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Discussion Starter #1
I'm on the warpath to getting a supercharged 5.7L Tundra engine/transmission inside the FJ. ((Yes, I am aware or the massive amount of work this will take. I'm not interested in an LS/LT swap until someone bridges the CAN Bus gap between the two systems))

Has anyone ever attempted to fit the front differential carrier from a Gen 3 Tundra in an FJ? It sure is a tight fit under there, but a solid 1" larger ring gear will really help handle the 550FT/LB's of torque that will be headed it's way.

I currently run 35" tires through 4.88 Nitro Gears and an ARB locker up front in the factory carrier, and I'm not sure if I am brave enough to test its durability.

My plan is to cut, fabricate, weld, and wiggle a Gen 3 Tundra front differential section with 4.88's and locker up front. I will use Tundra CV joints and a custom length axle shaft to a tundra bearing/hub inside a modified tundra knuckle. The tundra knuckle will be modified to fit an FJ spec 3.5" Total Chaos long travel kit.

I'll draw a picture later but the basic question is... Am I crazy or has anyone decided to try this?
 

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G'day Rock,
Can't say I have ever seen anyone adding a tundra front, into a J.... but that'll not stop you.....
More importantly.... to answer your question ...ummm...yeah you are crazy ...:rofl::rofl:
Own it, and do it !!!!
as someone once said....necessity is the mother of invention ....

As long as you understand, once you have built this monster rig....it ain't gonna be an FJ.... go for it

Cheers
Baz
:blueblob:
 

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Premium Member
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10,851 Posts
G'day Rock,
Daft idea here.... which you have probably already thought of and discounted....
would it not be easier to drop the FJ body onto a Tundra rolling chassis ...chop it and make it fit ...
Keeping all the tundra engine/transmissions/ electronics ...etc....
Cheers
Baz
:blueblob:
 

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5,659 Posts
Diffs: https://www.proformance.com.au/ifs-irs-diff

Based on our Race Proven U250mm Ultra Narrow Diff, the Ultra Narrow U290 uses a massive 11.25" (290mm) Ring Gear and massive 9.0" (230mm) Taper Roller Bearings to allow the use of Series 30 CV Joints
Proformance Ultra Narrow Diffs have the CV joints mounted up inside the Ring Gear Carrier, allowing for much longer Axles and much more wheel travel. Inboard Cv joints also provide protection of the CV boot from rocks and debris common if off road use.
The 290 is available with a Spool (locked drive), Detroit Locker, Inboard Brakes and accommodates the heavy duty "Series 30" CV Joints with 40 or 44 spline axles.
With inboard CV Joints, the CV mounting faces are only 40mm Apart.

Portal hubs: https://www.proformance.com.au/ultra4-ifs-irs-portal-reduction-hub
Proformance Portal Geared Hubs are designed specifically to provide the strongest drivetrain possible and the longest axle length for ULTRA 4 racing, Rock Bouncing and Off Road Racing
Our newest portal hub design provides the narrowest and strongest Geared Hub Reduction Drive for IFS and IRS vehicles. Complete with CTIS (Central Tyre Inflation) these hubs are perfect for ULTRA 4 and King of the Hammer Race Vehicles.
Increased Ground Clearance
More Power driven to the wheel
1.92:1 Reduction Ratio
Less Stress on the Diff and Axles (50% Less stress)
Axles and CV Joints are 200% stronger
Braking Force Multiplied by 200%
Inbuilt CTIS (Central Tyre Inflation Systems) Lines

They should work for you. Have a look at the designs and see if you could fit the wheel speed sensors to those portals.
 

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Premium Member
Joined
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10,851 Posts
Diffs: https://www.proformance.com.au/ifs-irs-diff

Based on our Race Proven U250mm Ultra Narrow Diff, the Ultra Narrow U290 uses a massive 11.25" (290mm) Ring Gear and massive 9.0" (230mm) Taper Roller Bearings to allow the use of Series 30 CV Joints
Proformance Ultra Narrow Diffs have the CV joints mounted up inside the Ring Gear Carrier, allowing for much longer Axles and much more wheel travel. Inboard Cv joints also provide protection of the CV boot from rocks and debris common if off road use.
The 290 is available with a Spool (locked drive), Detroit Locker, Inboard Brakes and accommodates the heavy duty "Series 30" CV Joints with 40 or 44 spline axles.
With inboard CV Joints, the CV mounting faces are only 40mm Apart.

Portal hubs: https://www.proformance.com.au/ultra4-ifs-irs-portal-reduction-hub
Proformance Portal Geared Hubs are designed specifically to provide the strongest drivetrain possible and the longest axle length for ULTRA 4 racing, Rock Bouncing and Off Road Racing
Our newest portal hub design provides the narrowest and strongest Geared Hub Reduction Drive for IFS and IRS vehicles. Complete with CTIS (Central Tyre Inflation) these hubs are perfect for ULTRA 4 and King of the Hammer Race Vehicles.
Increased Ground Clearance
More Power driven to the wheel
1.92:1 Reduction Ratio
Less Stress on the Diff and Axles (50% Less stress)
Axles and CV Joints are 200% stronger
Braking Force Multiplied by 200%
Inbuilt CTIS (Central Tyre Inflation Systems) Lines

They should work for you. Have a look at the designs and see if you could fit the wheel speed sensors to those portals.
Jrock might just wet himself when he reads this.... :rofl:
No offence meant Jrock....

I looked at portal hubs about 5 years ago for Bozo...but wasn't much available ....glad to see they are now offering IFS set ups...

Portals could be a game changer for some .... @Iconic_ ... @debFJVT .... @Firemedic831 ... to name just a few ..... :rofl:

Cheers
Baz
:blueblob:
 

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Desert Moderator
Joined
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5,659 Posts
Jrock might just wet himself when he reads this.... :rofl:
No offence meant Jrock....

I looked at portal hubs about 5 years ago for Bozo...but wasn't much available ....glad to see they are now offering IFS set ups...

Portals could be a game changer for some .... @Iconic_ ... @debFJVT .... @Firemedic831 ... to name just a few ..... :rofl:

Cheers
Baz
:blueblob:
And those diffs... That combo is going to beat any SFA setup by a country mile - and cost about the same all-in.
 

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MOAB SUPERSTAR
Joined
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5,759 Posts
Diffs: https://www.proformance.com.au/ifs-irs-diff

Based on our Race Proven U250mm Ultra Narrow Diff, the Ultra Narrow U290 uses a massive 11.25" (290mm) Ring Gear and massive 9.0" (230mm) Taper Roller Bearings to allow the use of Series 30 CV Joints
Proformance Ultra Narrow Diffs have the CV joints mounted up inside the Ring Gear Carrier, allowing for much longer Axles and much more wheel travel. Inboard Cv joints also provide protection of the CV boot from rocks and debris common if off road use.
The 290 is available with a Spool (locked drive), Detroit Locker, Inboard Brakes and accommodates the heavy duty "Series 30" CV Joints with 40 or 44 spline axles.
With inboard CV Joints, the CV mounting faces are only 40mm Apart.

Portal hubs: https://www.proformance.com.au/ultra4-ifs-irs-portal-reduction-hub
Proformance Portal Geared Hubs are designed specifically to provide the strongest drivetrain possible and the longest axle length for ULTRA 4 racing, Rock Bouncing and Off Road Racing
Our newest portal hub design provides the narrowest and strongest Geared Hub Reduction Drive for IFS and IRS vehicles. Complete with CTIS (Central Tyre Inflation) these hubs are perfect for ULTRA 4 and King of the Hammer Race Vehicles.
Increased Ground Clearance
More Power driven to the wheel
1.92:1 Reduction Ratio
Less Stress on the Diff and Axles (50% Less stress)
Axles and CV Joints are 200% stronger
Braking Force Multiplied by 200%
Inbuilt CTIS (Central Tyre Inflation Systems) Lines

They should work for you. Have a look at the designs and see if you could fit the wheel speed sensors to those portals.
Jrock might just wet himself when he reads this.... :rofl:
No offence meant Jrock....

I looked at portal hubs about 5 years ago for Bozo...but wasn't much available ....glad to see they are now offering IFS set ups...

Portals could be a game changer for some .... @Iconic_ ... @debFJVT .... @Firemedic831 ... to name just a few ..... :rofl:

Cheers
Baz
:blueblob:
OMG.............:jawdrop: That is some serious parts porn!!!!!
 

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Discussion Starter #8
Diffs: https://www.proformance.com.au/ifs-irs-diff


They should work for you. Have a look at the designs and see if you could fit the wheel speed sensors to those portals.
I'm not quiet sure what the application for these is... Monster trucks? Seems overkill even for Ultra4 racing. Maybe rock-bouncers; they encounter a pretty high amount of shock load.

Considering I can pick up a used Tundra front differential for about $200, and completely rebuild it with cryo-treated performance gears and add an ARB locker for another $1500, I think I'll stick to the Tundra option. I can't imagine one of these things being less than $15,000. Let alone it is six times larger that the differential I was asking about in the first place.
 

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Discussion Starter #9
G'day Rock,
Daft idea here.... which you have probably already thought of and discounted....
would it not be easier to drop the FJ body onto a Tundra rolling chassis ...chop it and make it fit ...
Keeping all the tundra engine/transmissions/ electronics ...etc....
Cheers
Baz
:blueblob:
Well, that is very close to my plan. I am looking to find a crashed/totaled complete Tundra from an auction and pull every single part of it and retrofit the two vehicles together. The chassis from the Tundra is way to different from the FJ's, and modifying body mount locations and manipulating internal sheet metal structures is way more difficult that shortening drive shafts and making some new mounts.

I plan on using the entire wiring harness from the Tundra to ensure the entire CAN Bus stays intact and the vehicle retains 100% factory drivability.

But all that is the easy part. Getting the front differential to fit properly and ensuring the front suspension geometry works is my first hurdle.
 

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11,613 Posts
IMO the mechanical and fab will be the easy part, electronics will be the crux of the build.
 

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So I haven't done one of these but I have done a tundra 4x2 into a 4x4 swap on a 2008 tundra.

You will have major issues with electronics. The entire ecu and wiring would need to be swapped including 4x4 controller and engine harness. You won't be able to just rig it to work with a separate manual switch. Trust me we tried and it was a major headache. You will need a complete donor truck

Transfer cases need to be swapped as well. FJ cruiser uses a manual transfer case. The tundra uses a push button.

The easiest part of the swap would be fabricating the mounts to fit the parts. Fabricating the driveshaft and getting custom Axles. The part that's going to keep you up at night and frustrated are all the computer and wiring

Keep us posted on progress. Good luck
 
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