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I’ve had this FD for about 15 months now, so I figured it’s about time to get off my rump and do a build thread… Here’s some pictures from my pre-purchase inspection trip to SC, November 16, 2019, and then some more pictures taken on delivery day at my place in MD.
Pre-purchase inspection trip, 11/16/19 Pre-purchase inspection trip, 11/16/19 Delivery day, 11/20/19, rolling off the transporter Delivery day, meeting the FC garage mate! Another on delivery day Engine bay shot
If you’re sensing some déjà vu from the pictures, it’s because the PO that I bought it from had a build thread on here too, here’s the link for the history buffs… https://www.rx7club.com/build-thread...build-1113634/
After spending lots of time hunting down a decent FD to use as a starting point for a resto-mod project, I stumbled on this one on FB. I wanted one with a clean & rust-free body, good paint, good interior, solid suspension & brakes. Mechanically, I was open to anything from OEM stock (i.e., twins) to a single turbo conversion (if it was done right). This one checked most of my boxes – key things being rust free clean body work with recent paint, relatively low mile chassis (< 68K miles when I got it), and the factor that sold me on it was the PO dropped a brand-new Mazda 13B-REW crate motor in it just before I did the pre-purchase inspection; I test drove it with less than 20 miles on the new motor. It was already modified, but for the most part the work was done right, and I can make use of most of the parts.
So here’s the specs and go-fast parts list as I got it:
Turblown S300 turbo kit; consisted of a Borg-Warner S364.5 SXE turbo with a 1.0 AR turbine housing; Turblown stainless tubular welded exhaust manifold with dual Turbosmart Comp 40 waste gates (40mm, 12Lb springs) & open dump tubes. The PO fabricated a V-banded 3” downpipe that mates up with a custom fabricated 3” exhaust system that he built. It’s 3” straight thru, except for a largish oval dual-tip muffler of unknown brand. Looks OEM, solid construction but it’s loud as hell and drones on the highway – plan to fix that with either a Racing Beat or Tanabe catback, a 3” resonated pre-silencer mid-pipe (probably RB), and some fab work to mate that stuff to the existing 3” DP.
On the air intake side, it had a large Apexi FMIC, a 90mm GM DBW throttle body, and a 13B-RE Cosmo UIM/LIM. On the fuel side, the FI’s are Bosch 1000cc extended tip EV14’s as primaries, and Bosch 2200cc secondaries. Plumbing is FFE fuel rails, Fuel Labs FPR, a Continental flex-fuel sensor, some hard line and SS braided with a Stabuli quick release/no leak coupling on the pressure side. Still running the OEM FD fuel pump though, so that’s on my upgrade short list.
Engine management is a Link G4+ Fury ECU. The PO did a nice job building a wiring harness for it, which included a mil-spec 55 pin circular firewall connector. Unfortunately, he didn’t wire in OMP support and a few other OEM integrations I’d like the Link to support, such as OEM-like 3 speed fan controls or wiring to support cruise control via the Link & DBW throttle. So I'll be doing a new wiring harness
On the interior, the plastics were in pretty decent shape all around, but tan. Easy enough to refinish using the SEM paints as described elsewhere on the forum. And since the PO was going for simple track beast when it was his build, there was no radio/speakers, so it had the pictured HVAC/radio panel that fits 6 gauges instead of a radio that I need to replace. The tan seat belts were also too filthy to get clean, and the webbing was looking worn. So besides adding an audio system and getting the belts re-webbed/restored, some interior restoration and possibly a full tan to black conversion is in the works.
No radio, but plenty of space for gauges
Suspension & brakes were pretty solid – Tokico Illumina adjustable (5 way) shocks with Tein springs front & rear. Not sure what model/spec the springs are – the car sits at what looks to me like stock ride height, maybe a smidge lower. Front stabilizer bar looks aftermarket, from diameter and red color, I think it’s the RB bar. Rear bar is OEM, and as far as I or the PO know, all the bushings are original OEM. I thought the pillow ball bushings would be shot by now, but they all seem to be holding upon inspection and test drives. One problem I found is the OEM liquid filled diff bushings have leaked, so fixing that is on my to-do list. Brakes are basically stock, with some aftermarket drilled/slotted rotors, and the ABS pump was removed & bypassed with the Alex Rodriguez kit and Wildwood proportioning valve.
Wheels & tires are a staggered setup, with Enkei RPF-1s, 17 x 8-1/2” Front & 17 x 9-1/2” Rear, with a set of Firestone Firehawk Indy 500s, 245/45R-17 Front, 275/40R-17 Rear. As far as I can see, they don’t rub anywhere.
My plans for this FD are to make it more comfortable and stealthier for street use, but still be stupid fast and fun to drive on twisty roads and an occasional track day. Essentially an FD version of my FC resto-mod! Something that can get me to & from Deals Gap in reasonable comfort on the interstate, and keep a s**t eating grin on my face when I’m driving the snot out of it on the twisty roads down there.
Being an engineer and project manager by trade, I always have a structured plan for my car projects. Below were my goals for "Phase 1" of my FD project. Thanks to this damned COVID pandemic, I had plenty of extra time and got all my goals done. I’ll share more details in subsequent posts
The following were my goals for Phase 1:
1. Complete a full rewire of the Link G4+ Fury ECU to implement all the features I wanted (e.g., OMP support, Cruise Control via DBW, add in knock, oil pressure & oil temp sensors), and bring any unused I/O out to accessible connector(s) for future use. 2. Install an FD OMP (2x used FD OMPs were provided by the PO with the car), along with an RA OMP adapter kit and 2-stroke oil tank (i.e., premix oil delivery managed by the Link ECU). This replicates the setup I have on my FC – I love not having to mess with adding premix at every gas stop. 3. Add an Oil Pan Brace to prevent leaks. 4. While engine is removed for the Oil Pan Brace installation, verify end play of the E-shaft, and do the E-shaft thermal pellet oil mod. 5. Add new oil pressure & oil temperature sensors for the Link ECU, and a Banzai Racing oil filter pedestal to mount the sensors. 6. Upgrade the single oil cooler setup to the OEM RX7 R1/R2 dual oil cooler configuration. 7. Revise/replace the existing Apexi front mount intercooler and Megan racing radiator arrangement to enable restoration of a working A/C system – this will involve going to a larger SMIC, or a V-mount arrangement. 8. Undo the PO’s battery relocation mod, and move the battery back under the hood. The battery relocation wasn't up to my standards. 9. Get the filthy tan seat belts rebuilt & re-webbed, and refinish most of the plastic interior panels from tan to black and add some sound insulation to the doors, hatch area and under the storage bins to reduce NVH. Not sure yet if I'm doing a full or partial tan-to-black conversion - I may retain the tan seat color & carpeting. 10. Replace the missing front bumper reinforcement bar, and missing plastic front undertray parts that I discovered. 11. Start restoring the A/C system - the PO chucked all the under hood A/C components to make room for the turbo & FMIC. Fortunately all the HVAC wiring is in place and unmolested, as is the OEM Denso evaporator core under the dash, which was properly plugged to keep critters out of it.
But before I could do any of that stuff, I needed to sort out the tune on the Link ECU - it was running stupid rich and the DBW & idle tuning was a bit jacked up when I got it. Fortunately I did my homework researching the Link G4+ ECU, and found their software and tuning app to be very intuitive and easy to learn. So it didn't take me long to get the idle, NA mode/off boost AFRs where they needed to be and get the DBW settings right. While doing that I logged almost 500 break-in miles on the new motor, so with that done, I was ready to start tearing int the project.
On this post, I’ll cover the Link G4+ ECU rewire and electrical integration with the OEM wiring. I’ve had professional engineering experience with military spec wiring on Army combat vehicles & electronics, but this is the first time I built my own ECU harness to motorsports/”mil-spec” design standards. It was a great learning experience, and the end result came out really well. I found a lot of useful tips and pointers about motorsports wiring practices from this website here: https://www.rbracing-rsr.com/wiring_ecu.html
I don’t have many pictures to share, but below are a few shots of the harness while it was under construction. Concentric twist wiring is more of an art than a science, especially when you have to deal with multiple wire gauges and twisted/shielded pair wiring running within the same harness. These pictures were a few of the many iterations, until I found what worked. Planning is key; ideally, you’ll want the longest wires of the bunch in the center core layer, then the next longest group that branches out in the next layer and so on. But you also need to take wire gauge into account too, and in order to make the concentric twist work (i.e., no gaps between conductors when twisted), sometimes you need to add “ballast” wires which serve no purpose as conductors other than to fill out the twist. What I ended up with had my 4x twisted/shielded pair cables in the center as the core, then the 1st layer of 20AWG wires, next layer of 20AWG wires wrapped in the opposite direction, then the last 2 layers were all the 18AWG wires. End result was worth it though, the harness is very flexible and designed to withstand lots of stress & vibration.
An early iteration Getting closer to end result, before the Raychem DR25 heat shrink. Re-pinned mil-spec connector reinstalled on the firewall
In addition to building out the main ECU harness, I had to integrate all the OEM wiring that rides on the removed OEM Emissions (EM) harness that still serve a purpose (e.g., speedo sensor, dash water temp gauge sensor, etc.). Fortunately, the PO didn’t hack up the OEM harnesses, so that job wasn’t too difficult, but I did have to reverse engineer the OEM cooling fan circuit, since those 4 fan relays were gone, and I wanted the fans to operate just like OEM (i.e., both fans run in parallel, 3 speeds available), with the exception that the Link is now controlling the fan on & off set points to my will. I no longer have the fan thermo switch, as it is no longer needed. Here’s a picture of the weather resistant relay box I got from Amazon, which contains 4x 40/60A Bosch 5-pin SPDT NC/NO relays that replace the OEM fan relays. I may end up relocating this box elsewhere, as it is currently taking up space that I may need for a cold air inlet duct to the air filter.
One of the advantages of DIY wiring is that I was able to create wiring schematics that rival the quality of the Mazda FSM – see the attached PDF, which is intended to be used as “change pages” for the FSM schematics (section Z). I created these schematics using a freeware electrical CAD program called TinyCAD, which was pretty easy to use for making schematics. So if you’re wiring a Link G4+ Fury, or the newer G4X Fury (which uses the same connector & pin assignments) into an USDM FD, feel free to use it – it will save you lots of time. I was really happy when I got the Link to successfully manage cruise control for me with the DBW throttle. Had to make a few wiring tweaks to the OEM cruise wiring at the cruise main switch connector (Q-02), and the Q-01 connector where the OEM cruise electronic brain used to reside to make the OEM switch gear compatible, but that was easy – see sheet #6 of the schematic.
As for parts & materials, all in I spent around $700 for all the wire, connectors, relays and miscellaneous supplies and tooling needed to complete the wiring project. I have a spreadsheet to track all that stuff, but I avoid looking at it. Some of the vendors I’ve used that I’d recommend:
ProwireUSA – https://www.prowireusa.com/ They were my go-to place for all of the 20 & 18 gauge M22759/32 Tefzel wire, M27500 twisted/shielded pair cable, all the Deutsch DTM & DP connector kits I used, and all the pins/sockets needed to re-pin my existing mil-spec bulkhead connector and the 2x AMP Superseal connectors used by the Link ECU.
CorsaTechnic – https://www.corsa-technic.com/ These guys had all the new Mazda OEM connectors I needed along with additional/spare terminals for them, such as the X14, X05, Sumitomo CAS connectors, etc.
CrimpZone – https://www.crimpzone.com/ These guys came in handy for the larger gauge (10, 12 & 14AWG) TXL wire that I needed for power distribution, fuel pump and fan wiring, and for the 4AWG battery cable I used to restore the Engine (E) harness that carries the starter +, ground and main power wiring
Tooling – I would have preferred to invest in a set of $300 crimpers with all the different dies, but these two pictured crimpers worked great on all the closed barrel size 20 mil-spec pins & sockets, and the Deutsch DTM (18 to 20 AWG) and DTP (12 to 14 AWG) pins/sockets, and were more than capable of getting the job done for me. They go for about $30~35 each on Amazon, brand is IWISS. The IWD-20 does the size 20 mil-spec and DTM crimps, the IWD-12 does the DTP terminals.
That PDF is incredible, Pete! I thought I did good making some half-*** notes in a binder .
Enjoying this thread!
Dale
Thanks! When I did the FC, my wiring documentation started out as a half-*** spreadsheet & notes, that I've since created a proper schematic for. Doing it from the start is much better - and I can get the PDF schematics printed on 11x17 paper at Staples, so I have fold-out diagrams to add to my paper FSM.
Still finding some weird issues in going from the native TinyCAD files (.dsn format), and printing them to .PDF files - some of the notes inexplicably disappear during the conversion. Easy enough to fix (make the notes boxes bigger in the TinyCAD program & print to PDF again), but you don't see the error until you print them.
On this post, I’ll cover heat exchangers – radiator, IC & oil coolers. As I mentioned in the 1st post, this FD came with a big Apexi FMIC, a Megan Racing radiator mounted in an almost upright position, and an OEM single oil cooler (this FD started life as a ’93 manual trans. Touring model). My challenge was to try to figure out how I can cram an OEM or aftermarket A/C condenser in there to restore my A/C, and still have enough space to reinstall the missing bumper reinforcement bar, air guide and plastic under tray pieces.
After sourcing those missing parts plus a used AC compressor, I was ready to start taking measurements and mocking things up see if I could fit a condenser in with the current radiator configuration. It quickly became obvious that there was nowhere to fit the A/C condenser in the current upright radiator configuration with the Apexi FMIC once the bumper rebar went back in, so my options were to spring for a full V-mount setup, or revert to an OEM radiator configuration (i.e., leaning forward) with a larger than stock SMIC. Another wrinkle was I wanted to be able to fit a normal sized battery back under the hood – because, well the battery relocation job I inherited from the PO looked like a car-B-Q waiting to happen.
My 1st attempt was to see if I could make the Megan racing radiator cooperate in the OEM configuration (i.e., leaning forward). Bottom line is the upper tank on the right side of this radiator interfered with the bumper rebar before it would fully drop down to where it needed to be sitting in a fabricated bracket. And since I didn’t want to hack up a perfectly good bumper rebar, I chucked that idea and decided to buy a Koyo N-flow radiator. I had to fabricate some simple aluminum brackets for the Koyo, as the OEM pieces were long gone, but that was easy. Here’s pictures of the Megan rad interference problem and the new Koyo install & brackets I fabricated for them. Installation was rather painless, and there was plenty of space for installing an AC condenser between the Koyo radiator face and the PS cooling line loop, just like OEM.
This shot shows where the Megan radiator interferes with the bumper rebar Close up of one the brackets I had to fabricate for the Koyo install Both brackets installed on Koyo Koyo as installed in the FD
Next up was oil cooling. Since this BW SXE turbo is only oil cooled, I thought additional oil cooling was a necessity, and decided to take the easy route for now – get all the parts from the OEM R1/R2 dual oil cooler setup on the used market. I scored a nice deal on almost everything I needed from Addicted Performance, so the only part I needed to buy new was the hose that goes from the front cover to the R1/R2 hard line assembly. As usual, I got that part from Ray Crowe. I didn’t have an oil temperature sensor installed before I did the dual cooler mod, to compare before & after oil temps, but now that I do (post re-wire), I’m seeing oil temps during the summer typically run below 190~195*F at the high end.
Last one up was the intercooler. After doing some mock up work with cardboard boxes, I decided to do a DIY replica of the M2 "medium" kit, which is about as much IC core as you can fit in a SMIC configuration and still keep a full-size battery up front. For the IC core, I found one that measures 18.25" W x 12" H x 3.25"D; core size is about 13"W x 12"H x 3.25"D. This is the old XSPower kit's core, that I was able to buy without the pipes from an Ebay retailer - the pipe kit that comes with the XSPower kit would have been useless with my single turbo & DBW setup anyway. For piping, I picked up some 180* and 135* mandrel bent 2.75” OD aluminum pipes, and started cutting sections out of those & mocking up the piping. End result didn’t require any complex pie cuts or too many welds – a plus since I had to contract out the AL pipe welding work. While I was in there, I also discovered a tiny coolant leak that was due to a crack in the cast AL thermostat housing, just above an NPT plug. So the same guy that welded the IC pipes repaired the crack in the T-stat housing casting. Some pictures of the process.
Mock up of IC piping with IC core That silver marker line on the T-stat housing was where the hairline crack was. My welder guy welded that over, so it's now leak free and sealed up tight
Now with all the heat exchangers in their final places, it was time to build some fresh air ducting for the IC. I didn’t have anything to start with, but I purchased a used Pettit SMIC duct from a forum member. This is the smaller of the Pettit IC ducts, so I knew it wouldn’t fully cover the entire core surface of my SMIC, but I figured I'd be able to use the "snout" portion of it to pull air in from the opening between radiator & bumper support, and graft that section onto a sheet metal fabricated section for the back side to cover the IC surface. The V1 IC duct was only a partial success – it was a good proof of concept, but the old rule of measure twice & cut once bit me in the butt. Fit was a bit off, and it still didn’t cover 100% of the core surface. Here’s some pictures of my V1 ducting failure:
This shot shows the Pettit duct installed as-is; obviously this won't work... And here's a test fit shot of the V1 duct I fabricated using the snout section from the Pettit duct. Not perfect, but decent proof of concept. On to Version 2...
Lesson learned; the V2 IC duct started life as a clean sheet of paper design done entirely in sheet aluminum. I posted a slightly more detailed thread for the V2 IC duct build here: https://www.rx7club.com/3rd-generati...-smic-1149118/
Here's some pictures of the new duct…
IC duct sheet metal fabrication complete... IC duct after painting with a truck bed liner coating. I wanted a coating that would be tough, look decent, and also provide a little bit of thermal insulation over the raw aluminum. Here's a shot with the IC duct installed. After a little bit of adjusting the IC piping and tightening everything, that gap you see on the top edge closes up, and the weather stripping added to the back of the IC duct frame compresses nicely. Skipping a few posts into the future, here's an engine bay shot after I finished the A/C plumbing and added that aluminum cover panel
Looking forward to getting back on the road again with the FD after the salt is off the roads and the weather warms up to see where my coolant, oil and IAT's look like in the logs!
Dang Pete!! Thats some sweet a$$ work.
#garageguybuild award to you 🍺🍺 .... No send it to a shop BS here...lol
Love the make it, do it on your own mentality. Can't wait to see more of the build!
Great job.. Hope to see it at DGRR this year!
Dang Pete!! Thats some sweet a$$ work.
#garageguybuild award to you 🍺🍺 .... No send it to a shop BS here...lol
Love the make it, do it on your own mentality. Can't wait to see more of the build!
Great job.. Hope to see it at DGRR this year!
Thanks Steve!
I don't think the FD will be ready for DGRR this year - I still need to do the exhaust before that trip because 650 miles each way with it as-is on the interstate and I'll be DEEEAF!
Also need to get it to a competent tuner/dyno to get the boosted portions of the tune done right. I'm confident enough with my own abilities to get the NA mode & low load/low boost parts of the map good enough for the road trip to & from DGRR, but don't want to risk blowing anything up if I push it a bit too hard while I'm down there.
On this post I’m going to cover the A/C restoration part of the project. When I got the car, all the A/C gear forward of the firewall was gone, but it still had a Denso evaporator core installed, and the HVAC wiring was unmolested and completely functional. Fortunately, the evaporator core ports were capped which kept it clean inside, but I decided it would be smart to remove the evaporator core so I could replace the expansion valve with a new one, flush the evaporator core with an A/C system solvent, and pressure test it on a bench to avoid any surprises later. Once it was out of the plastic core case, I verified that the core was the Denso type, with the block style expansion valve. The same OEM block style Denso expansion valves are readily available from a bunch of places, I got my new one from RockAuto for about $16.
Denso Evaporator core, expansion valve and pipe assembly - before cleaning. Close up of expansion valve
Since the foam seals on the evaporator core were mostly disintegrated, I removed what was left of them, and thoroughly cleaned the plastic case where they adhere to it. To replace the foam seals, I picked up some high & medium density rubber/foam weather stripping at a few different sizes from a local hardware store. This is the common stuff that has an adhesive strip on one edge. Did a little bit of trial-and-error test fitting to figure out which density & size foam worked best, and basically reapplied it to replicate the OEM sealing design. Best fit was the 3/4” wide by 7/16” thick rubber foam pictured to the lower right here.
The black rubber foam roll on the lower right worked best, so that's what I used.
With the evaporator core installed, next step was to get a compressor, and then figure out what to do for a condenser, dryer and all the remaining plumbing. The compressor was easy, scored a used Denso for $50, and sourced the 4x long M8x1.25 bolts from my local Fastenal shop, as I didn’t have that hardware. If you ever need rebuild parts for the compressor, it’s a Denso TV14C (more on that later…)
Used Denso compressor, getting ready for install Here's the Denso part #, TV14C
Initially, my approach was to try to hunt down used OEM parts for the condenser hoses & hard piping, but I had no joy finding a used condenser that didn’t look like it came from an FD that ran a demolition derby, so I decided to go with a generic parallel flow aftermarket unit and fabricated my own bracketry to install it. Picked up a nice 24” x 12” core unit off of Amazon for about $55; it had standard -6 and -8 male O-ring insert (MIO) A/C fittings, and was sealed & capped with a pressure charge of nitrogen in it, which was reassuring when I cracked open the caps and could hear the nitrogen escaping. Here's some pictures of the condenser install:
Overall condenser install view. Here's the left (driver's) side bracket - Note that I had to use "short drop" 90* fittings here to clear the frame rails. Here's the right (pass.) side brackets; had to grind away some of the mounting flange on this generic condenser to clear the PS cooling loop pipe.
I scored a set of compressor hoses, OEM dryer bracket, and the suction side of the hard piping from a local forum member, but when test fitting, I found that the hard pipe wouldn’t clear my turbo. Which meant that plumbing would need to be custom, but that also meant that I could find easier to replace aftermarket service parts like dryers, and place the service fittings right where I wanted them for easy serviceability. I decided to do all the plumbing with reduced barrier A/C hose and the corresponding crimped on bead lock fittings for the reduced barrier hose. FYI, reduced barrier A/C hose has the same inside diameter as “Standard” barrier A/C hose, but runs a smaller outside diameter – which makes them easier to route and fit in a tight engine bay. Same stuff all the OEMs use these days.
I had no luck finding a local shop to crimp these fittings on for me, so I invested in another tool. Picked up one of these, which does both standard & reduced barrier A/C bead lock fittings on Amazon:
For my fittings and hose, I got almost everything I needed from this shop: https://coldhose.com/ And for the one oddball metric fitting on the Denso evaporator core (smaller one), I found what I needed here: https://autoacfittings.com/. This shop also had the braze or weld-on MIO fittings I needed to rig up a way to connect to the compressor…
For the compressor hose fittings, what I did was salvage the “block” fittings from the OEM compressor hose assemblies. This website has a great how-to article on that whole process: Quality AC Hose Repair Products and Fittings from Compressor Tech The gist of it is you carefully cut off the crimp ferrule from the old hose, and remove the hose from the barb. Then you get your new ferrule & new hose, reassemble with correct orientation/clocking, and crimp on the new ferrule. At least that was Plan A, and how it was supposed to work in theory… But apparently the compressor hose Mazda used on the FD has slightly larger ID than your standard -8 and -10 reduced barrier A/C hoses I got, so no amount of lube, forcing or excessive cursing was going to get my new hoses on those damned compressor pipe barbs. Some pictures…
Here's the OEM suction side compressor hose & hard pipe assembly; hard pipe interferes with my turbo
Spare suction side compressor fitting (MANA?) that I used to practice - you split the ferrule with a Dremel tool as shown here. And here's the salvaged compressor pad fittings, ready for new hose & ferrules
So now it was on to Plan B: braze or weld on MIO fittings to the compressor pipes! I just brazed the aluminum fitting to the cleaned-up pipe end of each salvaged aluminum compressor hose fitting, here’s a picture of the end result. Both compressor fittings with MIO ends brazed on
This post continues in Part 2, apparently there's a picture limit...
Last edited by Pete_89T2; 03-13-21 at 11:28 PM.
Reason: fix typos
Now it was time to select a dryer, a binary switch and plumb it all together. I selected a generic dryer that fits in the OEM dryer bracket, and has a port for a binary hi/low pressure switch. Both the dryer and switch selected will work with R12, R134A and R152A (aka: computer duster gas), so I can charge the system with any of those. Here’s the dryer & binary switch kit I got: https://www.tbiproducts.com/index.cf...prod/prd63.htm
And here’s some pictures of the fully plumbed system…
Here's the Dryer & Binary Switch install. I added a 2nd high side service fitting on the input side of the dryer because a HVAC tech buddy said it's handy to have a 2nd fitting here for troubleshooting some A/C problems
Close up detail of the low & high side service fittings - easy access baby!
Detail of how I routed hoses around shock tower.Can't see it here, but the low & high sides connect to the evaporator core with 45* fittings
This shot shows how I routed the hose from the output side of the dryer and the suction side of the compressor along the IC support beam.
With that all done, it was time to pull a vacuum on the system and hope that it holds…. It didn’t. I found the first leak by partially charging the system with 1 can of duster gas (R152A), and hunting for it with my cheapo Harbor Freight electronic sniff tester. Quickly found the leak at my brazed-on MIO fitting on the compressor discharge pipe. Not too surprising, this was the 1st time I brazed aluminum. I yanked off the compressor discharge & suction fittings, un-brazed the MIO fittings, cleaned up the pipe ends, got a couple of new MIO fittings and brought them all to my local welder guy to get them welded instead.
With the welding done, I reconnected the lines and pulled a vacuum – it held, but not 100%. After about 3 hours, the vacuum dropped about 10 inHg (from about 29~30 inHg), which is a slow leak. Another partial charge with duster gas, and with the compressor running (and actually cooling the car’s interior), I found my slow leak at the compressor shaft seal with the electronic sniffer.
After consulting with the FSM, I think I’m going to try to rebuild the compressor, assuming I can find all the required replacement seals/parts needed. If that doesn’t work, I did find a new compressor here: https://ackits.net/product/14-3662nc/ so that’s Plan B.
This is a great build. Very similar to my build in many ways. My goal was the same as yours and I have also taken the time to review some of the parts. This is my type of build so I am excited and will stay tuned. Brap on brother.
Sometimes you get lucky and things really fall into place! Back to my 1st post, I mentioned how damned loud my FD was due to the custom fabricated exhaust the PO put in there, and I've been looking for either an RB cat-back or Tanabe Medallion cat-back to squelch the racket & drone. So I just pulled the trigger on the Tanabe - got it from Amazon for $398 shipped, sweet!
Unpacking the new Tanabe cat-back
Now since the PO told me that he didn't bother to design his cat-back & mid-pipe exhaust to be interchangeable with the stock parts, I was fully expecting to need to do some fabrication work to be able to install the new Tanabe. My plan was to get the Tanabe cat-back, and the RB 3" resonated mid-pipe, and then modify the custom DP to mate up with it. Today I decided to test fit the Tanabe, and was overjoyed to find out it dropped right in, fits perfectly and mates up with the PO's custom straight thru mid-pipe section! Some pictures...
Tanabe fits the OEM hangers perfectly WooHoo!!! It lines up and will bolt in! And bolts in & torqued up
So now I'm wondering just how "custom" my existing 3" DP & mid-pipe section really is? The Tanabe cat-back alone has taken a bit of the bark out of the exhaust's sound, but I think it's still too loud & drones too much on the highway - going to need a resonated mid-pipe to squelch it a bit more and finish the job. Based on the following pictures, do you guys think the RB pre-silencer/mid-pipe combo will bolt right in here? If not, it looks like there's plenty of room for me to get a generic 3" resonator? Thinking a Magnaflow, Borla, etc. if I have to go that route.
Here's a shot of the PO's mid-pipe where it mates with the DP.
Man I am very excited for you!!! Let me know how it sounds. I was thinking of going big single tip, but not sure how it will sound next to my RB dual tip.
Man I am very excited for you!!! Let me know how it sounds. I was thinking of going big single tip, but not sure how it will sound next to my RB dual tip.
Thanks, I should have thought to grab a "before & after" recording of the sound with my phone before I yanked the old cat-back off! It is definitely a LOT quieter than it was before, so I think the Tanabe would sound comparable to the dual tip RB system, if all things forward of the cat-back were the same. But mine still has that raspy drone, which I attribute to the PO's straight thru mid-pipe - I think if I splice a good resonator in there (i.e., largest can volume 3" in/out resonator I can fit), it will squelch all the annoying droning and high frequency raspy noises.
FWIW, RB makes a single tip version of their dual-tip cat-back, I've heard both types on similarly equipped FDs, and I couldn't hear a difference between the two.
Funny how long ago the big exhausts were sought after and now most of us want a quieter exhaust. I guess I really need to look into some other options because I wouldn't mind my RX-7 being a bit quieter.
Clip was taken maybe a minute or so after starting the car, and pulling it off the rack, so engine is still warming up at high idle, around 1300 RPMs or so. Also, this is with a basically straight 3" piping run from the single BW turbo to the cat back (no cat/no resonator/pre-silencer). It's still orders of magnitude quieter than the crappy Dynaflow muffler the PO had in there, but I think it would help to put a good resonator in the mid pipe section to filter out the high raspy notes when I get on the throttle, and the resonant droning sound you get at steady highway speeds over 70.
Due to the tight space available, to plumb this thing you'll need to to use "short drop" 90* fittings (as shown in my pictures), or fabricate hard lines instead.
Exhaust sounds good! Might be worth looking at a high-flow cat to reduce noise and stink as well.
Dale
Hey Dale,
I'm definitely going to put in a 3" resonated mid-pipe section, either the Racing Beat one or the similar resonated mid-pipe that Banzai racing sells for about $30 less. Either one should do a great job squelching the remaining raspy high notes I get when I stand on it at WOT, and the annoying highway drone resonance tones at cruise - both mid-pipes feature large volume, oval resonators, with all SS construction & mandrel bends.
Putting a cat back in would probably fall into the "too hard to do" category, since I'd think an air pump would be needed to get any kind of reasonable durability out of a cat. With the big BW single turbo, there's no room for an air pump, unless I rig up an electric air pump somehow. As for the stink, it's not too bad - once warm, it's happy idling just a bit richer than stoich, about 0.95~0.975 lambda, and no visible smoke now that I'm getting the OMP pre-mix delivery map dialed in correctly. In fact most of the stink there seems to be more a function of what brand pre-mix I'm using, and how much it's burning. Maybe the expensive Idmitsu pre-mix will smell better?
I've been running an SMB high-flow cat from Australia for at least 10 years now - big time reduction in stink and noise, flows awesome, and zero problems with no air pump. A good quality high-flow cat won't need the air. If you are looking to pass emissions you would need the air to help out - it helps the process burn more effectively.
Also, FYI, the electric air pumps like the RX-8's aren't designed to run full time. The RX-8 air pump only runs for 15-20 seconds on stone cold morning starts, that's it. Source: dailying an RX-8 right now. If you tried to run it full time it would die a quick death, it's only designed for intermittent use.
For some reason a number of years back something flipped in the smell part of the brain and no-cat exhaust stink drives me NUTS, it sticks in my nose forever too.
02-16-21, 07:15 PM
Some of the vendors I’ve used that I’d recommend:
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