Rolling the dice - slow moving turbo HZJ105 project (2 Viewers)

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Resident galah
Dec 17, 2007
Ina chónaí go buan ar an flerf
After collecting parts over the past couple of years, I finally started on turbo charging my HZJ105 cruiser.

This is a slow moving project as I am working away from home, so don't get much time in the shed.

A bit of back story:
My cruiser has been parked up for nearly two years already after the engine boiled and I discovered a cracked head, and blocked radiator due to mixing incompatible coolant types.

I got lucky and the bottom end had no damage, so I re-co'd and fitted a used head, all new cooling system including radiator, thermostat, heater core, hoses etc.
With the engine, I pulled the head, fitted a second hand head, cleaned up and lapped the valves, dropped the sump and cleaned out all the oil and water sludge and checked for white metal in the oil.
No sign of bearing metal.
Cylinder walls were all in good condition, as were piston crowns.
I put it all back together and turned it over with the injectors out. Oil pressure came up fairly quickly. so I put the injectors back in and got it running. After the IP and injectors were rimed, it fired up and ran pretty well straight away, though a little tappy up top. after running it up to operating temp it started sounding a little better.
After shutting it down, I pulled the rocker cover and went through and measured up for new valve shims, which I still have to fit.
so, seems like I dodged a bullet with the engine. I've since driven it 200km to relocate house, and it ran sweet.

While its been off the road, I did a full rebuild on the front end. New bearings and seals in the knuckles, new CV/birfield in left side (I'd blown one up and been running in rear wheel drive for a while), new DBA T3 rotors, new pads, new wheel bearings, rebuild kit through the calipers, fitted braided lines on the brakes, new TRE, new knuckle/steering arm studs and cone washers, new hub studs and cone washers etc. Re-fitted my rebuilt front factory locked diff centre, and upgraded the 3rd member studs and bolts to 10mm (the standard 8mm studs are known to fail).
Also re-did the rear brakes, wheel bearings etc, and fitted new uni joints in both driveshafts.

While my cruiser was parked up, it got wet inside and ended up all musty. I striped all the interior out (except the dash), threw out carpet underlay, and pressure washed the carpets, and scrubbed everything else clean.
While the interior was out, I added dynamat sound deadener to as many flat panels as I could including the underside of the roof, doors, quarter panels and floor. I then added a layer of 6mm, foil insulated closed cell foam for some heat and noise insulation.
Then I refitted the interior.

My cruiser is sort of stock :rofl: it's been wheeled failry hard, I think one or two panels have no dings.
it has 2" lift, with slotted/drilled bushes in the radius arms, and modified shock mounts and longer shock for an extra 60mm shock length front and back. No front sway bar, kept the rear to get sway bar in to make the front suspension flex.
The aim was for the travel of a 4" lift,with out the height.
285/75r16 All Terrains for daily use, and 315/75r16 for playtime on 1"offset rims.
5 speed manual trans (R151, possibly upgrade this later)
4.31:1 diff gears.
ARB rear locker, toyota e-locker in the front, (I had an e-locker in the rear from an 80series, but different axle specs caused me issues) lockers are set up to be switched individually, so front only can be used.
I cut out the sills/rockers and welded in a tapered RHS section with sliders built in, this gives great ground clearance with some protection from rocks.
I also built a rear bumper/tire carrier with similar ideas to keep ground clearance as high as possible.

Rolling the dice.
Over the past couple of weeks, I decided to go ahead with fitting a turbo. This is something I have wanted to do since I bought this car. My previous cruiser was a HDJ81 factory turboed 1hd-t which I had tuned up quite a bit (pre Gturbo days). The HZJ105 just doesn't live up to the power of a tuned up 1hd-t.
Turboing the 105 series 1HZ's is considered to be a gamble (hence "Rolling the Dice"). They have lighter pistons than earlier 1HZ's, and many people recommend NOT to turbo these engines. There are plenty of success stories, and plenty of cracked heads, cracked pistons, and hoed pistons, and overheating problems etc etc. Some people will say once turboed, the fuse has been lit?

I think that lots of these engines aren't turboed properly. They aren't tuned with regard to EGTs and AFRs, they are either tuned for power, and run too hot. Or they are tuned "conservatively" and run 7-10psi in the belief that too much boost is what kills the engines. Or they run poorly matched turbo's. Often they aren't intercooled.

A lot of these things can be avoided, and managed better than is often done.

My Plan is to wake up the 1HZzzzzzzzzzz, without going too stupid on it. I want it too last,so will be a little more conservative than I have in the past.
I will a boost compensator, intercooler, EGT, AFR, Oil pressure, and water temp guages fitted up before this is put into use.

I like to look for bargains, and alternatives to keep the cost down without doing stuff too much on the cheap. The end result has to live up to expectations.

I have a used standard Toyota turbo from a 100 series 1hd-fte. I have fitted a Supra 7MGTE front compressor housing to simplify connecting the intake. This turbo should give decent low end response, and reasonably high flow at modest boost numbers (for a stock turbo).
I have fitted a 1 bar waste gate actuator from Kinugawa turbo. (I had to re-drill the bracket to get it to fit)
I purchased a new 1HD-T exhaust manifold front half from Amayama. I couldn't find a used one, and amayama's price was about what I'd seen them sell for second hand.
Manifold has been drilled and tapped for pre-turbo EGT probe.

Fuel pump
I will be running the stock fuel pump.
I will fit an aneroid/boost compensator to it to improve tuning options. (still looking for a bargain )
I will have an EGT probe pre turbo, and will install an AFR/O2 sensor in the dump pipe. (not sure if the dump pipe is the best place for the AFR sensor??)

I am in the process of fabricating a new exhaust system, I've run out of parts and parts shop is on holidays!!
I have used 4" and 3" stainless pipe, and weld in mandrel bends, and v-band flanges. I have used a 3" and 2.5" elbow cut and shut to form the first bend of the dump pipe, and to separate turbine exhaust and waste gate exhaust.
This joins to a 4" v-band flange, then 4" pipe and elbow to the transfer case.
(The reason for 4" dump pipe is to provide an expansion chamber so turbo can spool up with absolutely no back pressure. I did this on my HDJ81 about 10 years ago, and it seemed to work really well, so figured I'd do the same again.)
At the transfer case, the pipe tapers to 3" to pass between the transfer and the chassis, I had to cut a lug off the side of the transfer for clearance. This section will all be hard mounted to the transfer case, so minimal clearance from the transfer is needed.
After the transfer case I have a 8" braided flex, then a 6x9x16" full flow muffler, before turning up over the rear diff, and out past my 90 litre Prado rear sub-tank, then into a 6x14" round full flow muffler at the rear.
The exhaust after the braided flex is mounted to the chassis using the Toyota brackets and rubber block mounts. I have kept minimum of 10mm (3/8) clearance to the chassis. with the 8" flex, this should be enough clearance.

My aim was to fit the largest mufflers I could, and use bends no greater than 45 degrees if possible and keep everything above the chassis rails. I will achieve this except for 60 degree bends for the dump pipe, and one 60 degree bend to get past my sub tank.
I've used several v-band flanges, as the last system I built for my HDJ81 was a complete ballsack to get in and out, so I've made this one in shorter pieces.

I will eventually make a 3" stainless snorkel, into a HDJ100 series air filter housing.
I intend to fit a 600x300x75mm FMIC, or possibly larger if I can. I will again aim to minimise bends in the intake tract, and keep it as short as possible. If I have to put a holesaw through sheet metal, so be it :hillbilly: my cruiser has been used and abused, and is no stranger to the 5" grinder and MIG, so its far from pristine.
I will eventually make up a custom intake manifold too with a larger plenum, and possibly bellmouths into the intake runners.

Pics to come.

turbo, manifold, and EGT pyro port

turbo, looks like it was made to fit in this hole

mounting lugs at rear of transfer case, 8" flex joint

front 2/3s welded up, dump pipe not quite complete

dump pipe, not complete. O2 sensor port for AFR gauge

3" into 4" dump pipe. O2 port on top

dump again

bits welded ready to go

trying to flatten out a 3" elbow to fit a 4" v-band flange

jig for dump pipe. 3" elbow for turbine exhaust, cut to allow waste gate exhaust to merge.
still needs 2.5" elbow spliced to the side for wastegate exhaust

jig for dump pipe. took lots of measuring to get this figured out.

jig for dump pipe
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I'd be happy to have some comments on my TIG welding skills. 1st TIG welding I've done in about 25years :hmm: bit of a challenge, but really enjoyed it.

jig I made to mark elbows accuratly for cutting

I used a piece of rigid plastic cut to fit around the pipe, and marked out a protractor on a piece of board, then fixed the plastic to the board to pivot from the elbow radius centre point. Position the elbow in the right spot, and swing the plastic template to the angle I want.
Cutting elbows like this gives a true circle at the cut so the elbow mates neatly to straight pipe or another cut elbow.
Tig looks fine to me man..... I'm liking the jigs and protractor settup.... seems to be a long way from turbo to your flex pipe would be my only concern..... keep the pics and updates coming....
Tig looks fine to me man..... I'm liking the jigs and protractor settup.... seems to be a long way from turbo to your flex pipe would be my only concern..... keep the pics and updates coming....

cheers. not bad for a chippy hey :D

I did almost identical set up on my old HDJ80, but with mild steel pipe. I made mounting lugs at the bellhousing and transfer so they could flex a little to allow for expansion along the pipe. I found it worked perfectly, with 10mm clearance at the chassis, I had no vibration, and no contact with the chassis. the most vibration was at engine shut down when the engine would shudder to a stop, even then, no contact anywhere

the flex is at the transition from pipe being rigid mounted to the engine/trans, to being soft mounted at the chassis.

will see how it goes this time, I know stainless expands more than mild steel
Looks great. I will look forward to watching it all come together.

The one thing I can contribute is that my innovate AFR gauge recommends the O2 probe to be no less than 24 inches after the turbo.
I love your layout and templates. Exactly how I would have done it.
Looks great. I will look forward to watching it all come together.

The one thing I can contribute is that my innovate AFR gauge recommends the O2 probe to be no less than 24 inches after the turbo.

Ahhh! I did wonder about this, after i welded the bung in! Doh!

will have to do some googling
thanks Dilby

looks like its probably to do with heat. the sensor can only tolerate max 900F (480C) measured at the bung. I'm guessing it'll see mre than that closer to the turbo :bang: :hillbilly:
so, with a bit more reading, it looks like my O2 sensor bung will be workable as is. I will need to keep an eye on max temperature at the bung. If it gets too hot, i can fit a heatsink at the sensor, or fit an extended heatsink bung insert to shift the sensor away fron the heat a bit.
I would install a new bung a wee bit downstream while you have the plumbing out of the truck. Easier to deal with now, rather than later.

O2 sensors need to be in the exhaust stream to get an accurate measurement, thus putting on a spacer/extension can give false readings...which is why folks use extensions in gassers to fool their ECM into thinking that the motor is running clean.

I ran an Innovate LM2 system in my Audi, and may install a bung in my 80 when the time comes to ramp up the fuel. Easy to use, and can log/plot tons of data.
Be sure to place the bung where there is enough room/clearance for the Bosch wideband sensor and related wiring. It is also best if oriented between 9 and 3 o'clock, so no moisture collects on the sensor after shutdown...helps the sensor live longer.
Be sure to place the bung where there is enough room/clearance for the Bosch wideband sensor and related wiring. It is also best if oriented between 9 and 3 o'clock, so no moisture collects on the sensor after shutdown...helps the sensor live longer.

On the topside of the pipe, if that wasn't already clear.
I got a little more done today. Definitely a slow moving project! Pics to follow

My son helped me bolt the completed exhaust sections in place under the car. This let me sort out a couple of the hangers, and gives me a definite point to work from for the last section from the rear diff to the bumper. I'll have to take a couple of sections back out to complete a couple of welds, and to add another O2 sensor port in a more suitable position.

A couple of my self-aligning V-band flanges warped slightly with welding which made them a bitch to get together.
** note to self, keep flanges clamped together during welding, or use non self-aligning V-bands :hillbilly:

for this project, I bought a new, genuine, turbo exhaust manifold front section intending to re-use the rear section from my 1hz. I've had the seized up manifold joint of my original manifold soaking with Rostoff for the past few weeks, and managed to separate the manifold today. The steel sealing rings are completely rusted into the grooves. I think I may end up buying the rear section too. Might try putting some heat to it tomorrow.

I need to order a couple more 3" bends to finish. The last section is going to be tricky to get past my 90litre Prado sub-tank, and the 45* bends I have aren't quite going to get me there.

I've been enjoying TIG welding! and had fun starting to teach my 14yr old how to TIG weld too.
Its hard to get decent pics under the truck!

this is from transfer case looking forward
you can just see the v-band clamp at the back of the 4-3" taper, 4" dump pipe disappearing up to the turbo.
I have about 12mm clearance from the chassis, and about 20mm from the front driveshaft.

this is looking from the 6 x 9 magnaflow muffler, forward to the transfer case. shows v-band and flex, then 10degree double offset to get past the transfer case, and the crossmember mounting bracket on the chassis rail. I cut a little tab off the side of the transfer to get some clearance.
there is about 10-12mm minimum clearance everywhere.
exhaust is hard mounted to the engine block, and transfer case to this point. Hangers are visible bolted to the transfer case. I made these with 20x3mm flat bar, and oriented them to allow some thermal expansion along the exhaust pipe. I also drilled through the flat bar, hoping to help it flex

looking from transfer case to the rear. 10" long flex, v-band, then 6 x 9 x 16" magnaflow straight through muffler. It has offset entry, centred exit. I canted it slightly to create a little more clearance at the tail shaft, and to raise the exit and improve the path from the muffler up over the cross member.
When I bought this muffler, I had a little dilemma whether to use this one, or one with offset entry, and offset exit. Having the double offset would have made it even easier to get over the chassis.
the exhaust from the flex back is mounted on OEM rubber mounting blocks

top of screen just picks up the last bend at the bottom of the 4" dump which tapers to 3" at the front of the transfer case.
On my hdj81, I used and offset taper, this one is concentric and it made it a little harder to pass the transfer.
I'd forgotten, but on my HDJ81, I shifted the rear transfer case mounting bolt holes 1/2 - 3/4" to the left of the vehicle to off set the driveline and create more space for the 3" exhaust to pass the transfer abd improved clearance to the front driveshaft

it's a little lost in the shadows, but this is the hanger (tacked only) on the 4" dump pipe, and bolted to the bell housing

this is the OEM 2" exhaust, the crushed shape is factory standard where it passes over the chassis cross member in front of the rear diff. Didn't think to set a piece of 3" pipe beside for comparison, but 3" pipe and v-band flange fit through the same gap with about 1/2" clearance all round
I could be out to lunch on this, but is the TC really something you want to mount the exhaust hangers to? The TC shifter vibrates in the cab like crazy, I'd think you wouldn't want all those vibes being transferred to the exhaust system. Have you run it like this yet to see if it's an issue? Otherwise looks like a great job!

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