Queensland Style LS Swap

[matt88]

Oh no, it's another LS swap!

Anyway here's my swap. You may have seen me asking questions in the forum over the last few years to guide me in the right direction. It's now finished, registered, insured and already rolling on the roads in my area.

Started on the swap about three years ago with just 3,000 km on the clock. Owned the 2017 car since new. I've done about 300 more Kms since then. So it's still fresh and like new.

Everything works and it totally rips. AGT Engineering canbus translator is the key. I did have a few bumps with it (and the harness that AGT supplied) but I got there in the end, including with upgrading the firmware to the latest.

Thanks to Ash at 29 Automotive for doing the mod plate so I could get it on the road.

Thanks to Kye at Knight Family Motorsport for doing the Dyno tune.

Also a special thanks to Febest (Pacific Auto Zone) in Victoria. They were particularly helpful with information on axles and CV joints when I was going through the process of making my custom axles out of Commodore and Landcruiser parts. Not only were they helpful in sharing information and measurements when needed, the parts I needed were in stock and I always received them in record times and at great prices. Very rare for any business today.

FYI I am on the Sunshine Coast in Queensland, Australia.

OK here's a rough list of everything I've done below. All parts were new. I did all the work myself. If you have any questions about anything specific and want more pics or info, please ask.

Crate 6.2 Litre LS3 with mildly upgraded cam, pushrods and springs.
Sikky Aluminium oil pan with remote mount oil filter.
Sikky Aluminium offset steering rack bushings.
TR-6060 Transmission in MER ratios.
MGW Short throw shifter assembly.
Custom clutch master cylinder assembly with remote reservoir.
GM ZF 8.6 Diff in 3.45 ratio.
Custom 3" inch chromoly steel slip yoke drive shaft with 1350 uni joints and solid aluminium couplers.
Custom CV axles made from Commodore inner CV's, Hardened 80 Series Landcruiser Birfield shafts and 100 Series Landcruiser outer CV's milled and hardened to match the Subaru hub splines.
Chrysler 300C SRT8 360x32 front vented brake rotors and 350x28 vented rear brake rotors.
C7 Corvette Grandsport Brembo 6 pot front and 4 pot rear brake calipers.
Wilwood disc caliper handbrake kit.
Ozzy Tyres Hussla GT 18x9.5 wheels +50 offset with 265/35/18 Semi slick tyres.
Shockworks coilovers with 8Kg spring rate.
Whiteline sway bars, bushing kits, camber kits.
Custom Ford Mustang 3 row high capacity radiator with custom overflow tank, dual 14 inch fans on custom shroud and dual PWM controllers.
AGT Engineering Canbus translator and LS3 swap wiring harness with GM e38 ECU.
AGT Engineering engine swap mount kit for engine and transmission mounts to factory mounting points (no firewall modifications).
Custom over-the-radiator intake and K&N air filter.
Custom 1 & 7/8 inch equal length shorty headers, 400 cell cats, full 3 inch stainless system throughout, X Pipe, dual 26 inch Classic Chambered Powerstick centre mufflers, ebay clones of Borla S type mufflers and Helmholtz resonators.
Custom fabricated aluminium 78 litre fuel tank with Camaro ZL1 65 psi fuel pump hanger and PWM fuel pump controller. Rollover safety, vents, EVAP purge and all such fuel safety systems remain in place.
Bosch alternator.
4HP High torque gear reduction starter.
Denso AC Compressor with custom AC plumbing.


OK I think that's it. I've surely missed something but am happy to elaborate with more info and pics if asked.

Pro tip: Rename the PDF file extension to MP4.....

Enjoy!
Matt





















run20240118_181633.pdf

[Clash0901]

Nice one mate!

[Rex1585]

Tell me more about the rear subframe

Sent from my Pixel 7 Pro using Tapatalk

[matt88]

Originally Posted by Rex1585

Tell me more about the rear subframe

Sent from my Pixel 7 Pro using Tapatalk

OK so I wanted to put in a larger diff because from all I could see online the standard 8 inch diff is ok, but only just ok and still has a few issues with too much power/torque here and there.

I also wanted a different ratio than the standard 4.15 (or whatever it was) as I knew that with the TR6060 trans and the 18 inch tyres I wanted 1st gear would be all but useless.

I used the Tremec gear ratio calculator, popped in my trans ratios and tyre size and then started playing around with various diff ratios such that redline (about 6200 rpm) I could get to 110Km/h in second gear. This was simply for the reason that if I was doing a 0-100kmh sprint I only wanted to have to do one gear change. I also plugged in the Commodore tyre size and ratio which is 3.70 to see how those numbers look. What do you know, with my slightly smaller tyre size than Commodore a 3.45 ratio was just right to mimic what the commodore does (also only one gear change to redline a 0-100kmh drag). Actually I think the commodore ute manual may use a 3.45?

Finally, after watching a few vids online it seemed that those who had swapped in the 3.73 replacement gearset into the standard 8 inch diff were still having troubles using first gear and struggling to manage wheelspin. Again, this lead me to believe something different than 3.70 was the target.

I started to investigate getting one of the rebuilt Ford diff kits from Grannas, but (as usual) being in Australia means that after option this, option that, need this extra thing, freight, duty etc etc, it was going to end up being about 5 to 6K AUD landed here in Aus. Considering (at the time) you could buy a brand new Commodore 8.6 IRS diff here in Australia for just 2,100 AUD (approx 1,400 USD) at the time, in many ratio options, it was easy enough to just buy one. That was in 2021.

The final idea I had about using a Commodore diff was that if I went through the headache of modifying my subframe to make it fit, if at a later date I felt that even this diff is too weak, I could very well bolt up the Camaro ZL1 diff which (I believe) has the same mounting ears/locations.

Ok so I bought the engine, trans and diff in 3.45 ratio all in one lot.

First job was to measure all the angles on the diff subframe so I could mimic those when I had the diff subframe off the car. I dropped the diff subframe and before taking out the diff just eyeballed and measured a few things and took some pics.

I took out the diff and made a simple wooden jig on the floor that I sat everything on.

From there I raised the subframe up and tried to sit it on top of the diff in the centre where it should go. And from there I just started cutting metal away from the subframe until I could get the diff into the centre area of the subframe. Taking note of a few critical measurements like how high the diff could be raised into the centre of the frame without sitting too high in relation to how high the old one sat. Ensuring it was straight with a spirit level, sitting at the angles the old one did, equally centred left to right etc., ensuring the input flange on the front was at the same angle the old one was, parallel to the subframe ears, ensuring the areas the CV inners would reside would be in the right area etc...

After that, when I thought that the diff was in a relatively good position it was then a matter of working out how best to come up with a mounting solution and what I felt was a good arrangement for strengthening any areas that were removed during surgery. Some cardboard aided design, templates, tape and whatever else we all use were engaged.

I charged forward to add a few pieces here and there, some gussets bla bla bla. Adding where I thought it was logical in adding strength. I used anywhere from 3 to 6mm thick steels which I felt were easily overkill for what I was looking to achieve. The pics below probably tell the story better than I am writing it.

After I got to a certain point where I was happy with everything tacked together I then took it to Limitless Chassis out the back of Coolum to be welded up. I am no means a welder of anything critical so I knew this would be something I needed to farm out.

After Limitless Chassis did their thing I then took it to the engineer so he could eyeball it before coating. He gave it the thumbs up and said he would be happy to engineer it once in the vehicle (so he could tie the VIN number to it).

I then took it home for test fitting. One issue was the diff was sitting about 20mm higher than the original and I felt it was too close to the EVAP canister. I took the bracket off the evap canister and shorted it by about 40mm (cut/weld/paint, for some reason it has an excessive amount of clearance above it to the boot of the car). This then still had the evap canister with about 20mm above it to the boot and more than an inch below it to the diff. So that was good.

After I was confident I had thought of everything I took it to Southeast Superior coatings in Coolum to be blasted and powder coated. It looked fantastic when done.

I then proceeded through the project and came across a challenge when I was making my axles. After test fitting the inner cv's with the boots on I realised I did not have enough clearance for them. Therefore I had to clearance the subframe and weld in some big old pieces to make the space I needed. The engineer inspected again and was still happy. So that meant I had to get it powder coated again.

If I had my way again I probably wouldn't have mounted it up so "high". I was simply trying to make it fit as tightly as I could because I thought I would need all the clearance I could get for the exhaust. In the end, if the diff was about an inch lower I probably wouldn't have had to do the clearancing for the cv boots and still would have likely had enough room for the exhaust. At this point, the axles are sitting almost completely straight at ride height, so the diff could easily be lower in the subframe and not cause issues as far as I can see.

Overall I spent 2100 AUD on the diff. 140 AUD two times (280 AUD total) for powder coating. Some scrap steel from my uncle's shed. 440 AUD for welding at limitless chassis. I also installed some new bushings from Whiteline. I can't remember how much they were.

So for circa 3k AUD (approx 2K USD) I got myself a nice new diff installed and ready to go in the ratio I thought was just right. And oh man, does it feel just right!

As above, if I could do it all again the only thing I would probably change is how high I made it sit. It could easily have been an inch lower.

After this portion of the project was complete, the next problem presented itself: The pinion for the drive shaft was then in an awkward position for the fuel tank/driveshaft. You can see in one of the pics where I have already started to mark up the area I knew I needed to clearance on the tank and heat shield. After a few minutes, I realised a completely custom replacement fuel tank was going to be needed. Oh well, I always wanted the chance to fit twin 3 inch exhaust pipes through.... The tank story is for another time.... Oh so I guess that is an important point. If you want to keep your stock tank you would need to mount a little lower and over to the right. How much? Who knows.

Edit: Took the pics out of this post and put them in Google drive instead. All the pics are here:
https://drive.google.com/drive/folde...usp=drive_link

[matt88]

Originally Posted by Clash0901

Nice one mate!

Thank you. Definitely proud of it!

[sam69]

Awesome job makes me want to get on a plane and come have a look

[RedReplicant]

Beautiful work on the rear subframe!

[Clash0901]

Did you build the gas tank or is that something you bought pre-made? Looks sweet!

Also, I would suggest you take all of your diff fab photos and upload to a google drive and just link to them on your post so it declutters a bit. Maybe lave a handful of them on your original post. Just my 2 cents, easy to get lost in all of those photos when scrolling. Diff fab work is fantastic as well by the way! Work of art.

Would love to see a video of this running maybe upload to YT? I'm on my phone so not as easy to change .pdf to .mp4

Cheers

[matt88]

Originally Posted by Clash0901

Did you build the gas tank or is that something you bought pre-made? Looks sweet!

Also, I would suggest you take all of your diff fab photos and upload to a google drive and just link to them on your post so it declutters a bit. Maybe lave a handful of them on your original post. Just my 2 cents, easy to get lost in all of those photos when scrolling. Diff fab work is fantastic as well by the way! Work of art.

Would love to see a video of this running maybe upload to YT? I'm on my phone so not as easy to change .pdf to .mp4

Cheers

Yes I built the tank myself. As I am proud of the tank build I will do a post on building it.

Yes you are right, will shift a lot of the pics away to google drive.

Diff subframe was a fun part of the project. I definitely have more confidence now in this department for future projects.

I don't have any videos on a youtube channel. Perhaps it is time.

[kask2_6.0]

Great work on the subframe and diff! I'm actually working on that project right now myself with the 8.6 diff. Happy to see someone else also went that route! Cheaper than the 8.8, slightly smaller packaging, and one other really cool fact is that the z/28 diff cover is available to easily add a built in liquid/liquid oil cooler.

[Irace86.2.0]

Extremely impressive.

[gt5759]

Very well done sir!