Since I’ve closed out my “build thread” having reached he goal of actually building and registering a road going turbocharged Exocet I’m opening up this thread to chronicle ongoing work. Specifically upgrades to make it a better car and things that I’m redoing because I was dumb/inexperienced the first time around.
First upgrade - Ignition.
Since I’m running MegaSquirt for engine management I decided to go with TrackSpeed Engineering’s Toyota COP kit. Super easy, not too expensive, should support decent boost but requires the ability to adjust dwell. I’ve set mine up to run wasted spark like the factory ignition to make things easier on myself. I can’t imagine /needing/ sequential ignition for the power levels I want to run on the car.
Took about 30 minutes to install and get running. I’ve set mine up as a sub-harness that will let me easily swap back to stock later on without having to further hack up and splice the factory harness.
I’m running BK7RE plugs gapped to 0.035 with these coils. First run on the COPs the car was noticeably smoother at idle. I’ve not had a chance to drive the car with them, it’s been a little too cold for casual driving/tuning the last couple of days.
The quality of the kit is tops, the installation is a snap, and so far seems to be everything it promises to be. I’m pleased.
While running around last Friday a few small electrical issues popped up, one affecting my fuel level gauge. The connectors (of unknown brand) on the gauge harness provided by Speedhut fit a bit loosely and so they could beak contact from vibration while driving. When that happened the gauge would see infinite resistance and drop to zero fuel immediately.
Solution: Crimp on new, tighter fitting Molex connectors that won’t randomly break contact with the car’s many vibrations.
Zero drop out on the fuel level gauge now.
I’ve preemptively replaced all of the janky fitting factory connectors on all of my Speedhut gauges with better fitting connectors.
Next small repair completed, oil pressure gauge never worked.
Spent time testing out all of the electricals with multi-meter and everything came back good. Figured it must be the sensor which sucks because it’s hard to get to tucked under the intake manifold. The oil feed, temp, and press sensor share a fitting off the oil galley.
Pulling the pressure sensor out it became instantly obvious what was going on. The temp sensor is too long, it had seated itself firmly against the oil pressure sensor’s transducer opening. You can from the crescent shaped indentation that it was very well sealed from seeing any oil pressure at all.
As a safety measure I swapped out the pressure sensor for a new one. ($28 on Amazon) I’m also relocating the oil temp sensor down into the sump where it should have been anyway. The only things plugged into the oil cube are the feed and pressure sensor. Now the oil pressure gauge actually works like it’s supposed to. Oil pressure is reading 50psi at cold idle which should be just about right for the 5W30 oil I'm currently running. I'll be switching a slightly heavier 10W40 at the next oil change.
Having a working oil pressure gauge again is a huge relief now that the car is turbocharged.
Small update as I chug along fixing small, broken things before diving into clutch and differential swaps next week.
Eventually I’ll get all of my gauges to be matched Speedhut Revolution series but for now I’m making due with two GlowShift gauges in the cluster because they were cheap, easy to get in a pinch, and good enough at the time I needed them. Boost and oil temp, by the way.
Problem is that, for whatever dumb reason, they require two +12V connections for the gauge faces to light up. One is main power and the other is a phantom power to keep the the gauge color setting “memorized.” The faces on the stupid things won’t light up at all if that phantom source has no juice. Since the lenses are tinted they’re impossible to read without face illumination.
I spent way too much time trying to sort it out only to realize at some point I’d blown the 3amp fuse I’ve been using for all devices that want a 12v constant to “maintain memory.” I really should start checking fuses first.
Not the best match in the world but they’ll work for now...and they’re actually working.
Updating the suspension. Going from cheap RaceLand coil-overs to Skunk2 coil-overs. The spring rate change puts a little more up front, a little less out back while increasing overall travel and adding selectable damping. (12 steps)
The RaceLands were always a temporary solution for my build, I needed dampers to get the car rolling and they were $300 on EBay. After a year and change they’ve held up reasonably well apart from the crumbling dust boots. They’re not great but they’re not terrible if you’re not driving the card hard/enthusiastically. Street car...eh, they work. Autocross or track? I want something better.
Skunk2 Pro STs should fit the ticket for a reasonable all around suspension setup.
Been a while. Still haven’t gotten around to the clutch. Work, life, and a bunch of other things have been making me not want to work out in the cold, damp garage. I’d really like for winter to go away now. Slow progress is slow in winter.
Anyway, the 4.10:1 LSD is in including new axels because I don’t even know how the previous axels were. (Probably as old as the donor.) No pretty pics of this since there are already a million and a half differential swap threads/videos available with easy Googling. I threw in a set of Energy Suspension differential bushings to compliment the poly engine mounts.
Totally a subjective thing but the car feels a lot more solid and connected with durometer bushings holding the driveline in. Haven’t really thrashed it with the LSD in but it also feels a lot better the open diff. Smoother.
On the side I’ve been chasing issues with boost spikes and creep impacting drivability. The TD04-19T with an eleven blade turbine spools low and fast, controlling it has been a small challenge. Boost very easily shoots past the seven pound wastegate spring and the car will bounce off the fuel cut. (currently set at one bar) My tuner reminded me that the TurboSmart wastegate actuator I’m using is significantly larger and better than a stock Subaru WGA, politely suggesting I’d set it up with too much preload. (He was right, when I checked it again I had about double Turbosmart’s the recommended preload dialed in.) I also pulled out the GrimmSpeed manual boost controller I’d installed to help me chase down the boost spikes. Next drive out, the car was great! No spiking in casual driving, logged a max of 5psi in casual driving with no more than 28% throttle seen during the drive. (Previously, it would spike to 14psi at 28% throttle.)
I also plumbed in an electronic boost control solenoid though it’s currently disabled in the ECU. That’s there for future tuning. I’ll be happy to run 7psi for for now, planning for 12-14psi when I can get some time on the dyno with my tuner.
Still working on the car, haven’t really driven it much lately. Between being too cold and rain there’ve not been a lot of good opportunities to get it out and really dial in the changes that I’ve been working. But work does continue.
Friday night I spent some time replacing, once again, my tank filler vent tube. The solution that I’d come up with leaks at the brass elbow regardless of how tight the clamps are. Not good.
Managed to find a relatively flexible section of low pressure fuel hose and got that into place without it kinking too much. The next time I take the rear cover off I’m going to replace that with some 5/8th hardline bent into the correct shape.
Saturday morning I spent a few minutes installing a set of steering rack spaces in the car to dial out some of the bump steer happening from lowering car. There are a few different kits out there for this, I picked GarageStar’s kit for no other reason that they’re based out of Sacramento, California, just a short drive from San Jose.
The install was literally removing four bolts, lifting the rack slightly, slipping the spacers under the rack, installing the new bolts that came with the kit.
I might need to add a little bit more “custom clearance” to my down pipe now but I won’t know for sure until I’ve gotten a chance to drive the car more. I might be able to do some adjustments to the steering column or I may need to make a new down pipe.
Iv’e also zipped that braided line out of the way.
Continuing on the with the laundry list of post-turbo installation changes, I spent yesterday doing two small changes.
The first, that I didn’t photograph, was wiring the clutch switch up to my MegaSquirt for launch control and flat shift. Simple enough.
The bigger work was swapping the intercooler. I decided to change it to a smaller core, going from an 18x11x3 core to a 10x11x3. I call them the Biggercooler and the Smallercooler. In relative terms, Smallercooler is about 56% smaller than Biggercooler. When I put the turbo system together I went with the Biggercooler knowing that it was oversized for my application primarily because I wanted the look of the intercooler completely filling the car’s mouth opening. It worked well but caused a few issues, mostly with packaging (2 issues) but also to a very small degree cooling.
The installation was pretty easy. The Smallercooler fit into the mount I’d built fo the Biggercooler with only a couple of small modifications to let me adjust the location of the cooler in the center of the mouth opening. The IC piping changes were also pretty minimal, I only needed to cut the J-bend into a U-bend and the straight piece cut off from the J-bend was long enough nicely replace the 90˚-bend on the hot-side of the Smallercooler. Moving the inlets toward the center of the car cleaned up a small issue with the IC pipes rubbing on the hood since they’re now under the center bulge. (Packaging issue #1 resolved.)
The Smallercooler also let me reinstall the horns back in the mounts where I’d placed them during my original build. I really couldn’t find anywhere else to put the horns that made me happy, I loved the look of the green caged dual-tones poking out from the mouth. (Packaging issue #2 resolved)
The Smallercooler also opens up a significant amount of the radiator to clean air. While the car wasn’t expressly overheating this should help to keep temperatures in check, back down where they were before I installed the turbo charger with the, especially in stop-and-go traffic. At some point I’m also going to need to wire up the second radiator fan but that’s a project for another time. (There are other cooling system changes that I want to make when I do that.)
I’m not too worried about Smallercooler being too small. I’m not planning to run a crazy amount of boost. Biggercooler is capable of supporting some 400-450ish horsepower, Smallercooler should be good for 350-ish horsepower. I’m not planning to produce much more than 250-ish horsepower if even that much. (Whatever the car makes at 12-14PSI) Since I’m using a larger compressor on my TD04 (19T vs a 13T) the turbo will flow more air at any given pressure with less heat rise marketing the Smallercooler an even better choice. Or so theory suggest.
First - Dang if the car ain’t good as it sits. The nose cut was amazing at a cars and coffee when it came time for people to look the motor over. So much easier to remove the hood. BUT....But the button latches sucked.
They’re very particular about angles to keep from binding up. Basically, they’re a HUGE pain in the butt to work with if they’re not set 100% perfectly correct. I’m an impatient human being at time so that wasn’t going to work well for me. I decided to replace the button latches with another set of aero catches.