1hz vs td42

[known 2]

heres an interesting comparo wich i coudn't find had bin done before in search?

so wich is the better motor what are there good points and what are there bad points and power outputs exetera in stock and turbo'd plus what is the max power u can actualy get out of these motors?

i am talking about both these motors in non turbo form as standard (i might be wrong about the nisan motor code corect me if i'm wrong)

[GQ TROL]

The 1HZ has more HP and I think torque too than the TD42 in standard form. The 1HZ uses 11mm plunger in the fuel pump, while the TD42 only has the 10mm, so the Toyota "should" be able to produce more HP once turboed than the TD42, without doing any major pump mods.

But, the 1HZ seems more fragile once turboed while the TD42 seems to take the abuse.

Practically speaking, they're both much the same when set up correctly and it would be hard to differentiate between them.

We run a turboed TD42 which last dynoed at 202HP at the wheels, and a mates turboed 1HZ dynoed at 207HP ATW. Both running same fuel pumps (12mm plunger) and same turbos (CT26). Give them more fuel and more air, with some LPG injection for good measure, they would both get around 300HP ATW. Bit of a time bomb though.

[Toy80Diesel]

QUOTE: We run a turboed TD42 which last dynoed at 202HP at the wheels, and a mates turboed 1HZ dynoed at 207HP ATW. Both running same fuel pumps (12mm plunger) and same turbos (CT26). Give them more fuel and more air, with some LPG injection for good measure, they would both get around 300HP ATW. Bit of a time bomb though.


I'm just wondering about these figures, after reading the latest 4wd monthly and its troopy 1hz turbo conversion. They got the power up to 134 HP at the wheels with LPG, Turbo, exhuast, and boost compensator.

How did you manage to get up to 207hp ATW??? As you said its a bit of a time bomb, so do you mean the fuel pump & turbo psi boost was high? if so how high? Was it running 1/3 LPG(2/3 diesel) same as the troopy?

Just curious as I would love to put a hairdryer on the 1hz in future but want the thing to last, as do the guys with the troopy. i.e. it still is getting 15lt/100km with diesel and better when you add the lpg (11.68lt/100km + lpg).

[GQ TROL]

The turboed 1HZ runs a 1HD-T fuel pump which more than doubles the fuel delivery, and it has a different cam plate and governor to let it rev out a bit more. From memory, that turbo (CT26 from 1HD-T also) runs around 16psi, which isn't a whole lot, but is enough for the fuel its getting.

We only played with LPG injection on the turboed TD42, and HP gains were impressive so I would suggest 300HP is possible in the Toyota too, but life of the engine would surely be reduced at that level. We only looked at it for performance, not fuel efficiency.

Keeping fuel, boost and LPG to a sensible level should give reasonable HP without compromising engine life too much.

[Toy80Diesel]

Ahh.. okay, and I'm guessing here but a standard 1hdt would have no more than 10psi? What sort of condition/km's was that 1hz in? and would you have an idea on how (un)economical it was on fuel? I remember when I first got the 1hz and asked around about turbo's and some installers said no due to the km's. It had 220 on it at the time, now its about 295.

Has the exhaust temp been monitored on this machine?

Thanks for the info, its good to know all this stuff and i've found out heaps on this forum, which will help when it comes time to install a turbo.

[GQ TROL]

I don't know about std 1HD-T boost, but it would fairly modest for reliability reasons I think?

1HZ had done 225,000kms when my mate got it. The 1HD-T turbo and pump had been on since 200,000. We swapped the turboed 1HZ in as a replacement for a tired 13-BT (truck is an FRP top BJ74), and promptly snapped the cam behind No. 1 cylinder because the cam belt tensioner was buggered and belt slipped.

It would get quite hot too, so the radiator was replaced with one from a late model 75/79 (I don't know exactly, not too familiar with them) series Cruiser and is much better. EGT's are around 550-600, or more if you keep pushing it, but as soon as you ease off the throttle the EGT drops back.

It also has one of those small DTS top mount intercoolers which gives a good temp drop across it. Nothing like a good water-to-air I/C though.

Its not very economical as it boosts from about 1200rpm, so even at highway speeds its constantly on boost and hence getting lots of fuel due to the way the aneroid is set up. But its a comp truck and tuned accordingly. For a daily driver / weekend truck you can have it taylored to your needs.

295,000kms is starting to get on in age, so would want to make sure its in good order before turboing. But it shouldn't be a problem to get another few 100,000kms from it before a rebuild if its setup sensibly.

[mule75]

ive got a 1hz. put turbo on at about 290k 4 years ago, now done 470k and still runs perfect. runnin max boost of 16psi and a big front mount cooler and 3in exhaust. gets 500kms+ to the tank (85 litres) in a lifted 75 runnin 35's. have got up to 610kms to the tank on hwy on 33's. got turbo and manifold from mtq engine systems in laverton, melb. very happy with engine. now a turbo diesel man for ever.

[Toy80Diesel]

Thanks for all that info GQ TROL.

I'm pretty sure my engine is very healthy at its 295km's, it sounds good and is very reliable. gets its oil & filter changed religiously too. So i dont think a turbo would hurt it, and I wouldn't be asking for too much grunt and consumption either, being a daily driver. Also, I just replaced the radiator with a new one (metal tanks) and the 80 series rad is quite large.


hey Mule75, good to get a vote of confidence from your machine there, I'm still on 33's (or 285/75/16's) so I should get similar results. does you front mount cooler affect your radiator cooling?

Personally, I would probably later down the track consider those new glycol water to air style with the little cooler in front and the tube item over the motor.

Might have to get some info from those people at MTQ and see what they have to say.

Thanks again

[known 2]

thast alot of helpfull imformation there guys i expected it to be a toyota vs nisan war when i started this thread.
i heard a rumour that u can get over 1000nm of torque out of a td42 is that posible?

[GQ TROL]

I think they're both solid, sound and reliable engines. When it comes to choosing one over the other, it's just individual preference.

[Mud_5lut]

personally i have owned both i currently own a gu 4.2 non turbo. my previous truck was a 1hz 75 ute, and with out doubt the ihz blew the pants of the td4.2 i do lot of towing and the ihz had more torque to. i found the 1hz wanted to rev more mine reved to 4000rpm easy (took it there wonce or twice) but the fuel econamy in the td42 is better. my 2 cents.

[Toy80Diesel]

personally i have owned both i currently own a gu 4.2 non turbo. my previous truck was a 1hz 75 ute, and with out doubt the ihz blew the pants of the td4.2 i do lot of towing and the ihz had more torque to. i found the 1hz wanted to rev more mine reved to 4000rpm easy (took it there wonce or twice) but the fuel econamy in the td42 is better. my 2 cents.

Could this have something to do with the weight of the GU being more than the 75ute? as said previously, the td42 has a smaller plunger in the pump, therefore less fuel going through, probably also affected it.

The 1hz rev's quite well, but it's only real drawback is long hills where it runs out of puff towards the end, even worse when towing. I tend to give it a good run up before an uphill so i can keep up.