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1987 RX7 turbo II autox build

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  • 1987 RX7 turbo II autox build

    Hey guys,

    As some of you know, I drove a 2008 STI the last few years in autoX, and decided to sell it earlier this year and get something with smaller monthly payments.

    I picked up a 1987 Mazda RX7 turbo II off of a local that used to autoX the car. It came with a long list of modifications and seemed ready to race right out of the box. It has since shown a few problems and is slated for several upgrades as well.

    The suspension on the car is a set of ksport coilovers with 11k front springs and 10k rear springs, which I haven't played much with and will likely be asking other members for setup advice as I know very little about suspension. It also has most suspension bushings available and upgraded swaybars at both ends.

    The engine was recently rebuilt, I was told it had very low miles, ~ 4000 I believe. But after chasing a rough idle for a couple days I ran a compression test and found low compression on two faces of the front rotor. I have since had the engine rebuilt and it is in the garage awaiting install in the car.

    The car came with a stock turbo as well as an aftermarket hybrid turbo that was on the car. When pulling the engine for the rebuild I found oil in the turbo inlet and pre-intercooler piping. This and the desire for a more modern turbo led to the purchase of a new turbo kit for the car. I am currently waiting on a turbo kit from Turblown, with a manifold, downpipe and internally gated EFR 8374, with ceramic coated manifold, turbo hotside, and downpipe.

    After fiddling with the palm pilot used to tune the modified stock ECU in the car I decided that it was not going to be sufficient for my future plans, and purchased a Megasquirt 3 with MS3X and necessary harnesses and sensors. I purchased a pre-assembled ECU, but will have to run the wiring harness.

    I think that's the major things that come to mind for now. The car is intended as an autocross car and fun summer driving car.

    Any suggestions or questions are welcomed.

    -Tyler

    Last edited by deddex; 03-27-2014, 10:37 PM.
    2008 STI- #91 ASP, or SM - Sold
    1987 RX7 - #91 SSM... once it runs again

  • #2
    Last edited by deddex; 03-27-2014, 10:36 PM.
    2008 STI- #91 ASP, or SM - Sold
    1987 RX7 - #91 SSM... once it runs again

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    • #3
      looks awesome! It looks like there will be a few of us running SSM this year. I'm excited for the competition!
      Gregory

      #99 DP 1996 Mazda Miata

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      • #4
        if i ever get my Windows 98 to load up and get working i'll be tuning my FC GTUs and running SSM i believe ^_^ lol
        Jake B. 89 FC, 74 Rx2, 95 Mx5, 06 MS6, 84 FB GSL

        Cell - 801-915-4810 - Nissan Technician

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        • #5
          Sounds like there should be some good competition. What tires will you guys be running this year? Are r comps going to be the norm or will you be opting for street tires?
          2008 STI- #91 ASP, or SM - Sold
          1987 RX7 - #91 SSM... once it runs again

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          • #6
            Originally posted by deddex View Post
            Sounds like there should be some good competition. What tires will you guys be running this year? Are r comps going to be the norm or will you be opting for street tires?
            i won't be running my FC this year due to trying t buy a home. BUT i think i'll be going Dual Tires, try and Run R Compunds and run Street Tires to see which way i'm most competitive.
            Jake B. 89 FC, 74 Rx2, 95 Mx5, 06 MS6, 84 FB GSL

            Cell - 801-915-4810 - Nissan Technician

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            • #7
              That thing needs to get finished... I want to see it.

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              • #8
                That's a lot of turbo for autoX. Should be fun though.
                SM 30
                # project cars: 4
                # running: 1...sometimes

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                • #9
                  It is a bit large, I was worried about late spool, but based on several recent dynos with the same turbo, and somewhat similar rotary engines it seems I should be making full boost fairly early i'm estimating 3200-3500rpm, and if I let it rev to 7500 rpm that gives a wide power band, and the EFR turbos are supposed to be very responsive between shifts. A smaller turbo may have spooled slightly sooner, but likely would have run out of steam up top without running a fairly high pressure ratio. The larger 8374 seems to allow more flow over a sufficient area with lower pressure ratios that the smaller turbos that were available. As well as allowing more head room if I decide to go for more power down the road.

                  Here is a link to the most recent dyno data from a setup with this turbo. It's on a newer engine, so I don't expect mine to look quite as good. My engine is lower compression as well as a less efficient intake design and more intercooler piping because of the front-mount.
                  http://www.rx7club.com/single-turbo-...sults-1060852/
                  2008 STI- #91 ASP, or SM - Sold
                  1987 RX7 - #91 SSM... once it runs again

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