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Went to Track...car's faster.....

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  • Went to Track...car's faster.....

    But NOT Quicker!!!!




    9.18@161.27 MPH

    I took the 'Vette down to a great little track in Lufkin TX yesterday...Pine Valley Raceway. It's about 240 miles one way from my house....but not a bad drive.

    The weather was about as perfect as can be. Mid 50's, low humidity , high pressure and nice sunshine. Great day for racing!

    To try and build a little boost at the line (think Street Outlaws popping and banging) I added a "two step" button that allows me to use some more of the Holley EFI parameters and pick a second rev limiter to retard timing and do whatever I want with fuel while it's depressed. It's called "Boost Builder". The idea is to retard timing and build some heat in the turbo's to get them spooling a little quicker off the line. Guys with automatics do it easily and load against the converter...sticks make it a little trickier. But it worked well and I could hit 7 PSI in just a second or so while sitting still. Makes lots of noise though! I decided to try it at 3800 RPM and only 2 PSI of boost.

    I also backed off my adjustable clutch to make it softer out of the hole to limit wheelies and tire spin. This is the lowest I've ever run it.

    So the first run I try that. I was the 3rd car down the track...so not much rubber on the track. Instant tire smoke.....grabbed second early and went into "John Force style" smoke show into 3rd gear and lifted and coasted through. I drove back around and went right back into line to try again. Had time to sit there for awhile before next attempt.

    I get called up and go through the burnout and pull to the line. All of a sudden my hydraulic clutch decides it doesn't want to work and won't release the clutch...it's engaging while the pedal is on the floor. It's happened twice before when I let it heat soak and sit after stop and go traffic stuff. After it cools a little it goes right back to working fine. Seems the fluid boils in the master cylinder which is pretty close to the left side turbo or the plastic master cylinder expands enough to bypass which seems more likely than boiling the fluid when the plastic doesn't appear damaged. Even though the turbo is wrapped and the lines to the clutch are wrapped...it apparently can still get toasty enough to boil fluid. They don't recommend DOT5 for it due to seal materials...but I'll move up to DOT4/5.1 maybe and add some more insulation to clutch master cylinder. After the little boost building excursion and a partial run then letting it sit there with hood closed..it got too toasty. On the upgrade list...but either way the run was wasted.

    I let it cool down and pulled back around to run it "old style" without trying to build more boost. I launched about 3500 and it came out fair...but still not good since I'm having to come out so softly as compared to the N/A days when I launched at 5000-5500 RPM usually. I guess I'm really going to have to work on power management where I pull just a little timing off the line to kill power and can bring RPM higher and ramp it back in quickly. But anyway....it ran a 9.18*161+ MPH which is new best MPH. 1/8th mile MPH picked up to 125+..so it definitely seemed to like the cooler weather! About 7950 RPM in the lights now.....

    Next run....I'm counting on the fact there's some rubber laid down now. I launch similarly and it picks up about a tenth and a half in the '60' which is fantastic.....down track banging gears and I hear it "pop" a couple of times...once at the top of second and then again in 3rd. I lifted and rolled through.

    Back in the pits I look everything over....nothing looks out of whack. So I head back up again....similar launch...but a LOT more popping.

    Back in pits...pulled valve covers to make sure all was good and it was. I wanted to eliminate mechanical issues first.

    Then I looked at data logs and noticed some goofy fuel pressure issues. I turned the key on and operated my two pumps separately and one of them sounds like it's eating rocks and vibrating! Soooooo....dead pump!

    Well....I got one real pass in....and ran a faster MPH. This whole excursion is definitely not about a HP issue...we've got power! I've taken it to the dragstrip 4 times now this year and it keeps getting faster...just not quicker yet. I've got stacks of timeslips between 9.10 and 9.30 with MPH from 158 to now 161. We'll get there eventually. Got another track rental on Dec 3rd.

    Maybe I ought to just take up 'Roll Racing"!




    It was fun to "out MPH" a lot of tube chassis/big slick nitrous guys. Folks kept coming around to stare at it. At one point one of the track owners came up on his golf cart and said..."You know you're making everyone jealous don't you?" LOL!!




    JIM

    PS- Not that I'm a pure attention whore...but there's a Poll going on the Corvette Forum in The C2 section for "C2 of the Month". Just sayin'.......

    https://www.corvetteforum.com/forums...or-2017-a.html


    Last edited by 540Hotrod; 10-29-2017, 04:15 PM.

  • #2
    Sounds like you had fun ... Just got my new Hoosier slicks in Sat and the temps are cooling of down here in FL .. Going to hit the track soon .... Oh ....I did turn up the boost 2 pounds

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    • #3
      Originally posted by 540Hotrod View Post

      About 7950 RPM in the lights now.....
      Don't I remember someone talking about having to "learn how to shift earlier and live with lower rpm?"

      I mean sure, it's no 9,200 rpm! But I think neither YOU, nor your valvetrain would like to relive THAT moment!

      Comment


      • #4
        Yeah.....that's what they told me.....but they also said "Let's cam it to peak around 6500 Max and then let those heads carry it through the higher RPM".

        THAT's what I'm doing! That little weenie cam hangs in there pretty good!

        I'm 4 votes ahead....everyone needs to keep at it!!

        JIM

        Comment


        • C5rider
          C5rider commented
          Editing a comment
          Can we vote numerous times?

          You know, "Vote early and vote often!" LOL.
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