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Jason M's Street Mod Project ~ 2015 ~

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  • Jason M's Street Mod Project ~ 2015 ~

    2015 is finally here along with the start of the racing season! I have not been on the forums much lately, however that does not mean I have not been working on my S13. In fact, I think I've been busier then ever! For anyone unfamiliar with the car and the build process, please refer to (1500+ posts, and 150-ish pages of street mod banter!)

    Last year I accomplished several long term goals, but fell short overall. The project is probably 1-2 years behind where I anticipated it being. A second place finish at my first nationals was not bad however, the finish was due to strategy. The car did not have the pace to compete with the Panda nor' Godzilla.

    Pic's from 2014 SCCA Solo Nat's (One of last years biggest accomplishments!)

    I'm going to break down last years performance charactoristics into segments.


    The car does not have very good turn in. I describe turn in as "vague". This may be because of the diff, or may be because of my roll stiffness front vs rear. The car was set up to be neutral in transition, which meant in steady state, it had a significant push. I believe this setup philosophy was a mistake.

    The car should be neutral-ish in steady state and should be driven with technique while in transition. The car will be unstable and more difficult to drive, but ultimately I believe faster on the auto-X course.

    Front Shocks: Bilstein 3kg's (off the shelf valving)
    Rear shocks: Last year Koni 8611's, 2015: Top secret (starts with a "P" ends with an "E")


    With the abs actuator mounted in the rear, and wildwood calipers front & rear.
    The pedal is far to soft, has excessive travel, and pedal feel is vague. I need to work on the brakes...


    Needs more boost, better spool up, and more power. Same old story...

    Old engine specs: Megasquirted Ka24de w/8k redline, ~11:1 compression, JWT 227 deg @ .050" cams, GTX3071, 5.5" quartermaster clutch, accusump, oem crank, ATI damper, crappy jgs log mani, and a 27lb cast aluminum oem intake. 442hp @27psi with no-intercooler on E-85.

    The engine bearings showed signs of excessive loading. and delamination/cratering I'll post pictures and elaborate later on...

    Goal is to make the new engine reliable @ 500rwhp, with boost that builds before 3krpm.


    OS Giken Spec S differential: Straight out of the box the diff is probably great for street cars, or cars on street tires with <400hp. On my s13 I've experienced inside wheel spin issues from day one with this diff. Even with redline 75w-90ns The diff would not lock on initial throttle application.

    Recently, I've been in communication with the guys @ OS Giken about my issues. After sending them my dyno sheets, videos of my car on the east and west course at last years Nat's, and a long phone conversation, OSG has game plan for my diff.

    We are going to change out the pressure ring to change the cam angle for more intial lockup, and lock timing will be softened up as much as possible by adding anti-preload springs. Also, the diff will be a 1 way vs the more common 1.5 or two way offerings.

    I'll elaborate on the detailed spec's one I have the diff back from Giken.


    The chassis was down to the minimum weight, and 60lbs of ballast was bolted to the car for nats last year, however, the car was front heavy. Solution: Fabricate by wet lay-up and vacuum baging, carbon fiber hood, bumper, headlight covers, fenders, splitter, sunroof delete panel, cf dual element wing-set, and custom headlights that are street legal. Once I've fabricated all of the above, I estimate some 200lbs of ballast, and a 51-52% front weight distribution vs last years 55%!

    More carbon fiber related project pictures and documentation to come in my next post, as this is the main subject of interest to me right now. Stay tuned!

    -Jason M

    Last edited by Jason M; 03-01-2015, 07:42 AM.

  • #2
    After months of online research, reading text books, and taking an introduction course at a local composite supply house (lifetime 20% discount along with the class!) I still hardly know what the hell I'm doing!

    My ultimate goal with my SM S13 project is to learn new skills, (welding, fabricating, machining, composites, etc..) not necessarily winning. That said, I do really want to win eventually!

    Skill of interest:Composites

    Goal's: Learn various plug making techniques, construct light weight carbon fiber panels and fiberglass molds.

    In order to achieve all of my composite goals I've had to learn many skills that might not seem apparent to others. I've had to learn how techniques involving plug making, mold making, and laminating.

    To make a plug for a mold I've had to learn how to apply and sand Bondo (not as easy as it sounds), apply the appropriate primer (also not as easy as it sounds), and apply a base-clear coat to said plugs (body panels). I did not even know what an HLVP gun was before a couple months ago, let alone how to tune one, or what nozzle to use for different products...

    There are so many products on the market, that its going to take a while to learn proper techniques and applications.

    Making a mold requires a plug. The plug must have a smooth shiny surface, as any imperfection will transfer itself into the mold. The shinier the plug, the shinier the mold, the shinier the part!

    For my S13 I am building a front bumper, front fenders, pop up headlamp covers, splitter, hood, sunroof delete panel, and a foam core wing-set out of Carbon fiber, using a wet layup-vacuum bagging technique. The resin system of choice will be vinyl ester, as it's superior to polyester resin and cheaper then epoxy. For some more complicated lay-ups, an epoxy system will be used due to the longer "pot life", or working time of epoxies.

    All of that said here are some pic's!

    Pop up headlamp cover, painted and cleared, then wet sanded and buffed to a shine! A flange was hot glued to the plugs (HL covers), then a plastic clay was used to create a filet that prevents the mold from undercutting the part and becoming mechanically locked. The flange is an important part of a mold, as this offers a pry point for splitting the mold!

    The plug is waxed several times with a mold release wax, then sprayed with a PVA release agent. After the PVA drys and creates a thin plastic bag like layer over the part, an orange tooling gel coat is applied using a G100 cup gun. (Orange is the gel coat of choice for contrasting carbon fiber, and black is great for fiber glassing projects).

    After the gel coat drys to a tack, multiple layers of fiberglass is laminated to the gelcoat. The first layer of laminate is critical! If it is not bonded correctly creating a void, the thin layer of gel coat will not have any support and it will chip away leaving a void on the crucial mold surface.

    I'm having trouble with the tight radius edges of these stamped steel headlamp covers. The first layer of CSM does not want to lay over. My solution is to apply loose strands to the corners then lay down a lightweight fiberglass fabric that conforms easily. A 1.5oz CSM mat is then apply to the top, sides, and flange using a stiff VE resin vs cheaper poly-ester.

    24+ hours later... The mold can be separated from the plug.

    Clean the wax from the mold flange, then apply several coats of mold release was, and buff to a shine!

    Next episode will be the vacuum bagging process!

    -Jason M
    Last edited by Jason M; 02-28-2015, 10:25 PM.


    • #3

      Vacuum Bagging

      10 yd's 60" wide 7oz 2x2 twill Carbon Fiber (minor blemishes $11/yd!!!)
      10 yd's vacuum bagging film
      Vacuum bagging tape
      Breather/absorber material
      Peel Ply
      VE Resin
      Harbor Freight Vacuum pump
      3/8" clear hose (from hardware store)

      Custom built lay-up table!

      Flat panel construction:

      Polyethylene Plastic (Resin is not supposed to stick to it). I now use a piece of glass, from an old double paned window vs the plastic block.

      Tape off perimeter of the surface (where the bagging tape will go) and apply several coats mold release wax.

      Supplies pre-cut (Sorry for the crappy pic's! I was using an old back-up phone at the time...)

      Apply resin, and layer the carbon fiber fabric as appropriate (using a throw away paint brush and a dabbing/stifling method), then smoothly apply peel-ply release fabric. (Peel ply leaves a rough texture useful for post laminating)

      Carefully tape the vacuum bagging film to create a leak free seal, then turn on the pump and drink a beer to reward yourself!

      Pic's of the pip up headlamp covers in the vacuum bag. (Obviously the finished part in the pic's still need to be trimmed, also these are the first parts I've ever made in a mold, and I'm still working on my process.)

      Small inclusions on the edges of the part. The vacuum bagging technique does not work well when dealing with a very tight radius. I have a solution to this. (more on this and other problems I'm facing later). If I were to apply a clear gel coat to the mold before laying my carbon fabric, I believe this would not be noticeable. I'm committed to NOT using gel coat to keep the weight down to a minimum.

      Flat panel, 3 layers, constructed on a sheet of glass. The glass was sprayed with several layers of PVA as a mold release agent.

      3 layer CF sunroof delete panel, 1lb .02oz! vs the old 12+lb sunroof glass and hardware! I'm not sure How its going to look after siliconing it to the roof. Eventually I'll probably take the time to laminate it on my co-drivers hard-top S13 to get the correct curvature. This will work for now though...

      Garage pic....

      Last edited by Jason M; 02-28-2015, 09:44 PM.


      • #4
        Good to see you back and still working on the car.

        Curious, If you are making a new front end, why not dump the pop ups. That is a huge weight savings right at the front. With all the new small headlights, it would be relatively easy for a man of your talents.

        I fabbed up a set using the old Camaro lights but sold the car before I put them on.

        Good Luck


        • #5
          When vacuum bagging a part with a small inside radius (anything 1/4" or below) the composite fabric, peel ply, and vacuum bagging material itself will have a hard time getting into the corners. The term for this issue is called "bridging". air pockets and lack of material on the inside corners of mold will leave inclusions/voids.

          Fancy diagrams of what bridging is!

          Talking with my supplier, they are recommending apply a thixotropic putty tinted black. I will basically run bead of the putty on all inside radii during the wet layup process. (Again my process does not use a clear gel coat as a surface layer like most aftermarket hoods)

          For reference this is what I'm trying to eliminate.

          Stamped steel parts on a production automobile are full of small radii. This is definetly a problem that needs to be addressed.

          Any advice for me would be appreciated! After building my hood, my next project is going to be very layup intense! The mold is going to have many compound inside radii.
          Sneak peak...


          • #6
            So much awesome here.

            I agree on ditching the pop ups. I'm on a very temporary set of those nasty eBay bug-eye lights, but will fab something up (probably not as nice as what you're doing!) to have some basic headlight functionality without too much weight.

            The headlight motors weigh so much that I actually had very significant fatigue cracks in ALL their mounting points. It was only a matter of time before they just flat fell off. They had never been removed from when the car was built, so it wouldn't surprise me that most S13s of this vintage had significant fatigue cracks around all the tiny M6 welded nuts.

            Stock front bumper is also heavy, so I'm thinking about a cheap fiberglass jobber. It'll also get some more flow in, and be easier to fab a splitter to work with.
            '18 Chevrolet Volt - Electric fun hatch for DD duty!

            DefSport Koni Sleeve and Spring Perch Buy!!!


            • #7
              I thought I was going all out this year... Your fab skills and optimism/drive are on another level!
              Chicago Region SCCA SM # 688
              TSSCC SM # 688


              • #8
                no disrespect because your fabrication work is looking awesome but..

                a part of me dies inside every time I see someone do a pop-up delete, I know they are raging retard heavy, and not extremely reliable either

                but they are like one of the single biggest reasons I love the s13


                • #9
                  I liked them for a street car. Beyond that, not a fan. The whole assembly weighed around 25 lbs IIRC.
                  '18 Chevrolet Volt - Electric fun hatch for DD duty!

                  DefSport Koni Sleeve and Spring Perch Buy!!!


                  • #10
                    I've been wishing someone would make those Ab Flug style headlights forever now.... maybe you should do it Jason... nudge nudge.


                    • #11
                      Originally posted by maxtherabbit View Post
                      no disrespect because your fabrication work is looking awesome but..

                      a part of me dies inside every time I see someone do a pop-up delete, I know they are raging retard heavy, and not extremely reliable either

                      but they are like one of the single biggest reasons I love the s13
                      I love my pop up headlamps! The reason I replicated the headlamp cover is so I can build custom pop-ups. They are either going to be cable actuated from the cockpit, or utilize an rc servo. They wont open as far as the oem's, but my car is going to be pop-up for life, so no worries!

                      I need to source some street legal lights for my build. Any ideas? I'm required to retain high and low beams. Ive seen an actauted all in one high/low beem on a SSM Miata, but I'm not sure where they were sourced from. I'm tempted to integrate two small round lights, or possibly leds into each headlamp assembly.

                      Each oem headlamp assembly weighs just over 10lbs. My carbon headlamp cover weighs something like 6oz. I'm hoping to end up with an assembly weight of about 2lbs for each unit.
                      Last edited by Jason M; 03-01-2015, 09:00 PM.


                      • #12
                        Awesome work. You've given me a few ideas for my car. I'm fortunate enough to have a friend who does that type of work for a living, (RedSIBaron on here). I'll be following for the rest of the thread.
                        '79 Datsun 280ZX-Awaiting the day I decide to actually work on it.
                        '05 Nissan 350Z Track-Weekend/track duties. Gets some of the the attention the 280ZX doesn't.
                        '08 Toyota Tundra-Daily/tow rig.


                        • #13
                          The 2.5" mini projectors have a flip up shield for high beams.
                          '18 Chevrolet Volt - Electric fun hatch for DD duty!

                          DefSport Koni Sleeve and Spring Perch Buy!!!


                          • #14
                            I like the idea of two smaller lenses under each pop up cover. Just kick on the inner set for high beams.
                            '95 240sx


                            • #15
                              Hella makes some light weight projectors. Sub 2 lbs for high or low beams, around 3lbs for high/low combination lights.