Looking for feedback on HDJ81 for US use (1 Viewer)

Joined
Dec 18, 2010
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27
Location
British Columbia
Any 1HDx platform that is tuned and modified correctly will give you excellent power.

28psi, 250rwhp (irrelevant with a full time 4wd) and 600ftlbs is no problem. Some even run 32+psi.

I am not sure why you are comparing the 1HDx to the 1FZx. They are so completely different in nearly every way including how they drive on and off-road.

The concerns of parts, some random mechanic know what to do and so forth are valid. Most diesel Cruiser owners in the USA either work on their own truck or have “their guy” who they have and do work with at least some what regularly. They truly are not hard to work on with a half dozen metric wrenchs and an FSM. They need far less maintenance or repairs than the gas engines. All a diesel needs to run is air, fuel and compression. I have seen 1HZs running on 100psi in a cylinder for an engine that should have 500psi.

Cheers
 
Joined
Dec 24, 2019
Messages
110
Location
Sydney, Australia
So a more detailed performance question for you - probably mostly for the Aussies and South Africans that see a bunch of these. I know these aren't strong performers, but I'm trying to get my hands around exactly how they'll behave.

1) Assuming a properly running and fully stock (no intercooler, no extra boost, etc) 1hd-t and 1hd-ft, how much will it struggle to do 75mph / 120kph on flat, level ground? What kind of EGT is it already pushing at a typical freeway speed and how much does it have left if required to pass somebody, ascend a small hill, etc?
2) how much different will the 1hd-t and -ft be in this respect?
3) Some of what I'm reading is that small boosts, like in the 15psi range, are potentially neutral or even positive from a reliability standpoint with respect to highway driving as they lower EGTs by improving the amount of air reaching the engine. Does that match real world experiences you guys are seeing? What all is entailed in that kind of baby boost and what other considerations are there? I would assume there has to be a downside or Toyota would have engineered this with a slightly bigger boost to begin with. My guess (and all this is assuming the stuff I've read elsewhere isn't crap) is that a small boost may indeed be more optimized for higher demand usage like freeways or sustained hills, but maybe you pay for it with higher EGTs on lower load driving.

I'm fully expecting this to be a step down in performance from the 4.7L in my 100. I'm just trying to figure out how much of one, how much I should prefer an -FT to a -T, and how I might configure mine after I get it.
I can give you some detail on this which I think will help. I've got a 1HZ in my HZJ80, which is a 4.2lt straight six, non-turbo diesel. It's officially rated at 96kW/129hp. With this rig, it'll get to 120km/h no worries on flat level ground. You could do that from a 5th gear change at 60km/h if you wanted, although I usually accelerate in 4th and coast at 5th. You won't be breaking any records, but it'll do it in a reasonable time, from my point of view. If you've got a slight incline, 5th gear (overdrive) struggles, so I drop down into 4th as a matter of course when I hit a rise. That's fine, because 4th is a 1:1 ratio and can go well past 120kph. You can accelerate up to 120km/h in fourth on gradual slopes, and maintain speed in 4th easily. For steeper rises, I'm thinking maybe anything over a 20 degree incline, I generally expect to need to drop into high 3rd. If you build up your revs in 4th before the rise you might avoid it, but if your speed starts to drop, rev it high in 3rd, and you can maintain 90km/h up basically anything, but that's close to your upper limit in that gear I feel. I'd downshift when I drop below 100km/h in 4th, which if you do it right will see you pick up above 90km/h in 3rd. If your cooling system is in good nick, you can sustain this probably indefinitely. I've done it for 10 minutes or so continuously on some hills here in Australia. If you get stuck behind a truck or someone slow on a hill though, if you're at that 20 degree inline or greater and you have to drop your revs, you won't get them back again until things ease off, so you could find yourself stuck at 60-70km/h up a steep incline if you don't have open road and there's something that makes you slow down.

Now, I have no experience with the 1HD-T and 1HD-FT, but the 1HD-T is rated at 121kW/162hp, and the 1HD-FT is rated at 125kw/168hp, so you'd have to expect on the numbers to have a bit more grunt, meaning you'd fare better on those steep hills in 4th than I do with my 1HZ. According to the owners manual, 3rd is rated at 94km/h max on the 1HZ, which rings true to me, but only 85km/h on the 1HD-FT, which is probably down to a different red line point on the odometer I assume.

What you and I feel is "enough power" or "fast enough acceleration" is subjective and will vary, but based on my experience driving diesels, and I don't drive them gently I'll add, if you're not afraid to put your foot down, rev high, and you know how to drive a manual properly, you can hold your own very well. My 80 is my DD, and I'm an aggressive impatient driver in the city, so frankly in my rig I'm doing the overtaking more often than not.
 
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Joined
Jul 23, 2008
Messages
191
I can give you some detail on this which I think will help. I've got a 1HZ in my HZJ80, which is a 4.2lt straight six, non-turbo diesel. It's officially rated at 96kW/129hp. With this rig, it'll get to 120km/h no worries on flat level ground. You could do that from a 5th gear change at 60km/h if you wanted, although I usually accelerate in 4th and coast at 5th. You won't be breaking any records, but it'll do it in a reasonable time, from my point of view. If you've got a slight incline, 5th gear (overdrive) struggles, so I drop down into 4th as a matter of course when I hit a rise. That's fine, because 4th is a 1:1 ratio and can go well past 120kph. You can accelerate up to 120km/h in fourth on gradual slopes, and maintain speed in 4th easily. For steeper rises, I'm thinking maybe anything over a 20 degree incline, I generally expect to need to drop into high 3rd. If you build up your revs in 4th before the rise you might avoid it, but if your speed starts to drop, rev it high in 3rd, and you can maintain 90km/h up basically anything, but that's close to your upper limit in that gear I feel. I'd downshift when I drop below 100km/h in 4th, which if you do it right will see you pick up above 90km/h in 3rd. If your cooling system is in good nick, you can sustain this probably indefinitely. I've done it for 10 minutes or so continuously on some hills here in Australia. If you get stuck behind a truck or someone slow on a hill though, if you're at that 20 degree inline or greater and you have to drop your revs, you won't get them back again until things ease off, so you could find yourself stuck at 60-70km/h up a steep incline if you don't have open road and there's something that makes you slow down.

Now, I have no experience with the 1HD-T and 1HD-FT, but the 1HD-T is rated at 121kW/162hp, and the 1HD-FT is rated at 125kw/168hp, so you'd have to expect on the numbers to have a bit more grunt, meaning you'd fare better on those steep hills in 4th than I do with my 1HZ. According to the owners manual, 3rd is rated at 94km/h max on the 1HZ, which rings true to me, but only 85km/h on the 1HD-FT, which is probably down to a different red line point on the odometer I assume.

What you and I feel is "enough power" or "fast enough acceleration" is subjective and will vary, but based on my experience driving diesels, and I don't drive them gently I'll add, if you're not afraid to put your foot down, rev high, and you know how to drive a manual properly, you can hold your own very well. My 80 is my DD, and I'm an aggressive impatient driver in the city, so frankly in my rig I'm doing the overtaking more often than not.
I appreciate the feedback. This makes it sound like an HZJ is a possibility as that sounds very drivable. They also sell for maybe 30-40% less than their turbocharged siblings at auction and a higher percentage of them appear to be in good condition as well - not exactly sure why that would be the case. I think I'd still rather get one of the turbo versions for the extra power (seldom have heard anyone complain their car had too much power), but it at least opens up another avenue.
 

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