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Physics /Math and an Alpine 4 into 1 header

Discussion in 'Rootes Racing' started by jdoclogan, Aug 21, 2020.

  1. jdoclogan

    jdoclogan Platinum Level Sponsor

    I previously wrote about applying physics and mathematics to determine the most effective Alpine 4 into 1 header design. The conclusion was utilizing 1 1/4" OD - 1" ID tubing of equal lengths (20") for the best scavenging of exhaust molecules. A unique method for doing a three dimensional design followed and now a prototype has been completed. I will make a better mating surface for the header tubes to head component. All aspects are mild steel. My intention is to also wrap the tubing for minimal heat transfer. Because the collector is just below the clutch slave cylinder I will also wrap it as well. A 2" to 1 3/4" reducer will be installed for the transition from the collector to a 1 3/4" stock exhaust. A stock exhaust size was determined by Jerry Titus and Doanne Spencer in 1962 to be the best sizing for an Alpine exhaust (Sports Car Graphic, Sept,1962).

    upload_2020-8-21_17-20-22.png upload_2020-8-21_17-21-28.png

    Advantage of the smaller tubing is the clearance around the generator and the starter motor. Disadvantage I couldn't find a header shop that works with 1 1/4" tubing. If anyone knows of a shop that would work with this size please let me know. For instance maybe there would be a motorcycle shop doing custom headers.
  2. spmdr

    spmdr Donation Time

    Jerry, I talked to a header manufacture and he said he can bend 1.25 OD tubing.

    Do you want to make the headers with one piece primary tubes,

    Based on your prototype effort?

    BTW, that #3 pipe is a bit of a sharp head exit.... just say'n....

  3. jdoclogan

    jdoclogan Platinum Level Sponsor

    Dan, I assume the header shop has a mandrel bending setup. Tubes with no joints would be a cleaner look (although I will be wrapping for heat containment) and would make for a continuously smooth surface inside the tubes. I haven't bore scoped the prototype tubes yet, but, I believe all the joints would have slight to moderate imperfections. I did change the middle section of #4 tube to give it a better flow and aesthetic look (compare to above photo). I would also want to work with any header manufacture to tweak the shape. #3 should flow well as it has a flowing bend as does #2. #1 (about 60 degrees) and #4 (about 75 degrees) have more angle at the head and that creates increased restriction for the molecules. Like I pointed out above I can see some fun tweaking with version 2.0. I'm going to work on the transition (reducers) from collector to exhaust today and ready the set for installation and "seat of the pants" testing with the Series IV experimental car. It would be nice to do dyno/test but I have many other aspects that need to be employed before that type of testing.

    Final.jpg Final 2.jpg
  4. jdoclogan

    jdoclogan Platinum Level Sponsor

    Dan, I went back to my original design on #3. Thanks for the observation. Plus the intake manifold clearance is better. I just have a passion for R&D. I must because it is a lot of work.

    Final 3.jpg

    I would like to think that with a header shop the curves would be better. You know to make the system look more______ (fill in the blank).
  5. alpine_64

    alpine_64 Donation Time


    Glad you straightened the exit of #3.. Per our zoom and dans follow up.. It came out an accute angle and i was sure there was room under your manifold to do it.
  6. jdoclogan

    jdoclogan Platinum Level Sponsor

    Final iteration with wrap. To get better intake manifold clearance again #3 got a bit of change.

    upload_2020-9-6_11-1-26.png upload_2020-9-6_11-1-52.png
  7. alpine_64

    alpine_64 Donation Time


    Did you have to sharpen the bend on #3 a bit more from the un-wrapped photo on Thursday ? It looks a bit more 90° at the bend than before, or is that just perspective in the photo?

    Are you having difficulty on that one clearing the mounting ear on the weber manifold? Im assuming the zenith manifold would be easy as its basically straight out and mounts above... You could also cut the water jacket off on the zenith manifold for clearance
  8. jdoclogan

    jdoclogan Platinum Level Sponsor

    Yes, it was clearing but I wanted a bit more. As a prototype it will provide useful information as development continues. If I can work directly with a header shop the design will be altered on #3 and tweaked on #4. Minimizing any curvature is a plus for enhanced fluid (gas molecules in this case) flow. I will fire the set up using a single down draft Weber today.
  9. jdoclogan

    jdoclogan Platinum Level Sponsor

    Here is the "seat of the pants" report. This will also serve as my memory reference for future tests. With a few battery cable adjustments and a generator charging adjustment the 4 into 1 header test began. I had previously bore scoped the engine and found the claim that it was rebuilt ( 25+ years ago was in excellent condition) was true. It had, if I remember correctly, around 150psi compression give or take 5psi across all cylinders. Using starter fluid the 1592 engine started right up and immediately quit. Repeated one more time and fuel reached the downdraft Weber and engine began running smoothly. There was an obvious difference in the exhaust tone. Very pure sounding. Very Purrr sounding. I recall the engine felt strong the last time I ran it with a stock header. It felt strong this time as well. I let it warm up and began to sense that the engine needed some timing adjustment. Throughout the start up there was no indication of any exhaust/manifold gasket leaks. The resonator tone at 3000 to 4000 rpm sounded smooth. Smoke began coming up off the exhaust as the titanium wrapping adjusted to the exhaust tube heat. The idle at running temperature was faltering again indicating adjustments needed. Keeping the revs at 2000+ I backed out of the lift bay and through the semi-truck bay door onto my driveway. Checked brakes during the process and set out down the short run to the street below. Once on the street, just like the first time I tested this Alpine, I gave it some serious throttle to feel the power. Being a longtime researcher I recognize the experimenter effect and it may have influenced some of my sensory impressions. That being said, "by the seat of my pants" this had more power. I could feel the torque staying with the band in the 3000 - 5000 range. Once I got down to the highway I choose to not be aggressive on the one mile run to a roundabout. Once around the Euro-circle I headed back to the shop. On the long straight I determined I had very good to torque up through 60??/70?? mph (I'm not certain how accurate the speedometer is). Torque did flatten at 5000 to 6000 rpm then I down shifted into my country neighborhood street. With a slight uphill grade I shifted from second to third with more power than I recall from the stock header experience. Fourth seemed to be about the same. It will be very interesting to try all of this utilizing a dynamo meter.
  10. Alpine 1789

    Alpine 1789 SAOCA President Platinum Level Sponsor

    That is a great report and very promising re: the header. But, let me be the first to say I am very jealous of the description of your shop!

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