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Thread: Custom QUIET Performance Exhaust

  1. #11
    Still Plays With Cars Loren's Avatar
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    Good news, my header has made it as far as Los Angeles. It was literally on a slow boat from China.

    That inspired me to try to take some measurements today. Unfortunately, the HP & Torque measurements I'm getting from the Torque app, while mostly in a reasonable range, are extremely inconsistent. Like HP ranging from low-mid 70's to as high as 80. (yes, I know that's not accurate... wheel hp should be right about 60-65) A measurement consistency error of 10% makes it impossible to measure an IMPROVEMENT of 5%!

    I'll have to get serious about it and go to one of my secret test facilities in Mexico where I can do lots of runs on the same stretch of road, both directions, and all that. See if I can come up with some consistent power and torque numbers. Or, at least consistent acceleration times. Worst case, I think I can get consistent torque numbers by doing mid-range pulls in 4th.

    But, at least I got my baseline sound measurements. And, no, these are not scientific at all. Just quick "once or twice and done" measurements to get an idea, rounded to approximately the nearest dB. I'll drop them here in case I lose my notes:

    In-car dBA
    48 - Idle w/ no fan
    50 - Idle w/ fan on 1
    57 - Idle w/ fan on 3
    63 - Rev to 3500 rpm
    75 - Rev to 6000 rpm
    71 - Cruise at 2500 in 5th
    72 - Cruise at 4000 in 3rd
    74 - Cruise at 5000 in 1st
    83 - Accel to redline in 1st and 2nd

    Outside Car dBA
    64 - Idle at 10 feet
    73 - 3500 rpm at 10 feet
    85 - 6000 rpm at 10 feet
    50 - idle at 50 feet (ambient, couldn't hear it)
    58 - 3500 rpm at 50 feet
    69 - 6000 rpm at 50 feet


    Simplify and add lightness.

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  3. #12
    Still Plays With Cars Loren's Avatar
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    Unexpected knock on my door this afternoon. USPS gets an A+ for timely delivery. C- for having updated delivery information.

    No box, but very well cocooned in many layers of bubble wrap, paper and tape. :thumbwink:


    Looks good enough. If it fits as good as it looks, I'll be very pleased!


    6 bolts and two O2 sensors. I may go ahead and install it tomorrow. (I have an autocross Sunday)
    Simplify and add lightness.

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  5. #13
    Moderator inuvik's Avatar
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    Quote Originally Posted by Loren View Post
    Unexpected knock on my door this afternoon. USPS gets an A+ for timely delivery. C- for having updated delivery information.

    No box, but very well cocooned in many layers of bubble wrap, paper and tape. :thumbwink:


    Looks good enough. If it fits as good as it looks, I'll be very pleased!


    6 bolts and two O2 sensors. I may go ahead and install it tomorrow. (I have an autocross Sunday)

    Looks great and well designed.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 automatic: 40.5 mpg (US) ... 17.2 km/L ... 5.8 L/100 km ... 48.7 mpg (Imp)


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    Member Qrush's Avatar
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    Thats exactly how mine came packaged. Took me forever to get to it, lol. You can really see the quality of the welds, they do good work. I hope you enjoy yours as much as I have mine.

  8. #15
    Still Plays With Cars Loren's Avatar
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    I'm sure it will be enjoyable!

    Tried to do some baseline acceleration testing earlier today, and found once again that the Torque app provides ridiculously inconsistent numbers for hp & torque. And it only does 0-30 and 0-60 acceleration. I didn't have a good place to do 0-60 runs, and 0-30 requires both a launch AND a shift, which makes it inherently not the best measure of "power".

    I was wanting to do some timed acceleration runs from like 5-whatever, but didn't have anyone to run the stopwatch for me. Totally forgot that I could use video and time it that way! Gonna go out and do that in a bit.
    Simplify and add lightness.

  9. #16
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    Thats a beautiful header, I may follow your steps to get a bit more powaahhhh from this car haha
    2018 mirage ES manual

        __________________________________________

        click to view fuel log View my fuel log 2018 Mirage Es 1.2 manual: 40.5 mpg (US) ... 17.2 km/L ... 5.8 L/100 km ... 48.7 mpg (Imp)


  10. #17
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    Let us know how the install goes. I've had my eye on this header since it came out.

  11. #18
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    Wow that flange looks super thick! What a nice looking piece...

        __________________________________________

        click to view fuel log View my fuel log 2014 Mirage ES 1.2 manual: 44.4 mpg (US) ... 18.9 km/L ... 5.3 L/100 km ... 53.3 mpg (Imp)


  12. #19
    Still Plays With Cars Loren's Avatar
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    Header Overview and Dimensions

    Yes, the quality is very good. Welds are very nice. Not "show car perfect", but very good TIG welds. The tubes are double-welded to the flange, a bead on the outside and one on the inside. There is a slight ridge around the inside of one of the holes of the flange. If I had a half-round file, it would take 30 seconds to get rid of it. I'm not going to bother. Otherwise, there's a pretty healthy set of gouges/scratches on the underside of one of the tubes near the flange. I'm not "that guy", I don't care. But, I know people (we all do) who would lose their mind over such a thing. They are significantly deep scratches. I didn't measure, but they're probably half the thickness of the tube material, and half-inch or so long. I don't think it will be a problem.

    The design is interesting. And imperfect. Nice, small diameter primary tubes and slightly larger collector tube. The imperfect part is that it's nowhere near an equal-length header. It's hard to measure a header tube, of course. But, two of the tubes are approximately 11.5" long, and the one with the O2 sensor in it is 8". Significant difference. Given that it's a 3-cylinder and not something like a "tri-y" design or anything complicated like that... I don't think it will matter much. Another intersting thing is that the collector necks down at the flange. I ran across something like this last week while reading about headers somewhere. This is a feature called "anti-reversion". And pressure wave that is reflected back from the exhaust is going to be interrupted by the abrupt change in diameter flowing in the reverse direction. It's a smoother change in diameter flowing in the correct direction. You can Google "anti-reversion chamber" if you want to know more. The way this is built, there would be benefit to making the first section of pipe after the header flange fairly large in diameter to have the desired effect.

    Measurements:
    Tubing Thickness = .045" (19 GA) (note that this is what I could measure at the collector end, the primary tubes could be thicker)
    Primary Tubing = 1.5" OD
    Primary Length = 11.5" / 11.5" / 8.0"
    Collector Tubing = 1.75" OD
    Collector Length (including flex joint) = 8.0"
    Anti-Reversion Tip = 1.5" OD
    Weight = 5 lb 8.8 oz (5.55 lbs) (kitchen scales are great for not-too-heavy parts!)
    Simplify and add lightness.

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  14. #20
    Still Plays With Cars Loren's Avatar
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    Alright, so I took some video of some 1st and 2nd gear 1500-6000 rpm runs. With no launch and no shifts, they were VERY consistent. But, I found the 2nd gear pulls to be a little easier to work with. (they took 8+ seconds... at 30 fps, that's 240 frames to work with... the 1st gear runs were <3 second, harder to get accurate data points from)

    I was able to get acceleration points for each 500 rpm in the range, normalize the data from 3 runs, and chart it. I'm not going to bother posting the chart just yet, I'll wait until I have the header installed and get something to compare it to.

    The chart is interesting, though. It doesn't quite match the torque curve or the power curve of the available stock Mirage dyno plot. But, it sort of follows the torque curve up to about 5000, then has a dip and then follows the power curve up from there. I guess this jives with what we feel. Low end torque is what we feel down low. Horsepower is what we feel up high.

    Total accel time from 1500-6000 rpm in 2nd is right 8.7 seconds.


    Simplify and add lightness.

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