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Ls2 swapped S12

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Joined: 18 Apr 2016

Posts: 3

PostPosted: Sun Aug 27, 2017 2:46 pm    Post subject: Ls2 swapped S12 Reply with quote

So I came to realize that after lurking here for about 2 years, I’ve never posted about my car.

Back in 2005 I bought a mint Nissan S12. I was 16 y/o at the time and this is my 2nd car (first being a RA64 Celica GT, which was also a nice and super tough car, but rotted to the bones).

Soon after owning it I started adding parts to it, coilover, wheels, brake upgrades, etc. Also took the car to some lapping events. After a few years of sorting out the suspension, changing the geometry and fabricating a few custom suspension parts I swapped in a KA24DE (which was a nice power upper from the 105bhp CA20E). The fun lasted a few years but I ended up wanting more power.

The CA20E in all it’s glory!

KA24DE… a bit better… still not enough

So I started hunting for a LS swap and lurking here to gather the info to help me through the swap. I ended up buying a LS2 swap from a CTS-V with the CXRacing S13 swap kit coming with it. I knew that the kit has some flaw, but since I knew I would have to mod the kit anyway to make it fit in the S12, I thought it wouldn’t matter too much.

Right from the start I knew it would be a bit different that swapping it in a S13/S14. Our car have a smaller transmission tunnel and the engine bay is a bit narrower, but other than that it’s pretty much the same.
Dropping the engine in for the first time!

I know some of the biggest complain about the CX kit is that they place the engine too far from the firewall, luckily for me, with a little bit of notching on the subframe the engine is ½’’ from the firewall which is perfect in my opinion.

Once the engine found it place it was time to attach the transmission to it and massage the transmission tunnel….or not. After a few hours of bashing the tunnel I came to the conclusion that it just wouldn’t work on a S12. So I took the cut off wheel and removed the top of the tunnel.
Now the CTS-V transmission had its own challenges. 1st to tackle was the shifter, which is remote and waaaaaaay too far back. So I ended up making a new shifter base that would bolt to the transmission.

I upgrade to a hurst short shifter at the same time. It brought some nice crisp shift with a higher knob placement than stock, which is perfect to me. It bring the knob closer to the steering wheel.
Then it was time to redo that transmission tunnel

Next was a few other things that needed to be addressed. I modified the heater core so the ports are about 4’’ outward from stock. The stock ports where pointing right behind the right engine head.
Extended heater tube

Here you can see the old firewall hole being filled with the new ports where the AC ports would be (car don’t have AC)

Painted engine bay

Next challenge caused by the CTS-V T56 was the driveshaft. It have a fixed output flange that doesn’t plunge in and out like a regular transmission. So the driveshaft need to be able to have that plunge. Driveshaftshop made me a nice custom aluminium driveshaft with a CV to absorb the axial movement.
Then it was the header fitment. The CXRacing headers have received a lot of hate… and I can agree that they are not the best swap header. I had to ding them to clear one of the starter bolt, grind a corner on the bellhousing and redo the bottom since they were aiming right at my floor pan.

I reduced the collector from 3’’ to 2 ½’’ and angle them so they clear the floor pan, then proceeded to make the exhaust. Y pipe to 3’’ straight into a Dynomax VT muffler.

The rest was pretty straight forward. I relocated the new fuel filter under the floor pan, installed a remote oil filter with the already existing oil cooler. I made a heater bypass circuit with some scrap aluminium and some old ski poles.
Yep that’s right they used to be ski poles haha

I have to say the engine feel right at home in the bay.

The cluster is still OEM and fully functional. The sensors for the oil pressure and temperature are the OEM ones. Had to adapt them to the engine but that wasn’t hard at all. The speedometer is taken care by a Cable-X from abbott (the S12 use a cable driven speedo). The toughest part was the tachometer. I had to build a pull up resistor circuit to boost the RPM signal coming out of the ECM to a square 0-12V and then reboost this signal using a tachometer signal booster that use a coil that get discharged to simulate the high voltage of an ignition coil discharging. The Dakota or any 12V signal just wouldn’t be strong enough to operate the S12 tachometer. It took some research to get it all to work but it’s so nice to have all the original dials working.
Cable-X unit is hiding where the audio deck used to be. There is a switch panel that cover it.

The swap was completed last month. I drove the car a bit, burned some msd ignition wires… The CXRacing header really does have a shitty plug wire clearance. I ended up making some brackets to keep two wires away from the headers and bought a set of Taylor wires. So far so good with this setup. In about two weeks the car will get his final tune on the Dyno! The engine management is a controller kit from GMPP that they sell to be used on their crate engine. So this part of the project was pretty much bolt on (the original ECM was smashed when the CTS-V got totalled).

So that’s about it for now! I’ll keep this updated as I break stuff and fix it I guess haha!

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Joined: 25 Nov 2007

Posts: 505
Location: FL

PostPosted: Tue Aug 29, 2017 2:50 pm    Post subject: Reply with quote

Awesome, can't wait for more picture's & video's!

Oh the joy Smile

11.7@119mph 1.7 60'
ASAPerformance built
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Joined: 09 May 2008

Posts: 313

PostPosted: Sun Sep 03, 2017 5:47 pm    Post subject: Reply with quote

That's pretty awesome. How are the rear ends in these?

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Joined: 18 Apr 2016

Posts: 3

PostPosted: Mon Sep 04, 2017 2:11 pm    Post subject: Reply with quote

They are pretty stout. The 2.0L S12s have a longnose R180.

I've swapped in a R200 longnose from a VG30 S12 (3.9 ratio) and installed a quaife lsd in it. It should be tough enough, especially since I don't really plan to drag race the car.

Weakest part would be the axle, I have a spare set just in case!

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Joined: 18 Apr 2016

Posts: 3

PostPosted: Tue Sep 12, 2017 10:35 am    Post subject: Reply with quote

So I took the car to the dyno. The numbers were above my expectations!

382whp and 388 lbs of torque

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