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    Discussion in 'The main mechanical design forum' started by faytmogan, Dec 30, 2012.

    1. faytmogan

      faytmogan New Member

      Dec 2012
      Likes Received:
      I wasn't sure where to post this.

      This is all in relation to a 90 degree v8
      I am looking for the highest frequency/note/tone/pitch I can get. I very much enjoy the higher, crisper, cleaner sound the european v8 makes. I hate with a passion the rumble of the harley/dumptruck American v8. I have heard flowmasters on these cars. I don't know if it was the particular flowmaster series or what. But that m3 was a dumptruck. I am trying to avoid that.

      I do not need to be informed about flatplane cranks vs crossplane.

      I am lost in design at this point. I have a few options as I see it, x pipe, headers, and muffler designs.

      Maserati has used ferrari engines since they were bought out by fiat. They use a cross plane crankshaft instead of a flat plane. They also use tri-y headers factory and an x pipe further back toward the mufflers.

      http://en.wikipedia.org/wiki/F...ons]Ferrari/Maserati engine - Wikipedia, the free encyclopedia
      a similar snarl that the Corsa gives the Domestic V8
      Un_sQtJA2iA]Maserati GranTurismo Exhaust Note! - YouTube
      http://www.atzonline.com/index...2a814fd6b316776454]A New V8 Engine Powers the Maserati GranTurismo S - ATZ online
      x pipe
      http://www.ebay.com/itm/08-Maserati...ufflers-silencers-/140868590912#vi-content]08 Maserati Gran Turismo 4.2 complete exhaust mufflers silencers | eBay
      The illustration shows Exh mani as a 4 into 1 design, shorty, primaries appear to be equal length. X pipe is a ways downstream
      same 136 engine only the tipo f136 has a flat plane.
      gwVlcgSUO0A]Ferrari]gwVlcgSUO0A]Ferrari458 Italia Exhaust Sound!! Lovely Downshifts! - 1080p HD - YouTube

      the alfa uses the same cross plane motor as the maserati. very similar. I am sure the slight differences of video quality and the bends in the exhaust that differ between the two can attest to the very slight difference in sound.- still sounds like a domestic with corsa's and an x pipe.
      0siqvB_7Sco]Alfa]0siqvB_7Sco]Alfa Romeo 8C Competizione Sound!! - 1080p HD - YouTube

      How about we turn to something that takes a traditional 90 degree motor (with itbs, dohc heads, and di) that uses tri-y headers and an x pipe factory.

      The s65 bmw motor is a lovely motor.
      sounds like a small block chev on the dyno to me, buts its the bmw m3 s65 v8.
      Y-mGGf5Ncx8]s65]Y-mGGf5Ncx8]s65 BMW Engine Dyno - YouTube

      compare that to this full exhaust system by ipe f1

      compare that to this
      BzvpgQcszFs&feature=related]E92]http://www.youtube.com/watch?v...&feature=related]E92 M3 Exhaust Compilation - YouTube

      and lastly compare those to this
      MIsc_9FLLIM&feature=related]E92]http://www.youtube.com/watch?v...&feature=related]E92 M3 - Megan exhaust - YouTube

      there really has to be more to it than the natural sound of the motor... I would agree that it is more than JUST one thing.

      "The crank pin offset is 90°, and for design reasons, a cylinder firing order of 1-5-4-8-7-2-6-3 was chosen
      for the S65, instead of the typical 1-5-4-8-6-3-7-2 firing order more commonly employed in other BMW V8 engines."
      if you can make some sense of that- its odd "Cylinder numbering is 1 through 4 on passenger (right) side and 5 through 8 on driver (left) side. numbers 1 and 5 are at the front, 4 and 8 are at the rear."

      Apparently, the fireing order is the same as the BMW Sauber F1 team v8.

      check out this s65 header. looks like a tri-y to me.

      The x pipe from the above video.

      I think the only reason that the ipe f1 exhaust is higher has to be that x pipe design. which is shown in the following link
      (not to scale dims) Note the taper of the x pipe and the hole that makes the air pass through a smaller opening on two ends. If you look very close at the x pipe design, its ALMOST as if its two x pipes in one.

      Now one thing to consider is the are resonators that cancel out particular noise. this is what Corsa mufflers do. The have chambers in the mufflers (which is more like an instrument than a traditional muffler) that are helmholtz resonators that are VERY small. They shoot for 3 particular resonate frequencies to cancel out. Now one thing about frequency is that it peaks, there is a range at the peak. The range will depend on many things and without actual testing it is not possible to know the range with math (that i am aware of to date).


      In use on an exhaust system

      Now if you actually understand the above link you will see that they are utilizing a Helmholtz Resonator and then packing around it with fiberglass to bring down the vibration(vibration of any kind will bring the volume of the devise up- so this muffles it).

      the purpous of a "muffler" is to MUFFLE sound not change the actual tone.

      the corsa i wouldn't even call a muffler per say. I would say it is more similar to the dr. gas freq mod, but a better design.
      http://freqmod.drgas.com/]FreqMod]http://freqmod.drgas.com/]FreqMod Mufflers
      corsa cut away

      I should also note that ferrari motors that have a 180 crankshaft do not require an x pipe to merge the exhaust pules efficiently because they already do that naturally with the design of the crankshaft (and firing order of course that goes along with it).

      oh as for the 180 header. I suppose I should post this- one of many, videos of a sbc with 180s sounding exotic as they do. The kelmarks, grant gts, and many other cars use these headers as well (gt40s too).

      I did forget to mention that (as far as i know) all inline 4s use a flat plane crankshaft.

      MSZTbR6C6Lw]Corvette]MSZTbR6C6Lw]Corvette with 180 Degree Headers - YouTube

      The complete setup of the engine.
      4.060 bore (3.25 stroke) inches
      team g intake single plane manifold
      jegs 195cc intake port, 64cc chamber heads aluminum strait plug
      Superflow sf 600 flow com
      air speed: 380-100FT, 375-410SC


      the cam will be setup for the intake/heads/headers that are selected in the end result. The cam will put the engine in the 3000rpm-7000rpm range and a redline of 7500, albeit will be designed around the intake/heads/headers flow etc.
      The compression will be at 10.5:1, so as to utilize pump gas.
      Forged crankshaft (small journal block, two bolt) cross plane style crank shaft I am not going to swap in a 180 crank (flat plane) as per Ferrari spec much too much work and $$ to do such a thing.
      I have decided I should pony up for 6" rods
      the rockers are at a 1.6 ratio.

      The engine is designed around the fact that I wanted a specific rpm range, the car is very light and tires are very limited. The max tread width I could find in the max rim size available was 8.5 inches. The section width of the tires are 245mm. The rim itself when measured end to end was 240mm. The car will weigh in at about 2800lbs. The donor car is a 1978 Datsun 280z five speed which is going through a sbc v8 conversion. The drivetrain (axles, transmission, and differential) that are available can hold to the hp (which I realize is tq(rpm)/5252). So the rpm of the motor has been raised to the 7000rpm mark to best match the transmission ratios and differential ratio as well as to produce more peak hp than low end tq. Too much tq will just cause the tires to spin and cause premature part failure.

      Continued in 2nd post...

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