LFX Engine Swap (GM V6) at GWR

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Re: LFX Engine Swap (GM V6) at GWR

Postby Ryan @ GWR » Wed Jan 11, 2017 1:11 pm

Just before the holidays hit I was deep in connecting hoses and wiring for the final time. Bit of a mess while sorting through what still needs to be figured out, needs to be tweaked, etc. but here's a quick snapshot of about where we are at the moment:


And, decided to spring for some trick fittings to go hand in hand with the quickly removable front end design, still waiting on parts to arrive but for now here's a teaser of the dry break fittings that will be going on the power steering lines:

Ryan @ GWR
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Re: LFX Engine Swap (GM V6) at GWR

Postby Ryan @ GWR » Mon Jan 16, 2017 11:31 pm

Doing some napkin math for other fun places the car may fit in.

Looking at NASA, when you move above the complicated mess of the lettered classes on up to ST/TT 1, 2, 3 things get much simpler. With a good bit of power taking the tighter-regulated TT4 out of the question it gets even simpler. Basically take a dyno and weight baseline which then applies modifiers for certain mods and you end up with an adjusted power/weight ratio and that's that. Everyone racing in the class has the same adjusted ratio. Obviously this favors a wide torque curve, and this motor should be great for that.

TT2 cars have an adjusted wt/hp of 8.00:1 or more (up to 10.00:1 which is TT3)
2300 lbs with driver / 300 whp = 7.67:1
Relevant adjustments:
Comp weight over 2200, less than 2599 = -0.2
Tire size 245 or smaller (DOT approved) = +0.7 or Tire size 275 or smaller (DOT approved) = +0.3
Non-production vehicle = -0.4

A note on the non-production vehicle bit.. have to take that due to the tubular front subframe, but this comes with some benefits. First, I don't have to take the -0.2 for cutting the rocker for exhaust routing for production vehicles, so it's really only -0.2 more than if it was considered a production car. But more importantly, with it considered a non-production car there's no concern about the tubular/removable front nose being OK.

So, with adjustments, 7.77:1 with 245 tires or 7.37:1 with 275's

Ballasting up to 2375 lbs with 245 hoosiers puts me at an est. adjusted 8.01:1, right at the pointy end of TT2.

TT2 is full of Corvettes and Vipers... always love a challenge! :twisted:
Ryan @ GWR
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Re: LFX Engine Swap (GM V6) at GWR

Postby Ryan @ GWR » Tue Jan 17, 2017 3:19 pm

Continuing to wait on a few more parts to arrive, so I took some time to get some of the suspension bits assembled.

Pressed out all of the old polyurethane bushings and now installing for evaluation a spherical bearing kit for the factory control arms from a shop up in Canada.


Spherical bearings within the press-in sleeves:


I've run into a couple snags with some of the parts in the kit, shot some feedback to them to get those bits resolved instead of having to machine my own solutions, and hopefully we'll get things sorted out. Nevertheless, the majority of the kit is installed and ready to rock.

Also going into the arms are Bauer extended lower ball joints and V8Roadsters rebuildable front upper ball joints:


Finally, I'm replacing the rear upper arms with V8R's tubular Pro series arms. Feedback from Steve about what they've seen on other cars, the rear upper arms are the ones responsible for wheel hop and other funkiness when putting big power down as that factory arm twists with enough torque. The tubular arm solves this, and the pro series has spherical bearings to match the rest of my arms.

Oh, and in my recent powdercoating frenzy I had all the factory arms done.

Ryan @ GWR
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Re: LFX Engine Swap (GM V6) at GWR

Postby Ryan @ GWR » Wed Feb 01, 2017 10:28 pm

While waiting on the last fittings to arrive, this past week I've been working on wiring plans in the evenings.

Because race car I'm pulling the entire Miata harness on the chassis side as well and will make a new harness for just the essentials. For the record, if this was a street car with many more factory systems I would keep the factory harness and just add things as needed. But since that's not the case, there's some planning to be done here if I want to wire everything up in one nice clean harness.

The engine harness itself has already been set up nicely for my needs by V8R. They trimmed out anything unnecessary, converted it from auto to manual, added an OBDII port for me and extended a few wires at my request. They also fused anything that needed it and added a main relay. All that's left for me to do on that side is carry a few voltage wires from the cabin/battery over to the engine side.

But, that doesn't get me out of the woods. I still need to sort out a chassis harness which includes several systems like fuel, ignition, etc. as well as the Racepak dash plus the sensor module for the dash. I also need a cooling fan circuit, and I need to get the OBDII port and the drive-by-wire connector into the cabin. To make things easy to service/remove, almost everything will pass through a single bulkhead connector in the firewall.

One unknown I ran into during planning was the question of how much info the digital dash can pull directly from the ECU via the OBDII port. Anything the dash can get straight from the ECU saves me time and wires. The guys at Racepak couldn't make any guarantees, they said you really just have to plug the dash into the car, start it up and see what data it can pull. Well that's great except I can't start my car yet - I need the wiring done before I can start it... but if I want to do the wiring all at once and not have to hack it up and add stuff later I need to know this answer before I do the wiring. Gotta love catch-22's.

Sean had a great idea for a solution - rent a V6 Camaro and wire the dash up to it.


Turns out it can pull quite a bit of info. I don't need most of it, but here's the full list of what the dash is getting from the OBDII port - noteworthy items that I'll probably be displaying on the dash in bold:

Fuel system status
Engine RPM
Vehicle speed
Calculated engine load value
Short term fuel % trim - Bank 1
Short term fuel % trim - Bank 2
Long term fuel % trim - Bank 1
Long term fuel % trim - Bank 2
Intake air temperature
Intake manifold absolute pressure
Timing advance
Engine coolant temperature
MAF air flow rate
Oxygen sensor Bank 1, Sensor 1
Oxygen sensor Bank 1, Sensor 2
Oxygen sensor Bank 2, Sensor 1
Oxygen sensor Bank 2, Sensor 2
Run time since engine start
Distance traveled with malfunction indicator lamp (MIL) on
Fuel pressure
Fuel rail pressure (diesel)
Fuel level input
Fuel type
Commanded evaporative purge
# of warm-ups since codes cleared
Distance traveled since codes cleared
Evap. system vapor pressure
Barometric pressure
Ambient air temperature
Control module voltage
Absolute load value
Command equivalence ratio
Throttle position
Relative throttle position
Absolute throttle position B
Absolute throttle position D
Absolute throttle position E
Command throttle actuator

In addition to the above bolded items, I'm adding temperature sensors for engine oil, transmission, differential and power steering fluid. These four will tie into a Racepak universal sensor module which transfers the data from those sensors to the dash via one cable. Between the stuff above and these four added sensors the dash should be able to keep an eye on everything important. I can set up warnings on the dash for any of these inputs, so I can focus on driving rather than worrying about checking gauges.

I'm disappointed that oil pressure isn't on that list. The ECU monitors this, but it appears it doesn't send that info to the OBDII port. I'll need to wire up a second OP sensor or figure out if I can piggy-back on the factory sensor's wires. Not sure yet on that front, but overall some good info gained and I can finish up my wiring plans now.
Ryan @ GWR
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Re: LFX Engine Swap (GM V6) at GWR

Postby Ryan @ GWR » Sat Feb 04, 2017 11:27 pm

With the last of the fittings arriving yesterday, today I completed everything that carries fluids in the front end. Now that I've finished that up and know for certain how it's all going together I can finally cover each system in its own post.

Power Steering

We begin with V8R's power steering kit. Included are fittings/lines to replace the hard lines that run along the rack itself with steel braided lines as well as fittings and a high pressure braided line for pump to rack. The kit leaves it to the user to sort out the low pressures lines (usually rubber) and reservoir (I've heard the factory Miata unit can be used), so that blue 180° hose barb fitting is supplied for the exit from the rack.


I used everything above except the hose barb fitting because this car will use braided lines throughout.

Removed the old lines from the rack and spent a good deal of time cleaning the rack up. The power rack I got from a donor car seemed to have been competing for the coveted title of thickest layer of grime, but it’s shiny now.


Here’s the rack with the V8R lines added. Also pictured is the early version of the rack to cooler line I made which I later added the in-line dry break to:


Closeup shot. This bunch sit close to the pan once installed so best to leave them loose and adjust the angles once both the engine and rack are in place:


Pic of the power steering pump. The black threaded outlet goes to the rack which V8R supplies a fitting for (that’s what I’m holding in the photo). The port above that is the inlet from the reservoir. That port has a barbed end for a rubber hose in the stock GM form, but as seen in this pic I removed that and drilled/tapped the hole to adapt it to an AN fitting:


A note on the power steering pump pulley -
To remove the pump from the engine you must remove the pulley from the pump first. This took us a combination of parts from a rather comprehensive pulley puller kit, something most home garages may not be equipped with. Reinstallation of the pulley is equally difficult. I’d recommend leaving the pump on the engine unless you absolutely have to remove it. However, there is a complication if you’re going to add an engine oil cooler; to remove the factory oil filter housing you have to remove the steering pump first because the filter housing’s bolts are too long and can’t be backed all the way out with the pump in place. For shame, GM! Later, when I installed the Keisler oil reroute plate in place of the stock filter housing I swapped two of the factory bolts out for shorter ones and now the plate can be installed/removed with the steering pump in place. At any rate, if you need to remove the filter housing you’ll have to take the pump off at least once.

Now back to our regularly scheduled programming…
The next piece to the puzzle was the steering fluid reservoir. The reservoir needs to sit higher than the pump as it is a gravity feed. The pump’s position on the motor is high enough that there was a good bit of head scratching and lots of looking around at various reservoir options/shapes/etc. to figure out what to do. The solution I came up with uses a Moroso reservoir mounted directly to the top of the pump NASCAR style. This eliminated the need for a hose and guarantees good flow from the reservoir to pump. This reservoir is actually intended for power steering so it has the appropriate internal baffles.

I don’t have a pic of the reservoir by itself but you’ll see it in following pics. The reservoir had an AN bung in the bottom for the drain so with a couple fittings the pump was set up for the direct-mount:


To hold the reservoir in place requires a bracket :) Always up for challenging myself, I decided to make it from aluminum. Here is an in-progress pic about 80% of the way done, just before tack welding the two halves I made together:


It turned out to be a funky looking little thing but it’s nice and light, piggy backs on existing factory bolts, and does just what’s needed:


Here it’s mounted up with the reservoir. Note the factory oil filter housing is still in place behind there, but that is removed later for the oil cooler:


The final piece in the power steering system is the cooler. Most cars doing any sort of performance driving will need one, you don’t want this system overheating and spraying flammable fluid around the engine bay. If you’re doing a more standard street setup with rubber lines there are lots of affordable cooler options with barbed ends built in. For this car I chose Earl’s 40700 cooler, which is a 13”x2”x2” unit, with -6AN ends. I erred on the small side to keep weight down but Earl’s stuff has efficient cores so I think it will do the trick. I’ll be monitoring fluid temp so I’ll know if it is sized well or needs to be upgraded:


Back when I was making the removable nose I made the brackets to hold the cooler in place. With the cooler, pump and reservoir all settled in all that’s left is to connect the dots with the lines. Embracing the idea of having the whole front nose section quickly removable, I picked up a pair of Radium -6AN dry break fittings for the power steering lines:


Long line below is cooler to reservoir, with the dry break junction fixed to the reservoir side. The short one is half of the rack to cooler line:


Here’s the other half of that lower line, I had already fixed it to the rack and didn’t want to remove it for the last pic. This section has a fire sleeve since it's in the vicinity of the exhaust:


Final setup installed:


That concludes the power steering setup. Tomorrow I'll write up the oil cooler system.
Ryan @ GWR
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Joined: Fri Oct 17, 2014 11:37 pm

Re: LFX Engine Swap (GM V6) at GWR

Postby Ryan @ GWR » Mon Feb 06, 2017 9:17 am

Oil Cooling

First the hurdle. The factory oil filter setup is a cast aluminum housing that bolts to the left side of the block and extends up to hold the filter canister up near the fill cap. You can see the housing just forwards of the dipstick:

LFX stock pic 1_zps9fzxlafe.JPG
LFX stock pic 1_zps9fzxlafe.JPG (73.27 KiB)

To run an oil cooler we need an inlet and outlet for the lines, but a traditional sandwich plate won’t work here because of the unique shape of the ports where the block and housing meet:


Conveniently, Keisler Automation has been working on a solution. Here is their oil reroute plate:


This plate has a pair of M16x1.5 ports to which I added the metric to -10AN adapters. It also has an ⅛ NPT port for a sensor, but I found its location to be too cramped beside the larger fittings (and the GM oil pressure sensor is M14x1.5 anyways) so after this pic was taken I plugged that port and put the sensor in the remote filter plate:


As I mentioned in the power steering post, the factory oil filter housing can’t be removed without taking the steering pump off because the factory bolts are too long. There’s no getting around this the first time, but when installing the Keisler plate I switched the two forward bolts to shorter ones - this makes it possible to remove/install the plate with the steering pump in place. I forgot to write it down but I believe I used M8x1.25x25mm:


With the in/out for the hoses sorted all that’s left is a remote filter and a cooler. For the remote filter adapter it was important to me for it to be mounted to the engine so that removing the engine requires as little disassembly as possible. I played with a few locations and came up with doubling up the filter adapter on the same bracket that holds the power steering reservoir. Here’s the filter adapter mounted up to that bracket (now powdercoated black) with the steering reservoir not yet mounted:


Here it is with the steering reservoir in place. The filter location ended up mimicking the factory location a bit. Oil changes will be a breeze:


Now for lines and the cooler. For the cooler I chose another Earl’s unit - same depth and length as the power steering unit but taller; 19 rows instead of 7.

Just as I did with the power steering system, in order to make the entire nose assembly quickly removable I chose to add dry breaks here. Staubli -10AN units for the oil lines:


Here’s the full system just before final install. I fit the dry breaks directly to the cooler so that the feed and return lines remained one line each rather than being split into two. Fire sleeves on the portion of the lines that are anywhere near the exhaust. The short line is oil plate outlet to remote filter inlet and the long lines of course go to the cooler:



Ryan @ GWR
Posts: 290
Joined: Fri Oct 17, 2014 11:37 pm

Re: LFX Engine Swap (GM V6) at GWR

Postby Ryan @ GWR » Tue Feb 07, 2017 8:02 pm

There's still a bunch of assembly to be done before it's driving (rear end, suspension, interior, etc.) but we're close to first test start. All that's left is wiring... not a small thing but I can feel it getting close!

Current view from the front:

Ryan @ GWR
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Joined: Fri Oct 17, 2014 11:37 pm

Re: LFX Engine Swap (GM V6) at GWR

Postby Ryan @ GWR » Fri Mar 10, 2017 11:16 am

Apologies for it being quiet for a little while, I've been spending long hours building the wiring harness. I wanted to be rid of the hacked up factory wiring mess once and for all so I chose to take the long road and removed every wire from the car, because now was the right opportunity to take the extra time and learn how to build good motorsports wiring from the ground up.

For now, here's a pic from way back on step 1 with wires laid out for the new chassis harness:

Ryan @ GWR
Posts: 290
Joined: Fri Oct 17, 2014 11:37 pm

Re: LFX Engine Swap (GM V6) at GWR

Postby Chuck H » Wed Mar 15, 2017 10:35 am

Absolutely loving following this build. Your car is going to be amazing when it's done! 8)

Just one question. At what point does it cross the line from "swapping an LFX into a Miata" to "building a whole new car around an LFX"? :wink:

Can't wait to see the final product and the track results!
2012 Copper Red Touring
Progress springs and sways
Chuck H
Posts: 127
Joined: Fri May 18, 2012 6:28 am

Re: LFX Engine Swap (GM V6) at GWR

Postby Ryan @ GWR » Thu Mar 16, 2017 10:54 am

Chuck H wrote:Absolutely loving following this build. Your car is going to be amazing when it's done! 8)

Just one question. At what point does it cross the line from "swapping an LFX into a Miata" to "building a whole new car around an LFX"? :wink:

Can't wait to see the final product and the track results!

Haha that's a fair point. I certainly went into it not having plans to do some of the things I later chose to do. Perhaps I'm somewhere in the wide and expansive gray area between the two? :lol:
Ryan @ GWR
Posts: 290
Joined: Fri Oct 17, 2014 11:37 pm

Re: LFX Engine Swap (GM V6) at GWR

Postby DavidM938 » Sun Mar 19, 2017 6:51 am

Hi Ryan, are you sure you haven't been collaborating with Nik Blackhurst for the last year(s)? Let's review:take a late model big-engine complete driveline out of a donor car, stuff in into an older, smaller, lighter car that it won't really fit in, hack the poor little car to pieces, then completely rebuild every component in the most fiendishly complex way possible. Also, keep the drama going for months and months, and have the viewers (who are all a bit looney to be watching in the first place) waiting for the next episode just to see if the bloody thing will actually ever run! Do I have that about right? Anyhoo, keep up the craziness, but that thing better be stupid fast to make up for all that work! David in Nashville
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Re: LFX Engine Swap (GM V6) at GWR

Postby Ryan @ GWR » Mon Mar 20, 2017 4:23 pm

DavidM938 wrote:Hi Ryan, are you sure you haven't been collaborating with Nik Blackhurst for the last year(s)? Let's review:take a late model big-engine complete driveline out of a donor car, stuff in into an older, smaller, lighter car that it won't really fit in, hack the poor little car to pieces, then completely rebuild every component in the most fiendishly complex way possible. Also, keep the drama going for months and months, and have the viewers (who are all a bit looney to be watching in the first place) waiting for the next episode just to see if the bloody thing will actually ever run! Do I have that about right? Anyhoo, keep up the craziness, but that thing better be stupid fast to make up for all that work! David in Nashville

Hah, I can't deny taking the long road most times, but I feel the result is worth the work. It had better be fast in the end, ultimately that's the whole point! Not long now, almost finished with wiring (que the mad scientist laugh).

And on that note, on to...


For the engine swap, the minimum wiring to get the thing fired up isn't bad, particularly if you opt to have V8R prep the engine harness for you (I did). You could certainly retain most of the factory wiring on the chassis side and just tie in where needed. However... I had a few things on the wish list for this car that meant there was more work to do.

Over the years of racing and modifying this car, the wiring has become a bit of a mess with things added, wiring cut to remove things, etc. etc. To eliminate any potential for issues for the future, I decided the best approach was to remove all of the existing wiring on the chassis side from the car and start from scratch with good materials, practices, and documentation. This is also the most time consuming approach, but c'est la vie.

Step 1 through 10 of a big wiring project is all planning, long before any tools or wires come out. As soon as you go down this path, if there's an issue in the future you can't just open up a factory service manual to check the wiring diagram. The ease or difficulty of service/troubleshooting in the future now comes down entirely to the quality of the documentation you create.

I began with drawing up an electrical diagram for my new chassis wiring:

Hyper_Electrical - Circuits - Chassis and Tail.jpg

Working off the electrical diagram, I made a spreadsheet listing each individual wire that would be present in the harness - including the wire's name/purpose and where each end terminates. Each wire is assigned a unique numerical ID. If you've ever tried to identify a certain wire in a harness you'll know the struggle that can be - even with the multitude of wire colors that factories use you still end up with duplicates of certain colors and you end up having to break out the multimeter to test wires and sort out what's what. By assigning each wire a unique ID and labeling the wire accordingly (more on that later) there is no guesswork left to do, just consult the master sheet and look up the wire number.

Here's a screenshot of the top of the list. All in, there's about 100 wires on the chassis side:

Hyper Electrical - wire list screenshot.jpg

A great feature with having this in spreadsheet form means that if you stay consistent with the info you put in each cell then once the list is done you can sort the list alphabetically by whichever column you need. This was really handy during the build as I could easily switch between sorting by harness, numerical order, system, etc.

The remaining piece to the puzzle is knowing how to lay out the harness. The simplest method is to just start laying wires in the car from point A to B to get lengths, but I wanted to be able to build the harness out of the car and also have the plans so that everything is replicable in the future if necessary.

I took measurements on the car and then drew up the build plans:

Hyper_Electrical - Build Plans - Chassis and Tail.jpg

Much of the above is a bit overkill. The key info there is the lengths between splits and the layout. The rest isn't necessary but I like to be thorough - with this plus the connector diagrams that I show just a bit further down, I could build a matching replacement harness without any need to refer to the car or the original harness.

With the planning sorted it was time to start laying out the harness. Transferred the measurements to a 4'x8' sheet of particle board with screws placed at each branch split for turning points.

ND harness build 1.jpg

Referring back to the wire list above, each wire gets labeled with cats ID number on both ends. Here is where the thermal label printer got a workout:

ND harness build 2.jpg

ND harness build 3.jpg

All of the wires used are milspec (shorthand for Military Specification) /32 series with tin plating and very abrasion/temperature resistant insulation. This stuff is a big jump forward from standard cross-link OE wire in terms of durability and is also more conductive and lighter weight. It sounds obvious but the wire is the core of the car's electonics and nothing else can make up for poor quality wire. IMO this isn't the place to scrimp.

With wires laid out and labels we begin to loom the harness. The black woven material is resin infused fiberglass braid that holds up to 1200 degrees. That gets finished at each end with short lengths of adhesive tube to prevent fraying and seal the wires where the harness splits. You can see that assembling the loom requires some forward-thinking because each section often needs several more various pieces sleeved over it that will be shrunk down later:

ND harness build 4.jpg

Also in the pic above is the bulkhead connector already assembled. That connector contains each wire that will pass from through the firewall into the engine bay, which makes it very quick and easy to disconnect the engine side of the wiring from the car so the engine can be pulled quickly without having to disconnect the wiring harness from the engine.

As I build the harness, I fill out a pin layout sheet for each connector in the harness. When I began the harness build this sheet had blank spaces next to each pin, and I filled the sheet out as I assembled connectors:

Hyper_Electrical - Connectors - All.jpg

And a few progress shots of the harness in various stages of the build...

This is the main break point where wires split off towards the center console switch area and the fuse/relay assembly:

ND harness build 5.jpg

Finishing the wire terminations:

ND harness build 6.jpg

Same set of wires complete with connectors:

ND harness build 7.jpg

Similarly finished ends that go to the fuse/relay box:

ND harness build 8.jpg

Close-up of the connector that goes to the new digital dash. Re-pinned with the milspec wire, labeled, etc.

ND harness build 9.jpg

Wiring up the fuse/relay box:

ND harness build 10.jpg

Backside of the finished fuse/relay box, tidied up with service/strain relief loops on each wire:

ND harness build 11.jpg

The finished fuse/relay box and harness:

ND harness build 12.jpg

Finished main chassis harness (connectors to Racepack dash, OE brake pedal , GM gas pedal, fuses/relays, OBDII, all switches, tail harness, diff temp sensor harness):

ND harness build 13.jpg

About to get installed in the car! Also pictured are some of the secondary harnesses, switch assemblies, etc.

ND harness build 14.jpg
Ryan @ GWR
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Joined: Fri Oct 17, 2014 11:37 pm

Re: LFX Engine Swap (GM V6) at GWR

Postby Chuck H » Mon Mar 20, 2017 7:07 pm

That's some amazing work. Looks like the stuff we build at work (major defense contractor), except that I think your drawings and spreadsheets are even better! :D
2012 Copper Red Touring
Progress springs and sways
Chuck H
Posts: 127
Joined: Fri May 18, 2012 6:28 am

Re: LFX Engine Swap (GM V6) at GWR

Postby Ryan @ GWR » Mon Mar 27, 2017 11:17 pm

Got the USM (Universal Sensor Module) sorted. The USM is a four channel add-on to the Racepack digital dash allowing the addition of any sensors you want. Black box in the pic below:


The USM is why I finally took the plunge on a digital display. The original plan had been to add at least two more Accutech SMI gauges to the two I already had in the car so I could keep track of temperatures of all the various important bits. I realized I was heading down a path to having a very busy interior with a lot of things to try to keep an eye on.

The digital dash simplifies everything into one place where I can program warnings for each input and leave the dash to monitor things while I just drive. The dash pulls most of the engine vitals info I need right through the OBDII but the USM makes it possible to add the extra sensors I wanted and simplifies the wiring by transferring everything to the display via one V-net cable.

The sensors are already installed in their various locations, documented earlier in this thread. Now, on to wiring up the sensors to the USM. Here I’m using milspec /32 wire same as previously, but this time in 22ga twisted pairs. The twisting is a method of shielding the signal from interference. Frankly, you don't need it for these types of sensor’s signals but here I used it because it helps keep things tidy:


Wiring within the USM box. The USM has a strain relief feature on the inlets which is a nice touch; tighten the outer nut and it clamps down on the wire to secure it in place:


The finished USM harness:


Mounting the box was done on the top/rear of the engine via a pair of simple brackets. Yes it’s tight back there. This is mounted to the engine so that all the sensor wiring can stay with the motor when it’s removed, just disconnect the single V-net cable connector:


With the box mounted we just need to run the V-net cable to the display. This could be done with one long cable that would need to pass through the firewall, or a bit cleaner version here that involves two shorter cables and a bulkhead connector:


Tidy :D


The remaining wiring to be done was to tie in where necessary on the GM wiring harness. Most of this was coming through the firewall from the chassis harness - things like ignition switch, start button, lights, fan, drive by wire throttle, OBDII, etc.

I blasted through this and forgot to take all but one picture - V8R advised that the throttle pedal signal is very sensitive to interference, so for this I ran a 6-wire shielded cable on both the chassis and engine side:


The rest was just patching stuff into the existing engine harness. The stuff I added is all on par with what I did on the chassis side, but I’d love to re-do the entire engine harness in the future so that it is all up to higher standards. However, for now it’s a good working harness and this thing needs to be running!

All of the wiring interface from chassis to engine converges in the rear right corner of the engine bay. Everything is set up to disconnect from the chassis quickly/simply and comes out intact with the engine. There’s only four total things to disconnect, all located here: main bulkhead connector, v-net connector, engine ground and one M6 bolt that holds the fuse/relay plate to the firewall. Not trying to hide wires or tuck anything away, the goal here is easily accessible and quickly removable:

Ryan @ GWR
Posts: 290
Joined: Fri Oct 17, 2014 11:37 pm

Re: LFX Engine Swap (GM V6) at GWR

Postby Ryan @ GWR » Wed Mar 29, 2017 11:41 pm

Taking a detour for a bit, our tech day at the shop is coming up this Saturday and a couple days ago I realized that April 1 will be the one year mark to the day from when the car rolled in to the shop and the old engine came out. Decided the car should be on the ground and on display out front on that day!

So, the next couple days will be a bit of jumping around with random updates as I prioritize just the things needed to get the car on the ground.

Front Suspension

Clearly we were in need of some suspension to set the car on! Installed the following:
Feal 442 coilovers (4.75" of stroke :) )
Control arms with spherical bearings
Spindles with fresh hubs
R package tie rod ends
V8R upper rebuildable ball joints
Bauer extended lower ball joints


- haven't sorted out the front sway bar yet but don't need that for Saturday.
- V8R front upper ball joints are tight until they lap in (takes a couple hundred miles). Correct assembly is to torque top cap down then back it off one "notch" of the lock ring and then install the lock ring. Reset the lash after first track day or 200 miles.

Setting the shock length/bump travel in the front (done with spring removed from the shock assembly):



Installed the driveshaft with rear subframe and differential. Has to be done together as the Getrag has a long shaft on the flange to the driveshaft that the driveshaft slides over, so you lower the diff about 12 inches, install the driveshaft and then raise the diff with the driveshaft attached.

The CV joint on the driveshaft gave us some trouble, the CV wants to spring apart and has to be held together while installed. During first install something came unseated inside and the bearings locked up. Quickly evident as the drivetrain wouldn't rotate because the CV was locked at one angle. Had to disassemble/reassemble the CV (and order the proper CV grease) and then reinstall. Everything is in and happy now. Forgot to take a pic.


V8R Stage 2 axles - first off, examining these in person they are very nice pieces.
Comes marked as one long and one short. Long one goes on the right side. The CV joints in these are packed with grease and the grease can keep the CVs from compressing fully so at first it appeared the axles were too long. Pulled them out and worked the joints around while putting body weight on them and they shortened up a lot and then installed fine.

Current state of affairs in the rear:


So, axles, hubs and spindles are in along with the V8R upper pro series control arms. What's NOT in are my lower control arms complete with spherical bearings. The placeholders right now are factory arms with rubber bushings that were laying around.

This spherical bearing kit had some dimensional issues in some of the rear pieces. Unfortunately the company who makes the bearing kit has been working at a snail's pace to make the necessary changes. As this kit is here for evaluation, this makes it hard to recommend it, but hopefully that stuff will get sorted out soon. As a last resort I can have the existing pieces machined to work right myself, but they assure me they're working on corrected pieces. We'll see, but for the moment these loaner rear lower arms will get the car on the ground.

Ran into one more hurdle in the rear. The beefy axles are larger in just about every dimension than stock Miata axles. Where the axles passes by the coilover, it's very tight. There's juuuuust enough clearance from the CV boot to the lower cup on the rear coilover, so that is OK but the lower lock ring on the coilover has a larger OD than the cup below it and that ring hits the boot:


Can't have these two bits contacting with the axle spinning of course. I believe I have a solution figured out, Feal is sending over some parts that I think I can modify to make a custom low-profile lock ring out of. That stuff arrives Friday.


Final thing tonight was getting fluid in the trans and diff since we'll be rolling the car around.

Trans is 75W90
Diff is 75W90 + 4oz Limited Slip Additive. Sounds like snake oil to me ;) but OK we'll follow the spec.
Ryan @ GWR
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Joined: Fri Oct 17, 2014 11:37 pm


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