Is single 3" exhaust too big for a 4.1L @ 200 HP?
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HT4100 4.1, 4.5, 4.9 Discussion, Is single 3" exhaust too big for a 4.1L @ 200 HP? in Cadillac Engine Technical Discussion; I lnow it's on the big side, but it won't kill low-RPM torque will it?...
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    SolidGoldsteen's Avatar
    SolidGoldsteen is offline Cadillac Owners Fanatic
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    Is single 3" exhaust too big for a 4.1L @ 200 HP?

    I lnow it's on the big side, but it won't kill low-RPM torque will it?

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    Re: Is single 3" exhaust too big for a 4.1L @ 200 HP?

    I didn't think exhaust sytems could be "too big".... LOL

    As long as you have some sort of muffler in the system I would not worry about killing low end torque.

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    Katshot's Avatar
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    Re: Is single 3" exhaust too big for a 4.1L @ 200 HP?

    There IS a possibility of having an exhaust TOO big but in your case, as Bbob said you should be okay. The question I would have is why use 3"? You certainly don't need it and it will only cost you more and be harder to route.

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    Re: Is single 3" exhaust too big for a 4.1L @ 200 HP?

    Quote Originally Posted by Katshot
    There IS a possibility of having an exhaust TOO big but in your case, as Bbob said you should be okay. The question I would have is why use 3"? You certainly don't need it and it will only cost you more and be harder to route.
    Most likely because he intends on super/turbo charging his caddy.

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    Formula94lt1 is offline Cadillac Owners Member
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    Re: Is single 3" exhaust too big for a 4.1L @ 200 HP?

    Actually backpressure doesnt help anything... except in applications where the motor has a great deal of overlap were it would prevent a bit of the intake charge from leaving out the exhaust from overscavenging at low rpm's... otherwise backpressure should be reduced as much as possible. However that doesnt mean bigger is always better, really as long as the pipes and the muffler/s flow atleast 2.2 cfm times the amount of horsepower you are expecting to make. In which case a 200 hp caddy would need only around a 440 cfm muffler, past that it will have less than 2% of an effect on power no matter how big you went and im talking muffler size here. As far as pipe diameter goes on this particular setup with the front manifold having a crossover into another manifold then out that manifold into a single pipe I dont think the cross section of the pipe being a tad too large is really detrimental at that point but its really never good to go TOO big kinda like with carbs. I would imagine that a single 2.75" pipe would work very well and not be too expensive, what does it come with stock 2.5"? I mean a 2.75" pipe, even though only 10% larger in diameter, is capable of flowing about 21% more. Now I got most of that info from David Vizard's testing so even though I have not done any in depth testing like he has I would imagine its pretty accurate. Google his name and the words "exhaust theory" for lots of cool info...

    Also how do you mount the superchager with the front of the motor so close to the passenger fender? and where in gods name would a turbo go?? Maybe you guys are way more creative than me or maybe its not in a caddy?

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    blue_eldo is offline Cadillac Owners Fanatic
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    Thumbs up Re: Is single 3" exhaust too big for a 4.1L @ 200 HP?

    Please keep in mind that the cross section area is a function of the radius squared. Do the math and you will find that the area difference between 2.5 and a 2.75" pipe is 20%. Specifically 4.9 sq" vs. 5.9 sq".
    A neighbor was parting out a wrecked 94 N* seville. I bought the entire exhaust system, including the converter for $20.00. It measures 2.75" in diameter. I installed it on my 94 4.9 deville, by simply adding an extension after the N* converter and adding the hanger from the Seville on the left rear bumper mount for the dual muffler. Result: Slight increase in sound at idle, and a solid 3 mpg increase while cruising at 72 MPH. With the old 2.5 single muffler, I observed a big drop in MPG in speeds over 64 MPH. Now with the bigger exhaust the drop off is not as great. Part of this increase may be attributable to the newer and larger Cat! The 4 stainless tips have a more sporting and manly look as well. One comment I received was that the tips looked "Ethnic". I am very satisfied with this modification.

    Blue_Eldo

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    CustomCaddys is offline Cadillac Owners Member
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    Re: Is single 3" exhaust too big for a 4.1L @ 200 HP?

    i have the 4.9 with stock exhaust manifold, 3 inch cat and 3 back to a 3 in and dual 2.5's out (flowmaster 80 series) then back up to 3inch tips... you can bring it back 3 inch just fine, at that point its up to the muffler size to determine low end torque loss.. i stayed 3 inch in and technically came out 5inch.. lost an almost un-noticed amount of low end but nothing else... if you ran 3 back and reduced to a 2.5 muffler you'd get much more sound and still have low end IMHO

    if it makes you feel any better, i'm thinking about running straight pipes.. lol

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