1 7/8th vs 1 3/4" headers
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2004-2007 Cadillac CTS-V Performance Mods Discussion, 1 7/8th vs 1 3/4" headers in Cadillac CTS-V Series Forum - 2004 - 2007; I was going to ask this question in another thread but felt bad about hijacking the thread. I am about ...
  1. #1
    crash32 is offline Cadillac Owners Fanatic
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    1 7/8th vs 1 3/4" headers

    I was going to ask this question in another thread but felt bad about hijacking the thread.

    I am about to purchase either B&B or Kooks headers and I see that the Kooks come in two sizes... the 1 7/8" and 1 3/4". I did not know if anyone has done a study to see which one produced the highest exit exhaust velocity.

    I could not imagine that it would make a big difference between those two, but if I have a choice...naturally i'd like the best one. One thing that makes me nervous is that I saw a picture of the 1 7/8" header basically rubbing up on the steering rod and I am not about to hammer dings into a brand new pair of headers due to clearance problems!!!!!

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    ctsv154's Avatar
    ctsv154 is offline Cadillac Owners Connoisseur
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    Re: 1 7/8th vs 1 3/4" headers

    If you're stock or close to it with stock ci engine, the smaller diameter will give you the most velocity. While you may or may not give up a tad on the top end, you will probably pick up low end grunt with the 1 3/4 vs the 1 7/8.

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    onebadcad's Avatar
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    Re: 1 7/8th vs 1 3/4" headers

    I would bet that any difference between the two sizes are very minimal, and if you also wanted to gauge the HP the ambient conditions would be a greater influence. With that said, consider fitment issues for both, as B&B headers mate perfectly with their exhaust.

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    Re: 1 7/8th vs 1 3/4" headers

    Quote Originally Posted by ctsv154 View Post
    If you're stock or close to it with stock ci engine, the smaller diameter will give you the most velocity. While you may or may not give up a tad on the top end, you will probably pick up low end grunt with the 1 3/4 vs the 1 7/8.
    He's right to the tune of about 3-5 horses (1 7/8ths side) or 3-5 torque (1 3/4 side) Basically, if the engine is going to be stock with headers and a tune, 1 3/4 will provide the best balance of power, a more even gain of horsepower and torque. However, the same stock engine with 1 7/8ths will add more very slightly more horsepower on the high end and loose a small amount of torque on the low end in terms of comparative gains. Imagine that the 1 3/4 is an even 15/15 gain, bringing your car to 415/415. 1 7/8ths would be more like 19/12.
    Now take that same motor, slap a set of ported heads and an intake on it, suddenly you have a use for that extra breathing room. In this circumstance the smaller headers will actually have a very slight tendency to decrease horsepower and increase torque compared to the 1 7/8ths because the engine is breathing more efficiently.

    I myself will be running 1 3/4 headers despite the TONS of mods Im planning for my little tiny LS6. Until I start screwing with the 454 LSX block, theyll be fine for street use.

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    crash32 is offline Cadillac Owners Fanatic
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    Re: 1 7/8th vs 1 3/4" headers

    Thanks guys, I am pretty sure that I am going to go with the 1 3/4" espeically since the only other mod I have is a cold air intake! Also, my main concern is low end grunt, not the high speed runs which I only actually do once a month... if that! I'm afraid of that one time that I will be doing a 140 mph run past a cop!!!!

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    SuperVeee is offline Cadillac Owners Fanatic
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    Re: 1 7/8th vs 1 3/4" headers

    Sounds like the 1 3/4 is proper for the stock V since you start to loose low end torque with the larger pipe.

    If you are doing mods here is a calculator to help find the exact right pipe size:

    http://dairally.net/daihard/chas/Mis...s/DaiPipes.htm

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    Re: 1 7/8th vs 1 3/4" headers

    I have the complete B&B system with headers and catback exhaust in 1 3/4" with the gutted cats. The car pulls much harder and has a lot more "grunt". I also think that since the B&B catback is 3" all the way back you get the best of both worlds in a sense. Another plus for the B&B is it is a total bolt-on and can be done easily by someone with basic mechanical skills. If you don't have visions of a "Maggie" sitting on top of your motor at a future date then I think the 1 3/4" would be the best choice. Be advised though that the complete B&B sounds awesome (and it is addictive), but it can be too noisy for some people. Just my.02 worth!

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    crash32 is offline Cadillac Owners Fanatic
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    Re: 1 7/8th vs 1 3/4" headers

    Did someone say too noisy???

    My only concern is when I sell my V...maybe in 12 months that nobody will want to purchase it because it is so loud. Guess I can always put the stock system back on and sell the headers and catback seperate.

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    Re: 1 7/8th vs 1 3/4" headers

    lol whats funny about the headers; before i got em, people used to say occasionally "nice cadillac." Now with long tubes, magnaflows and an xpipe the car gets ROUTINE attention, usually from guys over 50. "Thats a mans car right there!" or "Yeah, the way a caddy SHOULD sound!"

    Im never going back.

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    Re: 1 7/8th vs 1 3/4" headers

    Quote Originally Posted by crash32 View Post
    Did someone say too noisy???

    My only concern is when I sell my V...maybe in 12 months that nobody will want to purchase it because it is so loud. Guess I can always put the stock system back on and sell the headers and catback seperate.
    yeah part it out when you sell the . there will always be a demand for used headers.. they tend to keep their value even used. i have been looking for 1 3/4" headers in the $500 range.. i wont hold my breath

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    Re: 1 7/8th vs 1 3/4" headers

    Quote Originally Posted by shadybx7 View Post
    yeah part it out when you sell the . there will always be a demand for used headers.. they tend to keep their value even used. i have been looking for 1 3/4" headers in the $500 range.. i wont hold my breath
    I got mine new with cats and all associated hardware, gaskets, connectors for the o2s, etc for 800 bucks. My advice, wait till the wet season starts in the rest of the world and youll see a whole lot of Vs attempting to "mate" with large inanimate objects. Headers will be available then.

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    smashn808 is offline Cadillac Owners Fanatic
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    Re: 1 7/8th vs 1 3/4" headers

    Quote Originally Posted by shadybx7 View Post
    yeah part it out when you sell the . there will always be a demand for used headers.. they tend to keep their value even used. i have been looking for 1 3/4" headers in the $500 range.. i wont hold my breath
    There was just a set of Kooks 1 3/4" that were on Ebay. They went for $355 with $45 shipping. They were coated and pretty dented up though, but that's the cheapest i've seen them go for.

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    Re: 1 7/8th vs 1 3/4" headers

    Quote Originally Posted by soundexp View Post
    Be advised though that the complete B&B sounds awesome (and it is addictive), but it can be too noisy for some people. Just my.02 worth!
    No such thing,,, does not appear in Websters.

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    Re: 1 7/8th vs 1 3/4" headers

    Quote Originally Posted by crash32 View Post
    Did someone say too noisy???

    My only concern is when I sell my V...maybe in 12 months that nobody will want to purchase it because it is so loud. Guess I can always put the stock system back on and sell the headers and catback seperate.
    I might be ready for headers by then

  16. #15
    crash32 is offline Cadillac Owners Fanatic
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    Re: 1 7/8th vs 1 3/4" headers

    I have always been the kind of person that never keeps their cars for more than 12 months, but this V is fun so I might keep it for more than 12 months. But, when I do sell it I am pretty sure that I will be taking the headers and exhaust off and parting them out since I am paying MAJOR money for them!!!! It'd be nice to get some money out of them.

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