LFX Engine Swap (GM V6) at GWR

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LFX Engine Swap (GM V6) at GWR

Postby Ryan @ GWR » Tue May 03, 2016 12:02 am

In the never-ending search for more power, a full drivetrain swap has begun for the #13 time attack car, this thread will follow along and document the process. :mrgreen:

There's a separate thread in these forums for the car in general HERE so here we'll just focus on the conversion to the new drivetrain. Here's the car:

Image

This car is a 1990 chassis that has been running a turbocharged 1.6 for many seasons. Current power is around 215 hp, it's been enough to beat up on some much "faster" cars at the track thanks to good suspension, aerodynamics, and lightweight. However, with sights set on higher levels of competition that pit us against cars of all makes/models, many of which have big V8s and the like, it's time for some more firepower.

The donors for the new recipe are the Chevy Camaro and Cadillac CTS, with conversion parts from V8Roadsters and some good ol' fashion fabrication mixed in.

Engine comes from a 2012-2014 Camaro. Transmission can come from either the Camaro or CTS of those years. Differential comes from a 2006-2008 CTS:

80-chevrolet_camaro_rs_2012.jpg
80-chevrolet_camaro_rs_2012.jpg (32.42 KiB)

80-2012_cadillac_cts_sport_sedan_3.jpg
80-2012_cadillac_cts_sport_sedan_3.jpg (26.05 KiB)


Why the change? Why not go for more power with the Miata motor and turbo?

Well, take it from someone who has done a lot of racing with the turbo - it puts off a LOT of heat. I've melted just about every plastic or rubber part on the driver's side of the engine bay at one point or another! That heat also affects the motor in a lot of ways. Some might notice we don't sell a turbo kit for the 1990-2005 cars. That's because there isn't a kit on the market we feel we can endorse; there's a laundry list of changes that need doing to just about every kit out there to have a hope of running reliably under hard use. This car got there, but it took half a decade of custom revisions and improvements to get there. At the end of the day you can't get away from the fact that when you're asking a motor to put out 100-200% MORE power than it was originally intended to, longevity is not its strong suit any more. And that brings us here: the search for a great motor pairing for the car that was designed from the beginning to make all the power we want, which should make for not only a faster car but also a more reliable one.

We've done a lot of paper-napkin estimates about this swap, and on paper it looks very good for power and driveability without sacrificing light weight. There are more than a few reasons that it looks more appealing than a V8 swap - less chassis modifications needed, smoother and higher-revving than the V8s, better weight distribution, and more.

To top things off, V8Roadsters is working on CARB approval for this swap. No promises yet, but that could mean big things here in California. If the kits get CARB approval then we'll likely be doing a lot more of these swaps in the future, so this is a great opportunity to work through the process first-hand.

Follow along! In the next post I'll cover the engine details.
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Re: LFX Engine Swap (GM V6) at GWR

Postby Ryan @ GWR » Tue May 03, 2016 12:10 pm

The LFX Motor

The LFX is Chevy's "High Feature" 3.6L 60° V6 DOHC all-aluminum engine found in several different specs across the 2012-2014 Chevy and Cadillac line-up. It is packed with tech; direct injection, variable valve timing, a composite intake manifold to reduce weight, timing chain (not a belt), and an integrated exhaust manifold head design that collects exhaust gas into one single exhaust port on each side of the engine (in other words, a dream to fabricate exhaust for this).

3.6LFX Art.jpg
3.6LFX Art.jpg (59.79 KiB)

Although found in the Cadillac CTS, ATS, Chevy Impala and others, the one to get is from the Camaro. Rated at 323hp and 278 ft-lbs at the flywheel.

The LFX acronym denotes Flex Fuel capability, but there's some confusion on that subject because that feature wasn't officially advertised for the Camaro. I'm not yet sure whether the ECU has the capability to run a flex fuel sensor. However, it is confirmed that the fuel system's hardware is all designed to be E85-capable, with injectors sized at 109 lbs/hr (1,100cc). So even if flex fuel adapting on-the-fly isn't an option, it looks like switching to E85 is just a tune away - no hardware changes needed.

3.6LFX Side.jpg


Motor acquired here from a local salvage yard with 40k miles on the clock. Best to get the motor along with several of the other components you also need from the same donor car:

- Engine
- Alternator
- Power steering
- A/C
- Engine wiring harness
- Starter
- Gas pedal (for the drive-by-wire)
- ECU

Because this particular build is a race car, the air conditioning won't be retained and the power steering probably won't either but it's good to get those accessories even in this case so that we know pulley/belt layout.
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Re: LFX Engine Swap (GM V6) at GWR

Postby JamesK383 » Wed May 04, 2016 7:58 pm

I love this Outside the box build.

Can't wait to see more from this thread

:D
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Re: LFX Engine Swap (GM V6) at GWR

Postby jboemler » Wed May 04, 2016 8:26 pm

Seems like this would be promising for the NC, looking forward to lots of pictures!
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Re: LFX Engine Swap (GM V6) at GWR

Postby Chuck H » Thu May 05, 2016 9:10 am

jboemler wrote:Seems like this would be promising for the NC, looking forward to lots of pictures!


Was thinking exactly the same thing. Would be a pretty cool swap in an NC, and hopefully cheaper than the V8 swaps (athough probably not all that much cheaper).
2012 Copper Red Touring
Progress springs and sways
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Re: LFX Engine Swap (GM V6) at GWR

Postby Ryan @ GWR » Thu May 05, 2016 11:52 am

I really agree, these are putting down ~285 horsepower at the wheels in stock form. I think this would be awesome in an NC :twisted:

This first swap into the NA gets us valuable experience with the motor and drivetrain that carries over to other chassis. In the NC, it would just be a matter of different logistics in some areas, and different wiring.

I am in fact even planning to use an NC radiator for this swap (our new triple pass unit), in part because it is tilted forwards nearly 45° which is great for venting out the hood, but also because the flow direction is better suited to match the LFX than the NA/NB radiator.
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Re: LFX Engine Swap (GM V6) at GWR

Postby Ryan @ GWR » Thu May 05, 2016 12:19 pm

Previous setup was a 1.6L turbocharged motor. That's removed and off to a new local owner for use in his NA:

old motor pic.jpg


goodbye old motor.jpg


Looking forward to almost 100 more horsepower without all the heat generated by a turbo!

Keeping a close tab on the affect this swap will have on weight, and most importantly - weight balance. I'm weighing just about everything that comes off and goes on individually, but the real key to know is the finished weight. Here's the car on the scales just prior to getting stripped of the drivetrain.

Note the rather front-biased distribution. This is typical of an NA/NB that has the added weight of a turbo up front to make decent power. I'm expecting the LFX to add some weight to the car overall (but not as much as a V8), but that is in part due to a transmission and differential that are a bit heavier than the Miata's - both of which are low and centered or rearward. The engine itself is all-aluminum, so we're hoping to see an improvement in the weight balance with the new drivetrain:
Attachments
Ryans NA scaled BEFORE.jpg
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Re: LFX Engine Swap (GM V6) at GWR

Postby Ryan @ GWR » Wed May 11, 2016 4:01 pm

Transmission

The Camaro comes with an Aisin LY6 6-speed with the "MV5" designation. That box has some interesting ratios. From 1st to 6th gear: 4.48 / 2.58 / 1.63 / 1.19 / 1 / 0.75

1st and 2nd are super short, 3rd has a big drop and is very long, then 4th is very short again. I can think of arguments for and against this, depending on the specific scenario/track.

The base model Cadillac CTS uses the same engine, and has a manual gearbox option - that transmission is the MV7, and it has much more evenly-spaced ratios: 4.16 / 2.51 / 1.69 / 1.27 / 1 / 0.75

Because this is a road race car, the evenly spaced ratios look a bit more appealing. Here's our MV7, fresh out of a donor CTS:

MV7Trans.jpg
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Re: LFX Engine Swap (GM V6) at GWR

Postby jboemler » Thu May 12, 2016 12:05 am

That shift mechanism looks pretty klutzy -- how's it feel? Are you planning to make a bracket to emulate the cast turret that Mazda's have? Could make an interesting conversion product.

Oh, and what's the trans weigh?
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Re: LFX Engine Swap (GM V6) at GWR

Postby Ryan @ GWR » Thu May 12, 2016 9:10 am

We're teaming up with V8Roadsters for this swap, they are hard at work on many of the conversion parts necessary to fit this drivetrain to the Miata (as well as NC and RX8!), so you'll be seeing many of those parts as we progress with this project.

One of those parts is also the answer to your question - V8R LFX Shifter that replaces that steel linkage with a light aluminum assembly that drops on to the Miata's tunnel.

V8R_LFX_Shifter.JPG
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Re: LFX Engine Swap (GM V6) at GWR

Postby jboemler » Thu May 12, 2016 12:28 pm

Hmmmm, glad to see the progress, but it doesn't strike me like a great design. Unlike the Mazda design, where the shifter is a part of the trans, this one will get bolted to the tunnel. That means that when the drivetrain twists or vibrates, it will be translated as angular movement to the shifter, and multiplied by the ratio of top to bottom lengths of the shift lever. Bottom line, the car is going to shift like American Iron, when it could have been made to shift more like a Miata. :cry:
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Re: LFX Engine Swap (GM V6) at GWR

Postby Ryan @ GWR » Thu May 12, 2016 2:09 pm

Engine Bay Modification

To gain clearance for the wider V6, there are some adjustments to be done to the engine bay particularly so that the engine can sit as far back as possible for the best weight distribution. One very nice thing about this swap is that this motor and transmission do not need any modification to the transmission tunnel/firewall to clear the bell housing like the V8s do. With the V6 you only need to make a few changes to the engine bay itself.

The below pic is a stock photo of a stripped engine bay on which I've marked where the work is done.

The primary change is to the rear corners where the frame rails meet the firewall, these areas get squared off via cutting and welding as marked. The area around the heater hose holes in the firewall (circled area) just needs some massaging with a mallet to clear a protrusion on the rear of the V6's driver-side head:

stock bay cuts.jpg


After some cutting, we can see the internal structure. There is still a bit more cutting to do, as marked by the green lines:

Driver side engine bay cut.jpg


Passenger side engine bay cut.jpg


With the final cutting done, we made new plates in house to seal this area up, with accommodation for the steering rack to still pass through the driver's side section:

DR side bay cut 3.jpg


Px side bay cut 3.jpg


Lots of welding later, we have plenty of room for the V6:

Squared engine bay.jpg


Because this is a race car, it made sense to take this opportunity with the engine bay stripped to also stitch weld several key areas while in here. This adds a lot of time to the project, but it's worth it - stiffening the chassis with essentially zero weight added. (Sorry for the photo quality, this was taken late at night in the shop with low lighting so it turned out grainy):

Stitched Engine Bay.jpg


In these photos you can also see the new subframe, courtesy of V8Roadsters, which is a tubular unit lighter weight than the factory subframe yet super strong and with the proper engine mounts for this new motor:

V8R LFX Subframe.jpg


For now all of the welded areas in the engine bay have some primer sprayed on them to prevent rust, the final paint will be done later once all of the test fitting of various parts is complete. With the subframe installed it's looking almost ready for the motor to go in for the first time:

Engine Bay ready for motor.jpg


Note in that photo the area by the heater hose holes hasn't yet been "massaged" for clearance.
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Re: LFX Engine Swap (GM V6) at GWR

Postby Ryan @ GWR » Thu May 12, 2016 2:12 pm

jboemler wrote:Hmmmm, glad to see the progress, but it doesn't strike me like a great design. Unlike the Mazda design, where the shifter is a part of the trans, this one will get bolted to the tunnel. That means that when the drivetrain twists or vibrates, it will be translated as angular movement to the shifter, and multiplied by the ratio of top to bottom lengths of the shift lever. Bottom line, the car is going to shift like American Iron, when it could have been made to shift more like a Miata. :cry:


We shall see! This setup is already running in V8R's own test mule and shifting great I'm told. If I'm not happy with the shifting feel in this car, I'll revisit the design and see what needs changing, but only time will tell.
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Re: LFX Engine Swap (GM V6) at GWR

Postby Ryan @ GWR » Tue May 17, 2016 9:27 am

Differential

We'll be using the tried and true Getrag limited slip differential for this - the same differential used in many V8 Miata conversions. It's a clutch type limited slip with smooth engagement that can handle all the power we can throw at it. Sourced from the 2006-2008 CTS and several other GM cars, it's available with a 3.23, 3.42 or 3.73 ratio. Those all sound long in Miata terms, but with the short ratios of the transmission we're using it's actually a great set of options. This particular unit is a 3.42:

Getrag_1.JPG


As a bonus, the Getrags all have their ratio labeled on the back side, so it's very easy to know which ratio you've got:

Getrag_2.jpg


Temperature sensors

We're expecting that this new motor should run with much less heat than my last setup but I never want to leave anything to guessing. This car will see lots of extended hard use on the track so it's a perfect platform to put everything through the torture test and answer lots of questions.

To keep track of the temperature of the various parts in the drivetrain we'll need gauges that can be monitored at the track. The Accutech SMI gauges that we have in our catalog are a favorite of mine - super accurate and yet affordable they're perfect for the job. I'll use four in total; one for engine coolant temperature and another for engine oil temp, and then two more oil temperature units for the transmission and differential.

For the diff and trans we used a scope to investigate inside the unit for a safe place to drill and tap the case to install the sensors:

Getrag_Sensor1.jpg


The differential has a perfect location in a casting circle on the passenger side of the unit (note it's the rear circle of two). These sensors have 1/8" NPT threads:

Getrag_Sensor2.jpg


For the transmission, a spot just below the fill hole was selected (red X):

MV7_Sensor1.jpg


The Accutech SMI gauge's included sensors have high quality sealed wiring, which is part of the recipe for their accuracy. Gauges are very sensitive to resistance, so wire-it-yourself sensors usually end up with the wrong resistance and are inaccurate from day one.

MV7_Sensor2.jpg
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Re: LFX Engine Swap (GM V6) at GWR

Postby Ryan @ GWR » Tue May 17, 2016 10:19 am

Getting into the motor!

The new motor and car getting closer and closer in proximity...

Hello new motor.jpg


With engine on the stand there's a bit of prep to do, and I also wanted to poke around and get familiar with this new engine.

Going through the engine, cleaning each part as it comes off. Intake manifold is removed in these pics, wiring harness is off and crank pulley is removed (because we'll be swapping the pan), and you need to order a new crank pulley bolt as it is torque-to-yield:

LFX_1.jpg


On the back you can see the high pressure fuel pump and hard lines for the direct injection (1600psi!!!)

LFX_2.jpg


Intake manifold and throttle body drying after cleaning - the intake manifold is a composite to save weight, with just a small aluminum portion on the underside. Just about every part I remove from this motor impresses me with its weight, some parts are even lighter than the Miata's equivalents:

LFX_3.jpg


Front cover removed to get a look at the timing chain layout. Three timing chains which should be good for the life of the motor, no belts here. Variable valve timing on all four cams:

LFX_4.jpg


Some sockets that usually lie in the toolbox untouched in a Miata shop are getting some action on this new motor... 1/2", 15mm , 18mm, 22mm, etc.

Flipping the motor over with the pan removed we get a good look at the forged crank, very beefy 6-bolt main bearing caps (4 from the bottom plus two going in through the sides of the block) as well as the internal crank trigger wheel:

LFX_5.jpg


We're swapping oil pans to a modified unit supplied by V8Roadsters which has better ground clearance. Here's the stock pan beside the V8R pan. Convenient that we're swapping pans anyways since our LFX arrived with a big puncture in the bottom of its pan!:

Pan_1.jpg


Pan_2.jpg


Before the pan went on we drilled and tapped for the Accutech SMI engine oil temperature sensor just above the drain plug:

Pan_3.jpg
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