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Thread: The Bastard's Build

  1. #31
    Positron cvjoint's Avatar
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    We got V8 powah!

    It turns out the combination of silicon hoses to clear the tray and the apparently restrictive Jim Wolf Filter was collapsing the hoses on the intake. Shop revised the intake system by reducing the use of hoses and adding an even larger filter element and raised the rev limiter back to 8,000 rpm. The car is now at 274 wtq 395 whp, 310 tq and 450 hp at crank assuming 11.5% drivetrain loss. Max boost is 14 PSI at redline and Rotrex is spinning at 74,500rpm, far from the 90,000 rpm limit. The only dyno I've seen on the V8 was at 400whp so it's now up there with the big boys!

    Dyno 395 whp Atom 14 psi.jpg


    Dyno 395 whp Atom 14 psi boost.jpg



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  2. #32
    Positron cvjoint's Avatar
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    Finally, got some much needed R&R, i.e. Ran the Rotrex! 7 months of not driving made for some questionable driving moves, but the boost made up for it in shoves. Pinched a 1:32.2, think that's the quickest for an Atom at Laguna Seca. Anyone know of a faster time? Please post. Prior best was by DP, 1:33.1. I was running on 46 heat cycles so there is loads left in it. https://youtu.be/CqYvMVJcwho



    20200613_201106 compressed.jpg

  3. #33
    Lepton McFred's Avatar
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    Glad that you got the Boost issue figured out and that you got it retuned. That's great you got to run Laguna too. 1:32 with traffic is moving right along!

    Also your front wing sure moves around a lot, is that normal?

  4. #34
    Positron cvjoint's Avatar
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    Quote Originally Posted by McFred View Post
    Glad that you got the Boost issue figured out and that you got it retuned. That's great you got to run Laguna too. 1:32 with traffic is moving right along!

    Also your front wing sure moves around a lot, is that normal?
    I was definitely out of practice, winds were pushing us back at least a second, and the front tires were definitely roasted. Looking forward to running it again sometime in better conditions and with more practice.

    The front wing does move. I tried to move a stock wing on another Atom (with the owner's permission!) and it was far more solid than mine, so it must be the Ciro extensions that add the flex because I'm also using the OEM mount. If I get clean air it loads ok and stays fairly fixed, but when I follow other cars it's a bit of a flexy mess. I already added a cross brace on the Ciro mounts, and added spacers to widen the mounts on the wing itself to strengthen it but it's obviously not enough. I will have to redesign the front wing, it's my priority on the upgrade list. Next step I'm going to mount the wing straight to the OEM mount like the factory does their wing, and strengthen the OEM mount. If that doesn't work, I'll have to add triangulation by running supports from the frame to some mounting points farther out on the wing.
    Last edited by cvjoint; June 17, 2020 at 02:08 PM.

  5. #35
    Positron cvjoint's Avatar
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    The Bastard's heart exploded. On an unremarkable morning session, before pushing it at all for time trials, it popped at redline just 10 minutes into the session. Sputtering on only 2 cylinders The Bastard brought me all the way back to the trailer before the engine gave up the ghost entirely. Bless his heart.

    Diagnosis: CRACKED SLEEVE. OEM sleeve broke right off between cylinders 1 and 2. This is a surprise for me. I thought the OEM sleeves are good to 500hp, it's literally unheard of to crack one at 450hp but I suppose I tend to break things early on the way I use them. Metal from sleeve got into the combustion chamber so the head is toast as well. This will require a new build from scratch.


    atom 1.jpg
    atom 2.jpg
    atom 3.jpg

    Not much left to salvage from the HPD engine, except bottom end for sleeve rebuild, crank, valvecover, and half the valves.

    Boosting an HPD engine to the tune of 14 psi was quite an experiment. We rarely get to see what a K24Z7/K20Z3 build could do with forged pistons replacing the weak factory cast pistons. If you asked me what the weakest link was before this episode, I would answer headgasket, headbolts, or detonation due to pumping out 400whp on 11:1 compression. This was on bare bones Hondata as well, not your Motec fancy bits. So what we learned here is new in the world of Honda tuning. Second only to the cast pistons, the sleeves are the next weakest part of the combo. I say this because I don't see any sign of piston melting, and that the sleeves failed right where they are weakest, between cylinders.

    Hope ya'll enjoy the fruits of this engine's labor hours.

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