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DLRA Speedweek 2019

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  • #31
    Brilliant, well done team Coffee Snob Green.
    Zed's effort would appear awesome in light of conditions etc.

    Thanks for the read and pics

    Comment


    • #32
      Good article Jackster.
      Your guestimates are pretty close too


      Several assumptions:
      1) This is a gas engine we are talking about,
      E85 running about 50% more fuel than it's petrol cousin. Extra fuel used to cool the intake charge (as petroleum based fuels just boiled the engine in under a minute)


      2) it is a four-cycle gas engine
      Yep.


      3) Combustion will be stochiometric and complete
      Running 0.82 Lambda up the top-end, stoichiometric would turn it into an oxy-torch at about half track.


      4) the compression ratio is about 10:1,
      Closer to 8.2:1


      5) the engine is throttled (no variable valve timing),
      Correct


      6) normal aspirated engine (no turbocharger),
      Supercharged and near twice the volume of the stock supercharger and more efficient at high RPM. It's also driven faster and in round numbers is 10 times the engine RPM so at 12,500rpm it's spinning at 125,000 rpm, at redline of 14,400 it's spinning at 148,000 rpm.
      Super secret before and after pic:
      Click image for larger version

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      7) volumetric efficiency (the amount of air that makes it into the cylinder during the induction stroke) is 1.00
      My VE is lower than 1 looking at my graphical fuel maps.




      Originally posted by Jackster View Post
      But, you have a supercharged 1 litre, Google says 35psi (wow!). So let's say that's equivalent to a 3 litre aspirated engine.
      But the kicker is you not at 3000rpm, so triple the figure to 2150cfm.
      That's 61000 litres per minute!

      Obviously that is not much compared to the hole you are pushing in the air at 320kph..
      Not sure where you googled the blower output but the figure is pretty close. Stock H2 is 17psi boost, H2R is 22psi and this one we saw 37psi on the dyno. On the salt last week I wasn't logging boost (and too busy to look at the gauge) but we do log MAP (Manifold Abs Pressure) and it was 36psi odd at 10,500 rpm so would nearing 40psi and tears at redline just before I spit the crank out of the case and ran over it with the back wheel.

      Redline of 14,400 is unlikely to be seen (in one piece for long), we did the runs short shifting at about 6000rpm into top gear and roll-on the torque to 11,000rpm in top. The bike would do this up a wall, traction is my killer at the moment not HP or torque.

      A few of the fast guys (who were also wheel spinning the full length of the course) have 100kg of ballast in the swingarm, some even more. I suspect some of my off-season will be looking at pinning that tyre harder on the surface.

      Comment


      • #33
        That was the biggest eye opener that I had for salt lake racing. Vehicles are heavy!
        No aero, as it costs too much in drag. So they load up as much as they need in actual weight.
        The first year I went was a guy in a big block Jag (can't recall his name, but I think he was doing the lake entry inspections). I thought it looked impressive and asked if it was fast on the ¼ mile. He said not likely, it has a ¼" plate for the floor pan, and ½" in the boot.
        Click image for larger version

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        Weight is inconsequential, as there is 3 miles to get it chuffing. It's the frontal area and the aero shape behind the centre of gravity that seem to be most important.

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        • #34
          It's called Shaguar. See the DLRA Forum Build Diaries for a detailed description of its build process. Very interesting.

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          • #35
            That's Gary Satara, he's a member of the 200mph club in that Jag.
            https://www.dlra.org.au/profiles/418.htm

            He is a really good bloke and is still doing lake entry (at least the last 3 years I've raced). The guys on lake entry get dust, dust, dust and none of the fun on the lake. They do an amazing job.

            Comment


            • #36
              Originally posted by Andy View Post
              Interesting idea, I had heard of pointing it into the rear rim for a similar effect. Our class rules say the exhaust needs to finish in front of the rear of the rear tyre, point away from the rider and the salt surface. I think where it is now is inside the wake, unlike the previous bike that was outside.

              My bike also throws a 5 foot flame when backing off (spectacular in the dyno room)
              Yebbut... have you roasted beans with it...

              Comment


              • #37
                Originally posted by theonetruepath View Post
                Yebbut... have you roasted beans with it...
                Oh yeah, this is a coffee forum eh. Nice work getting it back on a topic of coffee.

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