LFX Engine Swap (GM V6) at GWR

Miata Parts, Intakes, Superchargers, Headers, Exhausts, Shocks, Springs, Sway Bars, Brake Kits, Autocross and track mods.
Ryan @ GWR
Posts: 497
Joined: Fri Oct 17, 2014 11:37 pm

Re: LFX Engine Swap (GM V6) at GWR

Post by Ryan @ GWR »

Alternator on the LFX had a bit of a clearance issue - the stud on the back contacts the V8R subframe. This specific motor/alternator was a 2012. I've heard from others with 2013 donors that the stud layout was a bit different so not everyone will run into this.

Solution we came up with was to clock the alternator. Four M4 bolts holding the front and rear together (remember to mark the studs position before clocking), then remove the plastic cover on the rear and finally remove the small plastic cover over the brushes in the center on the back:
alternator 1.jpg
Pull the two halves apart, rotate the assembly 180° and drop them back together. You have to push the brushes in for the center shaft to slide all the way back in.

With the alternator clocked, the stud is nice and far away from the subframe:
alternator 2.jpg
Ryan @ GWR
Posts: 497
Joined: Fri Oct 17, 2014 11:37 pm

Re: LFX Engine Swap (GM V6) at GWR

Post by Ryan @ GWR »

The finished subframe is back from powdercoating and looking good in 60% gloss black:
Getrag_Subframe_powdercoated.JPG
Diff gets installed once again and now the assembly is ready to go in the car:
Getrag_Subframe_Mounted.JPG
Before we can install this though, we'll need to get the fuel lines installed with the tank and the tank back in the car.
Ryan @ GWR
Posts: 497
Joined: Fri Oct 17, 2014 11:37 pm

Re: LFX Engine Swap (GM V6) at GWR

Post by Ryan @ GWR »

Fuel Lines

V8Roadsters supplies a very nice fuel line kit for the LFX. Very similar to their kits for V8 cars, it includes a Corvette filter, EFI fittings throughout, and assembled braided lines to replace all the factory lines in the car:
FuelKit (2).JPG
Dropped the fuel tank and took a look at things. The EFI fittings are very cool but they only work with the later-year fuel hard lines. Not a problem at the engine side because the LFX has the correct lines, but at the tank things need to be switched around since mine is an NA, so I need to swap to NB bits there.

We had a junker NB sitting beside the shop, so I pulled the fuel pump assembly out of that. With a little mix-and-matching of parts and swapping over my Walbro 255lph pump to the NB fixture it's good to go:
FuelKit.JPG
Using the NB's fuel pump fixture, the EFI fittings fit the hard lines perfectly:
FuelKit (5).JPG
Lines attached, the tank is ready to go back in.. this pic is after lots of scrubbing of the fuel tank to get it clean:
FuelKit (4).JPG
With the tank reinstalled, all that's left is to mount the filter and lines. Made a small bracket to hold the filter in place (don't have a pic of it), and the lines are routed along the inside of the frame rail. V8R says that they typically run the lines down the driver's side, but I found that running them down the passenger side I was able to shorten the line length by 12" (the easy route is to leave the line as-is and run down the driver's side):
FuelKit (3).JPG
Close-up of the attachments for the fuel line - these adel clamps are included in V8R's kit. This is the front-most mount, I added the small stand-off to move the line away from the frame rail so it cleared the hard brake line that you can also see running behind it, which I ran at the same time:
FuelKit (6).JPG
The end of the line curves up over the transmission and attaches to the LFX's fuel hard line and that's it, fuel system is done.
Ryan @ GWR
Posts: 497
Joined: Fri Oct 17, 2014 11:37 pm

Re: LFX Engine Swap (GM V6) at GWR

Post by Ryan @ GWR »

Cooling system

Time to get the radiator sorted out. A lot of components in the nose have to mingle together nicely, so there was a lot of figuring out several systems at the same time in my head before finalizing anything.

Now, this is where we begin to really digress away from your 'typical' LFX build, and why the time investment and costs of this build are a lot higher than someone could typically swap an LFX for. I'm still sharing everything because I think it helps give guys ideas and shows what you could do.

The EASY option for a typical build will be to use V8R's radiator which drops into the factory vertical position:

Image

Now, with that said, let's move on :mrgreen:

On this car the plan is to vent all the air that goes through the radiator up and out the hood via a large duct. This will maximize radiator efficiency and also reduce aero lift significantly. I also have plans for an intake that needs to extend over the top of the radiator, so for these various reasons we want to tilt the radiator forward quite a bit.

Based on that, I chose to center everything around our GWR triple-pass radiator for the NC chassis. NC radiators are already designed to be tilted forward so the brackets on the unit don't need any modification, and the NC units have 30% larger surface area than an NA/NB radiator - and we want all the cooling we can get at the racetrack.

Image

Of course, all of the mounts for the NA's radiator need to be discarded (cut out) and new brackets need to be made.

Here are the new lower brackets which cradle the radiator's bottom posts. These also have threaded locations to mount some of the air ducting that will come later:
Cooling.JPG
The radiator's top mounts tie in with a new cross-tube that runs laterally between the two frame rails. Designing this cross bar, I want it to be removable to make engine removal/install nice and easy, so that involved welding captive nuts inside the frame rails for it to bolt to (which took some creativity :wink: ). The radiator, intake, power steering cooler, and some of the air ducting will all tie in with this cross-bar:
Cooling 8.jpg
Cross-bar installed with the radiator in place. The radiator's upper brackets mount to the two outer threaded points on the bar, via rubber standoffs to isolate vibrations:
Cooling 7.jpg
With the radiator in place we can look at the main coolant feed and return lines.

In the few LFX swaps that are out there so far, everyone's re-used a factory GM return line, but because I'm using an NC radiator which has the feed/return on the correct sides of the radiator to match the LFX (as opposed to NA/NB rads which are opposite), I could actually make use of the more direct and simplified routing that this makes possible. But, that means I need to make a new return line...

Here's the new return line made with aluminum mandrel bends and beaded ends:
Cooling 9.JPG
Installed with silicone couplers on either end (45° at the engine and a straight coupler to the radiator):
Cooling (5).JPG
The feed line is a bit simpler, needing only a pair of 90° silicone couplers and a short aluminum joiner between the two. However, the outlet from the engine is 1.5" and the radiator is 1.25" so one of the 90° couplers must be a reducer.
Cooling (2).JPG
Above you get a sneak peek of the intake, which I'll cover in the next post :D

Also pictured above, I'll be using one slim SPAL 12" fan for the lightest weight possible. This will only get used while idling in the pits, won't need it when the car is up to speed and this car won't ever be sitting in traffic:
Cooling (4).JPG
All that's left is to sort out the expansion tank (radiator is no longer the highest point in the system) but that will be tackled in a few weeks.
Ryan @ GWR
Posts: 497
Joined: Fri Oct 17, 2014 11:37 pm

Re: LFX Engine Swap (GM V6) at GWR

Post by Ryan @ GWR »

Intake time!

The EASY method that will work for most typical swaps is much like V8Roadster's street NB:

Image

90° bend out of the throttle body (3" diameter) over to a filter location on the driver's side behind the headlight. For the air sensor you could use a coupler like this:
https://www.amazon.com/Spectre-Performa ... nk21197-20
Or this one which is a weld-in:
https://www.summitracing.com/ga/parts/n ... erformance

Now that we've covered that, for this car I wanted to try out an idea I've had bouncing around for a while - putting the filter forwards of the radiator, and the tilted radiator makes this possible. Turns out, the angle of the throttle body is spot-on for this without even any bends, as if it was meant to be :D

Couple pics of the creation process...

Made the air sensor flange from scratch:
LFX_Intake_1.JPG
Sensor is placed pointing down just ahead of the throttle body:
LFX_Intake_2.JPG
LFX_Intake_2.JPG (75.01 KiB) Viewed 20515 times
Intake tube in progress:
LFX_Intake_3.JPG
LFX_Intake_3.JPG (77.1 KiB) Viewed 20515 times
Bracket...
LFX_Intake_5.JPG
LFX_Intake_5.JPG (134.84 KiB) Viewed 20515 times
Supports the intake by the two center brackets on the cross-tube:
LFX_Intake_4.JPG
Notes on filter choice - the math says this motor needs about 460 CFM of intake flow. I like to oversize the filter by about 20% so shoot for a filter with 550-ish CFM. You can call K&N and get flow specs on any filter in their catalog if there's a particular shape/size you want to use.

Finished up:
LFX_Intake_6.JPG
Why this position?

I like this for a few reasons; While this car makes judicious use of vents to reduce both pressure and temperature under the hood, under-hood temps are still a good bit higher than the ambient temp outside even on the hottest days. Cooler air means more power with less chance of detonation - placing the filter ahead of the radiator means the engine gets ambient temp air all the time without the need for any additional ducting.

Second, the bumper mouth is the highest pressure area on the car at speed - particularly for race cars with tightly sealed ducting. While this is just a fraction of the kind of pressure a turbo or supercharger creates, at very high speeds it can add a few more hp, and every little bit will help at high speed tracks where we're pushing against aero drag somewhere around 150 mph.
Ryan @ GWR
Posts: 497
Joined: Fri Oct 17, 2014 11:37 pm

Re: LFX Engine Swap (GM V6) at GWR

Post by Ryan @ GWR »

Exhaust: Part 1

Another area where I've got some fun ideas to carry out on this project.

It's been a while since the last update, and that is because I'm currently 71 hours in on this exhaust project (I told you this swap would have some very different requirements than a typical one!). I'll have it finished up by the end of this weekend, so I can finally start posting about it and will have finished pics in a couple days. :mrgreen:

Before we get started, there's a BIG difference between the LFX and just about every other motor out there when it comes to the exhaust. The LFX collects the exhaust gasses from all three cylinders on each bank before they exit the head, so it all comes out in one single outlet on each side of the motor. People come by the shop to take a look at the car and ask "what are your plans for the headers" and the answer is... there aren't any headers! They are much more appropriately called Downpipes - as they are just a single tube on either side of the motor which drop down to the underside of the car much like a turbo system.
LFX Side.jpg
LFX Side.jpg (47.49 KiB) Viewed 19777 times
Now, the EASY route for doing your LFX exhaust:

V8Roadsters makes a tidy pair of downpipes that get you from the engine down to beside the bellhousing. Then it's a simple matter of taking the car to a good exhaust fab shop and get something made up to get things out to the back of the car with whichever combo of cats, resonators, and mufflers you want:

Image

For this project, we're going a different route. Always thinking towards maximizing the competitive advantage where possible, this exhaust is going to go out to the sides of the car. Benefits should be three-fold; it will be overall lighter, there will be less heat by the transmission and differential, and it will allow for several aerodynamic ideas that I want to implement on this car.

Fun idea, but this presents plenty of challenges - the biggest one is there's no space for a side exhaust on an NA chassis; there isn't room for a big wide wheel and race tire to turn with an exhaust tube trying to share the wheel well space, and there is nowhere to put resonators or mufflers along the side of the car without them hanging WAY off the car - which would not be good for drag or ground clearance.

Some drastic surgery will be required.

Started with drilling holes and using the scope to figure out the internal layout of the rockers, then with a rough idea of how I want things to end up I began cutting, taking a little bit out at a time then investigating, adjusting, cutting more, etc.
Rocker1.JPG
Nearly all the cutting is done in the pic above, but the pinch weld is still there. After a lot of test fitting, I decided to get the fitment I wanted with everything I was going to have to take that out too. This meant more work - this is a critical area of the car in terms of chassis rigidity so anything I remove I have to rebuild a replacement for.

Below pic has the pinch weld cut out as well, and we’ve got the resonator mocked up roughly in position:
Rocker2b.jpg
Now for the fun part. Need to rebuild the rocker in its new shape that accommodates the exhaust, and ideally we want the end result to be even stronger than the stock rocker.

The sections that will make up the main sides of the rockers:
Rocker4.jpg
The idea is to make the rocker concave instead of convex so there is room to nest the exhaust about half way up within the chassis. Something like this:
Rocker5.jpg
Holding that main piece up to the car it all looks pretty straightforward, which I wish it was :wink:

Creating the new rocker and the new lower section of the front wheel well took several pieces including a rather complicated 90° bend to transition between the two, plus a dozen or so additional pieces to rebuild the pinch weld inside the rocker so that all the chassis loads that normally transfer through that area can continue to do so, plus some additional gussets to make it all stronger than what was there before, To top it off it needed to be able to go together in a sequence that allowed me to weld each rocker piece to the ribs and gussets on their back side.
Rocker7.jpg
To put this all together took 5 yards of welding per side:
Rocker8.jpg
Cleaned up and primered:
Rocker9.jpg
Naturally, I weighed everything that got cut out and put in on this project. Thanks to a lot of careful figuring out, the new rocker matches the weight of what was removed within one pound.
Rocker10.jpg
Rocker10.jpg (139.46 KiB) Viewed 19777 times
At this point, I was lamenting the fact that this is a V engine and it was time to do this all over again on the driver's side :shock:

Both sides are done now and mirror each other, and you can see why this car took 40 hours of work on the exhaust... before I actually began making the exhaust.

Exhaust is in progress now and will be done by the end of the weekend, part 2 coming soon!
Ryan @ GWR
Posts: 497
Joined: Fri Oct 17, 2014 11:37 pm

Re: LFX Engine Swap (GM V6) at GWR

Post by Ryan @ GWR »

Exhaust: Part 2 (yes there's actually an exhaust is this part)

Before starting on the exhaust itself there were a few more brackets to make for the rockers. The final plans for this area include a rather complex side skirt for aero purposes that will also channel air from the front wheel well down the side of the car to continuously pull the heat of the exhaust away. I'm not making those yet since they aren't a priority to get the car up and running, but I've got them about 90% figured out in my head and now was the time to make the mounting considerations for them:
LFX_Exhaust4.JPG
Finally, on to the actual exhaust!

Materials ordered, not everything used is in this photo - ordered a few more parts later on. R2-D2 approved of the shiny stuff:
LFX_Exhaust1.JPG
Began with the downtube. V8R has the CNC formed downtubes for traditional down-the-tunnel exhausts, and I almost got a set of those to start off from but it seemed a shame to cut those up and only use the top half of them so I decided to do it from scratch. I strongly recommend getting V8R's downtubes for anything but the most custom needs because forming the round tube to the rectangular shape of the engine flange within the 90° bend of the tube where it needs to be is not easy.

Sacrificing an exhaust flange, I made a jig for the shop press that would press the tube into the shape of the flange, it's crude but got the shape to 95% and then hammer-formed it the rest of the way:
LFX_Exhaust2.JPG
Exhaust curves down quickly just like normal, but then makes a turn to head out towards the wheel well:
LFX_Exhaust9.JPG
I was in the zone and didn't get many pics of the build process. Woops! I did snap a pic of cutting the exhaust exit tips:
LFX_Exhaust10.JPG
Here we've got one of the finished downtubes tack welded together, joints sealed up and backpurging gas being piped in - to weld stainless steel properly you have to shield both sides of the tube from oxygen when welding it:
LFX_Exhaust3.JPG
Full exhaust finished! Measuring the total length of everything here and comparing to the length needed for an out-the-back exhaust, this side exit exhaust saves me 50 inches of length, approximately 10 lbs:
LFX_Exhaust6.JPG
The downtubes carry the exhaust from the engine down to the bend at the rocker, with a V-band flange pointing straight down the car from there so that the rest of the exhaust is modular. This allows me to easily make different straight sections if I want to test alternate resonators or mufflers. You'll also see two cats in the pic above (Wait, cats on a race car? Why??) I wanted to be sure I could fit cats in the system, and since those would be the largest thing I might be trying to fit there I made those first to be sure they fit, and will make a pair of straight cat deletes later that can be swapped in. Cats do a good job of reducing volume, and V8R reports this is a loud motor when you're on the GO pedal so I'll likely also use the cats as an option when I need to bring the volume level down at certain tracks, etc.

Installed, the exhaust tucks into the rocker nicely:
LFX_Exhaust5.JPG
Shot from below shows the full route well:
LFX_Exhaust7.JPG
From the perspective we'll be seeing it from more often, I'm quite happy with how it's tucked into the car. The exhaust won't ever be quite as exposed as it is here, since the side skirt will envelope it to direct air, but it will remain like this until it's up and running:
LFX_Exhaust8.JPG
Speaking of weight, the full 3" lightweight exhaust that came off this car for the 4 cylinder and turbo was 26 lbs including the downpipe but NOT including the cast iron manifold which was easily 10+ lbs. That exhaust had no cat and no muffler to save weight.

This new exhaust totals 30 lbs all-in, including the cats and everything up to the motor, so somehow in changing to a V6 which has to double everything and adding cats and resonators I've saved weight over the uber-minimalist turbo exhaust that came off the car. I'll take that!
porterhousestk
Posts: 18
Joined: Thu Jul 16, 2015 9:36 am

Re: LFX Engine Swap (GM V6) at GWR

Post by porterhousestk »

Fantastic work Ryan! I'm excited to see the final product! I looked up how much it would be to buy this motor from LKQ here in Texas and I found one with 34K miles for $1300. Transmission listed at ~$2000 and I haven't found any Getrag rear diffs online yet, but I would assume they would be around $1000. definitely a feasible option for someone looking to really increase horsepower with a newer motor! keep up the good work!
Ryan @ GWR
Posts: 497
Joined: Fri Oct 17, 2014 11:37 pm

Re: LFX Engine Swap (GM V6) at GWR

Post by Ryan @ GWR »

Thanks :D

The Getrags are affordable, $250-$350. If you can get the engine and transmission together you can usually get a bit of a package deal.
porterhousestk
Posts: 18
Joined: Thu Jul 16, 2015 9:36 am

Re: LFX Engine Swap (GM V6) at GWR

Post by porterhousestk »

This is WAY too cool, I cant quit thinking about how awesome it would be to have an LFX in my NC1. I just have a few questions, I see you are using the V8R Sub-frame, Crossmember/Frame Rails, and the differential mount on this NA. Does V8R have these available for swapping an LFX into an NC1? And do you plan to use the GM ECU from the Camaro? What would be the difference ECU wise for putting this in an NC? Good Luck! :mrgreen:
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