JZA80 1JZ VVTi Conversion

[Nat]

After a long process I have finally got the 1JZ VVTi engine into my Supra and running. A 1994 JZA80 Manual SZ. A large amount of research, time searching for an engine and many hours of wiring went into it all and I wanted to create a thread outlining some of the important parts of the conversion. I know a lot of people will be saying why not a 2JZ-GTE, but if i wanted one i might as well as sold the car and bought an RZ, I have had the car for years now wanted to keep it, and i really like the way the 1JZ VVTi performs so that is enough justification for me.Ill update this thread as i go though the photos and work out if anything else needs to be documented.

I completed the physical work and wiring myself so it can be done alone, but I would like to thank osman and TRD666 for answering questions, having people around who already been there is always helpful.

The engine purchased was in the form of a 1996 JZX100 Auto chaser front cut, ideally a late model JZZ30 soarer would be a better starting point, but I couldn't get one in the time frame wanted to complete the project. It was in pretty good condition complete and purchased for $2700 but being from a chaser it was a front sump variant which required a little more work. The supra was bone stock mechanically before the conversion and I didn't want it looking to over the top under the hood once it was finished. I was never after a huge power engine just wanted something responsive with more power than the 2JZ-GE. The car still retains the W58 5-Speed just waiting to see how it goes with the power, there is a spare in the shed from the 1/2 cut so if/when the first one lets go ill investigate getting a more substantial gearbox.

The total cost of the conversion was well worth the gains, a lot of new parts were purchased along the way including serviceable parts and a few aftermarket parts, like intercooler, exhaust, Aluminum radiator so it could have been done much cheaper than what this project was done for. Serviceable parts like the balancer, water pump, cam, crank seals, ect were also replaced while the engine was out. I already had an A80 1/2 cut as well so the extra parts I had made it easier in regards to the sump, wiring and keeping the car on the road while everything else was being worked on. The time involved and labour would be considerable if your paying for the job to be done, I wanted to attempt the conversion myself, it was a big learning experience but was way more rewarding doing it all yourself yourself. I spent around $6K total.

I just wanted to start this thread to outline some of the major things done with the conversion, not to detail the whole process, the engine install and removal process, clutch install that are detailed in the workshop manuals that are found online, and you can follow these for the most of the work.

Once the 1JZ is out and gearbox removed and on the stand you can change the serviceable parts much easier I replaced.

Front crank seal
Rear crank seal
Cam Seals
Water pump
Thermostat
Timing Belt
Dampener
Installed new clutch Exedy clutch, input shaft bearing and had the flywheel machined.



The front sump setup can be replaced with the sump from your non turbo -GE engine. To remove/install the sump, the lower oil pan needs to be removed to allow access to the bolts on the upper Aluminum part of the sump from the inside. The sump uses glue type gasket material and it is tight to get off, once you are sure all bolts are removed you can wedge a thin screwdriver/metal plate in between the block and the sump then wedge a another thin screwdriver/plate in a little further along take the first wedge out and put it in along a bit further and keep going till the sump comes loose, be careful not to damage the base of the block or the sump they may leak. When reinstalling a sump you will need to clean the sump and block surfaces and add liquid gasket material as per the service manual and install the top section of the sump and the same need to be done with the lower oil pan.

The -GE sump needs a basic modification, the oil return hole needs to be drilled out you can use a 20mm step drill and a round file to finish it off. The two bolt holes beside it can be drilled out to 6.5mm and tapped with a M8 tap.

Once the sump is installed on the engine due to the change in sump configuration you will need to either modify the existing turbo oil drain or install the oil drain setup off a VVTi JZZ30 Soarer engine. I did the latter the cost was $140 can’t beat bolt on for simplicity.

Part numbers are
15481 88410 Pipe
15474 88410 Pipe, Oil Turbo
15491 88410 Pipe

The fuel supply lines that go to the dampener attached to the block are also different or mine off the JZX100 was cut can’t remember now either way the -GE Fuel pulsation dampener setup was used so that the supply line would bolt straight to it. The line to the fuel rail will bolt onto the dampener. The fuel return line although routed differently will hook up from the 1JZ to the supra's fuel lines.

The engine mounts and brackets from the supra need to be installed on the 1JZ, the exhaust side uses different holes on the block that are further back, easily identifiable if you look at which ones are used on your -GE block. You may need to get some WD40 in the holes and a spare bolt that fits and clean out the threads a bit as they can get a little corroded and dirty. Install the brackets and mounts leave the bolts off the bottom of the mounts when installing the engine.

Before the -GE engine was removed from the supra the A/C pump and PS pump were unbolted and wired them to the side so that the A/C lines didn't have to be removed and re-gassed. This required the stud to be removed that holds the A/C pump in place it can be removed by attaching two nuts on the thread, tightening them together and undoing the bottom one, the stud will come with it.

For reinstalllation of the Power Steering pump, the throttle body was left off the intake manifold of the 1JZ and removed the Power steering fluid reisivior from the -GE (Catching the fluid and disgarding it) and replacing it with the suction port off the 1JZ PS pump with a new o-ring. It was blanked off until everything was reinstalled to stop fluid leaking. The new radiator was installed with new radiator pipes, the bottom was a new one I had from the -GE and fit fine, I used a new twin turbo supra top radiator hose the JZX100 hose was just a little to short, maybe the VVTi TT supra model hose would be more suitable the non VVTi one was the only one I could get locally at the time.


The heater hoses also needed replacing, it can be done by molding up some 2mm wire to the shape of the hoses needed and heading to the local auto parts shop and track down some suitable hose. What was found to suit was from a Holden camira and a VL commodore, they just need to be cut to length and one needed a joiner to attach to one of the factory JZX100 hose.

I Purchased a Greddy Power Extreme II Cat Back exhaust for the car and for the meantime will be using the Cat/Mid pipe that came with the car, it required some minor modification to mount up with the 3"JZX100 dump pipe used from the turbo back, the dump pipe did not foul on anything it was just the angle of the bottom flange didn't suit the A80 exhaust. It was very close to fitting the top of the flange that attaches to the dump pipe was about 3mm off the top of the flange although the bottom touched so it could be installed. The angle on the flange near the cat needed a minor change as the angle was pushing the exhaust to far up on the rear of the where it fouled the sub frame on the rear.

[Nat]

The HDI GT spec Tube and Fin intercooler setup for the JZA80 Twin Turbo suited pretty well. The bottom mounting plated didn't fit so needed to longer aliminium mounts, also Some of the hard lines in front of the radiator needed moving, just by undoing there mounts and moving the piping along a little, other wise it was installed as the instructions except for the pipe that goes to the turbo inlet. The first two Black JZX100 intercooler piping bits were kept as pictured, they don't mount up with the JZA80 piping but the end of the pipe left over JZA80 piping kit can be cut off the and used to join up to the factory piping, it fit well and keeps more of a factory appearance in the engine bay at least on the turbo side.





I was pretty happy when the car started first go, took it easy for the first couple of weeks to make sure everything was ok. Had a bit of a minor leak in the power steering, so I am going to rebuild one of my power steering pumps and flush the system with new fluid. Overall very happy with the performance very responsive engine, is running a stable 10.6 PSI, as it is have the HDI boost controller but not tried running more boost just yet. Feels to have plenty of power as it is at the moment, hope to get it on a dyno in the near future just to get an idea of what it is putting out.

[Nat]

Wiring and electronics
I will update this when I get a chance to get a chance to get all of the plug diagrams uploaded I have everything on paper at the moment, will take a while for me to get the time to get everything to digital form.


The Car is running the stock Auto ECU with a bridged netural start switch, the plan is to shortly upgrade to a manual power FC which is still available for the JZX100. I also installed the new HDI evolution boost controller and gauge.

As there was a spare loom from the A80 SZ ½ cut, the loom from both the JZX engine and JZA body were used to create a harness that allowed the engine loom to be plugged straight into the supra body loom. This made the job a lot easier and convenient being able to do all the work out of the car while the car was still on the road. The available JZX100 Wiring diagrams/information was not the best, I found the original Japanese diagram, and a multimeter was most useful and tested everything on the ½ cut.

The tacho from a regular RZ supra was also installed and worked perfectly with the 1JZ’s Ignition system.

Some of the fun

[Grega]

nice work guys
although the wiring spaghetti makes me wonder :|

[Shakotan_Aaron]

looks like a very good conversion so far, heaps tidy.

have to love the revvyness of 1j's

[Smokey228]

Looks very nce man, almost like it belongs

But i dont understand why you wouldnt have gone the 2JZGTE. I would have assumed that almost everything would have been a straight bolt up, and most wiring would have been a straight plug. And then very few minor changes here and there...

I understand you said, you like the 1j performance etc, but the 2j is basically the same, + something across the board, basically making it a better all round engine...
And ofcourse, swapping an engine to a 2J, is generally cheaper then swapping the entire car

But i wont say it doesnt look great man! Nice work!

Cheers,
Jase

[jure]

well done mate... awesome work!!

[Nat]

Thanks guys haven't had any time to do much lately but did get the chance to make up a Carbon/Kevlar Surround for the pod filter.

[Robbos_Toyotas]

wow, i really like that air filter cover - how did you make it?
cheers
Blake