comparing stock manifolds to long tubes is completely different that comparing shorty headers to long tubes. Porsche914LS6 is 100% accurate. Given equal primary diameter and a quality collector on each example, the shorty header will make more peak HP and at a higer RPM that the long tubes. Long tubes create more low end torque and allow you to tune the powerband to a point by changing primary tube length. However, shorty headers for the same application often have smaller primaries and inferior collectors to their full length cousin, restricting power and creating the illusion that shorties make less power.

  3. #23
    member since may 2000 nhraformula's Avatar
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    Quote Originally Posted by Marc 85Z28 View Post
    Because you have a junk comparison. Comparing stock manifolds to long tubes is completely different that comparing shorty headers to long tubes. Porsche914LS6 is 100% accurate. Given equal primary diameter and a quality collector on each example, the shorty header will make more peak HP and at a higer RPM that the long tubes. Long tubes create more low end torque and allow you to tune the powerband to a point by changing primary tube length. However, shorty headers for the same application often have smaller primaries and inferior collectors to their full length cousin, restricting power and creating the illusion that shorties make less power.
    me and a 1000 plus LS1 owners are wrong.
    my car lost tq down low while it picked up power from mid-high rpm.
    it is a well known fact that shorty headers on a ls1 will make 10 rwhp at best because its been proven by dyno pulls.
    ask any ls1 tuner that works on ls1 cars for a living and they will tell you what i just posted.
    long tubes are the way to go to make power.
    2000 nhra edition formula
    a few bolt ons, 379 rwhp
    11.96 @113.25

  4. #24
    Quote Originally Posted by nhraformula View Post
    me and a 1000 plus LS1 owners are wrong.
    Wrong, no. Not very bright and lacking in reading comprehension, yes. Let me quote this for you since you apparently missed it the first time: "Given equal primary diameter and a quality collector on each example". What LS1 shorty header has 1 3/4" primary tubes and a quality 3" collector...

    The 355 in my Z28 made 7 more peak HP with the SLP shorty headers than it did with the Hooker LTs on an engine dyno. And engine dyno number comparisons are MUCH more accurate than chassis dyno numbers when looking for gains.

  5. #25
    member since may 2000 nhraformula's Avatar
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    Quote Originally Posted by Marc 85Z28 View Post
    Wrong, no. Not very bright and lacking in reading comprehension, yes. Let me quote this for you since you apparently missed it the first time: "Given equal primary diameter and a quality collector on each example". What LS1 shorty header has 1 3/4" primary tubes and a quality 3" collector...

    The 355 in my Z28 made 7 more peak HP with the SLP shorty headers than it did with the Hooker LTs on an engine dyno. And engine dyno number comparisons are MUCH more accurate than chassis dyno numbers when looking for gains.
    was this 355 of yours an LS1?

  6. #26
    Quote Originally Posted by nhraformula View Post
    was this 355 of yours an LS1?
    No, never had my LS1 on an engine dyno.

    I am talking about the traditional SBC in my 85. I realize that this is an LS1 related question, but the arguement was over which header design makes more power. And unless were talking about a DOHC V12, rotary, or some other unusual engine, the LS1 - SBC comparo will work fine. I used my SBC results because of the accuracy and repeatability of the engine dyno. Try that on a chassis dyno

    And again, I ask you... Who make an LS1 1 3/4" primary shorty header will a good 3" collector? No one does. So you can't fairly compare the LS1 shorty to a long tube. They are other platforms out there with a better parts selection, the SBC being one of them.

  7. #27
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    Quote Originally Posted by SSwt00SS View Post
    heads/cam, full exhaust, gears, tune, a good set of D.R.s, and time at the track

    how much would all that cost? not including the D.R's?

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