What does it take to swap a V6 into a Toyota MR2? | Full parts list | Project Toyota MR2 V6

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Update by J.G. Pasterjak to the Toyota MR2 Turbo project car
Sep 28, 2022 | Toyota, MR2, Wilhelm Raceworks, Toyota MR2 Turbo, Frankenstein Motorworks

The term “plug and play” gets tossed around so much that it seems to have lost all meaning–at least when it comes to engine swaps. Even so, the more pieces we get in hand for our Toyota MR2’s upcoming V6 transplant, the less intimidating the project becomes.

We’re swapping a 2GR-FE engine–think Toyota Camry–into our 1991 Toyota MR2 Turbo. (The original engine got a little singed during an on-track fire.)

[How to react when your car catches fire | Project MR2 Turbo]

There’s a lot of passion and enthusiasm out there for this combination of quad-cam V6 and mid-engine sports car. Heck, Lotus basically did it when it introduced the 2GR-powered Evora. A big reason for our confidence going into this swap? The companies making top-notch parts to facilitate it.

Marc Labranche is an enduro racer and former programmer who left his job in the tech industry to build Toyota swap goodies full time. His company, Frankenstein Motorworks, produces most of the hard parts and lots of the electronics we’re using for our swap. The stuff is well engineered, the quality is OEM-grade, and Marc’s support of the community is legendary.

Alex Wilhelm is a former Formula SAE competitor who turned his training on the SW20 as well. Parts from Wilhelm Raceworks have graced the suspension and brake system of our MR2 for some time. We’ve raved about his chassis bits, but he also has some awesome problem-solvers when it comes to the 2GR swap.

Ty Saxon has been building cool MR2s and parts to make them perform better for years. His shop, TCS Motorsports, was one of the first major suppliers to jump on the SW20 bandwagon, and it brings mass-produced quality to bespoke parts. Every bit we’ve used from TCS has fit like a dream.

Now that we have our suppliers lined up, let’s talk about which parts are coming from each, what they do and what they cost.

Engine: As we discussed previously, our engine is a 3.5-liter 2GR-FE from a 2015 Camry. Ours cost $1450, including drop-gate shipping, from a recycler on eBay. We paid low-market, but that had more to do with spending way too much time on eBay than getting any kind of crazy deal. Still, these engines are available online any day of the week from $1500 to $2000.

Wiring harness: You’ll need a harness from an appropriate 2GR-FE-powered car, van or SUV. Frankenstein prefers Sienna and RAV4 harnesses, as they require the least amount of wire rerouting and extensions.

We nabbed a 2011 RAV4 harness for $310, but Sienna harnesses (the cheapest and most plentiful) are typically available easily for $250 to $350.

You’ll also need your old MR2 harness, mostly to reuse connectors so the new one can plug into your body integration ports.

The bad news here is that we sold our old harness with our 3S-GTE engine. A few of the connectors were melted, anyway, so we might not have even been able to use them. Our current plan is to try to track down the connectors we need through the MR2 community. Worst case, a used harness looks to cost around $300.

Upper oil pan with oil cooler ports: This is optional, but if you want to run an oil cooler, you’ll need an upper oil pan with the OEM oil cooler ports. If you got your V6 from a van or SUV with a tow package, you might already have them, but our Camry-sourced engine didn’t. We found one on the Frankenstein Motorworks Discord server for $75.

Oil pan baffle: Since the oil pan is coming off to install that new upper pan, we’ll take the time to install this trick pan baffle from Wilhelm Raceworks. Again, this is optional, but as our car will see mostly track and autocross use, we want to control the oil as best we can. This form-fitting baffle costs $150, drops into the lower pan, and features trap doors and screens to keep that oil pickup wet under high cornering loads.

Coolant expansion tank: Also from the Wilhelm catalog is this new coolant expansion tank. The pressurized tank replaces the MR2’s unpressurized tank and will make bleeding and filling the cooling system much simpler.

This hand-built tank mounts in the stock location and costs $180. Alternately, you can buy a modified $100 water neck and retain your unpressurized reservoir. Ours was looking a little long in the tooth, so we opted for the all-in-one upgrade.

Intake adapter: Wilhelm’s custom $80 silicone intake adapter is designed to work seamlessly with the Frankenstein Motorworks MAF adapter and has ports for an OEM resonator and PCV. The $25 resonator actually increases performance by smoothing the airflow and thus the data coming from the MAF sensor, so it’s not just a honk-muffler.

Fuel connections: You can certainly build your own fuel connections, but Wilhelm has engineered these $215 PTFE fuel hoses to easily connect the stock tank to the filter and regulator, and then to the engine. The kit includes all the necessary adapters and a regulator that connects to the stock fuel filter. It’s a simple, one-click solution.

Oil cooler: Again, an oil cooler is optional, but if you’re going to run one, you’ll need a way to adapt the stock ports to AN fittings. Wilhelm’s $75 adapter does just that and comes with the adapter plate and required AN fittings.

Exhaust headers: Stock 2GR-FE exhaust manifolds will work for the swap–sort of. More correctly, they can be made to work, but there are interference issues, wire and hose routing issues, and–just lots of issues.

The easy answer is the custom-designed cast headers from Frankenstein Motorworks. They’re $944 including gaskets and some really trick band clamps, and they hug the side of the engine and cleanly fit in the allotted space. They also connect directly to…

Y-pipe: …this $599 TCS Motorsports custom Y-pipe. It’s designed to link those Frankenstein headers to the rest of the MR2 exhaust system.

We don’t have ours in hand yet–TCS builds them in batches, and another run is in production now–but this was the easy button to complete the exhaust.

Our MR2 already has an aftermarket exhaust, and we’re going to keep it for now. At some point, it will get replaced with a single-outlet system.

Engine mount: To bolt our 2GR-FE to our MR2, we’ll need a custom mount for the passenger side of the powertrain. This bespoke mount from Frankenstein features OEM-grade insulation and places the engine right where it needs to be laterally. It costs $349.

The MR2’s stock, left-side mount will work for this swap–it connects to the transmission and bolts to the driver’s side of the chassis–but Frankenstein also offers a lighter, simpler mount that will do the job for $389 and look a whole lot nicer. We haven’t ordered one yet, but we’re waiting to see how the variable part of our budget shakes out to see if there’s any cash left for luxury touches.

Axle carrier: The stock, right-side axle carrier will work with some machining, but as it sits, it doesn’t quite line up when bolted to the 2GR-FE engine.

For just $125, this custom-machined carrier from Frankenstein saves you the mill time and replaces a 30-year-old piece of steel with a new piece of aluminum.

Gas pedal: Since the 2GR-FE is drive-by-wire, you’ll need an electronic pedal. You can junkyard dive for one or you can buy a new one with the appropriate bracket from Frankenstein. We opted for a Lexus IS-spec pedal cover, along with the optional prefabricated harness and plug. This route cost us $232.

MAF sensor mount: You’ll need a place to mount your MAF sensor, and this bespoke piece from Frankenstein ($173) provides that spot. It’s also dyno-optimized.

We’ll still need to add a stock MAF sensor. Those range from $30 or so for an aftermarket unit to about $80 for an OEM Toyota piece. Or there’s always the junkyard.

Engine control unit: To run this whiz-bang new engine of ours, we’ll need the proper ECU. The tricky part here is no stock Toyota with a 2GR-FE came with a manual transmission–or was installed in a 30-year-old MR2, for that matter. And a stock ECU from a Sienna, Camry, Highlander or whatever is going to have certain expectations that you just won’t be able to fulfill with your ancient sports car.

So your choices are to use a standalone ECU or a reprogrammed Toyota piece. Luckily, Marc Labranche has cracked the Toyota ECU and can provide a solution with much less cost and complexity than an aftermarket ECU.

Starting with Sienna and RAV4 computers, Marc tricks the code into working with a manual trans, raises the rev limit to 7200 rpm, and optimizes the tune for 93-octane fuel.

At $500, the cracked Sienna ECU seemed like a bargain given the development Marc has put into it and the support he provides his customers. Frankenstein also has a couple bare connectors and an ECU mount kit that make the job neater. These add about $110 to the ECU.

Flywheel: Not pictured, because we don’t have it yet, is a flywheel. Since the 2GR-FE never came with a manual trans in a Toyota application, we’ll need a suitable flywheel.

The ACT clutch we just installed in our MR2 will work fine, but to connect it to the crank, we’ll need either Frankenstein’s custom-built unit ($439), a stock one from a 1MZ Toyota engine, or an aftermarket one suitable for a 1MZ. Fidanza has a flywheel for what we need at around $350.

Starter: We’ll need a new one for a 2GR, so that means $50 to $200 depending on whether we go recycled or new.

Alternator: The swap will also need an internally regulated alternator from a 2GR application–also in the $50 to $200 range.

We’ll also need to invest in various gaskets, seals and OEM bits as we freshen anything obviously in need of replacement on our junkyard engine. And while we have the fuel tank out, we should freshen the fuel pump, too.

We also plan to upgrade the differential to a proper limited-slip unit while we have everything apart. Yes, scope creep is real and must be accounted for.

The current total for our on-hand parts is around $6000. That seems like a lot, but on the other hand, we’re buying a lot of stuff that could theoretically be fabricated or otherwise improvised in place.

Still, the parts we’re seeing are so well engineered that we’re comfortable the investment will pay dividends on the back end with ease of integration.

Basically, someone has already done the hard work, and it’s just up to us to plug and play. It’s that simple, right?

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Comments
Tyler H
Tyler H GRM+ Memberand UberDork
9/28/22 9:59 a.m.

Heck yes!  Watching this with interest.  A V6 in an MR2 is just right.

JG Pasterjak
JG Pasterjak Production/Art Director
9/28/22 11:48 a.m.
Tyler H said:

Heck yes!  Watching this with interest.  A V6 in an MR2 is just right.

Obviously I'm biased, but this really does seem like a nice combo, doesn't it?  A 7200rpm 300hp mid-engined V6 sports car has a real logical feel about it.

wspohn
wspohn SuperDork
9/28/22 11:51 a.m.

Makes sense to use another Toyota engine but I can't help but wonder how a modern turbo 4 cylinder would have worked out - more power, and probably save a little weight even with the turbo.  There are a number out there, mostly direct injection, with huge power possibilities.

BA5
BA5 GRM+ Memberand Reader
9/28/22 12:38 p.m.

I'm at the starter/alternator stage with my own V6 swap (Honda, not Toyota). 

Is this car going to be a track only car?  I could mount up an alternator easy enough, but I'm also considering running a total loss electrical system.  You guys ever do that or know anyone that did?

maschinenbau
maschinenbau GRM+ Memberand UberDork
9/28/22 3:18 p.m.

I love watching you spend real money to do an actual good quality version of the same swap I'm doing for less than $2000. 

And I can attest to Marc's legendary community support. He has been a huge help for the 2GR Lotus Europa so far.

GameboyRMH
GameboyRMH GRM+ Memberand MegaDork
9/28/22 4:48 p.m.
BA5 said:

I'm at the starter/alternator stage with my own V6 swap (Honda, not Toyota). 

Is this car going to be a track only car?  I could mount up an alternator easy enough, but I'm also considering running a total loss electrical system.  You guys ever do that or know anyone that did?

I've only heard of people doing that on go-karts and landspeed cars. The karts have very low electrical draw requirements, and the landspeed cars only have to run for a <10mins at a time between extensive prep for runs which includes charging. The landspeed cars can also run massive batteries since weight isn't an issue.

JG Pasterjak
JG Pasterjak Production/Art Director
9/28/22 5:15 p.m.
maschinenbau said:

I love watching you spend real money to do an actual good quality version of the same swap I'm doing for less than $2000. 

And I can attest to Marc's legendary community support. He has been a huge help for the 2GR Lotus Europa so far.

Yeah part of me sees the bills adding up and winces, but another part of me sees the quality and thought that went in to so many of the parts nd realizes how much heartache they're saving in the long run. 

It's like buying a dishwasher. Could I theoretically build a device that washed dishes cheaper than I could buy one for at Home Depot? Sure. Would it brak half my dishes and kill one of my neighbors? Yeah, probably. Home Depot wins this round.

J.A. Ackley
J.A. Ackley Senior Editor
9/28/22 5:15 p.m.
BA5 said:

I'm at the starter/alternator stage with my own V6 swap (Honda, not Toyota). 

Is this car going to be a track only car?  I could mount up an alternator easy enough, but I'm also considering running a total loss electrical system.  You guys ever do that or know anyone that did?

Many oval-track cars do that, but they don't have as many electronics as most track-day cars do. A distributor. An ignition. Spark plugs.  A starter. Some gauges. That's about it. They run up to 50 laps, but often have their batteries on a charger in between times they hit the track.

The key would be knowing how much power your car draws, how much time you would need that power, and how much battery it would take to keep it going.

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