Seven Wiki Available

Please check out our wiki available at:
See more
See less

Dyno run complete

  • Filter
  • Time
  • Show
Clear All
new posts

  • Dyno run complete

    I spent three happy hours with Bisi Moto yesterday with Mr Bisi running the car and dyno while I did the mapping. Scott E joined us and hung out with us in the shop.

    We ended up taking out a huge amount of fuel over the entire map and added 4-6 degrees of ignition over the entire rpm range at max load (max TPS).

    The verdict is attached: 217HP/181lbft at the wheels. With a 17% drive train loss in gearbox and diff, we are looking at ~252HP at the crank.

    The supertrapp took out approx 12 hp at the wheels. Bad, but not catastrophic. I have a map that runs 2% leaner for when I run with the supertrapp installed. One day I will find a better muffler solution.

    The attached chart shows the final power run with and without the supertrapp.

    The only downer to the day was we found a huge gash in the rear tire after something I've run over and that my altenator died on the way home and I had to tow the car for the last bit.

    I am not sure I will manage to get a new set of rear tires (Kumho V710) and a new alternator in time for Friday, so I may have to cancel Willow Springs.

    /Magnus F.

    Last edited by magnusfeuer; May 20, 2008, 10:17 AM.

  • #2
    Originally posted by magnusfeuer View Post
    The verdict is attached: 117HP/181lbft at the wheels.
    My jaw dropped when I first read this, but then I realized it HAD to be a typo. 217/181 at the wheels is a great result! If I knew the Swedish word for congratulations, ...well, I probably couldn't pronounce it properly anyway, so I would just say: "Congratulations!"
    | | Sean


    • #3
      Typo fixed. Sorry about that.

      Sean: The word you are looking for is "Gratulerar"


      • #4
        Wow, does that thing ever take off at 4200rpm! What are you using for an exhaust manifold? 4-1? Was this done on 91 octane? If so, any detonation with the 12:1 pistons?

        Westfield SEiW
        2.0L Duratec
        Throttle Steer


        • #5
          I had 91 octane with no detonations. The exhaust is standard Caterham primaries and 4-1 collector with a coast fabrication canister.

          The only issue (apart from the alternator) was ring flutter at 7500 RPM. A bit irritating, but I worked around it by cutting the engine at 7300. I'll talk to Cosworth about it.

          /Magnus F.


          • #6

            How can you tell you had ring flutter?


            • #7
              Oil out the valve cover vent at high RPM/load combined with a power loss.

              /Magnus F.


              • #8

                Nice result!

                How does this compare to what Cosworth claims their motor to put out?
                Tom "ELV15" Jones


                • #9
                  One day I will find a better muffler solution.
                  jesus christ, how many times do I have to point you here

                  I am not sure I will manage to get a new set of rear tires (Kumho V710) and a new alternator in time for Friday, so I may have to cancel Willow Springs.
                  Can't help w/ new tyres but I have some ACB10s mounted on 13s that I'd be willing to let you use. I'll only run them 1st session Saturday but don't have too so they're yours to use if you wish. They're not exactly slicks but it's all about seat time anyay really, hint hint.

                  As for the alternator, well, you don't really need it. I've done entire weekends just running off of my little motorcycle battery. I put it on the charger between sessions. I always bring a charger to the track, for obvious reasons. Also, at Willow, the brake lights use more electrical energy than anything else so I just don't use em (the brakes).:D

                  Edit: I bring an extra battery too, always.

                  There's a cheeseball alternator shop in Glendale that had a replacement for mine overnight. I can dig up the name if req'd.

                  Edit too: Today is Tuesday. Too late to refund your entry fee and too early for excuses. So we'll see you Saturday morning.
                  Last edited by moosetestbestanden; May 20, 2008, 09:57 PM.
                  A day you don't go a hundred is a day wasted


                  • #10
                    Seems like I will have to get used to brief views of the back of your seven.


                    • #11
                      Originally posted by moosetestbestanden View Post
                      jesus christ, how many times do I have to point you here
                      Gotta agree with Chris on this one. An engine that nice deserves a Raceco exhaust :)

                      Westfield SEiW
                      2.0L Duratec
                      Throttle Steer


                      • #12
                        Brad, power isn't the 2003 Infineon Sevens Fest there was a Lotus 7 S1 with skinny road tires and a wheezy engine who left most modern Sevens in the dust (apparently a long-time racer). My excuse was it being my 2nd track event ever.

                        Now, anybody knows how to fit a Duratec into a Birkin? ;-)


                        P.S.: While I don't have The Force of Cosworth origin at least I have the RACECO can. Nice piece of hardware.
                        Last edited by slomove; May 20, 2008, 10:49 PM.