Announcement

Collapse
No announcement yet.

Das Beast: My E30 track / street build

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Dyno results are back. These are cell phone screen grabs, pending the dyno sheets.

    Turbo 0.58 exhaust housing was a complete success. At 10 psi we're hitting peak torque about 500 RPMs earlier. That may not sound like much, but there is WAY more power under the curve sooner. You can really feel the car pull hard. I really like how wide and flat the torque curve is at this boost level. Surprisingly, peak torque and horsepower are higher with the smaller exhaust housing. Very interesting.



    Here's the 16 psi chart. Note the before line is bold in this case, after is thin. Torque and horsepower still comes on earlier, peaks are pretty much the same as 0.84 housing.



    20 psi grand finale. Our stroked, boosted M20 is making 425 HP and 412 ft-lb torque. And that's not pushing it. Tuner said we are leaving power on the table, but probably best to call it good here.



    We installed an aircraft grade driver/navigator headset intercom. This is GREAT for test driving and discussing what's going on in the car. Right rear tire is not getting hot BTW.



    Also plugged the last of the OEM holes in the floor. No more exhaust fumes getting into the car. Side exhaust is working out great.



    Driving impressions: At 20 psi this thing is scary freaking fast. There's no way to legally run WOT pulls. Gotta get it to the race track soon. :-) Tuner fixed the cold start issue, she fires up like a daily driver now. AFRs are solid all across the range. Here's some data at 20 psi. It literally spools from 0 to 20 psi at WOT in 1.0 seconds. And let me tell you, that's a heck of an experience in an ~2200 lb car.



    Final footnote: I think we blew out the right rear wheel bearing, but that's for another episode.
    "And then we broke the car. Again." Mark Donohue, "The Unfair Advantage"

    1987 E30 3L Turbo Stroker Das Beast
    2002 E39 M5

    Comment


      Back to building things. Today we're bolting on the diffuser.



      Drilling mounting holes into the frame.



      Previously fabbed diffuser ready for installation. Mr. Ferrari's chief aerodynamicist handily left his PHD thesis online. Thanks for that. :-)



      Jacked in place while we bolt it in.



      We MIGHT pipe the exhaust out through this channel built into the diffuser for just that purpose. Our only concern is possible drone. Putting a pin in it for later testing.



      Looking pretty sporty.



      Off for a test drive.


      Last edited by dvallis; 05-10-2020, 05:23 PM.
      "And then we broke the car. Again." Mark Donohue, "The Unfair Advantage"

      1987 E30 3L Turbo Stroker Das Beast
      2002 E39 M5

      Comment


        Looks great, great numbers too!

        Comment


          Celebratory burnout time!

          Comment


            That is some damn fine power.

            Comment


              Nice! That 10psi "curve" looks like a tabletop. That's exactly right for a road racing car. :)
              john@m20guru.com
              Links:
              Transaction feedback: Here, here and here. Thanks :D

              Comment


                P.S. what's with blocking out your eyes? Are you a top secret government operative?

                Comment


                  Was the difference between the housings? T3 0.84ar and a T4 0.58? Or were they both T4?
                  I do expect a smaller housing to make power sooner, but I do not expect it to make more peak power. This seems counter intuitive, but if this is correct, I may be sourcing a T4 0.58 for my 6266 instead of the 0.81
                  - AXIS POWERS - 2JZ E30 Build
                  Interested in drifting in the ArkLaTex? Join us!
                  318Racing.org

                  Comment


                    Originally posted by SLEEPYDUB View Post
                    Was the difference between the housings? T3 0.84ar and a T4 0.58? Or were they both T4?
                    They were both T4. The 0.84 was divided, 0.58 is single. Look back a few pages for comparison pics. My best guess on why more power is the 0.58 is optimally sized for the M20 head CFM. We probably didn't have enough exhaust gas flow to fill the bigger housing properly and drive the wheel to max efficiency.

                    Definitely go 0.58
                    "And then we broke the car. Again." Mark Donohue, "The Unfair Advantage"

                    1987 E30 3L Turbo Stroker Das Beast
                    2002 E39 M5

                    Comment


                      Originally posted by SLEEPYDUB View Post
                      This seems counter intuitive
                      Happens more than you'd think. It's very common for people to have the "bigger is better" thinking, and it may not always be true. Header/exhaust sizing one that often over-shot.

                      john@m20guru.com
                      Links:
                      Transaction feedback: Here, here and here. Thanks :D

                      Comment


                        Look forward to seeing this thing on the other side of the pandemic

                        Comment


                          Originally posted by ForcedFirebird View Post

                          Happens more than you'd think. It's very common for people to have the "bigger is better" thinking, and it may not always be true. Header/exhaust sizing one that often over-shot.
                          I mean I get that, but from what I've seen especially on M20's, they need as little exhaust back pressure as possible, and the 0.58 I assume would choke it down
                          - AXIS POWERS - 2JZ E30 Build
                          Interested in drifting in the ArkLaTex? Join us!
                          318Racing.org

                          Comment


                            I'm running a 3" mandrel bent downpipe and 3" exhaust all the way back. T4 0.58 housing looked well matched to it., Data says the M20 really likes it CFM-wise.
                            "And then we broke the car. Again." Mark Donohue, "The Unfair Advantage"

                            1987 E30 3L Turbo Stroker Das Beast
                            2002 E39 M5

                            Comment


                              Well fuck. Imgur was hacked and they put a fake email address in my account. I caught it in time and changed my password. Suggest anyone using Imgur does the same
                              "And then we broke the car. Again." Mark Donohue, "The Unfair Advantage"

                              1987 E30 3L Turbo Stroker Das Beast
                              2002 E39 M5

                              Comment


                                Community poll. Guess what this is and what's missing.



                                We caught it before anything bad happened. Will replace all 4 with aircraft grade shank drilled bolts & cotter pins.

                                Always nut & bolt your track toys.
                                "And then we broke the car. Again." Mark Donohue, "The Unfair Advantage"

                                1987 E30 3L Turbo Stroker Das Beast
                                2002 E39 M5

                                Comment

                                Working...
                                X